<?php



namespace LastFmApi\Lib;



/**

 * Stores the caching methods

 */



/**

 * Allows access to the caching methods to cache data when api calls are made

 */

class Cache

{



    /**

     * Stores the batabase class

     * @var class

     */

    private $db;



    /**

     * Stores the batabase type

     * @var string

     */

    private $type;



    /**

     * Stores the error details

     * @var array

     */

    public $error;



    /**

     * Stores the path to the sqlite database

     * @var string

     */

    private $path;



    /**

     * Stores the amount of time to cahce for

     * @var integer

     */

    private $cache_length;



    /**

     * Stores the config array

     * @var array

     */

    private $config;



    /**

     * States if caching is enabled or not

     * @var boolean

     */

    private $enabled;



    /**

     * Run when the class is created

     * @param array $config The config array

     * @uses lastfmApiDatabase

     */

    function __construct($config)

    {

        $this->config = $config;



        if (isset($this->config['cache_type'])) {

            $this->type = $this->config['cache_type'];

        } else {

            $this->type = 'sqlite';

        }



        $this->check_if_enabled();



        if ($this->enabled == true) {

            if ($this->type == 'sqlite') {

                $this->db = new Sqlite($this->config['path'] . '/phplastfmapi.sqlite3');

            } else {

                if (isset($this->config['database']['host']) && isset($this->config['database']['username']) && isset($this->config['database']['password']) && isset($this->config['database']['name'])) {

                    $this->db = new MySql($this->config['database']['host'], $this->config['database']['username'], $this->config['database']['password'], $this->config['database']['name']);

                } else {

                    $this->error = 'Not all mysql database variables were supplied';

                    return false;

                }

            }

            if (!empty($this->db->error)) {

                $this->error = $this->db->error;

                return false;

            } else {

                $this->check_table_exists();

            }

            //$this->show_all();

        }

    }



    /**

     * Internal method to chack if caching is enabled

     * @access private

     * @return void

     */

    private function check_if_enabled()

    {

        if ($this->config['enabled'] == true && extension_loaded('sqlite3')) {

            $this->enabled = true;

        } else {

            $this->enabled = false;

        }

    }



    /**

     * Internal method to check if the table exists

     * @access private

     * @return void

     */

    private function check_table_exists()

    {

        if ($this->type == 'sqlite') {

            $query = "SELECT count(*) FROM sqlite_master WHERE name='cache'";

            $result = $this->db->query($query);

            $numbers = $result->fetchAll();

            if ($numbers[0]['count(*)'] > 0) {

                // Ok

            } else {

                $this->create_table();

            }

        } else {

            $query = "show tables like 'cache'";

            $result = $this->db->query($query);

            if ($result->size() > 0) {

                // Ok

            } else {

                $this->create_table();

            }

        }

    }



    /**

     * Internal method to create the table if it doesn't exist

     * @access private

     * @return void

     */

    private function create_table()

    {

        if ($this->type == 'sqlite') {

            $auto_increase = '';

        } else {

            $auto_increase = ' AUTO_INCREMENT';

        }

        $query = "CREATE TABLE cache (cache_id INTEGER PRIMARY KEY" . $auto_increase . ", unique_vars TEXT, expires INT, body TEXT)";

        if ($this->db->query($query)) {

            // Ok

        } else {

            // TODO: Handle error

            echo $this->db->error;

        }

    }



    /**

     * Searches the database for the cahce date. Returns an array if it exists or false if it doesn't 

     * @access public

     * @param array $unique_vars Array of variables that are unique to this piece of cached data

     * @return string

     */

    public function get($unique_vars)

    {

        if ($this->enabled == true) {

            $query = "SELECT expires, body FROM cache WHERE unique_vars='" . htmlentities(serialize($unique_vars), ENT_QUOTES, 'UTF-8') . "' LIMIT 1";

            if ($result = $this->db->query($query)) {

                if ($result->size() > 0) {

                    $row = $result->fetch();

                    if ($row['expires'] < time()) {

                        $this->del($unique_vars);

                        return false;

                    } else {

                        //print_r(unserialize(html_entity_decode($row['body'], ENT_QUOTES, 'UTF-8')));

                        return unserialize(html_entity_decode($row['body'], ENT_QUOTES, 'UTF-8'));

                    }

                } else {

                    return false;

                }

            } else {

                // TODO: Handle error

                return false;

            }

        } else {

            return false;

        }

    }



    /**

     * Adds new cache data to the database

     * @access public

     * @param array $unique_vars Array of variables that are unique to this piece of cached data

     * @param string $body The contents of the cache to put into the database

     * @return boolean

     */

    public function set($unique_vars, $body)

    {

        if ($this->enabled == true) {

            $expire = time() + $this->config['cache_length'];

            $query = "INSERT INTO cache (unique_vars, expires, body) VALUES ('" . htmlentities(serialize($unique_vars), ENT_QUOTES, 'UTF-8') . "', '" . $expire . "', \"" . htmlentities(serialize($body), ENT_QUOTES, 'UTF-8') . "\")";

            if ($this->db->query($query)) {

                return true;

            } else {

                // TODO: Handle error

                return false;

            }

        } else {

            return false;

        }

    }



    /**

     * Internal method to delete unneeded cache data

     * @access private

     * @param array $unique_vars Array of variables that are unique to this piece of cached data

     * @return boolean

     */

    private function del($unique_vars)

    {

        $query = "DELETE FROM cache WHERE unique_vars='" . htmlentities(serialize($unique_vars), ENT_QUOTES, 'UTF-8') . "'";

        if ($this->db->query($query)) {

            return true;

        } else {

            // TODO: Handle error

            return false;

        }

    }



    /**

     * Internal method to show all cached data (used for debugging)

     * @access private

     * @return boolean

     */

    private function show_all()

    {

        $query = "SELECT expires, body FROM cache";

        if ($result = $this->db->query($query)) {

            if ($result->size() > 0) {

                $results = $result->fetchAll();

                echo '<pre>';

                print_r($results);

                echo '</pre>';

            } else {

                return false;

            }

        } else {

            // TODO: Handle error

            return false;

        }

    }



}