backend-spring/.gitignore

@@ -0,0 +1,8 @@
+.gradle/
+build/
+
+# Eclispe Directories
+/.classpath
+/.project
+/bin
+/.settings

backend-spring/Dockerfile

@@ -0,0 +1,17 @@
+FROM eclipse-temurin:25-jdk-alpine AS build
+
+WORKDIR /app
+COPY gradle ./gradle
+COPY gradlew build.gradle.kts settings.gradle.kts ./
+RUN ./gradlew dependencies --no-daemon
+
+COPY src ./src
+RUN ./gradlew bootJar --no-daemon -x test
+
+FROM eclipse-temurin:25-jre-alpine
+
+WORKDIR /app
+COPY --from=build /app/build/libs/*.jar app.jar
+
+EXPOSE 8080
+CMD ["java", "-jar", "app.jar"]

backend-spring/build.gradle.kts

@@ -0,0 +1,38 @@
+plugins {
+    java
+    id("org.springframework.boot") version "4.0.3"
+    id("io.spring.dependency-management") version "1.1.7"
+    id("io.freefair.lombok") version "9.2.0"
+}
+
+group = "be.seeseepuff"
+version = "0.0.1-SNAPSHOT"
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(25)
+    }
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("org.springframework.boot:spring-boot-starter-web")
+    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
+    implementation("org.springframework.boot:spring-boot-starter-thymeleaf")
+    implementation("org.springframework.boot:spring-boot-starter-flyway")
+    implementation("org.flywaydb:flyway-database-postgresql")
+    runtimeOnly("org.postgresql:postgresql")
+
+    testImplementation("org.springframework.boot:spring-boot-starter-test")
+    testImplementation("org.springframework.boot:spring-boot-testcontainers")
+    testImplementation("org.testcontainers:testcontainers-junit-jupiter:2.0.3")
+    testImplementation("org.testcontainers:testcontainers-postgresql:2.0.3")
+    testImplementation("io.rest-assured:rest-assured:6.0.0")
+}
+
+tasks.withType<Test> {
+    useJUnitPlatform()
+}

backend-spring/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.3.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

backend-spring/gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

backend-spring/gradlew.bat

@@ -0,0 +1,93 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

backend-spring/settings.gradle.kts

@@ -0,0 +1 @@
+rootProject.name = "allowance-planner"

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/AllowancePlannerApplication.java

@@ -0,0 +1,11 @@
+package be.seeseepuff.allowanceplanner;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class AllowancePlannerApplication {
+    static void main(String[] args) {
+        SpringApplication.run(AllowancePlannerApplication.class, args);
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/controller/AllowanceController.java

@@ -0,0 +1,221 @@
+package be.seeseepuff.allowanceplanner.controller;
+
+import be.seeseepuff.allowanceplanner.dto.*;
+import be.seeseepuff.allowanceplanner.service.AllowanceService;
+import be.seeseepuff.allowanceplanner.service.UserService;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+import java.util.Optional;
+
+@RestController
+@RequestMapping("/api")
+@CrossOrigin(origins = "*")
+public class AllowanceController {
+    private final UserService userService;
+    private final AllowanceService allowanceService;
+
+    public AllowanceController(UserService userService, AllowanceService allowanceService) {
+        this.userService = userService;
+        this.allowanceService = allowanceService;
+    }
+
+    @GetMapping("/user/{userId}/allowance")
+    public ResponseEntity<?> getUserAllowance(@PathVariable String userId) {
+        int id;
+        try {
+            id = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        if (!userService.userExists(id)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        return ResponseEntity.ok(allowanceService.getUserAllowances(id));
+    }
+
+    @PostMapping("/user/{userId}/allowance")
+    public ResponseEntity<?> createUserAllowance(@PathVariable String userId,
+                                                 @RequestBody CreateAllowanceRequest request) {
+        int id;
+        try {
+            id = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        if (request.name() == null || request.name().isEmpty()) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Allowance name cannot be empty"));
+        }
+
+        if (!userService.userExists(id)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        int allowanceId = allowanceService.createAllowance(id, request);
+        return ResponseEntity.status(HttpStatus.CREATED).body(new IdResponse(allowanceId));
+    }
+
+    @PutMapping("/user/{userId}/allowance")
+    public ResponseEntity<?> bulkPutUserAllowance(@PathVariable String userId,
+                                                  @RequestBody List<BulkUpdateAllowanceRequest> requests) {
+        int id;
+        try {
+            id = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        if (!userService.userExists(id)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        allowanceService.bulkUpdateAllowance(id, requests);
+        return ResponseEntity.ok(new MessageResponse("Allowance updated successfully"));
+    }
+
+    @GetMapping("/user/{userId}/allowance/{allowanceId}")
+    public ResponseEntity<?> getUserAllowanceById(@PathVariable String userId, @PathVariable String allowanceId) {
+        int uid;
+        try {
+            uid = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        int aid;
+        try {
+            aid = Integer.parseInt(allowanceId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid allowance ID"));
+        }
+
+        if (!userService.userExists(uid)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        Optional<AllowanceDto> allowance = allowanceService.getUserAllowanceById(uid, aid);
+        if (allowance.isEmpty()) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("Allowance not found"));
+        }
+        return ResponseEntity.ok(allowance.get());
+    }
+
+    @DeleteMapping("/user/{userId}/allowance/{allowanceId}")
+    public ResponseEntity<?> deleteUserAllowance(@PathVariable String userId, @PathVariable String allowanceId) {
+        int uid;
+        try {
+            uid = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        int aid;
+        try {
+            aid = Integer.parseInt(allowanceId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid allowance ID"));
+        }
+
+        if (aid == 0) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Allowance id zero cannot be deleted"));
+        }
+
+        if (!userService.userExists(uid)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        boolean deleted = allowanceService.deleteAllowance(uid, aid);
+        if (!deleted) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("History not found"));
+        }
+        return ResponseEntity.ok(new MessageResponse("History deleted successfully"));
+    }
+
+    @PutMapping("/user/{userId}/allowance/{allowanceId}")
+    public ResponseEntity<?> putUserAllowance(@PathVariable String userId, @PathVariable String allowanceId,
+                                              @RequestBody UpdateAllowanceRequest request) {
+        int uid;
+        try {
+            uid = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        int aid;
+        try {
+            aid = Integer.parseInt(allowanceId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid allowance ID"));
+        }
+
+        if (!userService.userExists(uid)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        boolean updated = allowanceService.updateAllowance(uid, aid, request);
+        if (!updated) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("Allowance not found"));
+        }
+        return ResponseEntity.ok(new MessageResponse("Allowance updated successfully"));
+    }
+
+    @PostMapping("/user/{userId}/allowance/{allowanceId}/complete")
+    public ResponseEntity<?> completeAllowance(@PathVariable String userId, @PathVariable String allowanceId) {
+        int uid;
+        try {
+            uid = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        int aid;
+        try {
+            aid = Integer.parseInt(allowanceId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid allowance ID"));
+        }
+
+        if (!userService.userExists(uid)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        boolean completed = allowanceService.completeAllowance(uid, aid);
+        if (!completed) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("Allowance not found"));
+        }
+        return ResponseEntity.ok(new MessageResponse("Allowance completed successfully"));
+    }
+
+    @PostMapping("/user/{userId}/allowance/{allowanceId}/add")
+    public ResponseEntity<?> addToAllowance(@PathVariable String userId, @PathVariable String allowanceId,
+                                            @RequestBody AddAllowanceAmountRequest request) {
+        int uid;
+        try {
+            uid = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        int aid;
+        try {
+            aid = Integer.parseInt(allowanceId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid allowance ID"));
+        }
+
+        if (!userService.userExists(uid)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        boolean result = allowanceService.addAllowanceAmount(uid, aid, request);
+        if (!result) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("Allowance not found"));
+        }
+        return ResponseEntity.ok(new MessageResponse("Allowance completed successfully"));
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/controller/HistoryController.java

