<?php
/**
 * @file
 *
 * This module provides support for "Profile Tabs" that can be added to
 * facebook pages (no longer allowed for user profiles).
 *
 * http://developers.facebook.com/docs/guides/canvas/#tabs
 *
 */
// hook_fb
define('FB_TAB_HOOK', 'fb_tab');

//// Hook_fb_tab operations
define('FB_TAB_OP_VIEW', 'fb_tab_view');
define('FB_TAB_OP_FORM', 'fb_tab_form');

define('FB_TAB_PATH_VIEW', 'fb_tab/view');
define('FB_TAB_PATH_FORM', 'fb_tab/config');
define('FB_TAB_PATH_FORM_ARGS', 2);

define('FB_TAB_VAR_PROCESS_FBML', 'fb_tab_process_fbml');
define('FB_TAB_VAR_PROCESS_IFRAME', 'fb_tab_process_iframe');
define('FB_TAB_VAR_PROCESS_ABSOLUTE', 'fb_tab_process_absolute_links');
define('FB_TAB_VAR_PROCESS_TO_CANVAS', 'fb_tab_process_to_canvas');

function fb_tab_menu() {
  $items = array();

  $items[FB_TAB_PATH_VIEW] = array(
    'page callback' => 'fb_tab_view',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items[FB_TAB_PATH_FORM] = array(
    'title' => 'Configure Tabs',
    'page callback' => 'fb_tab_pages',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items[FB_TAB_PATH_FORM . '/%'] = array(
    'page callback' => 'drupal_get_form',
    'page arguments' => array('fb_tab_config_form', FB_TAB_PATH_FORM_ARGS),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  // Admin pages
  $items[FB_PATH_ADMIN .'/fb_tab'] = array(
    'title' => 'Page Tabs',
    'description' => 'Configure Tabs',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('fb_tab_admin_settings'),
    'access arguments' => array(FB_PERM_ADMINISTER),
    'file' => 'fb_tab.admin.inc',
    'type' => MENU_LOCAL_TASK,
  );

  return $items;
}

/**
 * Implementation of hook_fb
 *
 * @param $op
 * @param $data -- data payload
 * @param $return
 */
function fb_tab_fb($op, $data, &$return) {
  $fb = isset($data['fb']) ? $data['fb'] : NULL;
  $fb_app = isset($data['fb_app']) ? $data['fb_app'] : NULL;

  if ($op == FB_OP_POST_INIT) {
    // Include our admin hooks.
    if (fb_is_fb_admin_page()) {
      require drupal_get_path('module', 'fb_tab') . '/fb_tab.admin.inc';
    }

    if (fb_is_tab()) {
      // Include our javascript.
      drupal_add_js(array(
                      'fb_tab' => array(
                        'fbu' => fb_facebook_user(),
                        'uid' => $GLOBALS['user']->uid,
                        'canvas' => $fb_app->canvas,
                      ),
                    ), 'setting');
      drupal_add_js(drupal_get_path('module', 'fb_tab') . '/fb_tab.js');
    }
  }
  elseif ($op == FB_OP_CURRENT_APP && fb_is_tab()) {
    if ($id = fb_settings(FB_SETTINGS_CB)) {
      // Using fb_url_rewrite.
      $fb_app = fb_get_app(array('id' => $id));

      if (!$fb_app) {
        // DEPRECATED.  For backward compatibility, accept apikey in FB_SETTINGS_CB
        $fb_app = fb_get_app(array('apikey' => $id));
      }

    }
    elseif ($id = fb_settings(FB_SETTINGS_ID)) {
      // New SDK includes ID when session is present.
      $fb_app = fb_get_app(array('id' => $id));
    }

    // Old, deprecated, FBML tabs.
    elseif (isset($_REQUEST['fb_sig_api_key'])) {
      $return = fb_get_app(array('apikey' => $_REQUEST['fb_sig_api_key']));
    }

    if ($fb_app) {
      $return = $fb_app;
    }
  }
  elseif ($op == FB_OP_INITIALIZE) {
    if (fb_is_tab()) {
      $config = _fb_tab_get_config($fb_app);
      if (!isset($GLOBALS['custom_theme'])) {
        $GLOBALS['custom_theme'] = $config['custom_theme'];
      }
      if (fb_settings(FB_SETTINGS_TYPE) == FB_SETTINGS_TYPE_PAGE_TAB &&
          variable_get(FB_TAB_VAR_PROCESS_IFRAME, TRUE)) {
        // Process iframe
        $use_ob = TRUE;
      }
      elseif (fb_settings(FB_SETTINGS_TYPE) == FB_SETTINGS_TYPE_PROFILE &&
          variable_get(FB_TAB_VAR_PROCESS_FBML, TRUE)) {
        // Process FBML
        $use_ob = TRUE;
      }
      else {
        $use_ob = FALSE;
      }

      // Hack to init the theme before _drupal_maintenance_theme initializes the wrong one.
      if (variable_get('site_offline', FALSE)) {
        $dummy = theme('dummy');
      }

