echo-todos/pkg/db/db.go

package db

import (
	"database/sql"
	"fmt"
	"log/slog"

	"git.wittern.io/public/echo-todos/model"
	_ "github.com/mattn/go-sqlite3"
)

var DB *sql.DB

func InitDB() (*sql.DB, error) {
	var err error

	todosDB := "./data/todos.db"

	DB, err = sql.Open("sqlite3", todosDB)
	if err != nil {
		slog.Error("cant open db", "Error", err)
	}

	if tableExists(DB, "todos") {
		DB, err = sql.Open("sqlite3", todosDB)
		if err != nil {
			slog.Error("cant open db", "Error", err)
		}
	} else {
		CreateTable(DB)
	}
	return DB, nil
}

func tableExists(db *sql.DB, tableName string) bool {
	var err error
	var result string

	query := "SELECT name FROM sqlite_master WHERE type='table' AND name=?;"
	err = db.QueryRow(query, tableName).Scan(&result)
	if err == sql.ErrNoRows {
		fmt.Println("Table does not exist, the database was likely just created.")
		return false
	} else if err != nil {
		slog.Error("unexpected db error", "Error", err)
	} else {
		fmt.Println("Table exists, the database was already initialized.")
		return true
	}
	return false
}

func CreateTable(db *sql.DB) error {
	query := `
	CREATE TABLE IF NOT EXISTS todos (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		title TEXT,
		done BOOLEAN
	);`
	_, err := db.Exec(query)
	return err
}

func InsertTodo(db *sql.DB, todo model.Todo) (error, int64) {
	query := `
    INSERT INTO todos (title, done )
    VALUES (?, ?);`
	result, err := db.Exec(query, todo.Title, 0)
	if err != nil {
		slog.Error("failed to insert todo", "Error", err)
		return err, 0
	}
	todoId, err := result.LastInsertId()
	if err != nil {
		slog.Error("failed to get last insert id", "Error", err)
		return err, 0
	}
	return nil, todoId
}

func ListTodos(db *sql.DB) ([]model.Todo, error) {
	query := `SELECT id, title, done FROM todos;`
	rows, err := db.Query(query)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var todos model.Todos
	for rows.Next() {
		var todo model.Todo
		err := rows.Scan(&todo.ID, &todo.Title, &todo.Done)
		if err != nil {
			return nil, err
		}
		todos = append(todos, todo)
	}
	return todos, nil
}

func DeleteTodoByID(db *sql.DB, todoID int) error {
	query := `DELETE FROM todos WHERE id = ?;`
	_, err := db.Exec(query, todoID)
	return err
}

func ToggleTodoByID(db *sql.DB, id int) ([]model.Todo, error) {
	query := `UPDATE todos SET done = NOT done WHERE id = ?;`
	_, err := db.Exec(query, id)
	if err != nil {
		return []model.Todo{}, err
	}

	todos, err := ListTodos(db)
	if err != nil {
		return []model.Todo{}, err
	}
	return todos, nil
}