/**
   *   Options Page and Input Validation for WPG3-Modules
   *
   *   Depends on WP-Settings Api
   *
   *    {@source}
   *
  **/
  public function wpg3_admin_init()
  {
    global $wp_rewrite;

    // MODULES register their options here
    $modules = array($this->get_module() );
    if($this->is_enabled){

      $xhttp = $this->get_module_instance('WPG3_Xhttp');
      array_push($modules, $xhttp->admin_init() );

      $template = $this->get_module_instance('WPG3_Template');
      array_push($modules, $template->admin_init() );
      /*
      $imagechoser = $this->get_module_instance('WPG3_Imagechoser');
      array_push($modules, $imagechoser->admin_init() );
      */
      if ( $wp_rewrite->using_permalinks() ){
        $gallerypage = $this->get_module_instance('WPG3_Rewrite');
        array_push($modules, $gallerypage->admin_init() );
      }
    }

    register_setting(
      'wpg3_options_grp', // settings group
      'wpg3_options', // settings
      array(&$this,'admin_validate_options') // fn to validate input
      );
    $page = 'wpg3_options_page';

    // load Settings API
    if (!function_exists('add_settings_section')){
      require_once(ABSPATH.'wp-admin/includes/template.php');
    }
    /* stores validation functions */
    $this->validate_fields = array();
    //  setting Option sections and fields
    foreach( $modules as $module){
      if ( $module ){
        add_settings_section( $module['unique_name'], $module['title'], $module['function'], $page);
        if( isset($module['settings_fields']) ){
          foreach($module['settings_fields'] as $field){
           add_settings_field($field['field_id'], $field['field_title'], $field['field_display'], $page, $module['unique_name']);
           if( isset($field['field_validate']) )$this->validate_fields[ $field['field_id'] ] = $field['field_validate'];
          }
        }
      }
    }
  }

/**
  *   get a module instance, load if required
  *
  *   {@source}
  *
  *   @param string Classname
  *   @return object instance
 **/
  public function get_module_instance($module, $override_options = false){
    $return = false;
    if (isset($this->modules[$module]) and !$override_options){
      $return = $this->modules[$module];
    }else{
      if (! isset($this->modules[$module])) $this->__autoload( $module );
      if ( $override_options){
        $this->wpg3_options = $override_options;
      }
      $instance = new $module( $this->wpg3_options );
      $this->modules[$module] = $instance;
      $return = $instance;
    }
   return $return;
  }

/**
  *   Create Options Page for WPG3
  *   @internal
 **/
  public function admin_add_page()
  {
    add_options_page(__('WPG3 Settings'),
                     __('WPG3'),
                     'manage_options',
                     __('WPG3'),
                     array(&$this,'admin_optins_page_fn')
                     );
  }

/**
  *   Echo Option Page
  *   @internal
 **/
  public function admin_optins_page_fn()
  {
    //echo "This is the admin_optins_page() ";
    echo "\n<div>\n";
    echo '<h2>'.__('WPG3 Settings')."</h2>\n";
    echo '<form action="options.php" method="post">'."\n";
    settings_fields('wpg3_options_grp'); // Group Name
    echo "\n";
    do_settings_sections('wpg3_options_page');
    echo "\n";
    echo '<p><input name="Submit" type="submit" value="'. __('Save Changes').'" /></p>'."\n";
    echo "</form>\n</div>\n";
  }

/**
  *   Validate Option Fields
  *
  *   @param array WP-secured Input from $_POST
  *   @return array Input validated
 **/
  public function admin_validate_options($input)
  {
    $wpg3_options = $this->wpg3_options;

    $validatable = array_intersect_key( $this->validate_fields,  $input);

    foreach ($validatable as $field => $function){
      $val = call_user_func ($function, $input[$field]);
      if( $val) $wpg3_options[$field] = $val;
   }
    return $wpg3_options;
  }		

/**
 *  Every Module can provide its own Options or return "false"
 *
**/
  private function get_module(){
     $main_mudule = array(
                // unique section ID
                'unique_name' =>'main_options',
                // visible Section Title
                'title' => __('Basic WPG3 Options'),
                // callback_fn displaying the Settings
                'function' => array( $this , 'admin_options_section_display' ),
                // FIELDS
                'settings_fields' => array(
                                        array(
                                        // unique ID
                                        'field_id' => 'g3Url',
                                        // field TITLE text
                                        'field_title' => __('Gallery3 Url'),
                                        // function CALLBACK, to display the input box
                                        'field_display' => array( $this , 'admin_options_section_display_g3Url'),
                                        // function CALLBACK validate field
                                        'field_validate' => array( $this , 'admin_options_section_validate_g3Url')
                                       ),
                                        array(
                                        // unique ID
                                        'field_id' => 'g3Resize',
                                        // field TITLE text
                                        'field_title' => __('Resize Options'),
                                        // function CALLBACK, to display the input box
                                        'field_display' => array( $this , 'admin_options_section_display_g3Resize'),
                                        // function CALLBACK validate field
                                        'field_validate' => array( $this , 'admin_options_section_validate_g3Resize')
                                       )
                               )
          );
    return $main_mudule;
  }

/**
 *  Section Header for Options Page
 *
**/
  public function admin_options_section_display()
  {?>
    <div style="width: 600px; margin-left: 10px;">

