<?php

require_once(INCLUDE_DIR.'/class.config.php');
class PluginConfig extends Config {
    var $table = CONFIG_TABLE;
    var $form;

    function __construct($name) {
        // Use parent constructor to place configurable information into the
        // central config table in a namespace of "plugin.<id>"
        parent::Config("plugin.$name");
    }

    /* abstract */
    function getOptions() {
        return array();
    }

    /**
     * Retreive a Form instance for the configurable options offered in
     * ::getOptions
     */
    function getForm() {
        if (!isset($this->form)) {
            $this->form = new Form($this->getOptions());
            if ($_SERVER['REQUEST_METHOD'] != 'POST')
                $this->form->data($this->getInfo());
        }
        return $this->form;
    }

    /**
     * commit
     *
     * Used in the POST request of the configuration process. The
     * ::getForm() method should be used to retrieve a configuration form
     * for this plugin. That form should be submitted via a POST request,
     * and this method should be called in that request. The data from the
     * POST request will be interpreted and will adjust the configuration of
     * this field
     *
     * Parameters:
     * errors - (OUT array) receives validation errors of the parsed
     *      configuration form
     *
     * Returns:
     * (bool) true if the configuration was updated, false if there were
     * errors. If false, the errors were written into the received errors
     * array.
     */
    function commit(&$errors=array()) {
        $f = $this->getForm();
        $commit = false;
        if ($f->isValid()) {
            $config = $f->getClean();
            $commit = $this->pre_save($config, $errors);
        }
        $errors += $f->errors();
        if ($commit && count($errors) === 0)
            return $this->updateAll($config);
        return false;
    }

    /**
     * Pre-save hook to check configuration for errors (other than obvious
     * validation errors) prior to saving. Add an error to the errors list
     * or return boolean FALSE if the config commit should be aborted.
     */
    function pre_save($config, &$errors) {
        return true;
    }

    /**
     * Remove all configuration for this plugin -- used when the plugin is
     * uninstalled
     */
    function purge() {
        $sql = 'DELETE FROM '.$this->table
            .' WHERE `namespace`='.db_input($this->getNamespace());
        return (db_query($sql) && db_affected_rows());
    }
}

class PluginManager {
    static private $plugin_info = array();
    static private $plugin_list = array();

    /**
     * boostrap
     *
     * Used to bootstrap the plugin subsystem and initialize all the plugins
     * currently enabled.
     */
    function bootstrap() {
        foreach ($this->allActive() as $p)
            $p->bootstrap();
    }

    /**
     * allActive
     *
     * Scans the plugin registry to find all installed and active plugins.
     * Those plugins are included, instanciated, and cached in a list.
     *
     * Returns:
     * Array<Plugin> a cached list of instanciated plugins for all installed
     * and active plugins
     */
    static function allInstalled() {
        if (static::$plugin_list)
            return static::$plugin_list;

        $sql = 'SELECT * FROM '.PLUGIN_TABLE;
        if (!($res = db_query($sql)))
            return static::$plugin_list;

        while ($ht = db_fetch_array($res)) {
            // XXX: Only read active plugins here. allInfos() will
            //      read all plugins
            $info = static::getInfoForPath(
                INCLUDE_DIR . $ht['install_path'], $ht['isphar']);
            list($path, $class) = explode(':', $info['plugin']);
            if (!$class)
                $class = $path;
            elseif ($ht['isphar'])
                require_once('phar://' . INCLUDE_DIR . $ht['install_path']
                    . '/' . $path);
            else
                require_once(INCLUDE_DIR . $ht['install_path']
                    . '/' . $path);
            if ($ht['isactive']) {
                static::$plugin_list[$ht['install_path']]
                    = new $class($ht['id']);
            }
            else {
                // Get instance without calling the constructor. Thanks
                // http://stackoverflow.com/a/2556089
                $a = unserialize(
                    sprintf(
                        'O:%d:"%s":0:{}',
                        strlen($class), $class
                    )
                );
                // Simulate __construct() and load()
                $a->id = $ht['id'];
                $a->ht = $ht;
                $a->info = $info;
                static::$plugin_list[$ht['install_path']] = &$a;
                unset($a);
            }
        }
        return static::$plugin_list;
    }

