<?php
	/**
	 * @package     Freemius
	 * @copyright   Copyright (c) 2015, Freemius, Inc.
	 * @license     https://www.gnu.org/licenses/gpl-3.0.html GNU General Public License Version 3
	 * @since       1.1.6
	 */

	if ( ! defined( 'ABSPATH' ) ) {
		exit;
	}

	class FS_Cache_Manager {
		/**
		 * @var FS_Option_Manager
		 */
		private $_options;
		/**
		 * @var FS_Logger
		 */
		private $_logger;

		/**
		 * @var FS_Cache_Manager[]
		 */
		private static $_MANAGERS = array();

		/**
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.3
		 *
		 * @param string $id
		 */
		private function __construct( $id ) {
			$this->_logger = FS_Logger::get_logger( WP_FS__SLUG . '_cach_mngr_' . $id, WP_FS__DEBUG_SDK, WP_FS__ECHO_DEBUG_SDK );

			$this->_logger->entrance();
			$this->_logger->log( 'id = ' . $id );

			$this->_options = FS_Option_Manager::get_manager( $id, true, true, false );
		}

		/**
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 *
		 * @param $id
		 *
		 * @return FS_Cache_Manager
		 */
		static function get_manager( $id ) {
			$id = strtolower( $id );

			if ( ! isset( self::$_MANAGERS[ $id ] ) ) {
				self::$_MANAGERS[ $id ] = new FS_Cache_Manager( $id );
			}

			return self::$_MANAGERS[ $id ];
		}

		/**
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 *
		 * @return bool
		 */
		function is_empty() {
			$this->_logger->entrance();

			return $this->_options->is_empty();
		}

		/**
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 */
		function clear() {
			$this->_logger->entrance();

			$this->_options->clear( true );
		}

		/**
		 * Delete cache manager from DB.
		 *
		 * @author Vova Feldman (@svovaf)
		 * @since  1.0.9
		 */
		function delete() {
			$this->_options->delete();
		}

		/**
		 * Check if there's a cached item.
		 *
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 *
		 * @param string $key
		 *
		 * @return bool
		 */
		function has( $key ) {
			$cache_entry = $this->_options->get_option( $key, false );

			return ( is_object( $cache_entry ) &&
					 isset( $cache_entry->timestamp ) &&
					 is_numeric( $cache_entry->timestamp )
			);
		}

		/**
		 * Check if there's a valid cached item.
		 *
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 *
		 * @param string   $key
		 * @param null|int $expiration Since 1.2.2.7
		 *
		 * @return bool
		 */
		function has_valid( $key, $expiration = null ) {
			$cache_entry = $this->_options->get_option( $key, false );

			$is_valid = ( is_object( $cache_entry ) &&
						  isset( $cache_entry->timestamp ) &&
						  is_numeric( $cache_entry->timestamp ) &&
						  $cache_entry->timestamp > WP_FS__SCRIPT_START_TIME
			);

			if ( $is_valid &&
				 is_numeric( $expiration ) &&
				 isset( $cache_entry->created ) &&
				 is_numeric( $cache_entry->created ) &&
				 $cache_entry->created + $expiration < WP_FS__SCRIPT_START_TIME
			) {
				/**
				 * Even if the cache is still valid, since we are checking for validity
				 * with an explicit expiration period, if the period has past, return
				 * `false` as if the cache is invalid.
				 *
				 * @since 1.2.2.7
				 */
				$is_valid = false;
			}

			return $is_valid;
		}

		/**
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 *
		 * @param string $key
		 * @param mixed  $default
		 *
		 * @return mixed
		 */
		function get( $key, $default = null ) {
			$this->_logger->entrance( 'key = ' . $key );

			$cache_entry = $this->_options->get_option( $key, false );

			if ( is_object( $cache_entry ) &&
				 isset( $cache_entry->timestamp ) &&
				 is_numeric( $cache_entry->timestamp )
			) {
				return $cache_entry->result;
			}

			return is_object( $default ) ? clone $default : $default;
		}

		/**
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 *
		 * @param string $key
		 * @param mixed  $default
		 *
		 * @return mixed
		 */
		function get_valid( $key, $default = null ) {
			$this->_logger->entrance( 'key = ' . $key );