@@ -0,0 +1,57 @@
+package be.seeseepuff.allowanceplanner.controller;
+
+import be.seeseepuff.allowanceplanner.dto.*;
+import be.seeseepuff.allowanceplanner.service.AllowanceService;
+import be.seeseepuff.allowanceplanner.service.UserService;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/api")
+@CrossOrigin(origins = "*")
+public class HistoryController {
+    private final UserService userService;
+    private final AllowanceService allowanceService;
+
+    public HistoryController(UserService userService, AllowanceService allowanceService) {
+        this.userService = userService;
+        this.allowanceService = allowanceService;
+    }
+
+    @PostMapping("/user/{userId}/history")
+    public ResponseEntity<?> postHistory(@PathVariable String userId, @RequestBody PostHistoryRequest request) {
+        int id;
+        try {
+            id = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        if (request.description() == null || request.description().isEmpty()) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Description cannot be empty"));
+        }
+
+        if (!userService.userExists(id)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+
+        allowanceService.addHistory(id, request);
+        return ResponseEntity.ok(new MessageResponse("History updated successfully"));
+    }
+
+    @GetMapping("/user/{userId}/history")
+    public ResponseEntity<?> getHistory(@PathVariable String userId) {
+        int id;
+        try {
+            id = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        List<HistoryDto> history = allowanceService.getHistory(id);
+        return ResponseEntity.ok(history);
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/controller/MigrationController.java

@@ -0,0 +1,23 @@
+package be.seeseepuff.allowanceplanner.controller;
+
+import be.seeseepuff.allowanceplanner.dto.*;
+import be.seeseepuff.allowanceplanner.service.MigrationService;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api")
+@CrossOrigin(origins = "*")
+public class MigrationController {
+    private final MigrationService migrationService;
+
+    public MigrationController(MigrationService migrationService) {
+        this.migrationService = migrationService;
+    }
+
+    @PostMapping("/import")
+    public ResponseEntity<?> importData(@RequestBody MigrationDto data) {
+        migrationService.importData(data);
+        return ResponseEntity.ok(new MessageResponse("Import successful"));
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/controller/TaskController.java

@@ -0,0 +1,116 @@
+package be.seeseepuff.allowanceplanner.controller;
+
+import be.seeseepuff.allowanceplanner.dto.*;
+import be.seeseepuff.allowanceplanner.service.TaskService;
+import be.seeseepuff.allowanceplanner.service.UserService;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+import java.util.Optional;
+
+@RestController
+@RequestMapping("/api")
+@CrossOrigin(origins = "*")
+public class TaskController {
+    private final UserService userService;
+    private final TaskService taskService;
+
+    public TaskController(UserService userService, TaskService taskService) {
+        this.userService = userService;
+        this.taskService = taskService;
+    }
+
+    @PostMapping("/tasks")
+    public ResponseEntity<?> createTask(@RequestBody CreateTaskRequest request) {
+        if (request.name() == null || request.name().isEmpty()) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Task name cannot be empty"));
+        }
+
+        if (request.schedule() != null) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Schedules are not yet supported"));
+        }
+
+        if (request.assigned() != null) {
+            if (!userService.userExists(request.assigned())) {
+                return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+            }
+        }
+
+        int taskId = taskService.createTask(request);
+        return ResponseEntity.status(HttpStatus.CREATED).body(new IdResponse(taskId));
+    }
+
+    @GetMapping("/tasks")
+    public List<TaskDto> getTasks() {
+        return taskService.getTasks();
+    }
+
+    @GetMapping("/task/{taskId}")
+    public ResponseEntity<?> getTask(@PathVariable String taskId) {
+        int id;
+        try {
+            id = Integer.parseInt(taskId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid task ID"));
+        }
+
+        Optional<TaskDto> task = taskService.getTask(id);
+        if (task.isEmpty()) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("Task not found"));
+        }
+        return ResponseEntity.ok(task.get());
+    }
+
+    @PutMapping("/task/{taskId}")
+    public ResponseEntity<?> putTask(@PathVariable String taskId, @RequestBody CreateTaskRequest request) {
+        int id;
+        try {
+            id = Integer.parseInt(taskId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid task ID"));
+        }
+
+        Optional<TaskDto> existing = taskService.getTask(id);
+        if (existing.isEmpty()) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("Task not found"));
+        }
+
+        taskService.updateTask(id, request);
+        return ResponseEntity.ok(new MessageResponse("Task updated successfully"));
+    }
+
+    @DeleteMapping("/task/{taskId}")
+    public ResponseEntity<?> deleteTask(@PathVariable String taskId) {
+        int id;
+        try {
+            id = Integer.parseInt(taskId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid task ID"));
+        }
+
+        if (!taskService.hasTask(id)) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("Task not found"));
+        }
+
+        taskService.deleteTask(id);
+        return ResponseEntity.ok(new MessageResponse("Task deleted successfully"));
+    }
+
+    @PostMapping("/task/{taskId}/complete")
+    public ResponseEntity<?> completeTask(@PathVariable String taskId) {
+        int id;
+        try {
+            id = Integer.parseInt(taskId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid task ID"));
+        }
+
+        boolean completed = taskService.completeTask(id);
+        if (!completed) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("Task not found"));
+        }
+        return ResponseEntity.ok(new MessageResponse("Task completed successfully"));
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/controller/TransferController.java

@@ -0,0 +1,28 @@
+package be.seeseepuff.allowanceplanner.controller;
+
+import be.seeseepuff.allowanceplanner.dto.*;
+import be.seeseepuff.allowanceplanner.service.TransferService;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api")
+@CrossOrigin(origins = "*")
+public class TransferController {
+    private final TransferService transferService;
+
+    public TransferController(TransferService transferService) {
+        this.transferService = transferService;
+    }
+
+    @PostMapping("/transfer")
+    public ResponseEntity<?> transfer(@RequestBody TransferRequest request) {
+        TransferService.TransferResult result = transferService.transfer(request);
+        return switch (result.status()) {
+            case SUCCESS -> ResponseEntity.ok(new MessageResponse(result.message()));
+            case BAD_REQUEST -> ResponseEntity.badRequest().body(new ErrorResponse(result.message()));
+            case NOT_FOUND -> ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse(result.message()));
+        };
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/controller/UserController.java

@@ -0,0 +1,42 @@
+package be.seeseepuff.allowanceplanner.controller;
+
+import be.seeseepuff.allowanceplanner.dto.*;
+import be.seeseepuff.allowanceplanner.service.UserService;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+import java.util.Optional;
+
+@RestController
+@RequestMapping("/api")
+@CrossOrigin(origins = "*")
+public class UserController {
+    private final UserService userService;
+
+    public UserController(UserService userService) {
+        this.userService = userService;
+    }
+
+    @GetMapping("/users")
+    public List<UserDto> getUsers() {
+        return userService.getUsers();
+    }
+
+    @GetMapping("/user/{userId}")
+    public ResponseEntity<?> getUser(@PathVariable String userId) {
+        int id;
+        try {
+            id = Integer.parseInt(userId);
+        } catch (NumberFormatException e) {
+            return ResponseEntity.badRequest().body(new ErrorResponse("Invalid user ID"));
+        }
+
+        Optional<UserWithAllowanceDto> user = userService.getUser(id);
+        if (user.isEmpty()) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(new ErrorResponse("User not found"));
+        }
+        return ResponseEntity.ok(user.get());
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/controller/WebController.java

