<?php
// $Id: panels_everywhere.module,v 1.12 2010-08-20 23:26:31 merlinofchaos Exp $

/**
 * @file panels_everywhere.module
 *
 * This module overrides the page theme to allow Panels to be used on all pages.
 */

/**
 * Implementation of hook_menu().
 */
function panels_everywhere_menu() {
  $items = array();

  $items['admin/build/panels/settings/everywhere'] = array(
    'title' => 'Everywhere',
    'file' => 'panels_everywhere.admin.inc',
    'page callback' => 'drupal_get_form',
    'access arguments' => array('administer page manager'),
    'page arguments' => array('panels_everywhere_settings_page'),
    'type' => MENU_LOCAL_TASK,
  );
  if (variable_get('panels_everywhere_site_template_enabled', FALSE)) {
    $items['admin/build/pages/site_template'] = array(
      'title' => 'Edit site template',
      'page callback' => 'panels_everywhere_edit_site_template',
      'type' => MENU_LOCAL_TASK,
      'access arguments' => array('use page manager'),
    );
  }

  return $items;
}

/**
 * Implementation of hook_theme()
 */
function panels_everywhere_theme() {
  $theme = array();
  $path = drupal_get_path('module', 'panels_everywhere') . '/theme';
  $base = array(
    'file' => 'theme.inc',
    'path' => $path,
  );
  $theme['pane_header'] = array(
    'arguments' => array(),
    'template' => 'pane-header',
  ) + $base;
  $theme['pane_messages'] = array(
    'arguments' => array(),
    'template' => 'pane-messages',
  ) + $base;
  $theme['pane_navigation'] = array(
    'arguments' => array(),
    'template' => 'pane-navigation',
  ) + $base;

  return $theme;
}

/**
 * Implementation of hook_ctools_plugin_directory()
 */
function panels_everywhere_ctools_plugin_directory($module, $plugin) {
  if ($module == 'page_manager' || $module == 'ctools') {
    return 'plugins/' . $plugin;
  }
}

function panels_everywhere_should_override_theme() {
  if (!variable_get('panels_everywhere_override_page_tpl', FALSE))
    return FALSE;

  if (!variable_get('panels_everywhere_site_template_per_theme', FALSE))
    return TRUE;

  global $theme;
  return variable_get('panels_everywhere_override_theme_' . $theme, FALSE);
}

/**
 * Implementation of hook_theme_registry_alter()
 *
 * This is the magic of this module, which allows us to completely override
 * how pages are output.
 */
function panels_everywhere_theme_registry_alter($registry) {
  if (!panels_everywhere_should_override_theme())
    return;

  // Test to see if we should exclude the administrative theme.
  if (!variable_get('panels_everywhere_site_template_enabled_admin', FALSE)) {
    global $theme;
    $admin_theme = variable_get('admin_theme', '0');
    if ($admin_theme && $admin_theme == $theme) {
      return;
    }
  }

  $registry['original page'] = $registry['page'];
  // If we've been set to override the page template, we completely override it:
  $registry['page']['template'] = 'page';
  $registry['page']['type'] = 'module';
  $registry['page']['path'] = drupal_get_path('module', 'panels_everywhere') . '/theme';
  $registry['page']['theme path'] = $registry['page']['path'];
  $registry['page']['theme paths'] = array(
    drupal_get_path('module', 'system'),
    $registry['page']['path'],
  );
  $registry['page']['preprocess functions'] = array(
    'panels_everywhere_page_preprocess',
    'template_preprocess',
    'panels_everywhere_page_preprocess_elements',
  );

  // Let modules continue to do their thing
  foreach (module_implements('preprocess') as $module) {
    $registry['page']['preprocess functions'][] = $module . '_preprocess';
  }
  foreach (module_implements('preprocess_page') as $module) {
    if ($module != 'ctools') {
      $registry['page']['preprocess functions'][] = $module . '_preprocess_page';
    }
  }

  // CTools wants to be last
  $registry['page']['preprocess functions'][] = 'ctools_preprocess_page';
}

/**
 * Page preprocess to run the page content into our site template task.
 *
 * This is NOT named by the normal rules because this is not picked up
 * automatically. It is controlled by an alter so that it can come first.
 */
function panels_everywhere_page_preprocess(&$vars) {
  // For safety reasons, do not run this on the actual page configuration
  // pages and instead allow a more traditional output.
  if (strpos($_GET['q'], 'admin/build/pages/nojs/operation/site_template') === 0) {
    return panels_everywhere_fallback_page($vars);
  }
  if (strncmp($_GET['q'], 'admin/build/pages/site_template', 21) == 0) {
    return panels_everywhere_fallback_page($vars);
  }

