package cmd

import (
	"log"
	"time"

	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

type Todo struct {
	ID        uint64
	Desc      string
	DueDate   time.Time
	CreatedAt time.Time
	IsDone    bool
}

// errPanic exits program with msg and error details if there is an error.
func errPanic(err error, msg string) {
	if err != nil {
		log.Fatalf(msg, err)
	}
}

// parseDateString returns parsed time from string or time.Time{}.
func parseDateString(date string) time.Time {
	var (
		t       time.Time
		err     error
		layouts = []string{
			"02/01/2006",
			"02/01/2006T15:04",
		}
	)
	for _, layout := range layouts {
		t, err = time.Parse(layout, date)
		if err == nil {
			return t
		}
	}

	return time.Time{}
}

// openDB returns gorm database.
func openDB() *gorm.DB {
	db, err := gorm.Open(sqlite.Open("/home/user/.todo.db"), &gorm.Config{})
	errPanic(err, "failed to connect database")

	return db
}

// createTodo creates todo entry in the database.
func createTodo(desc string, date string, comp bool) {
	db := openDB()
	err := db.AutoMigrate(&Todo{})
	errPanic(err, "failed to migrate database")
	d := parseDateString(date)

	t := Todo{Desc: desc, DueDate: d, CreatedAt: time.Now(), IsDone: comp}
	db.Create(&t)
}

// updateTodo updates an entry of id todo in the database.
func updateTodo(id uint64, desc string, date string, comp bool) {
	db := openDB()
	var t Todo
	res := db.First(&t, id)
	errPanic(res.Error, "failed to find id")
	if desc != "" {
		t.Desc = desc
	}
	if date != "" {
		d := parseDateString(date)
		t.DueDate = d
	}
	if comp {
		t.IsDone = !t.IsDone
	}
	db.Model(&t).Updates(t)
}

// deleteTodo deletes an entry of id todo in the database.
func deleteTodo(ids []uint64) {
	db := openDB()
	for _, id := range ids {
		db.Delete(&Todo{}, id)
	}
}

// getAllTodos return all todos from the database.
func getAllTodos() []Todo {
	db := openDB()
	var todos []Todo
	res := db.Find(&todos)
	errPanic(res.Error, "failed to get all todos")

	return todos
}

// getDoneTodos returns all completed todos.
func getDoneTodos() []Todo {
	db := openDB()
	var todos []Todo
	res := db.Where(&Todo{IsDone: true}).Find(&todos)
	errPanic(res.Error, "failed to get all todos")

	return todos
}

// getDoneTodos returns all uncompleted todos.
func getUnDoneTodos() []Todo {
	db := openDB()
	var todos []Todo
	res := db.Where("is_done = ?", false).Find(&todos)
	errPanic(res.Error, "failed to get all todos")

	return todos
}