<?php
// $Id: spaces.module,v 1.25.4.33.2.1 2009-04-06 18:59:21 yhahn Exp $

define('SPACES_FEATURE_DISABLED', 0);

/**
 * Implementation of hook_init().
 */
function spaces_init() {
  spaces_router('menu');

  // Rebuild spaces menu on page callbacks where there is the
  // potential for the addition/removal/alteration of features.
  switch ($_GET['q']) {
    case 'admin/build/context':
    case 'admin/build/features':
      spaces_features_map(NULL, TRUE);
      break;
  }
}

/**
 * Implementation of hook_perm().
 */
function spaces_perm() {
  return array('administer spaces', 'configure spaces features');
}

/**
 * Implementation of hook_purl_provider().
 */
function spaces_purl_provider() {
  $items = array();
  foreach(spaces_types() as $type => $info) {
    $items['spaces_'. $type] = array(
      'name' => $info['title'],
      'description' => t('Sets a spaces context.'),
      'callback' => 'spaces_init_context',
      'callback arguments' => array($type),
      'example' => 'my-space',
    );
  }
  return $items;
}

/**
 * Context prefix provider callback.
 */
function spaces_init_context($type, $sid) {
  static $once;
  if (empty($once)) {
    $space = spaces_load($type, $sid, TRUE);
    spaces_set_space($space);
    $once = TRUE;
  }
}

/**
 * Implementation of hook_menu().
 */
function spaces_menu() {
  $items = array();
  $items['admin/build/spaces'] = array(
    'title' => t('Spaces presets'),
    'description' => t('Create and configure spaces for your site.'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('spaces_preset_default_form'),
    'type' => MENU_NORMAL_ITEM,
  );
  $items['admin/build/spaces/presets'] = array(
    'title' => t('Presets'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('spaces_preset_default_form'),
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -1,
  );
  $items['admin/build/spaces/presets/add'] = array(
    'title' => t('Add'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('spaces_preset_form', 'add'),
  );
  $items['admin/build/spaces/presets/edit'] = array(
    'page callback' => 'drupal_get_form',
    'page arguments' => array('spaces_preset_form', 'edit'),
  );
  $items['admin/build/spaces/presets/export'] = array(
    'title' => t('Export preset'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('spaces_preset_export'),
  );
  $items['admin/build/spaces/presets/delete'] = array(
    'page callback' => 'drupal_get_form',
    'page arguments' => array('spaces_preset_delete_form', 5, 6),
  );
  $items['admin/build/spaces/presets/disable'] = array(
    'page callback' => '_spaces_preset_disable_page',
  );
  $items['admin/build/spaces/presets/enable'] = array(
    'page callback' => '_spaces_preset_enable_page',
  );
  foreach ($items as $path => $item) {
    $items[$path]['access callback'] = 'user_access';
    $items[$path]['access arguments'] = array('administer spaces');
    $items[$path]['file'] = 'spaces_admin.inc';
    if (!isset($item['type'])) {
      $items[$path]['type'] = MENU_CALLBACK;
    }
  }
  $items['spaces-access-denied'] = array(
    'title' => t('Access denied'),
    'description' => t('Page callback for early-stack spaces router access denied.'),
    'page callback' => 'spaces_access_denied',
    'page arguments' => array(),
    'access callback' => FALSE,
    'type' => MENU_CALLBACK,
  );
  return $items;
}

/**
 * Menu callback for early access_denied calls. Going through the a menu
 * callback allows Drupal bootstrap to complete.
 */
function spaces_access_denied() {
  drupal_access_denied();
  exit;
}

/**
 * Implementation of hook_help().
 */
function spaces_help($path, $arg) {
  switch ($path) {
    case 'admin/build/spaces/presets/export':
      return "<p>". t('You can use exported presets in your modules by returning an array of presets in <code>hook_spaces_presets()</code>.') ."</p>";
  }
}

