<?php

namespace Yatra\Core;

// Exit if accessed directly
defined('ABSPATH') || exit;

/**
 * Session Class
 *
 * @since 2.1.12
 */
class Session
{

    /**
     * Holds our session data.
     *
     * @var array
     * @access private
     * @since 2.1.12
     */
    private $session;

    /**
     * Whether to use PHP $_SESSION or WP_Session.
     *
     * @var bool
     * @access private
     * @since 2.1.12
     */
    private $use_php_sessions = false;

    /**
     * Session index prefix
     *
     * @var string
     * @access private
     * @since 2.1.12
     */
    private $prefix = '';

    /**
     * Constructor.
     *
     * Defines our WP_Session constants, includes the necessary libraries and
     * retrieves the WP Session instance.
     *
     * @since 2.1.12
     */
    public function __construct()
    {
        $this->use_php_sessions = $this->use_php_sessions();

        if ($this->use_php_sessions) {
            if (is_multisite()) {
                $this->prefix = '_' . get_current_blog_id();
            }

            // Use PHP SESSION (must be enabled via the YATRA_USE_PHP_SESSIONS constant)
            add_action('init', array($this, 'maybe_start_session'), -2);
        } else {
            if (!$this->should_start_session()) {
                return;
            }

            // Use WP_Session (default)
            if (!defined('WP_SESSION_COOKIE')) {
                define('WP_SESSION_COOKIE', 'yatra_wp_session');
            }

            if (!class_exists('Recursive_ArrayAccess')) {
                require_once YATRA_ABSPATH . 'core/Libraries/class-recursive-arrayaccess.php';
            }

            if (!class_exists('WP_Session')) {
                require_once YATRA_ABSPATH . 'core/Libraries/class-wp-session.php';
                require_once YATRA_ABSPATH . 'core/Libraries/wp-session.php';
            }

            add_filter('wp_session_expiration_variant', array($this, 'set_expiration_variant_time'), 99999);
            add_filter('wp_session_expiration', array($this, 'set_expiration_time'), 99999);
        }

        // Based off our session handling, we need to use different hooks and priorities.
        if (empty($this->session) && !$this->use_php_sessions) {
            $hook = 'plugins_loaded';
            $priority = 10;
        } else {
            $hook = 'init';
            $priority = -1;
        }

        add_action($hook, array($this, 'init'), $priority);
    }

    /**
     * Setup the WP_Session instance.
     *
     * @since 2.1.12
     */
    public function init()
    {
        if ($this->use_php_sessions) {
            $key = 'yatra' . $this->prefix;
            $this->session = isset($_SESSION[$key]) && is_array($_SESSION[$key])
                ? $_SESSION[$key]
                : array();
        } else {
            $this->session = \WP_Session::get_instance();
        }

        $use_cookie = $this->use_cart_cookie();
        $cart = $this->get('yatra_tour_cart');
        $purchase = $this->get('yatra_tour_purchase');

        if ($use_cookie) {
            if (!empty($cart) || !empty($purchase)) {
                $this->set_cart_cookie();
            } else {
                $this->set_cart_cookie(false);
            }
        }

        return $this->session;
    }

    /**
     * Retrieve session ID.
     *
     * @return string Session ID
     * @since 2.1.12
     *
     */
    public function get_id()
    {
        return $this->session->session_id;
    }

    /**
     * Retrieve a session variable.
     *
     * @param string $key Session key.
     * @return mixed Session variable.
     * @since 2.1.12
     *
     */
    public function get($key)
    {
        $key = sanitize_key($key);
        $return = false;

        if (isset($this->session[$key]) && !empty($this->session[$key])) {
            preg_match('/[oO]\s*:\s*\d+\s*:\s*"\s*(?!(?i)(stdClass))/', $this->session[$key], $matches);

            if (!empty($matches)) {
                $this->set($key, null);
                return false;
            }
            if (is_numeric($this->session[$key])) {
                $return = $this->session[$key];
            } else {
                $maybe_json = json_decode($this->session[$key]);

                // Since json_last_error is PHP 5.3+, we have to rely on a `null` value for failing to parse JSON.
                if (is_null($maybe_json)) {
                    $is_serialized = is_serialized($this->session[$key]);
                    if ($is_serialized) {
                        $value = @unserialize($this->session[$key]);
                        $this->set($key, (array)$value);
                        $return = $value;
                    } else {
                        $return = $this->session[$key];
                    }
                } else {
                    $return = json_decode($this->session[$key], true);
                }
            }

        }


        return $return;
    }

    /**
     * Set a session variable.
     *
     * @param string $key Session key.
     * @param int|string|array $value Session variable.
     *
     * @return mixed Session variable
     * @since 2.1.12
     *
     */
    public function set($key, $value)
    {
        $key = sanitize_key($key);

        if (is_array($value)) {
            $this->session[$key] = wp_json_encode($value);
        } else {
            $this->session[$key] = esc_attr($value);
        }

        if ($this->use_php_sessions) {
            $_SESSION['yatra' . $this->prefix] = $this->session;
        }

        return $this->session[$key];
    }

    /**
     * Set a cookie to identify whether the cart is empty or not.
     *
     * This is for hosts and caching plugins to identify if caching should be disabled.
     *
     * @param bool $set Whether to set or destroy. Default true.
     * @since 2.1.12
     *
     */
    public function set_cart_cookie($set = true)
    {