      // Store entire page in output buffer.  Will post-process on exit.
      if ($use_ob) {
        ob_start();
        $GLOBALS['fb_tab_post_process'] = TRUE;
      }

    }
  }
  elseif ($op == FB_OP_EXIT && fb_is_tab()) {
    if (isset($GLOBALS['fb_tab_post_process']) && $GLOBALS['fb_tab_post_process']) {
      $output = ob_get_contents();
      ob_end_clean();
      include_once(drupal_get_path('module', 'fb') . '/fb.process.inc');

      if (variable_get(FB_TAB_VAR_PROCESS_TO_CANVAS, TRUE)) {
        $to_canvas = $fb_app->canvas;
      }
      else {
        $to_canvas = FALSE;
      }

      if (fb_settings(FB_SETTINGS_TYPE) == FB_SETTINGS_TYPE_PAGE_TAB) {
        // Process iframe
        $output = fb_process($output, array(
                               'add_target' => '_top',
                               'absolute_links' => TRUE,
                               'to_canvas' => $to_canvas,
                             ));
      }
      elseif (fb_settings(FB_SETTINGS_TYPE) == FB_SETTINGS_TYPE_PROFILE) {
        // Process FBML (deprecated)
        $output = fb_process($output, array(
                               'add_target' => FALSE,
                               'absolute_links' => TRUE,
                               'to_canvas' => $to_canvas,
                             ));
      }
      if (isset($output)) {
        print($output);
      }
    }
  }
}

/**
 * Implements fb_tab_form_alter.
 */
function fb_tab_form_alter(&$form, &$form_state, $form_id) {
  if (isset($form['fb_app_data']) && is_array($form['fb_app_data'])) {
    // Add our settings to the fb_app edit form.
    //require 'fb_canvas.admin.inc';
    fb_tab_admin_form_alter($form, $form_state, $form_id);
  }

  if (fb_is_tab()) {
    // Most Drupal forms have an action that assumes Drupal's base_path.
    // But in the case of FBML, we need to make it explicit.
    $form['#action'] = url($_GET['q'], array('absolute' => TRUE));
    //dpm(__FUNCTION__ . " changed action to " . $form['#action']);
  }
}

function _fb_tab_make_form_action_local($action = NULL) {
  global $base_path;

  if (!isset($action)) {
    // Is this ever reached?
    $action = $_GET['q'];
  }

  // If action is fully qualified, do not change it
  if (strpos($action, ':')) {
    return $action;
  }

  $relative = url('');
  $absolute = url('', array('absolute' => TRUE));
  $base_path = base_path(); // By default, '#action' will be request_uri(), which starts with base_path();
  global $_fb_app;

  if (strpos($action, $relative) === 0) {
    // If here, the action was made by call to url() and we prepended
    // canvas_name.  Now remove the canvas name for a proper absolute url.
    // (Comment forms reach this clause but node forms do not.)
    $action = substr($action, strlen($relative));
  }
  elseif ($base_path && strpos($action, $base_path) === 0) {
    $action = substr($action, strlen($base_path));
  }

  $action = url(ltrim($action, '/'), array('absolute' => TRUE));

  return $action;

}

/**
 * Helper returns configuration for this module, on a per-app basis.
 */
function _fb_tab_get_config($fb_app) {
  $fb_app_data = fb_get_app_data($fb_app);
  $config = isset($fb_app_data['fb_tab']) ? $fb_app_data['fb_tab'] : array();

  // Merge in defaults
  $config += array(
    'custom_theme' => NULL,
    'tab_default_name' => isset($fb_app->title) ? $fb_app->title : NULL,
    'profile_tab_url' => FB_TAB_PATH_VIEW,
  );
  return $config;
}

/**
 * Another module provides the contents of the tab depending
 * on the context that we give it (who is calling it, etc.)
 */
function fb_tab_view() {
  $fb_app = $GLOBALS['_fb_app'];
  $fb = $GLOBALS['_fb'];

  $profile_id = fb_settings(FB_SETTINGS_CB_PAGE);

  $config = fb_tab_fetch_config($fb_app, $profile_id);

  $data = array(
    'fb_app' => $fb_app,
    'fb' => $fb,
    'profile_id' => $profile_id,
    'config' => isset($config['data']) ? $config['data'] : NULL,
  );

  $content = fb_invoke(FB_TAB_OP_VIEW, $data, array(), FB_TAB_HOOK);

  return drupal_render($content);
}

/**
 * Build the tab config form.  Invokes hook_fb_tab() to get the custom settings.
 */
function fb_tab_config_form($form_state, $profile_id) {
  $fb_app = $GLOBALS['_fb_app'];
  $fb = $GLOBALS['_fb'];

  $config = fb_tab_fetch_config($fb_app, $profile_id);

  $data = array(
    'fb_app' => $fb_app,
    'fb' => $fb,
    'profile_id' => $profile_id,
    'config' => isset($config['data']) ? $config['data'] : NULL,
  );

  try {
    //$fbu = fb_facebook_user($fb);
    $fbu = fb_require_authorization($fb);
    $page_info = $fb->api($profile_id, array(
                            'access_token' => fb_get_token($fb),
                          ));
    $admin_info = fb_fql_query($fb, "SELECT uid, type FROM page_admin WHERE uid=$fbu AND page_id=$profile_id"); // FQL not SQL, no {curly_brackets}
    //dpm($admin_info, __FUNCTION__);

    // @TODO: if not page admin, prompt user to login or deny access.