/**
 *  Implementation of hook_theme().
 */
function spaces_theme() {
  $items = array();
  $items['spaces_features_form'] =
  $items['spaces_customize_item'] =
  $items['spaces_preset_default_form'] =
  $items['spaces_form_presets'] =
  $items['spaces_block_customizer_settings_form'] = array(
    'file' => 'spaces.theme.inc',
  );
  return $items;
}

/**
 *  Implementation of hook_user().
 */
function spaces_user($op, &$edit, &$account, $category = NULL) {
  switch ($op) {
    case 'view':
      spaces_router('user view', $account);
      break;
    case 'form':
      spaces_router('user form', $account);
      break;
  }
}

/**
 * Implementation of hook_nodeapi().
 */
function spaces_nodeapi(&$node, $op, $teaser = NULL, $page = NULL) {
  if ($op == 'view' && $page && menu_get_object() === $node) {
    spaces_router('node view', $node);
  }
}

/**
 * Implementation of hook_flush_caches().
 */
function spaces_flush_caches() {
  spaces_features_map(NULL, TRUE);
  return array();
}

/**
 * Implementation of hook_form_alter().
 */
function spaces_form_alter(&$form, $form_state, $form_id) {
  switch ($form_id) {
    case 'system_modules':
      spaces_features_map(NULL, TRUE);
      break;
    default:
      if ($form['#id'] == 'node-form' && (arg(0) .'/'. arg(1) != 'admin/content')) {
        spaces_router('node form', $form['#node']);
      }
      break;
  }
}

/**
 * Implementation of hook_spaces_settings().
 */
function spaces_spaces_settings() {
  return array(
    'home' => 'space_setting_home',
  );
}

/**
 * Implementation of hook_spaces_customizers().
 */
function spaces_spaces_customizers() {
  return array(
    'menu' => 'space_customizer_menu',
    'block' => 'space_customizer_block',
  );
}

/**
 * Implementation of hook_views_api().
 */
function spaces_views_api() {
  return array(
    'api' => 2,
    'path' => drupal_get_path('module', 'spaces') .'/includes',
  );
}

/**
 * Implementation of hook_context_conditions().
 */
function spaces_context_conditions() {
  $type_options = array();
  foreach (spaces_types() as $type => $info) {
    $type_options[$type] = $info['title'];
  }

  $items = array();
  $items['spaces_type'] = array(
    '#title' => t('Spaces type'),
    '#type' => 'checkboxes',
    '#options' => $type_options,
    '#description' => t('Set this context when the selected space types are active.'),
  );
  return $items;
}

/**
 * SPACES API =========================================================
 */

/**
 * Interface for space objects.
 */
interface space {
  /**
   * Core API-related functions
   */
  function __construct($type, $sid = NULL, $is_active = FALSE);
  function save();
  function delete();

  /**
   * Method that defines the feature options available for this space
   * type.
   *
   * @return array
   *   A FormAPI suitable options array of feature options.
   */
  function feature_options();

  /**
   * Method that allows the space type to add to/modify the utility
   * "links" provided to visitors in a space.
   *
   * @param $links
   *   The current space utility links (for use with theme_links) array
   *   passed by reference.
   */
  function links(&$links);

  /**
   * Method that provides a space-type specific check for whether the
   * provided feature is accessible by the current user.
   *
   * @param $feature
   *   The feature identifier string.
   *
   * @return bool
   *   TRUE if the user has access to this feature. FALSE if not.
   */
  function feature_access($feature = NULL);

  /**
   * Method that provides a space-type specific check for whether the
   * the space can be administered by the current user.
   *
   * @return bool
   *   TRUE if the user has admin access to this space. FALSE if not.
   */
  function admin_access();