    static function allActive() {
        $plugins = array();
        foreach (static::allInstalled() as $p)
            if ($p instanceof Plugin && $p->isActive())
                $plugins[] = $p;
        return $plugins;
    }

    function throwException($errno, $errstr) {
        throw new RuntimeException($errstr);
    }

    /**
     * allInfos
     *
     * Scans the plugin folders for installed plugins. For each one, the
     * plugin.php file is included and the info array returned in added to
     * the list returned.
     *
     * Returns:
     * Information about all available plugins. The registry will have to be
     * queried to determine if the plugin is installed
     */
    static function allInfos() {
        foreach (glob(INCLUDE_DIR . 'plugins/*',
                GLOB_NOSORT|GLOB_BRACE) as $p) {
            $is_phar = false;
            if (substr($p, strlen($p) - 5) == '.phar'
                    && Phar::isValidPharFilename($p)) {
                try {
                // When public key is invalid, openssl throws a
                // 'supplied key param cannot be coerced into a public key' warning
                // and phar ignores sig verification.
                // We need to protect from that by catching the warning
                // Thanks, https://github.com/koto/phar-util
                set_error_handler(array('self', 'throwException'));
                $ph = new Phar($p);
                restore_error_handler();
                // Verify the signature
                $ph->getSignature();
                $p = 'phar://' . $p;
                $is_phar = true;
                } catch (UnexpectedValueException $e) {
                    // Cannot find signature file
                } catch (RuntimeException $e) {
                    // Invalid signature file
                }

            }

            if (!is_file($p . '/plugin.php'))
                // Invalid plugin -- must define "/plugin.php"
                continue;

            // Cache the info into static::$plugin_info
            static::getInfoForPath($p, $is_phar);
        }
        return static::$plugin_info;
    }

    static function getInfoForPath($path, $is_phar=false) {
        static $defaults = array(
            'include' => 'include/',
            'stream' => false,
        );

        $install_path = str_replace(INCLUDE_DIR, '', $path);
        $install_path = str_replace('phar://', '', $install_path);
        if ($is_phar && substr($path, 0, 7) != 'phar://')
            $path = 'phar://' . $path;
        if (!isset(static::$plugin_info[$install_path])) {
            // plugin.php is require to return an array of informaiton about
            // the plugin.
            $info = array_merge($defaults, (include $path . '/plugin.php'));
            $info['install_path'] = $install_path;

            // XXX: Ensure 'id' key isset
            static::$plugin_info[$install_path] = $info;
        }
        return static::$plugin_info[$install_path];
    }

    function getInstance($path) {
        static $instances = array();
        if (!isset($instances[$path])
                && ($ps = static::allInstalled())
                && ($ht = $ps[$path])
                && ($info = static::getInfoForPath($path))) {
            // $ht may be the plugin instance
            if ($ht instanceof Plugin)
                return $ht;
            // Usually this happens when the plugin is being enabled
            list($path, $class) = explode(':', $info['plugin']);
            if (!$class)
                $class = $path;
            else
                require_once(INCLUDE_DIR . $info['install_path'] . '/' . $path);
            $instances[$path] = new $class($ht['id']);
        }
        return $instances[$path];
    }

    /**
     * install
     *
     * Used to install a plugin that is in-place on the filesystem, but not
     * registered in the plugin registry -- the %plugin table.
     */
    function install($path) {
        $is_phar = substr($path, strlen($path) - 5) == '.phar';
        if (!($info = $this->getInfoForPath(INCLUDE_DIR . $path, $is_phar)))
            return false;

