<?php
// $Id: panels_everywhere.module,v 1.12.2.3 2010-11-09 19:36:34 merlinofchaos Exp $

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

// ---------------------------------------------------------------------------
// Core hooks

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

  $items['admin/structure/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/structure/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;
}

/**
 * Implement 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(
    'variables' => array(),
    'template' => 'pane-header',
  ) + $base;
  $theme['pane_messages'] = array(
    'variables' => array(),
    'template' => 'pane-messages',
  ) + $base;
  $theme['pane_navigation'] = array(
    'variables' => array(),
    'template' => 'pane-navigation',
  ) + $base;

  // Our alternative to theme('page').
  $theme['panels_everywhere_page'] = array(
    'render element' => 'page',
  ) + $base;

  return $theme;
}

/**
 * Impleme 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_page_build(&$page) {
  if (!panels_everywhere_should_override()) {
    return;
  }

  $task = page_manager_get_task('site_template');

  // Test to see if something has specified that we use a specific
  // template on this page.
  if ($handler_name = panels_everywhere_get_site_template()) {
    $handler = page_manager_load_task_handler($task, '', $handler_name);
  }

  // If not, ask.
  if (empty($handler)) {
    $handlers = page_manager_load_sorted_handlers($task, '', TRUE);

    // If there are no handlers, don't bother.
    if (!$handlers) {
      return;
    }

    ctools_include('context');
    ctools_include('context-task-handler');

    // Normally the args contain the page content, but since this is just
    // choosing the handler not actually rendering it, we'll leave that
    // blank and let the page content be added later.
    $args = array('');
    $contexts = ctools_context_handler_get_task_contexts($task, '', $args);

    $handler_name = ctools_context_handler_get_render_handler($task, '', $handlers, $contexts, $args);
    if ($handler_name) {
      $handler = $handlers[$handler_name];
    }
  }

  // If a handler was selected, change the render method.
  if (!empty($handler)) {
    global $theme;

    // Reset the page theme to use the panels everywhere output
    // instead of the normal page.
    $page['#theme'] = 'panels_everywhere_page';
    $page['#handler'] = $handler;

    // This completely disables blocks on a page without disabling block.module
    // and without going through the extra processor time of building blocks that
    // do not exist.

    // Ensure the list of themes is built.
    $themes = list_themes();

    // Get the real list so we can modify it.
    $list = &drupal_static('list_themes', array());

    // Clear out the list of regions. Block module will not try to
    // render anything not in this regions list.
    $list[$theme]->info['regions'] = array();
  }
}

// ---------------------------------------------------------------------------
// Core hooks

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

/**
 * Implement hook_ctools_plugin_api().
 *
 * We use this for our default 'sample' task handler for the site template.
 */
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);
  }
}

// ---------------------------------------------------------------------------
// General API

/**
 * Determine if Panels Everywhere should override the page.
 */
function panels_everywhere_should_override() {
  // Is our site template even enabled?
  if (!variable_get('panels_everywhere_site_template_enabled', FALSE)) {
    return FALSE;
  }

  // Protect the main editing template from possible destruction.
  if (strpos($_GET['q'], 'admin/structure/pages/nojs/operation/site_template') === 0) {
    return FALSE;
  }

  // The theme system might not yet be initialized. We need $theme.
  drupal_theme_initialize();
  global $theme;

  if (!variable_get('panels_everywhere_site_template_per_theme', FALSE)) {
    // If we've not selected to override 'per theme' check to see if we
    // should override based on the admin theme.
    if (!variable_get('panels_everywhere_site_template_enabled_admin', FALSE)) {
      $admin_theme = variable_get('admin_theme', '0');
      if ($admin_theme && $admin_theme == $theme) {
        return FALSE;
      }
    }

    return TRUE;
  }

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

/**
 * 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 = &drupal_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 drupal_static('panels_everywhere_site_template');
}

/**
 * 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'));
}

/**
 * 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;
}

// ---------------------------------------------------------------------------
// Page Manager support
//
// We use this to add an item to the page manager edit so that managed pages
// can easily set which template they will use.

/**
 * 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;
}

/**
 * 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,
  );

  return $form;
}

/**
 * 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'];
}

/**
 * Implement hook_ctools_render_alter()
 *
 * 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, $context) {
  if ($context['task']['name'] == 'site_template') {
    // Make sure the handler actually used is available later on.
    $info['handler'] = $context['handler'];
    return;
  }

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