  /**
   * Master router method that allows the space type to define routing
   * workflow rules. Currently called at the following hooks:
   *
   * hook_menu(), where $may_cache == FALSE
   * hook_nodeapi(), where $op == 'view'
   * hook_form_alter(), when editing a node
   * hook_user(), where $op == 'view'
   *
   * @param $op
   *   The current hook from which the router is being called.
   *   Can be one of the following: 'menu', 'node view', 'node form',
   *   'user view'
   * @param $object
   *   The object relevant to the current $op called. e.g. when
   *   $op == 'node view', $object is the node object.
   * @param $is_active
   *   Boolean for whether this router has been called as part of a
   *   fully instantiated space object. If FALSE, the router should
   *   not assume the space has been fully constructed and should take
   *   the appropriate actions as necessary.
   *
   * @return bool
   *   TRUE to allow the user to pass through. FALSE to return a
   *   drupal_access_denied() page to the user.
   */
  function router($op, $object = NULL, $is_active = TRUE);

  /**
   * Redirect handler that abstracts redirect logic and allows space
   * types to define their own definitions of various spaces concepts.
   *
   * @param $op
   *   The page being redirected to. Currently only $op value is 'home'
   */
  function redirect($op = 'home');

  /**
   * Allows the space type to implement custom form options on the
   * feature/preset form.
   *
   * @return array
   *   A FormAPI element array. It will be included as a child element
   *   of the master space feature form.
   */
  function form();

  /**
   * Validate handler for the space type's custom form.
   *
   * @param $values
   *   The submitted values.
   */
  function validate($values);

  /**
   * Custom submit handler for the space type's custom form. For
   * example, allows the space type to process values in preparation
   * for spaces_save().
   *
   * @param $values
   *   The submitted values.
   * 
   * @return array
   *   An array of values.
   */
  function submit($values);

  /**
   * Views filter callback that allows the space type to filter views
   * when it is the current active space.
   *
   * @param $query
   *   The views query object.
   */
  function views_filter($is_active, &$query);

  /**
   * Allows the space type to take additional action when enforcing a
   * preset against the current space.
   *
   * @param $preset
   *   A spaces preset definition.
   */
  function preset_enforce($preset);
}

/**
 * Interface for space settings.
 */
interface space_setting {
  function __construct($id = NULL);
  function form($space, $value = array());
  function validate($space, $value);
  function submit($space, $value);
}

/**
 * Interface for space customizers.
 */
interface space_customizer {
  function form($space, $feature);
  function validate($space, $feature, $value);
  function submit($space, $feature, $value);
}

/**
 * Provides a homepage setting for each space.
 */
class space_setting_home implements space_setting {
  var $id;
  function __construct($id = NULL) {
    if ($id) {
      $this->id = $id;
    }
    else {
      $this->id = 'home';
    }
  }

  function form($space, $value = array()) {
    $options = array(0 => '---');
    $links = features_menu_links();
    foreach ($links as $link) {
      $options[$link['href']] = $link['title'];
    }
    $form = array(
      '#title' => t('Homepage'),
      '#description' => t('The default page for this space.'),
      '#type' => 'select',
      '#options' => $options,
      '#validate' => array('spaces_setting_validate' => array($this->id)),
      '#default_value' => $value ? $value : 0,
    );
    return $form;
  }

  function validate($space, $value) {
    // Exclude space "prototypes" (like that used for the preset form)
    /*
    if ($space->sid) {
      if (!$value && is_array($space->features) && (array_sum($space->features) != 0)) {
        form_set_error('settings]['. $this->id, t('You must select a homepage for this space.'));
      }
    }
    */
  }

  function submit($space, $value) {
    return $value;
  }
}

/**
 * Customizer for feature menus.
 */
class space_customizer_menu implements space_customizer {

  var $name = 'Menu';