@@ -0,0 +1,149 @@
+package be.seeseepuff.allowanceplanner.controller;
+
+import be.seeseepuff.allowanceplanner.dto.CreateAllowanceRequest;
+import be.seeseepuff.allowanceplanner.dto.CreateTaskRequest;
+import be.seeseepuff.allowanceplanner.service.AllowanceService;
+import be.seeseepuff.allowanceplanner.service.TaskService;
+import be.seeseepuff.allowanceplanner.service.UserService;
+import jakarta.servlet.http.Cookie;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+
+import java.util.Arrays;
+
+@Controller
+public class WebController {
+    private final UserService userService;
+    private final AllowanceService allowanceService;
+    private final TaskService taskService;
+
+    public WebController(UserService userService, AllowanceService allowanceService, TaskService taskService) {
+        this.userService = userService;
+        this.allowanceService = allowanceService;
+        this.taskService = taskService;
+    }
+
+    @GetMapping("/")
+    public String index(HttpServletRequest request, HttpServletResponse response, Model model) {
+        Integer currentUser = getCurrentUser(request, response);
+        if (currentUser == null) {
+            model.addAttribute("users", userService.getUsers());
+            return "index";
+        }
+        return renderWithUser(model, currentUser);
+    }
+
+    @GetMapping("/login")
+    public String login(@RequestParam(required = false) String user, HttpServletResponse response) {
+        if (user != null && !user.isEmpty()) {
+            Cookie cookie = new Cookie("user", user);
+            cookie.setMaxAge(3600);
+            cookie.setHttpOnly(true);
+            response.addCookie(cookie);
+        }
+        return "redirect:/";
+    }
+
+    @PostMapping("/createTask")
+    public String createTask(@RequestParam String name, @RequestParam double reward,
+                             @RequestParam(required = false) String schedule,
+                             HttpServletRequest request, HttpServletResponse response, Model model) {
+        Integer currentUser = getCurrentUser(request, response);
+        if (currentUser == null) {
+            return "redirect:/";
+        }
+
+        if (name.isEmpty() || reward <= 0) {
+            model.addAttribute("error", "Invalid input");
+            return "index";
+        }
+
+        CreateTaskRequest taskRequest = new CreateTaskRequest(name, reward, null,
+                (schedule != null && !schedule.isEmpty()) ? schedule : null);
+        taskService.createTask(taskRequest);
+        return "redirect:/";
+    }
+
+    @GetMapping("/completeTask")
+    public String completeTask(@RequestParam("task") int taskId) {
+        taskService.completeTask(taskId);
+        return "redirect:/";
+    }
+
+    @PostMapping("/createAllowance")
+    public String createAllowance(@RequestParam String name, @RequestParam double target,
+                                  @RequestParam double weight,
+                                  HttpServletRequest request, HttpServletResponse response, Model model) {
+        Integer currentUser = getCurrentUser(request, response);
+        if (currentUser == null) {
+            return "redirect:/";
+        }
+
+        if (name.isEmpty() || target <= 0 || weight <= 0) {
+            model.addAttribute("error", "Invalid input");
+            return "index";
+        }
+
+        allowanceService.createAllowance(currentUser, new CreateAllowanceRequest(name, target, weight, ""));
+        return "redirect:/";
+    }
+
+    @GetMapping("/completeAllowance")
+    public String completeAllowance(@RequestParam("allowance") int allowanceId,
+                                    HttpServletRequest request, HttpServletResponse response) {
+        Integer currentUser = getCurrentUser(request, response);
+        if (currentUser == null) {
+            return "redirect:/";
+        }
+        allowanceService.completeAllowance(currentUser, allowanceId);
+        return "redirect:/";
+    }
+
+    private Integer getCurrentUser(HttpServletRequest request, HttpServletResponse response) {
+        Cookie[] cookies = request.getCookies();
+        if (cookies == null) {
+            return null;
+        }
+        String userStr = Arrays.stream(cookies)
+                .filter(c -> "user".equals(c.getName()))
+                .map(Cookie::getValue)
+                .findFirst()
+                .orElse(null);
+        if (userStr == null) {
+            return null;
+        }
+        try {
+            int userId = Integer.parseInt(userStr);
+            if (!userService.userExists(userId)) {
+                unsetUserCookie(response);
+                return null;
+            }
+            return userId;
+        } catch (NumberFormatException e) {
+            unsetUserCookie(response);
+            return null;
+        }
+    }
+
+    private void unsetUserCookie(HttpServletResponse response) {
+        Cookie cookie = new Cookie("user", "");
+        cookie.setMaxAge(0);
+        cookie.setPath("/");
+        cookie.setHttpOnly(true);
+        response.addCookie(cookie);
+    }
+
+    private String renderWithUser(Model model, int currentUser) {
+        model.addAttribute("users", userService.getUsers());
+        model.addAttribute("currentUser", currentUser);
+        model.addAttribute("allowances", allowanceService.getUserAllowances(currentUser));
+        model.addAttribute("tasks", taskService.getTasks());
+        model.addAttribute("history", allowanceService.getHistory(currentUser));
+        return "index";
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/AddAllowanceAmountRequest.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record AddAllowanceAmountRequest(double amount, String description) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/AllowanceDto.java

@@ -0,0 +1,7 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+
+@JsonInclude(JsonInclude.Include.ALWAYS)
+public record AllowanceDto(int id, String name, double target, double progress, double weight, String colour) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/BulkUpdateAllowanceRequest.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record BulkUpdateAllowanceRequest(int id, double weight) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/CreateAllowanceRequest.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record CreateAllowanceRequest(String name, double target, double weight, String colour) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/CreateTaskRequest.java

@@ -0,0 +1,8 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record CreateTaskRequest(
+        String name,
+        Double reward,
+        Integer assigned,
+        String schedule) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/ErrorResponse.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record ErrorResponse(String error) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/HistoryDto.java

@@ -0,0 +1,6 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+import java.time.Instant;
+
+public record HistoryDto(double allowance, Instant timestamp, String description) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/IdResponse.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record IdResponse(int id) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/MessageResponse.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record MessageResponse(String message) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/MigrationDto.java

@@ -0,0 +1,24 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+import java.util.List;
+
+public record MigrationDto(
+        List<MigrationUserDto> users,
+        List<MigrationAllowanceDto> allowances,
+        List<MigrationHistoryDto> history,
+        List<MigrationTaskDto> tasks
+) {
+    public record MigrationUserDto(int id, String name, long balance, double weight) {
+    }
+
+    public record MigrationAllowanceDto(int id, int userId, String name, long target, long balance, double weight,
+                                        Integer colour) {
+    }
+
+    public record MigrationHistoryDto(int id, int userId, long timestamp, long amount, String description) {
+    }
+
+    public record MigrationTaskDto(int id, String name, long reward, Integer assigned, String schedule,
+                                   Long completed, Long nextRun) {
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/PostHistoryRequest.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record PostHistoryRequest(double allowance, String description) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/TaskDto.java

@@ -0,0 +1,7 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+
+@JsonInclude(JsonInclude.Include.ALWAYS)
+public record TaskDto(int id, String name, double reward, Integer assigned, String schedule) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/TransferRequest.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record TransferRequest(int from, int to, double amount) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/UpdateAllowanceRequest.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record UpdateAllowanceRequest(String name, double target, double weight, String colour) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/UserDto.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record UserDto(int id, String name) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/dto/UserWithAllowanceDto.java

@@ -0,0 +1,4 @@
+package be.seeseepuff.allowanceplanner.dto;
+
+public record UserWithAllowanceDto(int id, String name, double allowance) {
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/entity/Allowance.java

@@ -0,0 +1,32 @@
+package be.seeseepuff.allowanceplanner.entity;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
+@Entity
+@Table(name = "allowances")
+@Getter
+@Setter
+public class Allowance {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private int id;
+
+    @Column(name = "user_id", nullable = false)
+    private int userId;
+
+    @Column(nullable = false)
+    private String name;
+
+    @Column(nullable = false)
+    private long target;
+
+    @Column(nullable = false)
+    private long balance = 0;
+
+    @Column(nullable = false)
+    private double weight;
+
+    private Integer colour;
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/entity/History.java