			$cache_entry = $this->_options->get_option( $key, false );

			if ( is_object( $cache_entry ) &&
				 isset( $cache_entry->timestamp ) &&
				 is_numeric( $cache_entry->timestamp ) &&
				 $cache_entry->timestamp > WP_FS__SCRIPT_START_TIME
			) {
				return $cache_entry->result;
			}

			return is_object( $default ) ? clone $default : $default;
		}

		/**
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 *
		 * @param string $key
		 * @param mixed  $value
		 * @param int    $expiration
		 * @param int    $created Since 2.0.0 Cache creation date.
		 */
		function set( $key, $value, $expiration = WP_FS__TIME_24_HOURS_IN_SEC, $created = WP_FS__SCRIPT_START_TIME ) {
			$this->_logger->entrance( 'key = ' . $key );

			$cache_entry = new stdClass();

			$cache_entry->result    = $value;
			$cache_entry->created   = $created;
			$cache_entry->timestamp = $created + $expiration;
			$this->_options->set_option( $key, $cache_entry, true );
		}

		/**
		 * Get cached record expiration, or false if not cached or expired.
		 *
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.7.3
		 *
		 * @param string $key
		 *
		 * @return bool|int
		 */
		function get_record_expiration( $key ) {
			$this->_logger->entrance( 'key = ' . $key );

			$cache_entry = $this->_options->get_option( $key, false );

			if ( is_object( $cache_entry ) &&
				 isset( $cache_entry->timestamp ) &&
				 is_numeric( $cache_entry->timestamp ) &&
				 $cache_entry->timestamp > WP_FS__SCRIPT_START_TIME
			) {
				return $cache_entry->timestamp;
			}

			return false;
		}

		/**
		 * Purge cached item.
		 *
		 * @author Vova Feldman (@svovaf)
		 * @since  1.1.6
		 *
		 * @param string $key
		 */
		function purge( $key ) {
			$this->_logger->entrance( 'key = ' . $key );

			$this->_options->unset_option( $key, true );
		}

		/**
		 * Extend cached item caching period.
		 *
		 * @author Vova Feldman (@svovaf)
		 * @since  2.0.0
		 *
		 * @param string $key
		 * @param int    $expiration
		 *
		 * @return bool
		 */
		function update_expiration( $key, $expiration = WP_FS__TIME_24_HOURS_IN_SEC ) {
			$this->_logger->entrance( 'key = ' . $key );

			$cache_entry = $this->_options->get_option( $key, false );

			if ( ! is_object( $cache_entry ) ||
				 ! isset( $cache_entry->timestamp ) ||
				 ! is_numeric( $cache_entry->timestamp )
			) {
				return false;
			}

			$this->set( $key, $cache_entry->result, $expiration, $cache_entry->created );

			return true;
		}

		/**
		 * Set cached item as expired.
		 *
		 * @author Vova Feldman (@svovaf)
		 * @since  1.2.2.7
		 *
		 * @param string $key
		 */
		function expire( $key ) {
			$this->_logger->entrance( 'key = ' . $key );

			$cache_entry = $this->_options->get_option( $key, false );

			if ( is_object( $cache_entry ) &&
				 isset( $cache_entry->timestamp ) &&
				 is_numeric( $cache_entry->timestamp )
			) {
				// Set to expired.
				$cache_entry->timestamp = WP_FS__SCRIPT_START_TIME;
				$this->_options->set_option( $key, $cache_entry, true );
			}
		}

		#--------------------------------------------------------------------------------
		#region Migration
		#--------------------------------------------------------------------------------

		/**
		 * Migrate options from site level.
		 *
		 * @author Vova Feldman (@svovaf)
		 * @since  2.0.0
		 */
		function migrate_to_network() {
			$this->_options->migrate_to_network();
		}

		#endregion
	}