  function form($space, $feature) {
    $menu = spaces_features_items('menu', $feature);
    if (!empty($menu)) {
      $form = array();
      $menu_items = menu_navigation_links('features');
      $default_items = $menu_items;
      $this->customize($space, $menu_items);
      foreach ($menu_items as $key => $item) {
        if (in_array($item['href'], $menu)) {
          $form[$item['href']] = array(
            '#title' => $item['href'],
            '#type' => 'fieldset',
            '#tree' => TRUE,
          );
          $form[$item['href']]['title'] = array(
            '#title' => t('Title'),
            '#type' => 'textfield',
            '#size' => 40,
            '#maxlength' => 255,
            '#default_value' => $item['title'],
          );
          $form[$item['href']]['default'] = array(
            '#type' => 'value',
            '#value' => $default_items[$key]['title'],
          );
        }
      }
    }
    return $form;
  }

  function validate($space, $feature, $value) {
    return;
  }

  function submit($space, $feature, $value) {
    $customizer = $space->customizer['menu'];
    foreach ($value as $path => $item) {
      if ($item['title'] != $item['default']) {
        $customizer[$path] = $item['title'];
      }
    }
    return $customizer;
  }

  function customize($space, &$menu = NULL) {
    foreach ($menu as $k => $item) {
      if (!empty($space->customizer['menu'][$item['href']])) {
        $menu[$k]['title'] = $space->customizer['menu'][$item['href']];
      }
    }
  }
}

/**
 * Customizer for feature blocks.
 */
class space_customizer_block implements space_customizer {

  var $name = 'Blocks';
  var $info = array();

  /**
   * Helper method to return the block info.
   */
  function get_block_info($module, $delta) {
    if (!isset($this->info[$module])) {
      $this->info[$module] = module_invoke($module, 'block', 'list');

      // If the block is provided by Views, doctor the info to strip out the
      // view name leaving only the block's display name.
      if ($module == 'views') {
        foreach ($this->info[$module] as $k => $v) {
          $viewname = strpos($v['info'], ':');
          if ($viewname !== FALSE) {
            $v['info'] = substr($v['info'], $viewname + 2);
            $this->info[$module][$k] = $v;
          }
        }
      }
    }
    return !empty($this->info[$module][$delta]['info']) ? $this->info[$module][$delta]['info'] : '';
  }

  /**
   * Implementation of form().
   */
  function form($space, $feature) {
    $master_form = array(
      '#theme' => 'spaces_block_customizer_settings_form',
      'contexts' => array('#tree' => TRUE),
      'defaults' => array('#tree' => TRUE),
    );

    global $theme_key;
    init_theme();
    $regions = system_region_list($theme_key);

    // Collect all contexts associated with this feature
    $feature_contexts = drupal_map_assoc(spaces_features_items('context', $feature));
    $contexts = context_enabled_contexts();
    $contexts = array_intersect_key($contexts, $feature_contexts);

    foreach ($contexts as $identifier => $context) {
      if (!empty($context->block)) {

        // Get customized values -- unfortunately we can't use our own customization
        // methods as block customization is a bit more complex.
        $customizer = !empty($space->customizer['block'][$identifer]) ? $space->customizer['block'][$identifier] : array();
        $subject = !empty($space->customizer['block']['subject']) ? $space->customizer['block']['subject'] : array();

        $form = array( '#title' => $identifier, '#tree' => TRUE);
        $defaults = array('#tree' => TRUE);

        foreach ($context->block as $i => $block) {
          // @TODO: remove this once context is less confused about itself.
          $block = (array) $block;
          $bid = "{$block['module']}-{$block['delta']}";

          // Sanity check that this region exists
          if (!empty($block['region']) && !empty($regions[$block['region']])) {
            $region = $block['region'];
            if (!isset($form[$region])) {
              $form[$region] = array('#title' => $regions[$region], '#tree' => TRUE);
            }

            $block_details = module_invoke($block['module'], 'block', 'view', $block['delta']);
            $default_subject = !empty($block_details['subject']) ? $block_details['subject'] : '';
            $default_weight = isset($block[$i]['weight']) ? $block[$i]['weight'] : 0;
            $default_status = isset($block[$i]['status']) ? $block[$i]['status'] : 1;