@@ -0,0 +1,26 @@
+package be.seeseepuff.allowanceplanner.entity;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
+@Entity
+@Table(name = "history")
+@Getter
+@Setter
+public class History {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private int id;
+
+    @Column(name = "user_id", nullable = false)
+    private int userId;
+
+    @Column(nullable = false)
+    private long timestamp;
+
+    @Column(nullable = false)
+    private long amount;
+
+    private String description;
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/entity/Task.java

@@ -0,0 +1,30 @@
+package be.seeseepuff.allowanceplanner.entity;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
+@Entity
+@Table(name = "tasks")
+@Getter
+@Setter
+public class Task {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private int id;
+
+    @Column(nullable = false)
+    private String name;
+
+    @Column(nullable = false)
+    private long reward;
+
+    private Integer assigned;
+
+    private String schedule;
+
+    private Long completed;
+
+    @Column(name = "next_run")
+    private Long nextRun;
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/entity/User.java

@@ -0,0 +1,24 @@
+package be.seeseepuff.allowanceplanner.entity;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
+@Entity
+@Table(name = "users")
+@Getter
+@Setter
+public class User {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private int id;
+
+    @Column(nullable = false)
+    private String name;
+
+    @Column(nullable = false)
+    private double weight = 10.0;
+
+    @Column(nullable = false)
+    private long balance = 0;
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/repository/AllowanceRepository.java

@@ -0,0 +1,26 @@
+package be.seeseepuff.allowanceplanner.repository;
+
+import be.seeseepuff.allowanceplanner.entity.Allowance;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+import java.util.Optional;
+
+@Repository
+public interface AllowanceRepository extends JpaRepository<Allowance, Integer> {
+    List<Allowance> findByUserIdOrderByIdAsc(int userId);
+
+    Optional<Allowance> findByIdAndUserId(int id, int userId);
+
+    int countByIdAndUserId(int id, int userId);
+
+    void deleteByIdAndUserId(int id, int userId);
+
+    @Query("SELECT a FROM Allowance a WHERE a.userId = :userId AND a.weight > 0 ORDER BY (a.target - a.balance) ASC")
+    List<Allowance> findByUserIdWithPositiveWeightOrderByRemainingAsc(int userId);
+
+    @Query("SELECT COALESCE(SUM(a.weight), 0) FROM Allowance a WHERE a.userId = :userId AND a.weight > 0")
+    double sumPositiveWeights(int userId);
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/repository/HistoryRepository.java

@@ -0,0 +1,12 @@
+package be.seeseepuff.allowanceplanner.repository;
+
+import be.seeseepuff.allowanceplanner.entity.History;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public interface HistoryRepository extends JpaRepository<History, Integer> {
+    List<History> findByUserIdOrderByIdDesc(int userId);
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/repository/TaskRepository.java

@@ -0,0 +1,15 @@
+package be.seeseepuff.allowanceplanner.repository;
+
+import be.seeseepuff.allowanceplanner.entity.Task;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+import java.util.Optional;
+
+@Repository
+public interface TaskRepository extends JpaRepository<Task, Integer> {
+    List<Task> findByCompletedIsNull();
+
+    Optional<Task> findByIdAndCompletedIsNull(int id);
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/repository/UserRepository.java

@@ -0,0 +1,12 @@
+package be.seeseepuff.allowanceplanner.repository;
+
+import be.seeseepuff.allowanceplanner.entity.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface UserRepository extends JpaRepository<User, Integer> {
+    @Query("SELECT COALESCE(SUM(h.amount), 0) FROM History h WHERE h.userId = :userId")
+    long sumHistoryAmount(int userId);
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/service/AllowanceService.java

