package main

import (
	"errors"
	"log"
	"time"

	"gitea.seeseepuff.be/seeseemelk/mysqlite"
)

type Db struct {
	db *mysqlite.Db
}

func NewDb(datasource string) *Db {
	// Open a file-based database
	db, err := mysqlite.OpenDb(datasource)
	if err != nil {
		log.Fatal(err)
	}

	// Apply migrations
	err = db.MigrateDb(migrations, "migrations")
	if err != nil {
		log.Fatal(err)
	}

	return &Db{db: db}
}

func (db *Db) GetUsers() ([]User, error) {
	var err error
	users := make([]User, 0)

	for row := range db.db.Query("select id, name from users").Range(&err) {
		user := User{}
		err = row.Scan(&user.ID, &user.Name)
		if err != nil {
			return nil, err
		}
		users = append(users, user)
	}
	if err != nil {
		return nil, err
	}
	return users, nil
}

func (db *Db) GetUser(id int) (*UserWithAllowance, error) {
	user := &UserWithAllowance{}

	err := db.db.Query("select u.id, u.name, (select ifnull(sum(h.amount), 0) from history h where h.user_id = u.id) from users u where u.id = ?").
		Bind(id).ScanSingle(&user.ID, &user.Name, &user.Allowance)
	if err != nil {
		return nil, err
	}
	return user, nil
}

func (db *Db) UserExists(userId int) (bool, error) {
	count := 0
	err := db.db.Query("select count(*) from users where id = ?").
		Bind(userId).ScanSingle(&count)
	if err != nil {
		return false, err
	}
	return count > 0, nil
}

func (db *Db) GetUserGoals(userId int) ([]Goal, error) {
	goals := make([]Goal, 0)
	var err error

	for row := range db.db.Query("select id, name, target, progress, weight from goals where user_id = ?").
		Bind(userId).Range(&err) {
		goal := Goal{}
		err = row.Scan(&goal.ID, &goal.Name, &goal.Target, &goal.Progress, &goal.Weight)
		if err != nil {
			return nil, err
		}
		goals = append(goals, goal)
	}
	if err != nil {
		return nil, err
	}
	return goals, nil
}

func (db *Db) CreateGoal(userId int, goal *CreateGoalRequest) (int, error) {
	// Check if user exists before attempting to create a goal
	exists, err := db.UserExists(userId)
	if err != nil {
		return 0, err
	}
	if !exists {
		return 0, errors.New("user does not exist")
	}

	tx, err := db.db.Begin()
	if err != nil {
		return 0, err
	}
	defer tx.MustRollback()

	// Insert the new goal
	err = tx.Query("insert into goals (user_id, name, target, progress, weight) values (?, ?, ?, 0, ?)").
		Bind(userId, goal.Name, goal.Target, goal.Weight).
		Exec()

	if err != nil {
		return 0, err
	}

	// Get the last inserted ID
	var lastId int
	err = tx.Query("select last_insert_rowid()").ScanSingle(&lastId)
	if err != nil {
		return 0, err
	}

	// Commit the transaction
	err = tx.Commit()
	if err != nil {
		return 0, err
	}

	return lastId, nil
}

func (db *Db) DeleteGoal(userId int, goalId int) error {
	// Check if the goal exists for the user
	count := 0
	err := db.db.Query("select count(*) from goals where id = ? and user_id = ?").
		Bind(goalId, userId).ScanSingle(&count)
	if err != nil {
		return err
	}
	if count == 0 {
		return errors.New("goal not found")
	}

	// Delete the goal
	err = db.db.Query("delete from goals where id = ? and user_id = ?").
		Bind(goalId, userId).Exec()
	if err != nil {
		return err
	}

	return nil
}

func (db *Db) CreateTask(task *CreateTaskRequest) (int, error) {
	tx, err := db.db.Begin()
	if err != nil {
		return 0, err
	}
	defer tx.MustRollback()

	// Insert the new task
	err = tx.Query("insert into tasks (name, reward, assigned) values (?, ?, ?)").
		Bind(task.Name, task.Reward, task.Assigned).
		Exec()

	if err != nil {
		return 0, err
	}

	// Get the last inserted ID
	var lastId int
	err = tx.Query("select last_insert_rowid()").ScanSingle(&lastId)
	if err != nil {
		return 0, err
	}

	// Commit the transaction
	err = tx.Commit()
	if err != nil {
		return 0, err
	}

	return lastId, nil
}

func (db *Db) GetTasks() ([]Task, error) {
	tasks := make([]Task, 0)
	var err error

	for row := range db.db.Query("select id, name, reward, assigned from tasks").Range(&err) {
		task := Task{}
		err = row.Scan(&task.ID, &task.Name, &task.Reward, &task.Assigned)
		if err != nil {
			return nil, err
		}
		tasks = append(tasks, task)
	}
	if err != nil {
		return nil, err
	}
	return tasks, nil
}

func (db *Db) GetTask(id int) (Task, error) {
	task := Task{}

	err := db.db.Query("select id, name, reward, assigned from tasks where id = ?").
		Bind(id).ScanSingle(&task.ID, &task.Name, &task.Reward, &task.Assigned)
	if err != nil {
		return Task{}, err
	}
	return task, nil
}

func (db *Db) HasTask(id int) (bool, error) {
	count := 0
	err := db.db.Query("select count(*) from tasks where id = ?").
		Bind(id).ScanSingle(&count)
	if err != nil {
		return false, err
	}
	return count > 0, nil
}

func (db *Db) UpdateTask(id int, task *CreateTaskRequest) error {
	tx, err := db.db.Begin()
	if err != nil {
		return err
	}
	defer tx.MustRollback()

	err = tx.Query("update tasks set name=?, reward=?, assigned=? where id = ?").
		Bind(task.Name, task.Reward, task.Assigned, id).
		Exec()
	if err != nil {
		return err
	}
	return tx.Commit()
}

func (db *Db) AddAllowance(userId int, allowance *PostAllowance) error {
	tx, err := db.db.Begin()
	if err != nil {
		return err
	}
	defer tx.MustRollback()

	err = tx.Query("insert into history (user_id, date, amount) values (?, ?, ?)").
		Bind(userId, time.Now().Unix(), allowance.Allowance).
		Exec()
	if err != nil {
		return err
	}
	return tx.Commit()
}