            // Store defaults to compare against changed values in submit handler
            $defaults[$region][$bid]['weight'] = array('#type' => 'value', '#value' => $default_weight);
            $defaults[$region][$bid]['status'] = array('#type' => 'value', '#value' => $default_status);
            $defaults[$region][$bid]['subject'] = array('#type' => 'value', '#value' => $default_subject);

            $form[$region][$bid] = array(
              '#tree' => TRUE,
              '#weight' => isset($customizer[$region][$bid]['weight']) ? $customizer[$region][$bid]['weight'] : 0,
            );
            $form[$region][$bid]['weight'] = array(
              '#type' => 'weight',
              '#delta' => 25,
              '#default_value' => isset($customizer[$region][$bid]['weight']) ? $customizer[$region][$bid]['weight'] : 0,
            );
            $form[$region][$bid]['status'] = array(
              '#type' => 'checkbox',
              '#default_value' => isset($customizer[$region][$bid]['status']) ? $customizer[$region][$bid]['status'] : 1,
            );
            // If the block subject is empty, it's likely to be for a good reason
            // e.g. the subject is generated dynamically or the block is slimmed
            // down. Let's respect that.
            if (!empty($default_subject)) {
              $form[$region][$bid]['subject'] = array(
                '#type' => 'textfield',
                '#default_value' => !empty($subject[$bid]) ? $subject[$bid] : $default_subject,
                '#description' => $this->get_block_info($block['module'], $block['delta']),
              );
            }
            else {
              $form[$region][$bid]['subject'] = array(
                '#type' => 'markup',
                '#value' => $this->get_block_info($block['module'], $block['delta']),
              );
            }
          }
        }

        $master_form['contexts'][$identifier] = $form;
        $master_form['defaults'][$identifier] = $defaults;
      }
    }
    return $master_form;
  }

  /**
   * Implementation of validate().
   */
  function validate($space, $feature, $value) {
    return;
  }

  /**
   * Implementation of submit().
   * Iterate through and only record the aspects of each block that have been customized.
   */
  function submit($space, $feature, $value) {
    $customizer = $space->customizer['block'];
    foreach ($value['contexts'] as $identifier => $context) {
      foreach ($context as $region => $blocks) {
        foreach ($blocks as $bid => $block) {
          foreach ($block as $k => $v) {
            // Clear out values that haven't changed from defaults
            if ($v === $value['defaults'][$identifier][$region][$bid][$k]) {
              unset($block[$k]);
            }
            // Store subjects "flatly"
            else if ($k == 'subject') {
              unset($block[$k]);
              $customizer['subject'][$bid] = $v;
            }
          }
          if (!empty($block)) {
            $customizer[$identifier][$region][$bid] = $block;
          }
        }
      }
    }
    return $customizer;
  }

  /**
   * Implementation of customize().
   */
  function customize($space, $identifier, &$block = NULL) {
    // Unset disabled blocks and change weights based on customizer settings. See spaces_context_active_contexts_alter.
    if (!empty($space->customizer['block'][$identifier])) {
      $customizer = $space->customizer['block'][$identifier];
      foreach ($block as $key => $b) {
        // @TODO: remove this once context is less confused about itself.
        $b = (array) $b;
        $block[$key] = (array) $block[$key];
        $bid = "{$b['module']}-{$b['delta']}";
        // If the block is not enabled, yank it out of the blocks array
        if (!empty($customizer[$b['region']][$bid])) {
          if (isset($customizer[$b['region']][$bid]['status']) && $customizer[$b['region']][$bid]['status'] === 0) {
            unset($block[$key]);
          }
          if (isset($customizer[$b['region']][$bid]['weight'])) {
            $block[$key]['weight'] = $customizer[$b['region']][$bid]['weight'];
          }
        }
      }
    }
  }

  /**
   * Additional method: customize_subject() for customizing a block subject.
   */
  function customize_subject($space, &$block) {
    $bid = "{$block->module}-{$block->delta}";
    if (!empty($space->customizer['block']['subject'][$bid])) {
      $block->subject = $space->customizer['block']['subject'][$bid];
    }
  }
}