@@ -0,0 +1,258 @@
+package be.seeseepuff.allowanceplanner.service;
+
+import be.seeseepuff.allowanceplanner.dto.*;
+import be.seeseepuff.allowanceplanner.entity.Allowance;
+import be.seeseepuff.allowanceplanner.entity.History;
+import be.seeseepuff.allowanceplanner.entity.User;
+import be.seeseepuff.allowanceplanner.repository.AllowanceRepository;
+import be.seeseepuff.allowanceplanner.repository.HistoryRepository;
+import be.seeseepuff.allowanceplanner.repository.UserRepository;
+import be.seeseepuff.allowanceplanner.util.ColourUtil;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+@Service
+public class AllowanceService {
+    private final AllowanceRepository allowanceRepository;
+    private final UserRepository userRepository;
+    private final HistoryRepository historyRepository;
+
+    public AllowanceService(AllowanceRepository allowanceRepository,
+                            UserRepository userRepository,
+                            HistoryRepository historyRepository) {
+        this.allowanceRepository = allowanceRepository;
+        this.userRepository = userRepository;
+        this.historyRepository = historyRepository;
+    }
+
+    public List<AllowanceDto> getUserAllowances(int userId) {
+        User user = userRepository.findById(userId).orElseThrow();
+        List<AllowanceDto> result = new ArrayList<>();
+
+        // Add the "rest" allowance (id=0)
+        result.add(new AllowanceDto(0, "", 0, user.getBalance() / 100.0, user.getWeight(), ""));
+
+        // Add named allowances
+        for (Allowance a : allowanceRepository.findByUserIdOrderByIdAsc(userId)) {
+            result.add(toDto(a));
+        }
+        return result;
+    }
+
+    public Optional<AllowanceDto> getUserAllowanceById(int userId, int allowanceId) {
+        if (allowanceId == 0) {
+            return userRepository.findById(userId)
+                    .map(u -> new AllowanceDto(0, "", 0, u.getBalance() / 100.0, u.getWeight(), ""));
+        }
+        return allowanceRepository.findByIdAndUserId(allowanceId, userId)
+                .map(this::toDto);
+    }
+
+    @Transactional
+    public int createAllowance(int userId, CreateAllowanceRequest request) {
+        int colour = ColourUtil.convertStringToColour(request.colour());
+        Allowance allowance = new Allowance();
+        allowance.setUserId(userId);
+        allowance.setName(request.name());
+        allowance.setTarget(Math.round(request.target() * 100.0));
+        allowance.setWeight(request.weight());
+        allowance.setColour(colour);
+        allowance = allowanceRepository.save(allowance);
+        return allowance.getId();
+    }
+
+    @Transactional
+    public boolean deleteAllowance(int userId, int allowanceId) {
+        int count = allowanceRepository.countByIdAndUserId(allowanceId, userId);
+        if (count == 0) {
+            return false;
+        }
+        allowanceRepository.deleteByIdAndUserId(allowanceId, userId);
+        return true;
+    }
+
+    @Transactional
+    public boolean updateAllowance(int userId, int allowanceId, UpdateAllowanceRequest request) {
+        if (allowanceId == 0) {
+            User user = userRepository.findById(userId).orElseThrow();
+            user.setWeight(request.weight());
+            userRepository.save(user);
+            return true;
+        }
+
+        Optional<Allowance> opt = allowanceRepository.findByIdAndUserId(allowanceId, userId);
+        if (opt.isEmpty()) {
+            return false;
+        }
+
+        int colour = ColourUtil.convertStringToColour(request.colour());
+        Allowance allowance = opt.get();
+        allowance.setName(request.name());
+        allowance.setTarget(Math.round(request.target() * 100.0));
+        allowance.setWeight(request.weight());
+        allowance.setColour(colour);
+        allowanceRepository.save(allowance);
+        return true;
+    }
+
+    @Transactional
+    public void bulkUpdateAllowance(int userId, List<BulkUpdateAllowanceRequest> requests) {
+        for (BulkUpdateAllowanceRequest req : requests) {
+            if (req.id() == 0) {
+                User user = userRepository.findById(userId).orElseThrow();
+                user.setWeight(req.weight());
+                userRepository.save(user);
+            } else {
+                allowanceRepository.findByIdAndUserId(req.id(), userId).ifPresent(a ->
+                {
+                    a.setWeight(req.weight());
+                    allowanceRepository.save(a);
+                });
+            }
+        }
+    }
+
+    @Transactional
+    public boolean completeAllowance(int userId, int allowanceId) {
+        Optional<Allowance> opt = allowanceRepository.findByIdAndUserId(allowanceId, userId);
+        if (opt.isEmpty()) {
+            return false;
+        }
+
+        Allowance allowance = opt.get();
+        long cost = allowance.getBalance();
+        String allowanceName = allowance.getName();
+
+        // Delete the allowance
+        allowanceRepository.delete(allowance);
+
+        // Add a history entry
+        History history = new History();
+        history.setUserId(userId);
+        history.setTimestamp(Instant.now().getEpochSecond());
+        history.setAmount(-cost);
+        history.setDescription("Allowance completed: " + allowanceName);
+        historyRepository.save(history);
+
+        return true;
+    }
+
+    @Transactional
+    public boolean addAllowanceAmount(int userId, int allowanceId, AddAllowanceAmountRequest request) {
+        long remainingAmount = Math.round(request.amount() * 100);
+
+        // Insert history entry
+        History history = new History();
+        history.setUserId(userId);
+        history.setTimestamp(Instant.now().getEpochSecond());
+        history.setAmount(remainingAmount);
+        history.setDescription(request.description());
+        historyRepository.save(history);
+
+        if (allowanceId == 0) {
+            if (remainingAmount < 0) {
+                User user = userRepository.findById(userId).orElseThrow();
+                if (remainingAmount > user.getBalance()) {
+                    throw new IllegalArgumentException("cannot remove more than the current balance: " + user.getBalance());
+                }
+            }
+            User user = userRepository.findById(userId).orElseThrow();
+            user.setBalance(user.getBalance() + remainingAmount);
+            userRepository.save(user);
+        } else if (remainingAmount < 0) {
+            Allowance allowance = allowanceRepository.findByIdAndUserId(allowanceId, userId).orElse(null);
+            if (allowance == null) {
+                return false;
+            }
+            if (remainingAmount > allowance.getBalance()) {
+                throw new IllegalArgumentException("cannot remove more than the current allowance balance: " + allowance.getBalance());
+            }
+            allowance.setBalance(allowance.getBalance() + remainingAmount);
+            allowanceRepository.save(allowance);
+        } else {
+            Allowance allowance = allowanceRepository.findByIdAndUserId(allowanceId, userId).orElse(null);
+            if (allowance == null) {
+                return false;
+            }
+
+            long toAdd = remainingAmount;
+            if (allowance.getBalance() + toAdd > allowance.getTarget()) {
+                toAdd = allowance.getTarget() - allowance.getBalance();
+            }
+            remainingAmount -= toAdd;
+
+            if (toAdd > 0) {
+                allowance.setBalance(allowance.getBalance() + toAdd);
+                allowanceRepository.save(allowance);
+            }
+
+            if (remainingAmount > 0) {
+                addDistributedReward(userId, (int) remainingAmount);
+            }
+        }
+        return true;
+    }
+
+    public void addDistributedReward(int userId, int reward) {
+        User user = userRepository.findById(userId).orElseThrow();
+        double userWeight = user.getWeight();
+
+        double sumOfWeights = allowanceRepository.sumPositiveWeights(userId) + userWeight;
+
+        int remainingReward = reward;
+
+        if (sumOfWeights > 0) {
+            List<Allowance> allowances = allowanceRepository.findByUserIdWithPositiveWeightOrderByRemainingAsc(userId);
+            for (Allowance allowance : allowances) {
+                int amount = (int) ((allowance.getWeight() / sumOfWeights) * remainingReward);
+                if (allowance.getBalance() + amount > allowance.getTarget()) {
+                    amount = (int) (allowance.getTarget() - allowance.getBalance());
+                }
+                sumOfWeights -= allowance.getWeight();
+                allowance.setBalance(allowance.getBalance() + amount);
+                allowanceRepository.save(allowance);
+                remainingReward -= amount;
+            }
+        }
+
+        // Add remaining to user's balance
+        user = userRepository.findById(userId).orElseThrow();
+        user.setBalance(user.getBalance() + remainingReward);
+        userRepository.save(user);
+    }
+
+    public List<HistoryDto> getHistory(int userId) {
+        return historyRepository.findByUserIdOrderByIdDesc(userId).stream()
+                .map(h -> new HistoryDto(
+                        h.getAmount() / 100.0,
+                        Instant.ofEpochSecond(h.getTimestamp()),
+                        h.getDescription()))
+                .toList();
+    }
+
+    @Transactional
+    public void addHistory(int userId, PostHistoryRequest request) {
+        long amount = Math.round(request.allowance() * 100.0);
+        History history = new History();
+        history.setUserId(userId);
+        history.setTimestamp(Instant.now().getEpochSecond());
+        history.setAmount(amount);
+        history.setDescription(request.description());
+        historyRepository.save(history);
+    }
+
+    private AllowanceDto toDto(Allowance a) {
+        return new AllowanceDto(
+                a.getId(),
+                a.getName(),
+                a.getTarget() / 100.0,
+                a.getBalance() / 100.0,
+                a.getWeight(),
+                ColourUtil.convertColourToString(a.getColour()));
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/service/MigrationService.java