    $form = array(
      'info' => array(
        '#type' => 'markup',
        '#value' => t('Tab settings for <a href="!href">%page</a>', array(
                        '!href' => $page_info['link'],
                        '%page' => $page_info['name'],
                      )),
        '#prefix' => '<h3>',
        '#suffix' => '</h3>',
        '#weight' => -99,
      ),
      'label' => array(
        '#type' => 'value',
        '#value' => $fb_app->label,
      ),
      'profile_id' => array(
        '#type' => 'value',
        '#value' => $profile_id,
      ),
      'data' => array(
        // Modules will add their fields here.
        '#tree' => TRUE,
      ),
      'submit' => array(
        '#type' => 'submit',
        '#value' => t('Submit'),
        '#weight' => 90,
      ),
    );

    if (isset($config['fb_tab_id'])) {
      $form['fb_tab_id'] = array(
        '#type' => 'value',
        '#value' => $config['fb_tab_id'],
      );
    }

    $form['data'] = fb_invoke(FB_TAB_OP_FORM, $data, $form['data'], FB_TAB_HOOK);

    //print('<pre>' . print_r($data, 1) . '</pre>'); flush();
    //print(print_r($content, 1)); flush();

    return $form;
  }
  catch (Exception $e) {
    fb_log_exception($e, t('Failed to get details for facebook page %profile_id', array(
                             '%profile_id' => $profile_id,
                           )));
    return array(
      'error' => array(
        '#value' => t('Unable to set properties.'),
      ),
    );
  }
}

/**
 * Submit handler for tab config form.
 */
function fb_tab_config_form_submit($form, &$form_state) {
  if ($profile_id = $form_state['values']['profile_id']) {
    fb_tab_write_config($form_state['values']);
    $data = fb_fql_query($GLOBALS['_fb'], "SELECT page_id, name, pic_small, page_url, type FROM page WHERE page_id=$profile_id"); // FQL, no {curly_brackets}
    drupal_set_message(t('The tab settings for <a href="!url">%page</a> have been updated.', array(
                           '!url' => $data[0]['page_url'],
                           '%page' => $data[0]['name'],
                         )));
  }
}

/*
 * Store configuration data for a tab by application.
 */
function fb_tab_write_config(&$row) {
  if (!isset($row['created']))
    $row['created'] = time();
  $row['data'] = serialize($row['data']);
  return drupal_write_record('fb_tab', $row,
                             isset($row['fb_tab_id']) ? array('fb_tab_id') : NULL);
}

/*
 * Return configuration of a tab by application (access via 'label') and page ID.
 * Page ID exists because an app can present different views on different pages.
 */
function fb_tab_fetch_config($fb_app, $profile_id) {
  $result = db_query("SELECT * FROM {fb_tab} WHERE label = '%s' AND profile_id = %d" , $fb_app->label, $profile_id);

  $row = db_fetch_array($result);
  if ($row) {
    $row['data'] = unserialize($row['data']);
    return $row;
  }
  else {
    return array();
  }
}

/**
 * This page callback will show the user a list of pages they have authority to configure.
 */
function fb_tab_pages() {
  if ($fbu = fb_facebook_user()) {
    $result = fb_fql_query($GLOBALS['_fb'], "SELECT page_id, name, pic_small, page_url, type FROM page WHERE has_added_app=1 AND page_id IN (SELECT page_id FROM page_admin WHERE uid=$fbu)"); // FQL, no {curly_brackets}
    //dpm($result, __FUNCTION__);
    if (count($result)) {
      $output['pages'] = array(
        '#prefix' => '<ul>',
        '#suffix' => '</ul>',
      );
      foreach ($result as $data) {
        $output['pages'][$data['page_id']] = array(
          '#value' => l($data['name'], fb_tab_config_url($data['page_id'], array('fb_canvas' => fb_is_canvas()))),
          '#prefix' => '<li>',
          '#suffix' => '</li>',
        );
      }
      $output['intro'] = array(
        '#value' => t('Select one of your pages to configure:'),
        '#prefix' => '<p>',
        '#suffix' => '</p>',
      );
    }
    else {
      $output['intro'] = array(
        '#value' => t('Found no pages to configure.'),
        '#prefix' => '<p>',
        '#suffix' => '</p>',
      );
    }
    return drupal_render($output);
  }
  else {
    fb_access_denied();
  }
}


/**
 * Provides the URL of the settings page for a given facebook page.
 */
function fb_tab_config_url($profile_id = NULL, $options = array()) {
  if (!$profile_id) {
    $profile_id = fb_settings(FB_SETTINGS_CB_PAGE);
  }
  return url(FB_TAB_PATH_FORM . '/' . $profile_id, $options);
}