package main

import (
	"database/sql"

	"github.com/google/uuid"
	_ "github.com/mattn/go-sqlite3"
)

var DB *sql.DB

func initDB() error {
	db, err := sql.Open("sqlite3", "./db.sqlite")
	if err != nil {
		return err
	}
	DB = db
	err = createDatabase()
	if err != nil {
		return err
	}
	return nil
}

func createDatabase() error {
	sqlStatement := `
	CREATE TABLE IF NOT EXISTS users (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		username VARCHAR(255) NOT NULL,
		password VARCHAR(255) NOT NULL,
		uuid VARCHAR(255) NOT NULL,
		client_token VARCHAR(255) NOT NULL,
		auth_token VARCHAR(255) NOT NULL,
		created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
	);
	`
	_, err := DB.Exec(sqlStatement)
	if err != nil {
		return err
	}
	return nil
}

func insertUser(username string, password string) error {
	playeruuid := uuid.New().String()
	sqlStatement := `
	INSERT INTO users (username, password, uuid, client_token, auth_token) VALUES (?, ?, ?, ? ,?);
	`
	_, err := DB.Exec(sqlStatement, username, password, playeruuid, "", "")
	if err != nil {
		return err
	}
	return nil
}

func getAuthToken(username string, password string) (string, error) {
	sqlStatement := `
	SELECT auth_token FROM users WHERE username = ? AND password = ?;
	`
	rows, err := DB.Query(sqlStatement, username, password)
	if err != nil {
		return "", err
	}
	defer rows.Close()

	// check amount of rows
	if rows.Next() {
		// get auth token
		var authToken string
		rows.Scan(&authToken)
		rows.Close()
		if authToken == "" {
			// generate new authToken
			authToken = uuid.New().String()
			// update authToken
			sqlStatement := `
			UPDATE users SET auth_token = ? WHERE username = ? AND password = ?;
			`
			_, err := DB.Exec(sqlStatement, authToken, username, password)
			if err != nil {
				return "", err
			}
		}
		return authToken, nil
	} else {
		return "", &NotFoundError{}
	}
}

func checkClientToken(clientToken string, userName string) (string, error) {
	// assumes user is already logged in
	sqlStatement := `
	SELECT id FROM users WHERE client_token = ? AND username = ?;
	`
	rows, err := DB.Query(sqlStatement, clientToken, userName)
	if err != nil {
		return "", err
	}
	defer rows.Close()

	// check amount of rows
	if rows.Next() {
		return clientToken, nil
	} else {
		clientToken = uuid.New().String()
		sqlStatement := `
		UPDATE users SET client_token = ? WHERE username = ?;
		`
		_, err := DB.Exec(sqlStatement, clientToken, userName)
		if err != nil {
			return "", err
		}
		clearAuthToken(userName)
		return clientToken, nil
	}
}

func clearAuthToken(username string) error {
	// runs when user logs out
	sqlStatement := `
	UPDATE users SET auth_token = ? WHERE username = ?;
	`
	_, err := DB.Exec(sqlStatement, "", username)
	if err != nil {
		return err
	}
	return nil
}

// func insertAuthToken(authToken string, userName string) error {
// 	sqlStatement := `
// 	UPDATE users SET auth_token = ? WHERE username = ?;
// 	`
// 	_, err := DB.Exec(sqlStatement, authToken, userName)
// 	if err != nil {
// 		return err
// 	}
// 	return nil
// }

func createUser(username string, adminToken string) (string, error) {
	// check if adminToken is valid
	if validateAdminToken(adminToken) {
		password := uuid.New().String()
		insertUser(username, password)
		return password, nil
	} else {
		return "", &InvalidCredentialsError{}
	}
}

func getPlayerUUID(username string) (string, error) {
	sqlStatement := `
	SELECT uuid FROM users WHERE username = ?;
	`
	rows, err := DB.Query(sqlStatement, username)
	if err != nil {
		return "", err
	}
	defer rows.Close()

	// check amount of rows
	if rows.Next() {
		// get uuid
		var uuid string
		err = rows.Scan(&uuid)
		if err != nil {
			return "", err
		}
		return uuid, nil
	} else {
		return "", &NotFoundError{}
	}
}

func refreshTokens(refresh RefreshPayload) (RefreshPayload, error) {
	sqlStatement := `
	SELECT id FROM users WHERE auth_token = ? and client_token = ?;
	`
	rows, err := DB.Query(sqlStatement, refresh.AccessToken, refresh.ClientToken)
	if err != nil {
		return RefreshPayload{}, err
	}
	if rows.Next() {
		// get id
		var id int
		err = rows.Scan(&id)
		rows.Close()
		if err != nil {
			return RefreshPayload{}, err
		}
		// generate new authToken
		authToken := uuid.New().String()
		// update authToken
		sqlStatement := `
		UPDATE users SET auth_token = ? WHERE id = ?;
		`
		_, err := DB.Exec(sqlStatement, authToken, id)
		if err != nil {
			return RefreshPayload{}, err
		}
		// generate new clientToken
		clientToken := uuid.New().String()
		// update clientToken
		sqlStatement = `
		UPDATE users SET client_token = ? WHERE id = ?;
		`
		_, err = DB.Exec(sqlStatement, clientToken, id)
		if err != nil {
			return RefreshPayload{}, err
		}
		refresh.AccessToken = authToken
		refresh.ClientToken = clientToken
		return refresh, nil
	} else {
		return refresh, nil
	}
}

func validateTokens(authToken string, clientToken string) (bool, error) {
	sqlStatement := `
	SELECT id FROM users WHERE auth_token = ? and client_token = ?;
	`
	rows, err := DB.Query(sqlStatement, authToken, clientToken)
	if err != nil {
		return false, err
	}
	if rows.Next() {
		return true, nil
	} else {
		return false, nil
	}
}

func invalidateTokens(authToken string, clientToken string) error {
	sqlStatement := `
	UPDATE users SET auth_token = ?, client_token = ? WHERE auth_token = ? and client_token = ?;
	`
	_, err := DB.Exec(sqlStatement, "", "", authToken, clientToken)
	if err != nil {
		return err
	}
	return nil
}

func invalidateTokensWithLogin(username string, password string) error {
	sqlStatement := `
	UPDATE users SET auth_token = ?, client_token = ? WHERE username = ? AND password = ?;
	`
	_, err := DB.Exec(sqlStatement, "", "", username, password)
	if err != nil {
		return err
	}
	return nil
}