@@ -0,0 +1,97 @@
+package be.seeseepuff.allowanceplanner.service;
+
+import be.seeseepuff.allowanceplanner.dto.MigrationDto;
+import be.seeseepuff.allowanceplanner.repository.AllowanceRepository;
+import be.seeseepuff.allowanceplanner.repository.HistoryRepository;
+import be.seeseepuff.allowanceplanner.repository.TaskRepository;
+import be.seeseepuff.allowanceplanner.repository.UserRepository;
+import jakarta.persistence.EntityManager;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+public class MigrationService {
+    private final UserRepository userRepository;
+    private final AllowanceRepository allowanceRepository;
+    private final HistoryRepository historyRepository;
+    private final TaskRepository taskRepository;
+    private final EntityManager entityManager;
+
+    public MigrationService(UserRepository userRepository,
+                            AllowanceRepository allowanceRepository,
+                            HistoryRepository historyRepository,
+                            TaskRepository taskRepository,
+                            EntityManager entityManager) {
+        this.userRepository = userRepository;
+        this.allowanceRepository = allowanceRepository;
+        this.historyRepository = historyRepository;
+        this.taskRepository = taskRepository;
+        this.entityManager = entityManager;
+    }
+
+    @Transactional
+    public void importData(MigrationDto data) {
+        // Delete in dependency order
+        taskRepository.deleteAll();
+        historyRepository.deleteAll();
+        allowanceRepository.deleteAll();
+        userRepository.deleteAll();
+
+        // Insert users with original IDs using native SQL to bypass auto-increment
+        for (MigrationDto.MigrationUserDto u : data.users()) {
+            entityManager.createNativeQuery(
+                            "INSERT INTO users (id, name, balance, weight) VALUES (:id, :name, :balance, :weight)")
+                    .setParameter("id", u.id())
+                    .setParameter("name", u.name())
+                    .setParameter("balance", u.balance())
+                    .setParameter("weight", u.weight())
+                    .executeUpdate();
+        }
+
+        // Insert allowances with original IDs
+        for (MigrationDto.MigrationAllowanceDto a : data.allowances()) {
+            entityManager.createNativeQuery(
+                            "INSERT INTO allowances (id, user_id, name, target, balance, weight, colour) VALUES (:id, :userId, :name, :target, :balance, :weight, :colour)")
+                    .setParameter("id", a.id())
+                    .setParameter("userId", a.userId())
+                    .setParameter("name", a.name())
+                    .setParameter("target", a.target())
+                    .setParameter("balance", a.balance())
+                    .setParameter("weight", a.weight())
+                    .setParameter("colour", a.colour())
+                    .executeUpdate();
+        }
+
+        // Insert history with original IDs
+        for (MigrationDto.MigrationHistoryDto h : data.history()) {
+            entityManager.createNativeQuery(
+                            "INSERT INTO history (id, user_id, timestamp, amount, description) VALUES (:id, :userId, :timestamp, :amount, :description)")
+                    .setParameter("id", h.id())
+                    .setParameter("userId", h.userId())
+                    .setParameter("timestamp", h.timestamp())
+                    .setParameter("amount", h.amount())
+                    .setParameter("description", h.description())
+                    .executeUpdate();
+        }
+
+        // Insert tasks with original IDs
+        for (MigrationDto.MigrationTaskDto t : data.tasks()) {
+            entityManager.createNativeQuery(
+                            "INSERT INTO tasks (id, name, reward, assigned, schedule, completed, next_run) VALUES (:id, :name, :reward, :assigned, :schedule, :completed, :nextRun)")
+                    .setParameter("id", t.id())
+                    .setParameter("name", t.name())
+                    .setParameter("reward", t.reward())
+                    .setParameter("assigned", t.assigned())
+                    .setParameter("schedule", t.schedule())
+                    .setParameter("completed", t.completed())
+                    .setParameter("nextRun", t.nextRun())
+                    .executeUpdate();
+        }
+
+        // Reset sequences so new inserts don't collide with migrated IDs
+        entityManager.createNativeQuery("SELECT setval('users_id_seq', COALESCE((SELECT MAX(id) FROM users), 0))").getSingleResult();
+        entityManager.createNativeQuery("SELECT setval('allowances_id_seq', COALESCE((SELECT MAX(id) FROM allowances), 0))").getSingleResult();
+        entityManager.createNativeQuery("SELECT setval('history_id_seq', COALESCE((SELECT MAX(id) FROM history), 0))").getSingleResult();
+        entityManager.createNativeQuery("SELECT setval('tasks_id_seq', COALESCE((SELECT MAX(id) FROM tasks), 0))").getSingleResult();
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/service/TaskService.java

@@ -0,0 +1,120 @@
+package be.seeseepuff.allowanceplanner.service;
+
+import be.seeseepuff.allowanceplanner.dto.CreateTaskRequest;
+import be.seeseepuff.allowanceplanner.dto.TaskDto;
+import be.seeseepuff.allowanceplanner.entity.History;
+import be.seeseepuff.allowanceplanner.entity.Task;
+import be.seeseepuff.allowanceplanner.entity.User;
+import be.seeseepuff.allowanceplanner.repository.HistoryRepository;
+import be.seeseepuff.allowanceplanner.repository.TaskRepository;
+import be.seeseepuff.allowanceplanner.repository.UserRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.Instant;
+import java.util.List;
+import java.util.Optional;
+
+@Service
+public class TaskService {
+    private final TaskRepository taskRepository;
+    private final UserRepository userRepository;
+    private final HistoryRepository historyRepository;
+    private final AllowanceService allowanceService;
+
+    public TaskService(TaskRepository taskRepository,
+                       UserRepository userRepository,
+                       HistoryRepository historyRepository,
+                       AllowanceService allowanceService) {
+        this.taskRepository = taskRepository;
+        this.userRepository = userRepository;
+        this.historyRepository = historyRepository;
+        this.allowanceService = allowanceService;
+    }
+
+    @Transactional
+    public int createTask(CreateTaskRequest request) {
+        Task task = new Task();
+        task.setName(request.name());
+        task.setReward(Math.round((request.reward() != null ? request.reward() : 0.0) * 100.0));
+        task.setAssigned(request.assigned());
+        task = taskRepository.save(task);
+        return task.getId();
+    }
+
+    public List<TaskDto> getTasks() {
+        return taskRepository.findByCompletedIsNull().stream()
+                .map(this::toDto)
+                .toList();
+    }
+
+    public Optional<TaskDto> getTask(int taskId) {
+        return taskRepository.findByIdAndCompletedIsNull(taskId)
+                .map(this::toDto);
+    }
+
+    @Transactional
+    public boolean updateTask(int taskId, CreateTaskRequest request) {
+        Optional<Task> opt = taskRepository.findByIdAndCompletedIsNull(taskId);
+        if (opt.isEmpty()) {
+            return false;
+        }
+        Task task = opt.get();
+        task.setName(request.name());
+        task.setReward(Math.round((request.reward() != null ? request.reward() : 0.0) * 100.0));
+        task.setAssigned(request.assigned());
+        taskRepository.save(task);
+        return true;
+    }
+
+    public boolean hasTask(int taskId) {
+        return taskRepository.existsById(taskId);
+    }
+
+    @Transactional
+    public void deleteTask(int taskId) {
+        taskRepository.deleteById(taskId);
+    }
+
+    @Transactional
+    public boolean completeTask(int taskId) {
+        Optional<Task> opt = taskRepository.findById(taskId);
+        if (opt.isEmpty()) {
+            return false;
+        }
+
+        Task task = opt.get();
+        long reward = task.getReward();
+        String rewardName = task.getName();
+
+        // Give reward to all users
+        List<User> users = userRepository.findAll();
+        for (User user : users) {
+            // Add history entry
+            History history = new History();
+            history.setUserId(user.getId());
+            history.setTimestamp(Instant.now().getEpochSecond());
+            history.setAmount(reward);
+            history.setDescription("Task completed: " + rewardName);
+            historyRepository.save(history);
+
+            // Distribute reward
+            allowanceService.addDistributedReward(user.getId(), (int) reward);
+        }
+
+        // Mark task as completed
+        task.setCompleted(Instant.now().getEpochSecond());
+        taskRepository.save(task);
+
+        return true;
+    }
+
+    private TaskDto toDto(Task t) {
+        return new TaskDto(
+                t.getId(),
+                t.getName(),
+                t.getReward() / 100.0,
+                t.getAssigned(),
+                t.getSchedule());
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/service/TransferService.java

@@ -0,0 +1,86 @@
+package be.seeseepuff.allowanceplanner.service;
+
+import be.seeseepuff.allowanceplanner.dto.TransferRequest;
+import be.seeseepuff.allowanceplanner.entity.Allowance;
+import be.seeseepuff.allowanceplanner.repository.AllowanceRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.Optional;
+
+@Service
+public class TransferService {
+    private final AllowanceRepository allowanceRepository;
+
+    public TransferService(AllowanceRepository allowanceRepository) {
+        this.allowanceRepository = allowanceRepository;
+    }
+
+    @Transactional
+    public TransferResult transfer(TransferRequest request) {
+        if (request.from() == request.to()) {
+            return TransferResult.success();
+        }
+
+        int amountCents = (int) Math.round(request.amount() * 100.0);
+        if (amountCents <= 0) {
+            return TransferResult.badRequest("amount must be positive");
+        }
+
+        Optional<Allowance> fromOpt = allowanceRepository.findById(request.from());
+        if (fromOpt.isEmpty()) {
+            return TransferResult.notFound();
+        }
+
+        Optional<Allowance> toOpt = allowanceRepository.findById(request.to());
+        if (toOpt.isEmpty()) {
+            return TransferResult.notFound();
+        }
+
+        Allowance from = fromOpt.get();
+        Allowance to = toOpt.get();
+
+        if (from.getUserId() != to.getUserId()) {
+            return TransferResult.badRequest("Allowances do not belong to the same user");
+        }
+
+        long remainingTo = to.getTarget() - to.getBalance();
+        if (remainingTo <= 0) {
+            return TransferResult.badRequest("target already reached");
+        }
+
+        int transfer = amountCents;
+        if (transfer > remainingTo) {
+            transfer = (int) remainingTo;
+        }
+
+        if (from.getBalance() < transfer) {
+            return TransferResult.badRequest("Insufficient funds in source allowance");
+        }
+
+        from.setBalance(from.getBalance() - transfer);
+        to.setBalance(to.getBalance() + transfer);
+        allowanceRepository.save(from);
+        allowanceRepository.save(to);
+
+        return TransferResult.success();
+    }
+
+    public record TransferResult(Status status, String message) {
+        public static TransferResult success() {
+            return new TransferResult(Status.SUCCESS, "Transfer successful");
+        }
+
+        public static TransferResult badRequest(String message) {
+            return new TransferResult(Status.BAD_REQUEST, message);
+        }
+
+        public static TransferResult notFound() {
+            return new TransferResult(Status.NOT_FOUND, "Allowance not found");
+        }
+
+        public enum Status {
+            SUCCESS, BAD_REQUEST, NOT_FOUND
+        }
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/service/UserService.java