        $sql='INSERT INTO '.PLUGIN_TABLE.' SET installed=NOW() '
            .', install_path='.db_input($path)
            .', name='.db_input($info['name'])
            .', isphar='.db_input($is_phar);
        if (!db_query($sql) || !db_affected_rows())
            return false;
        static::clearCache();
        return true;
    }

    static function clearCache() {
        static::$plugin_list = array();
    }
}

/**
 * Class: Plugin (abstract)
 *
 * Base class for plugins. Plugins should inherit from this class and define
 * the useful pieces of the
 */
class Plugin {
    /**
     * Configuration manager for the plugin. Should be the name of a class
     * that inherits from PluginConfig. This is abstract and must be defined
     * by the plugin subclass.
     */
    var $config_class = null;
    var $id;
    var $info;

    function Plugin($id) {
        $this->id = $id;
        $this->load();
    }

    function load() {
        $sql = 'SELECT * FROM '.PLUGIN_TABLE.' WHERE
            `id`='.db_input($this->id);
        if (($res = db_query($sql)) && ($ht=db_fetch_array($res)))
            $this->ht = $ht;
        $this->info = PluginManager::getInfoForPath($this->ht['install_path'],
            $this->isPhar());
    }

    function getId() { return $this->id; }
    function getName() { return $this->info['name']; }
    function isActive() { return $this->ht['isactive']; }
    function isPhar() { return $this->ht['isphar']; }
    function getInstallDate() { return $this->ht['installed']; }

    function getIncludePath() {
        return realpath(INCLUDE_DIR . $this->info['install_path'] . '/'
            . $this->info['include_path']) . '/';
    }

    /**
     * uninstall
     *
     * Removes the plugin from the plugin registry. The files remain on the
     * filesystem which would allow the plugin to be reinstalled. The
     * configuration for the plugin is also removed. If the plugin is
     * reinstalled, it will have to be reconfigured.
     */
    function uninstall() {
        if ($this->pre_uninstall() === false)
            return false;

        $sql = 'DELETE FROM '.PLUGIN_TABLE
            .' WHERE id='.db_input($this->getId());
        PluginManager::clearCache();
        if (db_query($sql) && db_affected_rows())
            return $this->getConfig()->purge();
        return false;
    }

    /**
     * pre_uninstall
     *
     * Hook function to veto the uninstallation request. Return boolean
     * FALSE if the uninstall operation should be aborted.
     * TODO: Recommend a location to stash an error message if aborting
     */
    function pre_uninstall() {
        return true;
    }

    function enable() {
        $sql = 'UPDATE '.PLUGIN_TABLE
            .' SET isactive=1 WHERE id='.db_input($this->getId());
        PluginManager::clearCache();
        return (db_query($sql) && db_affected_rows());
    }

    function disable() {
        $sql = 'UPDATE '.PLUGIN_TABLE
            .' SET isactive=0 WHERE id='.db_input($this->getId());
        PluginManager::clearCache();
        return (db_query($sql) && db_affected_rows());
    }

    /**
     * upgrade
     *
     * Upgrade the plugin. This is used to migrate the database pieces of
     * the plugin using the database migration stream packaged with the
     * plugin.
     */
    function upgrade() {
    }

    function getConfig() {
        static $config = null;
        if ($config === null && $this->config_class)
            $config = new $this->config_class($this->getId());

        return $config;
    }

    function source($what) {
        $what = str_replace('\\', '/', $what);
        if ($what && $what[0] != '/')
            $what = $this->getIncludePath() . $what;
        include_once $what;
    }

    static function lookup($id) { //Assuming local ID is the only lookup used!
        $path = false;
        if ($id && is_numeric($id)) {
            $sql = 'SELECT install_path FROM '.PLUGIN_TABLE
                .' WHERE id='.db_input($id);
            $path = db_result(db_query($sql));
        }
        if ($path)
           return PluginManager::getInstance($path);
    }
}

?>