    <p>
       You must enable REST-Module in Gallery3 in Order to use WPG3.
    </p>
    </div>

<?php }

/**
 *  Options Page Output for "g3Resize"
 *
 *  @todo Pass the Width-param from WPG3-Tag to Template
**/
  public function admin_options_section_display_g3Resize()
  {
    $options = $this->wpg3_options; 

    $field_id = 'g3Resize';
    $val = isset($options[$field_id])? $options[$field_id] : array('max_thumb' => 100, 'max_resize' => 300) ;
    ?>
    <p style = "width:600px;">Gallery 2 <strong>offered custom Resizes</strong>. Gallery3 not yet.<br />
       You can chose which reize to use in WPG3 for the width parameter in WPGX-Tags<br />
       <strong>Note:</strong><em> The Numbered width paramater is available in the Template to adjust width by CSS.</em>
    </p>
    <table >
      <tr>
        <td style = "text-align: right;">Max pixel width<br />to use Thumb</td>
      <?php
        echo '<td><input id="'.$field_id.'[max_thumb]" name="wpg3_options['.$field_id.'][max_thumb]" size="10" type="text" value="'.$val['max_thumb'].'" /> px</td>'."\n";
        echo '<td style = "text-align: center;">Max pixel width<br />to use Medium</td>';
        echo '<td><input id="'.$field_id.'[max_resize]" name="wpg3_options['.$field_id.'][max_resize]" size="10" type="text" value="'.$val['max_resize'].'" /> px</td>'."\n";
      ?>
      <td>For higher width values<br />we use the Fullsize Image</td>
    </tr>
   </table>
   <p>According to this settings WPG3 will chose the
   'thumb', 'resize' or 'full' G3-Image to be inserted for a width parameter</p>
<?php
  }

/**
 *  Validation Page Validation for "g3Resize"
 *
**/
  public function admin_options_section_validate_g3Resize($field_val)
  {
   $return = isset($this->wpg3_options['g3Resize']) ? $this->wpg3_options['g3Resize'] : array('max_thumb' => 60, 'max_resize' => 500 );
    if ( is_array($field_val)){

      if ( intval( $field_val['max_thumb']) > 0  and intval( $field_val['max_resize'] ) > $field_val['max_thumb']){
        $return['max_thumb'] = $field_val['max_thumb'];
      }else{
      add_settings_error('g3Resize',
                         'settings_updated',
                         __('The Thumb width must be lower than the Medium width @ g3Resize<br /> You entered:<br /> max_thumb = '.$field_val['max_thumb'].'px<br />max_resize = '.$field_val['max_resize'].'px'));
      }
      if ( intval( $field_val['max_resize']) > 0 and $field_val['max_resize'] > $return['max_thumb'] ){
       $return['max_resize'] = $field_val['max_resize'];
      }
    }
    return $return;
  }

/**
 *  Options Page Output for "g3Url"
 *
**/
  public function admin_options_section_display_g3Url()
  { $field_id = 'g3Url';
    $options = $this->wpg3_options; // we should use data of $this !! ?>
    <p>The Url of you Gallery3 installation
       e.g. <strong>http://wpg3.local/gallery3/index.php</strong>
    </p>
    <?php
    $val = isset($options[$field_id])?$options[$field_id]:get_bloginfo('url').'/gallery3/index.php';
    !$this->is_enabled ? $enabled = ' style="color: red;" ': $enabled ='';
    echo '<input id="'.$field_id.'" name="wpg3_options['.$field_id.']" '.$enabled.'size="60" type="text" value="'.$val.'" />'."\n";
  }

/**
 *  Validate field "restReqestKey"
 *
 *  @todo validate g3Url against REST
**/
  public function admin_options_section_validate_g3Url($field_val)
  {
    $return = false;
    // validate input
    if ( preg_match('#^http\\:\\/\\/[a-z0-9\-]+\.([a-z0-9\-]+\.)?[a-z]+#i', $field_val)){
        if( substr( $field_val, -1 ) === "/" ) $field_val = substr ( $field_val, 0 , -1 );
        // unset REST API Key
        unset($this->wpg3_options['restReqestKey']);
        $return = $field_val;
    }else{
      // create a nice Error including you field_id
      add_settings_error('g3Url',
                         'settings_updated',
                         __('A valid Gallery3 Url is required @ g3Url<br /> You entered: "'.$field_val.'"'));
    }
    return $return;
  }

  private function __autoload($class_name) {
    include 'wpg3_class_'.$class_name . '.php';
  }
/**
 *  Get WPG3 Options
 *  @return array wpg3_options
**/
	public function get_options() {
    return $this->wpg3_options;
  }
/**
 *  WPG3 enabled?
 *  @return bool true/false
**/
  public function is_enabled($type){
    $return = false;
    if (isset($this->wpg3_options[$type]) and $this->wpg3_options[$type] == "enabled") $return = true;
    return $return;
  }

}// END class WPG3_Main

	add_action('init', array(&$wpg3, 'wpg3_init') );
	add_action('admin_init', array(&$wpg3, 'wpg3_admin_init') );
   /* Add options Page */
    add_action('admin_menu', array(&$wpg3, 'admin_add_page') );
  if($wpg3->is_enabled){
    add_filter('the_content', array(&$wpg3, 'wpg3_content_callback') );