@@ -0,0 +1,37 @@
+package be.seeseepuff.allowanceplanner.service;
+
+import be.seeseepuff.allowanceplanner.dto.UserDto;
+import be.seeseepuff.allowanceplanner.dto.UserWithAllowanceDto;
+import be.seeseepuff.allowanceplanner.repository.UserRepository;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.Optional;
+
+@Service
+public class UserService {
+    private final UserRepository userRepository;
+
+    public UserService(UserRepository userRepository) {
+        this.userRepository = userRepository;
+    }
+
+    public List<UserDto> getUsers() {
+        return userRepository.findAll().stream()
+                .map(u -> new UserDto(u.getId(), u.getName()))
+                .toList();
+    }
+
+    public Optional<UserWithAllowanceDto> getUser(int userId) {
+        return userRepository.findById(userId)
+                .map(u ->
+                {
+                    long totalAmount = userRepository.sumHistoryAmount(userId);
+                    return new UserWithAllowanceDto(u.getId(), u.getName(), totalAmount / 100.0);
+                });
+    }
+
+    public boolean userExists(int userId) {
+        return userRepository.existsById(userId);
+    }
+}

backend-spring/src/main/java/be/seeseepuff/allowanceplanner/util/ColourUtil.java

@@ -0,0 +1,33 @@
+package be.seeseepuff.allowanceplanner.util;
+
+public class ColourUtil {
+    private ColourUtil() {
+    }
+
+    public static int convertStringToColour(String colourStr) {
+        if (colourStr == null || colourStr.isEmpty()) {
+            return 0xFF0000; // Default colour
+        }
+        if (colourStr.charAt(0) == '#') {
+            colourStr = colourStr.substring(1);
+        }
+        if (colourStr.length() != 6 && colourStr.length() != 3) {
+            throw new IllegalArgumentException("colour must be a valid hex string");
+        }
+        int colour = Integer.parseInt(colourStr, 16);
+        if (colourStr.length() == 3) {
+            int r = (colour & 0xF00) >> 8;
+            int g = (colour & 0x0F0) >> 4;
+            int b = (colour & 0x00F);
+            colour = (r << 20) | (g << 12) | (b << 4);
+        }
+        return colour;
+    }
+
+    public static String convertColourToString(Integer colour) {
+        if (colour == null) {
+            return "";
+        }
+        return String.format("#%06X", colour);
+    }
+}

backend-spring/src/main/resources/application.properties

@@ -0,0 +1,8 @@
+spring.application.name=allowance-planner
+spring.datasource.url=jdbc:postgresql://localhost:5432/allowance_planner
+spring.datasource.username=postgres
+spring.datasource.password=postgres
+spring.jpa.hibernate.ddl-auto=validate
+spring.jpa.open-in-view=false
+spring.flyway.enabled=true
+server.port=8080

backend-spring/src/main/resources/db/migration/V1__initial.sql

@@ -0,0 +1,42 @@
+CREATE TABLE users
+(
+    id      SERIAL PRIMARY KEY,
+    name    TEXT             NOT NULL,
+    weight  DOUBLE PRECISION NOT NULL DEFAULT 10.0,
+    balance BIGINT           NOT NULL DEFAULT 0
+);
+
+CREATE TABLE history
+(
+    id          SERIAL PRIMARY KEY,
+    user_id     INTEGER NOT NULL,
+    timestamp   BIGINT  NOT NULL,
+    amount      BIGINT  NOT NULL,
+    description TEXT
+);
+
+CREATE TABLE allowances
+(
+    id      SERIAL PRIMARY KEY,
+    user_id INTEGER          NOT NULL,
+    name    TEXT             NOT NULL,
+    target  BIGINT           NOT NULL,
+    balance BIGINT           NOT NULL DEFAULT 0,
+    weight  DOUBLE PRECISION NOT NULL,
+    colour  INTEGER
+);
+
+CREATE TABLE tasks
+(
+    id        SERIAL PRIMARY KEY,
+    name      TEXT   NOT NULL,
+    reward    BIGINT NOT NULL,
+    assigned  INTEGER,
+    schedule  TEXT,
+    completed BIGINT,
+    next_run  BIGINT
+);
+
+INSERT INTO users (name)
+VALUES ('Seeseemelk'),
+       ('Huffle');