  $task = page_manager_get_task('site_template');

  $content = new stdClass();
  $content->title = drupal_get_title();
  $content->content = $vars['content'];

  // Load the node into a context.
  ctools_include('context');
  ctools_include('context-task-handler');

  $page = page_manager_get_current_page();
  if (version_compare(CTOOLS_API_VERSION, 1.8, '<')) {
    $args = array($_GET['q'], $content, $page);
  }
  else {
    $args = array($content);
  }

  $contexts = ctools_context_handler_get_task_contexts($task, '', $args);

  // Test to see if a site template has been specifically assigned to the
  // current page. If so, render that variant just as though
  // it were rendered by the access checker.
  if ($handler_name = panels_everywhere_get_site_template()) {
    // This is the "no template" variant meaning we do absolutely nothing here.
    if ($handler_name == -1) {
      return;
    }

    $handler = page_manager_load_task_handler($task, '', $handler_name);
    if ($handler && ($function = page_manager_get_renderer($handler))) {
      // Render this with $test == FALSE to make it skip access checking.
      if ($info = $function($handler, $contexts, $args, FALSE)) {
        drupal_alter('ctools_render', $info, $page, $args, $contexts, $task, '', $handler);
      }
    }
  }

  // If there is no $info, meaning the above had no template or the template
  // chose not to render, go through the normal process for finding one.
  if (empty($info)) {
    // Since we're inside theme('page') we must call ctools_context_handler_render as though
    // we don't own the page, because crazy as it sounds, we don't.
    $info = ctools_context_handler_render($task, '', $contexts, $args, FALSE);
  }

  if ($info && !empty($info['content'])) {
    // Because we run so early, we have to use drupal_set_title() and not
    // just set $vars['title']. Otherwise it will get overwritten.
    if (isset($info['title'])) {
      drupal_set_title($info['title']);
    }
    $vars['content'] = $info['content'];
    if (!empty($info['no_blocks'])) {
      $vars['show_blocks'] = FALSE;
    }

    $vars['panels_everywhere_site_template'] = array(
      'name' => 'site_template',
      'task' => $task,
      'subtask' => '',
      'contexts' => $contexts,
      'arguments' => $args,
      'handler' => $info['handler'],
    );
  }
}

function panels_everywhere_fallback_page(&$vars) {
  if (!panels_everywhere_should_override_theme()) {
    print theme('original page', $vars['content'], $vars['show_blocks'], $vars['show_messages']);
    // There's no easy way to short circuit the rest of our processing, and
    // this is a pretty rare case anyway, so just do it.
    module_invoke_all('exit');
    exit;
  }
}

/**
 * Manually set the template to use.
 *
 * This can be used to force the page to use the specified template rather
 * than going through the access rules.
 *
 * @param $handler
 *   The name of the task handler to use.
 */
function panels_everywhere_set_site_template($handler) {
  $store = &ctools_static('panels_everywhere_site_template');
  $store = $handler;
}

/**
 * Get the site template to be used.
 *
 * If the site template has been manually set via
 * panels_everywhere_set_site_template(), this function will return what it
 * was set to.
 */
function panels_everywhere_get_site_template() {
  return ctools_static('panels_everywhere_site_template');
}

/**
 * Preprocess variables on our stripped down page template.
 *
 * Since when we take over the page rendering mechanism, we cut core's
 * page preprocessing out of the loop, we need to replace it with our
 * own stripped down version to do just the minimum.
 */
function panels_everywhere_page_preprocess_elements(&$variables) {
  // Add favicon
  if (theme_get_setting('toggle_favicon')) {
    drupal_set_html_head('<link rel="shortcut icon" href="'. check_url(theme_get_setting('favicon')) .'" type="image/x-icon" />');
  }

  // @todo add a settings form to control the following parts of this:
  // separator
  // use site name in title
  // use slogan in title
  // Construct page title

  $head_title = array();
  $page_title = drupal_get_title();
  if ($page_title) {
    $head_title[] = strip_tags($page_title);
  }

  if (variable_get('panels_everywhere_head_title_include_name', TRUE)) {
    $head_title[] = strip_tags(variable_get('site_name', 'Drupal'));
  }

  if (!$page_title && variable_get('panels_everywhere_head_title_include_slogan', TRUE)) {
    $head_title[] = strip_tags(variable_get('site_slogan', ''));
  }

