<?php
namespace YTKNS;

use Exception;

class UserNotFoundException extends Exception {}
class UserCreationFailedException extends Exception {}
class UserCreationInvalidNameException extends Exception {}
class UserCreationInvalidPasswordException extends Exception {}
class UserCreationInvalidMailException extends Exception {}

class User {
    public function __construct() {
    }

    public function getId(): int {
        return $this->user_id ?? 0;
    }
    private function setId(int $userId): void {
        $this->user_id = $userId;
    }

    public function getUsername(): string {
        return $this->username ?? '';
    }

    public static function byId(int $userId): self {
        $getUser = DB::prepare('
            SELECT `user_id`, `username`, `email`, `password`, `user_created`
            FROM `ytkns_users`
            WHERE `user_id` = :user
        ');
        $getUser->bindValue('user', $userId);
        $getUser->execute();
        $user = $getUser->fetchObject(self::class);

        if($user === false)
            throw new UserNotFoundException;

        return $user;
    }

    public static function forLogin(string $usernameOrEmail): self {
        $getUser = DB::prepare('
            SELECT `user_id`, `username`, `email`, `password`, `user_created`
            FROM `ytkns_users`
            WHERE LOWER(`username`) = LOWER(:username)
            OR LOWER(`email`) = LOWER(:email)
        ');
        $getUser->bindValue('username', $usernameOrEmail);
        $getUser->bindValue('email', $usernameOrEmail);
        $getUser->execute();
        $user = $getUser->fetchObject(self::class);

        if($user === false)
            throw new UserNotFoundException;

        return $user;
    }

    public static function forProfile(string $username): self {
        $getUser = DB::prepare('
            SELECT `user_id`, `username`, `email`, `password`, `user_created`
            FROM `ytkns_users`
            WHERE LOWER(`username`) = LOWER(:username)
        ');
        $getUser->bindValue('username', $username);
        $getUser->execute();
        $user = $getUser->fetchObject(self::class);

        if($user === false)
            throw new UserNotFoundException;

        return $user;
    }

    public static function validatePassword(string $password): bool {
        $chars = [];
        $length = mb_strlen($password);

        for($i = 0; $i < $length; $i++) {
            $current = mb_substr($password, $i, 1);

            if(!in_array($current, $chars, true))
                $chars[] = $current;
        }

        return count($chars) >= 6;
    }

    public static function hashPassword(string $password): string {
        return password_hash($password, PASSWORD_ARGON2ID);
    }

    public static function create(string $userName, string $password, string $email): self {
        if(!preg_match('#^([a-zA-Z0-9-_]{1,20})$#', $userName))
            throw new UserCreationInvalidNameException;
        if(!filter_var($email, FILTER_VALIDATE_EMAIL))
            throw new UserCreationInvalidMailException;
        if(!self::validatePassword($password))
            throw new UserCreationInvalidPasswordException;

        $password = self::hashPassword($password);

        $createUser = DB::prepare('
            INSERT INTO `ytkns_users` (
                `username`, `email`, `password`
            ) VALUES (
                :username, :email, :password
            )
        ');
        $createUser->bindValue('username', $userName);
        $createUser->bindValue('email', $email);
        $createUser->bindValue('password', $password);
        $userId = $createUser->execute() ? (int)DB::lastInsertId() : 0;

        try {
            return self::byId($userId);
        } catch(UserNotFoundException $ex) {
            throw new UserCreationFailedException;
        }
    }
}