<?php defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * Authorization_Token
 * ----------------------------------------------------------
 * API Token Generate/Validation
 * 
 * @author: Jeevan Lal
 * @version: 0.0.1
 */

require_once APPPATH . 'third_party/php-jwt/JWT.php';
require_once APPPATH . 'third_party/php-jwt/BeforeValidException.php';
require_once APPPATH . 'third_party/php-jwt/ExpiredException.php';
require_once APPPATH . 'third_party/php-jwt/SignatureInvalidException.php';

use \Firebase\JWT\JWT;

class Authorization_Token 
{
    /**
     * Token Key
     */
    protected $token_key;

    /**
     * Token algorithm
     */
    protected $token_algorithm;

    /**
     * Token Request Header Name
     */
    protected $token_header;

    /**
     * Token Expire Time
     */
    protected $token_expire_time; 


    public function __construct()
    {
        $this->CI =& get_instance();

        /** 
         * jwt config file load
         */
        $this->CI->load->config('jwt');

        /**
         * Load Config Items Values 
         */
        $this->token_key        = $this->CI->config->item('jwt_key');
        $this->token_algorithm  = $this->CI->config->item('jwt_algorithm');
        $this->token_header  = $this->CI->config->item('token_header');
        $this->token_expire_time  = $this->CI->config->item('token_expire_time');
    }

    /**
     * Generate Token
     * @param: {array} data
     */
    public function generateToken($data = null)
    {
        if ($data AND is_array($data))
        {
            // add api time key in user array()
            $data['API_TIME'] = time();

            try {
                return JWT::encode($data, $this->token_key, $this->token_algorithm);
            }
            catch(Exception $e) {
                return 'Message: ' .$e->getMessage();
            }
        } else {
            return "Token Data Undefined!";
        }
    }

    /**
     * Validate Token with Header
     * @return : user informations
     */
    public function validateToken($headers, $login = false)
    {
        /**
         * Check Session Login
         */
        if(!$this->session_exp($login)){
            return ['status' => FALSE, 'message' => 'Please try login again.'];
        }
        
        /**
         * Authorization Header Exists
         */
        $token_data = $this->tokenIsExist($headers);
        if($token_data['status'] === TRUE)
        {
            try
            {
                /**
                 * Token Decode
                 */
                try {
                    $token_decode = JWT::decode($token_data['token'], $this->token_key, array($this->token_algorithm));
                }
                catch(Exception $e) {
                    $this->session_exp($login);
                    return ['status' => FALSE, 'message' => $e->getMessage()];
                }

                if(!empty($token_decode) AND is_object($token_decode))
                {
                    // Check Token API Time [API_TIME]
                    if (empty($token_decode->API_TIME OR !is_numeric($token_decode->API_TIME))) {
                        $this->session_exp($login);
                        return ['status' => FALSE, 'message' => 'Token Time Not Define! Please try login again.'];
                    }
                    else
                    {
                        /**
                         * Check Token Time Valid 
                         */
                        $time_difference = strtotime('now') - $token_decode->API_TIME;
                        if( $time_difference >= $this->token_expire_time )
                        {
                            // remove session datas
                            $this->session_exp($login);
                            return ['status' => FALSE, 'message' => 'Token Time Expire! Please try login again.'];

                        }else
                        {
                            /**
                             * All Validation False Return Data
                             */
                            return ['status' => TRUE, 'data' => $token_decode];
                        }
                    }
                    
                }else{
                    // $this->session_exp($login);
                    return ['status' => FALSE, 'message' => 'Forbidden'];
                }
            }
            catch(Exception $e) {
                $this->session_exp($login);
                return ['status' => FALSE, 'message' => $e->getMessage().'! Please try login again.'];
            }
        }else
        {
            $this->session_exp($login);
            // Authorization Header Not Found!
            return ['status' => FALSE, 'message' => $token_data['message'].'! Please try login again.' ];
        }
    }

    private function session_exp($login){
        if ($login) {
            return true;
        }else{
           return false; 
       }


   }

    /**
     * Token Header Check
     * @param: request headers
     */
    private function tokenIsExist($headers)
    {
        if(!empty($headers) AND is_array($headers)) {
            foreach ($headers as $header_name => $header_value) {
                if (strtolower(trim($header_name)) == strtolower(trim($this->token_header)))
                    return ['status' => TRUE, 'token' => $header_value];
            }
        }
        return ['status' => FALSE, 'message' => 'Token is not defined.'];
    }
}