<?php
/**
 * PEAR_Frontend, the singleton-based frontend for user input/output
 *
 * PHP versions 4 and 5
 *
 * @category   pear
 * @package    PEAR
 * @author     Greg Beaver <cellog@php.net>
 * @copyright  1997-2009 The Authors
 * @license    http://opensource.org/licenses/bsd-license.php New BSD License
 * @version    CVS: $Id: Frontend.php 276383 2009-02-24 23:39:37Z dufuz $
 * @link       http://pear.php.net/package/PEAR
 * @since      File available since Release 1.4.0a1
 */

/**
 * Include error handling
 */
//require_once 'PEAR.php';

/**
 * Which user interface class is being used.
 * @var string class name
 */
$GLOBALS['_PEAR_FRONTEND_CLASS'] = 'PEAR_Frontend_CLI';

/**
 * Instance of $_PEAR_Command_uiclass.
 * @var object
 */
$GLOBALS['_PEAR_FRONTEND_SINGLETON'] = null;

/**
 * Singleton-based frontend for PEAR user input/output
 *
 * @category   pear
 * @package    PEAR
 * @author     Greg Beaver <cellog@php.net>
 * @copyright  1997-2009 The Authors
 * @license    http://opensource.org/licenses/bsd-license.php New BSD License
 * @version    Release: 1.9.0
 * @link       http://pear.php.net/package/PEAR
 * @since      Class available since Release 1.4.0a1
 */
class PEAR_Frontend extends PEAR
{
    /**
     * Retrieve the frontend object
     * @return PEAR_Frontend_CLI|PEAR_Frontend_Web|PEAR_Frontend_Gtk
     * @static
     */
    function &singleton($type = null)
    {
        if ($type === null) {
            if (!isset($GLOBALS['_PEAR_FRONTEND_SINGLETON'])) {
                $a = false;
                return $a;
            }
            return $GLOBALS['_PEAR_FRONTEND_SINGLETON'];
        }

        $a = PEAR_Frontend::setFrontendClass($type);
        return $a;
    }

    /**
     * Set the frontend class that will be used by calls to {@link singleton()}
     *
     * Frontends are expected to conform to the PEAR naming standard of
     * _ => DIRECTORY_SEPARATOR (PEAR_Frontend_CLI is in PEAR/Frontend/CLI.php)
     * @param string $uiclass full class name
     * @return PEAR_Frontend
     * @static
     */
    function &setFrontendClass($uiclass)
    {
        if (is_object($GLOBALS['_PEAR_FRONTEND_SINGLETON']) &&
              is_a($GLOBALS['_PEAR_FRONTEND_SINGLETON'], $uiclass)) {
            return $GLOBALS['_PEAR_FRONTEND_SINGLETON'];
        }

        if (!class_exists($uiclass)) {
            $file = str_replace('_', '/', $uiclass) . '.php';
            if (PEAR_Frontend::isIncludeable($file)) {
                include_once $file;
            }
        }

        if (class_exists($uiclass)) {
            $obj = new $uiclass;
            // quick test to see if this class implements a few of the most
            // important frontend methods
            if (is_a($obj, 'PEAR_Frontend')) {
                $GLOBALS['_PEAR_FRONTEND_SINGLETON'] = &$obj;
                $GLOBALS['_PEAR_FRONTEND_CLASS'] = $uiclass;
                return $obj;
            }

            $err = PEAR::raiseError("not a frontend class: $uiclass");
            return $err;
        }

        $err = PEAR::raiseError("no such class: $uiclass");
        return $err;
    }

    /**
     * Set the frontend class that will be used by calls to {@link singleton()}
     *
     * Frontends are expected to be a descendant of PEAR_Frontend
     * @param PEAR_Frontend
     * @return PEAR_Frontend
     * @static
     */
    function &setFrontendObject($uiobject)
    {
        if (is_object($GLOBALS['_PEAR_FRONTEND_SINGLETON']) &&
              is_a($GLOBALS['_PEAR_FRONTEND_SINGLETON'], get_class($uiobject))) {
            return $GLOBALS['_PEAR_FRONTEND_SINGLETON'];
        }

        if (!is_a($uiobject, 'PEAR_Frontend')) {
            $err = PEAR::raiseError('not a valid frontend class: (' .
                get_class($uiobject) . ')');
            return $err;
        }

        $GLOBALS['_PEAR_FRONTEND_SINGLETON'] = &$uiobject;
        $GLOBALS['_PEAR_FRONTEND_CLASS'] = get_class($uiobject);
        return $uiobject;
    }

    /**
     * @param string $path relative or absolute include path
     * @return boolean
     * @static
     */
    function isIncludeable($path)
    {
        if (file_exists($path) && is_readable($path)) {
            return true;
        }

        $fp = @fopen($path, 'r', true);
        if ($fp) {
            fclose($fp);
            return true;
        }

        return false;
    }

    /**
     * @param PEAR_Config
     */
    function setConfig(&$config)
    {
    }

    /**
     * This can be overridden to allow session-based temporary file management
     *
     * By default, all files are deleted at the end of a session.  The web installer
     * needs to be able to sustain a list over many sessions in order to support
     * user interaction with install scripts
     */
    function addTempFile($file)
    {
        $GLOBALS['_PEAR_Common_tempfiles'][] = $file;
    }

    /**
     * Log an action
     *
     * @param string $msg the message to log
     * @param boolean $append_crlf
     * @return boolean true
     * @abstract
     */
    function log($msg, $append_crlf = true)
    {
    }

    /**
     * Run a post-installation script
     *
     * @param array $scripts array of post-install scripts
     * @abstract
     */
    function runPostinstallScripts(&$scripts)
    {
    }

    /**
     * Display human-friendly output formatted depending on the
     * $command parameter.
     *
     * This should be able to handle basic output data with no command
     * @param mixed  $data    data structure containing the information to display
     * @param string $command command from which this method was called
     * @abstract
     */
    function outputData($data, $command = '_default')
    {
    }

    /**
     * Display a modal form dialog and return the given input
     *
     * A frontend that requires multiple requests to retrieve and process
     * data must take these needs into account, and implement the request
     * handling code.
     * @param string $command  command from which this method was called
     * @param array  $prompts  associative array. keys are the input field names
     *                         and values are the description
     * @param array  $types    array of input field types (text, password,
     *                         etc.) keys have to be the same like in $prompts
     * @param array  $defaults array of default values. again keys have
     *                         to be the same like in $prompts.  Do not depend
     *                         on a default value being set.
     * @return array input sent by the user
     * @abstract
     */
    function userDialog($command, $prompts, $types = array(), $defaults = array())
    {
    }
}
