/*
YetAnotherToDoList
Copyright © 2023 gilex-dev gilex-dev@proton.me

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, version 3.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package database

import (
	"database/sql"
	"errors"
	"strconv"

	"somepi.ddns.net/gitea/gilex-dev/YetAnotherToDoList/graph/model"
)

// GetOwner takes a todoId and return the owner's userId. Call before Update/Get/DeleteTodo when not IS_admin.
func (db CustomDB) GetOwner(todoId string) (string, error) {
	numTodoId, err := strconv.Atoi(todoId)
	if err != nil {
		return "", errors.New("malformed todoId")
	}

	statement, err := db.connection.Prepare("SELECT FK_User_userId, FROM Todo WHERE todoId = ?")
	if err != nil {
		return "", err
	}

	result := statement.QueryRow(numTodoId)
	var owner string
	if err := result.Scan(&owner); err != nil {
		if err == sql.ErrNoRows {
			return "", errors.New("invalid todo Id")
		}
		return "", err
	}

	return owner, nil
}

// GetTodo takes a *model.Todo with at least ID set and adds the missing fields.
func (db CustomDB) GetTodo(todo *model.Todo) (*model.Todo, error) {
	numTodoId, err := strconv.Atoi(todo.ID)
	if err != nil {
		return nil, errors.New("malformed todoId malformatted todoId")
	}

	statement, err := db.connection.Prepare("SELECT text, IS_done, FK_User_userId FROM Todo WHERE todoId = ?")
	if err != nil {
		return nil, err
	}

	todo.User = &model.User{} // TODO: check if this overrides something
	result := statement.QueryRow(numTodoId)
	if err := result.Scan(&todo.Text, &todo.Done, &todo.User.ID); err != nil {
		if err == sql.ErrNoRows {
			return nil, errors.New("invalid todo Id")
		}
		return nil, err
	}

	return todo, nil
}

// GetTodosFrom gets all todos from the passed *model.User. ID must be set.
func (db CustomDB) GetTodosFrom(user *model.User) ([]*model.Todo, error) {
	id, err := strconv.Atoi(user.ID)
	if err != nil {
		return nil, errors.New("malformed userId")
	}
	statement, err := db.connection.Prepare("SELECT todoId, text, IS_done FROM Todo WHERE FK_User_userId = ?")
	if err != nil {
		return nil, err
	}

	rows, err := statement.Query(id)
	if err != nil {
		return nil, err
	}

	defer rows.Close()

	var all []*model.Todo
	for rows.Next() {
		todo := model.Todo{User: user}
		if err := rows.Scan(&todo.ID, &todo.Text, &todo.Done); err != nil {
			return nil, err
		}
		all = append(all, &todo)
	}
	return all, nil
}

// GetAllTodos gets all todos from the database. Check if the source has the rights to call this.
func (db CustomDB) GetAllTodos() ([]*model.Todo, error) {
	rows, err := db.connection.Query("SELECT todoID, text, IS_done, FK_User_userID FROM Todo")
	if err != nil {
		return nil, err
	}

	defer rows.Close()

	var todos []*model.Todo
	for rows.Next() {
		var todo = model.Todo{User: &model.User{}}
		if err := rows.Scan(&todo.ID, &todo.Text, &todo.Done, &todo.User.ID); err != nil {
			return nil, err
		}
		todos = append(todos, &todo)
	}
	return todos, nil
}

// CreateTodo creates a Todo for the passed newTodo.UserID. Check if the source has the rights to call this.
func (db CustomDB) CreateTodo(newTodo model.NewTodo) (*model.Todo, error) {
	statement, err := db.connection.Prepare("INSERT INTO Todo (text, FK_User_userID) VALUES (?, ?)")
	if err != nil {
		return nil, err
	}

	rows, err := statement.Exec(newTodo.Text, newTodo.UserID)
	if err != nil {
		return nil, err
	}

	num, err := rows.RowsAffected()
	if err != nil {
		return nil, err
	}

	if num < 1 {
		return nil, errors.New("no rows affected")
	}

	insertId, err := rows.LastInsertId()
	if err != nil {
		return nil, err
	}
	return &model.Todo{ID: strconv.FormatInt(insertId, 10), Text: newTodo.Text, Done: false, User: &model.User{ID: newTodo.UserID}}, nil
}

func (db CustomDB) UpdateTodo(todoId string, changes *model.UpdateTodo) (*model.Todo, error) {

	numTodoId, err := strconv.Atoi(todoId)
	if err != nil {
		return nil, errors.New("malformed todoId")
	}

	statement, err := db.connection.Prepare("UPDATE Todo SET text = IFNULL(?, text), IS_done = IFNULL(?, IS_done) WHERE todoId = ?")
	if err != nil {
		return nil, err
	}

	rows, err := statement.Exec(changes.Text, changes.Done, numTodoId)
	if err != nil {
		return nil, err
	}

	num, err := rows.RowsAffected()
	if err != nil {
		return nil, err
	}

	if num < 1 {
		return nil, errors.New("no rows affected")
	}

	return db.GetTodo(&model.Todo{ID: todoId})
}

func (db CustomDB) DeleteTodo(todoId string) (deletedTodoId *string, err error) {
	numTodoId, err := strconv.Atoi(todoId)
	if err != nil {
		return nil, errors.New("malformed todoId")
	}

	statement, err := db.connection.Prepare("DELETE FROM Todo WHERE todoId = ?")
	if err != nil {
		return nil, err
	}

	rows, err := statement.Exec(numTodoId)
	if err != nil {
		return nil, err
	}

	num, err := rows.RowsAffected()
	if err != nil {
		return nil, err
	}

	if num < 1 {
		return nil, errors.New("no rows affected")
	}

	return &todoId, nil
}

// GetTodoOwner takes a *model.Todo with at least ID set and returns an *model.User with Id set to the todo's owner Id.
func (db CustomDB) GetTodoOwner(todo *model.Todo) (owner *model.User, err error) {
	numTodoId, err := strconv.Atoi(todo.ID)
	if err != nil {
		return nil, errors.New("malformed todoId")
	}

	statement, err := db.connection.Prepare("SELECT FK_User_userId FROM Todo WHERE todoId = ?")
	if err != nil {
		return nil, err
	}

	user := &model.User{} // TODO: check if this overrides something
	result := statement.QueryRow(numTodoId)
	if err := result.Scan(&user.ID); err != nil {
		if err == sql.ErrNoRows {
			return nil, errors.New("invalid todo Id")
		}
		return nil, err
	}

	return user, nil
}