Add support for schedules (#137)

Reviewed-on: #137

backend/db.go

@@ -3,6 +3,7 @@ package main
 import (
 	"errors"
 	"fmt"
+	"github.com/adhocore/gronx"
 	"log"
 	"math"
 	"time"
@@ -313,10 +314,20 @@ func (db *Db) CreateTask(task *CreateTaskRequest) (int, error) {
 	}
 	defer tx.MustRollback()
 
+	var nextRun *int64
+	if task.Schedule != nil {
+		nextRunTime, err := gronx.NextTick(*task.Schedule, false)
+		if err != nil {
+			return 0, fmt.Errorf("failed to calculate next run: %w", err)
+		}
+		nextRunTimeAsInt := nextRunTime.Unix()
+		nextRun = &nextRunTimeAsInt
+	}
+
 	// Insert the new task
 	reward := int(math.Round(task.Reward * 100.0))
-	err = tx.Query("insert into tasks (name, reward, assigned) values (?, ?, ?)").
-		Bind(task.Name, reward, task.Assigned).
+	err = tx.Query("insert into tasks (name, reward, assigned, schedule, next_run) values (?, ?, ?, ?, ?)").
+		Bind(task.Name, reward, task.Assigned, task.Schedule, nextRun).
 		Exec()
 
 	if err != nil {
@@ -340,13 +351,17 @@ func (db *Db) CreateTask(task *CreateTaskRequest) (int, error) {
 }
 
 func (db *Db) GetTasks() ([]Task, error) {
-	tasks := make([]Task, 0)
-	var err error
+	err := db.UpdateScheduledTasks()
+	if err != nil {
+		return nil, fmt.Errorf("failed to update scheduled tasks: %w", err)
+	}
 
-	for row := range db.db.Query("select id, name, reward, assigned from tasks").Range(&err) {
+	tasks := make([]Task, 0)
+
+	for row := range db.db.Query("select id, name, reward, assigned, schedule from tasks where completed is null").Range(&err) {
 		task := Task{}
 		var reward int64
-		err = row.Scan(&task.ID, &task.Name, &reward, &task.Assigned)
+		err = row.Scan(&task.ID, &task.Name, &reward, &task.Assigned, &task.Schedule)
 		task.Reward = float64(reward) / 100.0
 		if err != nil {
 			return nil, err
@@ -362,16 +377,78 @@ func (db *Db) GetTasks() ([]Task, error) {
 func (db *Db) GetTask(id int) (Task, error) {
 	task := Task{}
 
-	var reward int64
-	err := db.db.Query("select id, name, reward, assigned from tasks where id = ?").
-		Bind(id).ScanSingle(&task.ID, &task.Name, &reward, &task.Assigned)
-	task.Reward = float64(reward) / 100.0
+	err := db.UpdateScheduledTasks()
 	if err != nil {
-		return Task{}, err
+		return Task{}, fmt.Errorf("failed to update scheduled tasks: %w", err)
 	}
+
+	var reward int64
+	err = db.db.Query("select id, name, reward, assigned, schedule from tasks where id = ? and completed is null").
+		Bind(id).ScanSingle(&task.ID, &task.Name, &reward, &task.Assigned, &task.Schedule)
+	if err != nil {
+		return task, err
+	}
+	task.Reward = float64(reward) / 100.0
 	return task, nil
 }
 
+func (db *Db) UpdateScheduledTasks() error {
+	type ScheduledTask struct {
+		ID       int
+		Schedule string
+		Expires  int64
+	}
+	tasks := make([]ScheduledTask, 0)
+	var err error
+
+	for row := range db.db.Query("select id, schedule, next_run from tasks where schedule is not null").Range(&err) {
+		task := ScheduledTask{}
+		err := row.Scan(&task.ID, &task.Schedule, &task.Expires)
+		if err != nil {
+			return err
+		}
+		if time.Now().Unix() >= task.Expires {
+			tasks = append(tasks, task)
+		}
+	}
+	if err != nil {
+		return fmt.Errorf("failed to fetch scheduled tasks: %w", err)
+	}
+
+	tx, err := db.db.Begin()
+	if err != nil {
+		return err
+	}
+	defer tx.MustRollback()
+
+	for _, task := range tasks {
+		nextRun, err := gronx.NextTickAfter(task.Schedule, time.Now(), false)
+		if err != nil {
+			return fmt.Errorf("failed to calculate next run for task %d: %w", task.ID, err)
+		}
+
+		err = tx.Query("insert into tasks (name, reward, assigned, schedule, next_run) select name, reward, assigned, schedule, ? from tasks where id = ?").
+			Bind(nextRun.Unix(), task.ID).
+			Exec()
+		if err != nil {
+			return err
+		}
+
+		err = tx.Query("update tasks set schedule = null where id = ?").Bind(task.ID).Exec()
+		if err != nil {
+			return err
+		}
+
+		tx.Query("select last_insert_rowid()").MustScanSingle(&task.ID)
+		log.Printf("Task %d scheduled for %s", task.ID, nextRun)
+	}
+	if err != nil {
+		return err
+	}
+
+	return tx.Commit()
+}
+
 func (db *Db) DeleteTask(id int) error {
 	tx, err := db.db.Begin()
 	if err != nil {
@@ -453,7 +530,10 @@ func (db *Db) CompleteTask(taskId int) error {
 	}
 
 	// Remove the task
-	err = tx.Query("delete from tasks where id = ?").Bind(taskId).Exec()
+	err = tx.Query("update tasks set completed=? where id = ?").Bind(time.Now().Unix(), taskId).Exec()
+	if err != nil {
+		return err
+	}
 
 	return tx.Commit()
 }