        // Bail if headers already sent.
        if (headers_sent()) {
            return;
        }

        if ($set) {
            @setcookie('yatra_items_in_cart', '1', time() + 30 * 60, COOKIEPATH, COOKIE_DOMAIN, is_ssl());
        } elseif (isset($_COOKIE['yatra_items_in_cart'])) {
            @setcookie('yatra_items_in_cart', '', time() - 3600, COOKIEPATH, COOKIE_DOMAIN, is_ssl());
        }
    }

    /**
     * Force the cookie expiration variant time to 23 hours.
     *
     * @param int $exp Default expiration (1 hour).
     * @return int Cookie expiration variant time.
     * @since 2.1.12
     *
     */
    public function set_expiration_variant_time($exp = 1)
    {
        return HOUR_IN_SECONDS * 23;
    }

    /**
     * Force the cookie expiration time to 24 hours.
     *
     * @param int $exp Default expiration (1 hour).
     * @return int Cookie expiration time.
     * @since 2.1.12
     *
     */
    public function set_expiration_time($exp = 1)
    {
        return HOUR_IN_SECONDS * 24;
    }

    /**
     * Starts a new session if one hasn't started yet.
     *
     * Checks to see if the server supports PHP sessions
     * or if the YATRA_USE_PHP_SESSIONS constant is defined
     *
     * @return bool $ret True if we are using PHP sessions, false otherwise.
     * @since 2.1.12
     */
    public function use_php_sessions()
    {

        // Set default return value to false.
        $ret = false;

        // If the database variable is already set, no need to run autodetection.
        $yatra_use_php_sessions = (bool)get_option('yatra_use_php_sessions');

        if (!$yatra_use_php_sessions) {

            // Attempt to detect if the server supports PHP sessions
            if (function_exists('session_start')) {
                $this->set('yatra_use_php_sessions', 1);

                if ($this->get('yatra_use_php_sessions')) {
                    $ret = true;

                    // Set the database option
                    update_option('yatra_use_php_sessions', true);
                }
            }
        } else {
            $ret = $yatra_use_php_sessions;
        }

        // Enable or disable PHP Sessions based on the YATRA_USE_PHP_SESSIONS constant.
        if (defined('YATRA_USE_PHP_SESSIONS') && YATRA_USE_PHP_SESSIONS) {
            $ret = true;
        } else if (defined('YATRA_USE_PHP_SESSIONS') && !YATRA_USE_PHP_SESSIONS) {
            $ret = false;
        }

        // Filter & return.
        return (bool)apply_filters('yatra_use_php_sessions', $ret);
    }

    /**
     * Determines if a user has set the YATRA_USE_CART_COOKIE.
     *
     * @return bool If the store should use the yatra_items_in_cart cookie to help avoid caching
     * @since 2.1.12
     *
     */
    public function use_cart_cookie()
    {

        // Set default return value to true.
        $ret = true;

        if (defined('YATRA_USE_CART_COOKIE') && !YATRA_USE_CART_COOKIE) {
            $ret = false;
        }

        // Filter & return.
        return (bool)apply_filters('yatra_use_cart_cookie', $ret);
    }

    /**
     * Determines if we should start sessions.
     *
     * @return bool True if sessions should start, false otherwise.
     * @since 2.1.12
     *
     */
    public function should_start_session()
    {

        // Set default return value to true.
        $start_session = true;

        if (!empty($_SERVER['REQUEST_URI'])) {
            $blacklist = $this->get_blacklist();
            $uri = ltrim($_SERVER['REQUEST_URI'], '/');
            $uri = untrailingslashit($uri);

            if (in_array($uri, $blacklist, true)) {
                $start_session = false;
            }

            if (false !== strpos($uri, 'feed=')) {
                $start_session = false;
            }

            // We do not want to start sessions in the admin unless we're processing an ajax request.
            if (is_admin() && false === strpos($uri, 'wp-admin/admin-ajax.php')) {
                $start_session = false;
            }

            // Starting sessions while saving the file editor can break the save process, so don't start.
            if (false !== strpos($uri, 'wp_scrape_key')) {
                $start_session = false;
            }
        }

        // Filter & return.
        return (bool)apply_filters('yatra_start_session', $start_session);
    }

    /**
     * Retrieve the URI blacklist.
     *
     * These are the URIs where we never start sessions.
     *
     * @return array URI blacklist.
     * @since 2.1.12
     *
     */
    public function get_blacklist()
    {
        $blacklist = apply_filters('yatra_session_start_uri_blacklist', array(
            'feed',
            'feed/rss',
            'feed/rss2',
            'feed/rdf',
            'feed/atom',
            'comments/feed'
        ));

        // Look to see if WordPress is in a sub folder or this is a network site that uses sub folders
        $folder = str_replace(network_home_url(), '', get_site_url());

        if (!empty($folder)) {
            foreach ($blacklist as $path) {
                $blacklist[] = $folder . '/' . $path;
            }
        }

        return $blacklist;
    }

    /**
     * Starts a new session if one hasn't started yet.
     *
     * @since 2.1.12
     */
    public function maybe_start_session()
    {

        // Bail if should not start session.
        if (!$this->should_start_session()) {
            return;
        }

        // Bail if headers already sent.
        if (headers_sent()) {
            return;
        }

        // Start if old version of PHP & no session ID exists.
        if (version_compare(PHP_VERSION, '5.4', '<') && !session_id()) {
            session_start();

            // Start if modern PHP and session-status is not active.
        } elseif (defined('PHP_SESSION_ACTIVE') && (session_status() !== PHP_SESSION_ACTIVE)) {
            session_start();
        }
    }
}