<?php

class User {

private $data;
private $errors;
public CONST FIELD_OPTION = [
    'user_login' => [
        'callback' => 'is_user_login_exists',
        'error_message' => 'is already exists',
        'response' => true
    ],
    'user_email' => [
        'callback' => 'is_email_exists',
        'error_message' => 'Email is already exists',
        'response' => true
    ],
    'user_pwd' => [
        'callback' => 'is_password_valid',
        'error_message' => 'Password is not valid',
        'response' => false
    ]
];

function __construct( array $data = [] ) {
    $this->dataParser( $data );
}

/**
 *
 */
public function get( array $filters = [] ) {

    $db = db();

    $query = $db->dsql()->table('users');

    if(!empty($filters) && is_array($filters)) {
        foreach($filters as $key) {
            try {
                $value = $this->getData($key, true);
                $query->where($key, $value);
            }

            catch(Exception $e) {
                $this->errors['data'][$key] = $e->getMessage();
            }

        }
    }

    return $query->get();

}

/**
 * Create new user
 */
public function create() {

    $db = db();

    $data = [
        'user_pwd' => $this->getData('user_pwd'),
        'user_login' => $this->getData('user_login'),
        'user_email' => $this->getData('user_email'),
        'user_name' => $this->getData('user_name')
    ];

    $query = $db->dsql()->table('users')->set($data);

    $insert = $query->insert();

    return $insert;

}

/**
 * Verifying all fields
 *
 * @param  mixed(bool on failire|null on success)    $fields
 */
public function vertify_fields( $requireds ) {

    if(is_string($requireds)) {
        $requireds = [$requireds];
    }

    if(!is_array($requireds)) {
        return false;
    }

    $fields = self::FIELD_OPTION;

    foreach( $requireds as $field_name ) {

        $field = $fields[$field_name];
        $value = $this->getData($field_name);
        if( empty($value) ) {
            $this->errors['fields'][$field_name] = 'This field is required';
            continue;
        }

        if($field['response'] === call_user_func_array($field['callback'],[$value])) {
            $this->errors['fields'][$field_name] = $field['error_message'];
        }

    }

}

public function identify() {
    /**
     * We identify user by :
     * @string $user_login
     * @string $user_pwd
     */
    $user_login = $this->getData('user_login');
    $user_pwd = $this->getData('user_pwd');

    $db  = db();

    $query = $db->dsql()->table('users')->where('user_login', $user_login)->limit(1);

    $user = $query->getRow();

    if(!$user) {
        return false;
    }

    $user_pwd_hash = $user['user_pwd'];
    return password_verify($user_pwd, $user_pwd_hash);

}

/**
 * Return mixed(null|array)
 */
public function get_errors() {
    return $this->errors;
}

/**
 * check if @prop $errors is null or not
 */
public function have_errors() : bool {
    return ($this->errors === null) ? false : true;
}

/**
 *
 * @param   mixed   $key
 * @return string
 */
private function getData( $key, bool $force = false ) {
    $value = $this->data->$key ?? null;
    if( $force && is_null($value) ) {
        throw new Exception($key . ' is missing');
    }

    return $value;

}

private function dataParser( array $data ) : void {
    $this->data = (object) $data;
}

}

function create_user_ajax() {

    $response = ['status' => 'error'];

    $User = new User($_POST);

    $User->vertify_fields(['user_email', 'user_login', 'user_pwd']);

    if($User->have_errors()) {
        $response['errors'] = $User->get_errors();
    }else{
        $User->create();
        $response['status'] = 'success';
    }

    echo json_encode($response);

}