  $variables['head_title']        = implode(variable_get('panels_everywhere_head_title_separator', ' | '), $head_title);
  $variables['base_path']         = base_path();
  $variables['front_page']        = url();
  $variables['head']              = drupal_get_html_head();
  $variables['css']               = drupal_add_css();
  $variables['styles']            = drupal_get_css();
  $variables['scripts']           = drupal_get_js();
  $variables['language']          = $GLOBALS['language'];
  $variables['language']->dir     = $GLOBALS['language']->direction ? 'rtl' : 'ltr';

  // Closure should be filled last.
  $variables['closure']           = theme('closure');
}

/**
 * Implementation of hook_ctools_plugin_api().
 */
function panels_everywhere_ctools_plugin_api($module, $api) {
  if (variable_get('panels_everywhere_provide_sample', FALSE) && $module == 'page_manager' && $api == 'pages_default') {
    return array('version' => 1);
  }
}

/**
 * Drupal has a bug that causes theme file includes to get lost. However,
 * it is really convenient to have preprocess functions separated out
 * so that they 1) don't load code when unnecessary and 2) are easy to
 * find for non-developers.
 *
 * Until this bug http://drupal.org/node/591804 is fixed, we must have
 * this include.
 */
function panels_everywhere_init() {
  ctools_include('theme', 'panels_everywhere', 'theme');
}

/**
 * Callback to edit our site template.
 *
 * This is just a pass-through that allows us to add a special tab to make
 * it easier to edit the site template.
 */
function panels_everywhere_edit_site_template() {
  ctools_include('context');
  ctools_include('page_manager.admin', 'page_manager', '');
  return page_manager_edit_page(page_manager_get_page_cache('site_template'));
}

/**
 * Alter the panel context settings form
 */
function panels_everywhere_page_manager_variant_operations_alter(&$operations, $handler) {
  // Do not add this to variants on the site template, as tempaltes
  // cannot select templates.
  if ($handler->task == 'site_template') {
    return;
  }

  // Use this obnoxious construct to safely insert our item.
  reset($operations['children']);
  $new = array();
  while (list($key, $value) = each($operations['children'])) {
    $new[$key] = $value;
    if ($key == 'summary') {
      $new['panels_everywhere'] = array(
        'title' => t('Template'),
        'description' => t('Choose which site template to use for this page.'),
        'form' => 'panels_everywhere_variant_template',
      );
    }
  }
  $operations['children'] = $new;
}

/**
 * Get a list of variants on the site template that can be used to select.
 */
function panels_everywhere_get_site_templates() {
  $task = page_manager_get_task('site_template');
  $handlers = page_manager_load_sorted_handlers($task, '');

  $templates = array();
  foreach ($handlers as $id => $handler) {
    $plugin = page_manager_get_task_handler($handler->handler);
    $templates[$id] = page_manager_get_handler_title($plugin, $handler, $task, '');
  }

  return $templates;
}

/**
 * Handle the form to add a template setting to any variant.
 */
function panels_everywhere_variant_template(&$form, &$form_state) {
  $handler = $form_state['handler'];
  $templates = panels_everywhere_get_site_templates();

  $defaults = array(
    '' => t('- Let the system choose -'),
    '-1' => t('- No template -'),
  );

  // We can use simple array addition because the default values are not valid
  // so no worries about collisions.

  $options = $defaults + $templates;
  if (empty($handler->conf['panels_everywhere_site_template'])) {
    $handler->conf['panels_everywhere_site_template'] = '';
  }

  $form['panels_everywhere_site_template'] = array(
    '#type' => 'select',
    '#title' => t('Site template'),
    '#default_value' => $handler->conf['panels_everywhere_site_template'],
    '#options' => $options,
  );
}

/**
 * Store the template for this page, if we have one.
 */
function panels_everywhere_variant_template_submit(&$form, &$form_state) {
  $form_state['handler']->conf['panels_everywhere_site_template'] = $form_state['values']['panels_everywhere_site_template'];
}

/**
 * When a Page Manager page is rendered, set the selected site template
 * if it has been chosen.
 */
function panels_everywhere_ctools_render_alter($info, $page, $args, $contexts, $task, $subtask, $handler) {
  if ($task['name'] == 'site_template') {
    // Make sure the handler actually used is available later on.
    $info['handler'] = $handler;
    return;
  }

  if (!empty($handler->conf['panels_everywhere_site_template'])) {
    panels_everywhere_set_site_template($handler->conf['panels_everywhere_site_template']);
  }
}