backend-spring/src/main/resources/templates/index.html

@@ -0,0 +1,122 @@
+<!DOCTYPE html>
+<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<head>
+    <title>Allowance Planner 2000</title>
+    <style>
+        tr:hover {
+            background-color: #f0f0f0;
+        }
+    </style>
+</head>
+<body>
+<h1>Allowance Planner 2000</h1>
+
+<div th:if="${error != null}">
+    <h2>Error</h2>
+    <p th:text="${error}"></p>
+</div>
+
+<div th:if="${error == null}">
+    <h2>Users</h2>
+    <span th:each="user : ${users}">
+        <strong th:if="${currentUser != null and currentUser == user.id()}" th:text="${user.name()}"></strong>
+        <a th:href="@{/login(user=${user.id()})}"
+           th:text="${user.name()}" th:unless="${currentUser != null and currentUser == user.id()}"></a>
+    </span>
+
+    <div th:if="${currentUser != null and currentUser > 0}">
+        <h2>Allowances</h2>
+        <form action="/createAllowance" method="post">
+            <table border="1">
+                <thead>
+                <tr>
+                    <th>Name</th>
+                    <th>Progress</th>
+                    <th>Target</th>
+                    <th>Weight</th>
+                    <th>Actions</th>
+                </tr>
+                </thead>
+                <tbody>
+                <tr>
+                    <td><label><input name="name" placeholder="Name" type="text"/></label></td>
+                    <td></td>
+                    <td><label><input name="target" placeholder="Target" type="number"/></label></td>
+                    <td><label><input name="weight" placeholder="Weight" type="number"/></label></td>
+                    <td><input type="submit" value="Create"/></td>
+                </tr>
+                <tr th:each="allowance : ${allowances}">
+                    <td th:if="${allowance.id() == 0}">Total</td>
+                    <td th:if="${allowance.id() != 0}" th:text="${allowance.name()}"></td>
+                    <td th:if="${allowance.id() == 0}" th:text="${allowance.progress()}"></td>
+                    <td th:if="${allowance.id() != 0}">
+                        <progress th:max="${allowance.target()}" th:value="${allowance.progress()}"></progress>
+                        (<span th:text="${allowance.progress()}"></span>)
+                    </td>
+                    <td th:if="${allowance.id() == 0}"></td>
+                    <td th:if="${allowance.id() != 0}" th:text="${allowance.target()}"></td>
+                    <td th:text="${allowance.weight()}"></td>
+                    <td th:if="${allowance.id() != 0 and allowance.progress() >= allowance.target()}">
+                        <a th:href="@{/completeAllowance(allowance=${allowance.id()})}">Mark as completed</a>
+                    </td>
+                    <td th:if="${allowance.id() == 0 or allowance.progress() < allowance.target()}"></td>
+                </tr>
+                </tbody>
+            </table>
+        </form>
+
+        <h2>Tasks</h2>
+        <form action="/createTask" method="post">
+            <table border="1">
+                <thead>
+                <tr>
+                    <th>Name</th>
+                    <th>Assigned</th>
+                    <th>Reward</th>
+                    <th>Schedule</th>
+                    <th>Actions</th>
+                </tr>
+                </thead>
+                <tbody>
+                <tr th:each="task : ${tasks}">
+                    <td th:text="${task.name()}"></td>
+                    <td>
+                        <span th:if="${task.assigned() == null}">None</span>
+                        <span th:if="${task.assigned() != null}" th:text="${task.assigned()}"></span>
+                    </td>
+                    <td th:text="${task.reward()}"></td>
+                    <td th:text="${task.schedule()}"></td>
+                    <td>
+                        <a th:href="@{/completeTask(task=${task.id()})}">Mark as completed</a>
+                    </td>
+                </tr>
+                <tr>
+                    <td><label><input name="name" placeholder="Name" type="text"/></label></td>
+                    <td></td>
+                    <td><label><input name="reward" placeholder="Reward" type="number"/></label></td>
+                    <td><label><input name="schedule" placeholder="Schedule" type="text"/></label></td>
+                    <td><input type="submit" value="Create"/></td>
+                </tr>
+                </tbody>
+            </table>
+        </form>
+
+        <h2>History</h2>
+        <table border="1">
+            <thead>
+            <tr>
+                <th>Timestamp</th>
+                <th>Allowance</th>
+            </tr>
+            </thead>
+            <tbody>
+            <tr th:each="item : ${history}">
+                <td th:text="${item.timestamp()}"></td>
+                <td th:text="${item.allowance()}"></td>
+            </tr>
+            </tbody>
+        </table>
+    </div>
+</div>
+</body>
+</html>

backend-spring/src/test/java/be/seeseepuff/allowanceplanner/ColourUtilTest.java

@@ -0,0 +1,28 @@
+package be.seeseepuff.allowanceplanner;
+
+import be.seeseepuff.allowanceplanner.util.ColourUtil;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ColourUtilTest {
+    @Test
+    void convertStringToColourWithSign() {
+        assertEquals(0x123456, ColourUtil.convertStringToColour("#123456"));
+    }
+
+    @Test
+    void convertStringToColourWithoutSign() {
+        assertEquals(0x123456, ColourUtil.convertStringToColour("123456"));
+    }
+
+    @Test
+    void convertStringToColourWithSignThreeDigits() {
+        assertEquals(0xA0B0C0, ColourUtil.convertStringToColour("#ABC"));
+    }
+
+    @Test
+    void convertStringToColourWithoutSignThreeDigits() {
+        assertEquals(0xA0B0C0, ColourUtil.convertStringToColour("ABC"));
+    }
+}

backend/db.go

@@ -779,3 +779,59 @@ func (db *Db) TransferAllowance(fromId int, toId int, amount float64) error {
 
 	return tx.Commit()
 }
+
+func (db *Db) ExportAllData() (*ExportData, error) {
+	var err error
+	data := &ExportData{
+		Users:      make([]ExportUser, 0),
+		Allowances: make([]ExportAllowance, 0),
+		History:    make([]ExportHistory, 0),
+		Tasks:      make([]ExportTask, 0),
+	}
+
+	for row := range db.db.Query("select id, name, balance, weight from users").Range(&err) {
+		u := ExportUser{}
+		if err = row.Scan(&u.ID, &u.Name, &u.Balance, &u.Weight); err != nil {
+			return nil, err
+		}
+		data.Users = append(data.Users, u)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	for row := range db.db.Query("select id, user_id, name, target, balance, weight, colour from allowances").Range(&err) {
+		a := ExportAllowance{}
+		if err = row.Scan(&a.ID, &a.UserID, &a.Name, &a.Target, &a.Balance, &a.Weight, &a.Colour); err != nil {
+			return nil, err
+		}
+		data.Allowances = append(data.Allowances, a)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	for row := range db.db.Query("select id, user_id, timestamp, amount, description from history").Range(&err) {
+		h := ExportHistory{}
+		if err = row.Scan(&h.ID, &h.UserID, &h.Timestamp, &h.Amount, &h.Description); err != nil {
+			return nil, err
+		}
+		data.History = append(data.History, h)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	for row := range db.db.Query("select id, name, reward, assigned, schedule, completed, next_run from tasks").Range(&err) {
+		t := ExportTask{}
+		if err = row.Scan(&t.ID, &t.Name, &t.Reward, &t.Assigned, &t.Schedule, &t.Completed, &t.NextRun); err != nil {
+			return nil, err
+		}
+		data.Tasks = append(data.Tasks, t)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return data, nil
+}

backend/dto.go

@@ -86,3 +86,45 @@ type TransferRequest struct {
 	To     int     `json:"to"`
 	Amount float64 `json:"amount"`
 }
+
+type ExportUser struct {
+	ID      int     `json:"id"`
+	Name    string  `json:"name"`
+	Balance int64   `json:"balance"`
+	Weight  float64 `json:"weight"`
+}
+
+type ExportAllowance struct {
+	ID      int      `json:"id"`
+	UserID  int      `json:"userId"`
+	Name    string   `json:"name"`
+	Target  int64    `json:"target"`
+	Balance int64    `json:"balance"`
+	Weight  float64  `json:"weight"`
+	Colour  *int     `json:"colour"`
+}
+
+type ExportHistory struct {
+	ID          int    `json:"id"`
+	UserID      int    `json:"userId"`
+	Timestamp   int64  `json:"timestamp"`
+	Amount      int64  `json:"amount"`
+	Description string `json:"description"`
+}
+
+type ExportTask struct {
+	ID        int     `json:"id"`
+	Name      string  `json:"name"`
+	Reward    int64   `json:"reward"`
+	Assigned  *int    `json:"assigned"`
+	Schedule  *string `json:"schedule"`
+	Completed *int64  `json:"completed"`
+	NextRun   *int64  `json:"nextRun"`
+}
+
+type ExportData struct {
+	Users      []ExportUser      `json:"users"`
+	Allowances []ExportAllowance `json:"allowances"`
+	History    []ExportHistory   `json:"history"`
+	Tasks      []ExportTask      `json:"tasks"`
+}

backend/main.go

@@ -51,6 +51,16 @@ const DefaultDomain = "localhost:8080"
 // The domain that the server is reachable at.
 var domain = DefaultDomain
 
+func exportData(c *gin.Context) {
+	data, err := db.ExportAllData()
+	if err != nil {
+		log.Printf("Error exporting data: %v", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": ErrInternalServerError})
+		return
+	}
+	c.IndentedJSON(http.StatusOK, data)
+}
+
 func getUsers(c *gin.Context) {
 	users, err := db.GetUsers()
 	if err != nil {
@@ -713,6 +723,7 @@ func start(ctx context.Context, config *ServerConfig) {
 	router.DELETE("/api/task/:taskId", deleteTask)
 	router.POST("/api/task/:taskId/complete", completeTask)
 	router.POST("/api/transfer", transfer)
+	router.GET("/api/export", exportData)
 
 	srv := &http.Server{
 		Addr:    config.Addr,