/**
 * Implementation of hook_context_active_contexts_alter().
 */
function spaces_context_active_contexts_alter(&$contexts) {
  $space = spaces_get_space();
  foreach ($contexts as $identifier => $context) {
    if (!empty($context->block)) {
      space_customizer_block::customize($space, $identifier, $context->block);
    }
  }
}

/**
 * Load a space.
 *
 * @param $type
 *   The type of the space to be loaded. Must be one of the keys in the
 *   array returned by spaces_types(). 
 * @param $sid
 *   The id of the space to be loaded. If omitted, a "prototype" space
 *   will be constructed.
 * @param $is_active
 *   Optional boolean flag for whether this space is active or not.
 *   Defaults to FALSE.
 *
 * @return
 *   The requested space object or FALSE if something went wrong.
 */
function spaces_load($type, $sid = NULL, $is_active = FALSE) {
  $types = spaces_types();
  if (isset($types[$type])) {
    $class = $types[$type]['class'];

    // Create a new space object
    $space = new $class($type, $sid, $is_active);

    // Initialize various space variables
    $space->type = $type;
    $space->features = array();
    $space->settings = array();
    $space->customizer = array();

    // Initialize space specific settings if $sid is provided
    if ($sid) {
      $space->sid = $sid;

      // Load the PURL modifier
      if ($modifier = purl_load(array('provider' => "spaces_{$type}", 'id' => $sid))) {
        $space->purl = $modifier['value'];
      }

      // Load features
      $result = db_query('SELECT id, value FROM {spaces_features} WHERE sid = %d AND type = "%s" ORDER BY weight ASC', $sid, $type);
      while ($row = db_fetch_object($result)) {
        $space->features[$row->id] = $row->value;
      }

      // Load settings
      $result = db_query('SELECT id, value FROM {spaces_settings} WHERE sid = %d AND type = "%s"', $sid, $type);
      while ($row = db_fetch_object($result)) {
        $space->settings[$row->id] = unserialize($row->value);
      }

      // Load customizer & preset
      $row = db_fetch_object(db_query("SELECT customizer, preset FROM {spaces} WHERE sid = %d AND type = '%s'", $space->sid, $space->type));
      $space->customizer = $row->customizer ? unserialize($row->customizer) : array();

      // Enforce preset or use default if not found
      $default_presets = variable_get('spaces_default_presets', array());
      if ($row->preset) {
        $space->preset = $row->preset;
      }
      else if (empty($space->preset) && isset($default_presets[$type])) {
        $space->preset = $default_presets[$type];
      }
      if (!empty($space->preset)) {
        spaces_preset_enforce($space);
      }
    }

    return $space;
  }
  return false;
}

/**
 * Saves a space object's feature/setting values.
 *
 * @param $space
 *   The space object to save.
 *
 * @return
 *   Returns TRUE on success, FALSE on failure.
 */
function spaces_save($space) {
  if ($space->sid) {
    // Enforce the preset
    spaces_preset_enforce($space);

    // Update features
    db_query("DELETE FROM {spaces_features} WHERE sid = %d AND type = '%s'", $space->sid, $space->type);
    $valid_features = spaces_features($space->type);
    $weight = -10;
    foreach ($space->features as $feature => $value) {
      if (isset($valid_features[$feature])) {
        $values = array($space->sid, $space->type, $feature, $value, $weight);
        db_query('INSERT INTO {spaces_features} (sid, type, id, value, weight) VALUES (%d, "%s", "%s", "%s", %d)', $values);
        $weight++;
      }
    }

    // Update settings
    db_query("DELETE FROM {spaces_settings} WHERE sid = %d AND type = '%s'", $space->sid, $space->type);
    // Build list of valid settings including those associated with features.
    $valid_settings = spaces_settings($space->type);
    foreach (spaces_features() as $feature) {
      if (isset($feature->info['spaces']['settings'])) {
        foreach ($feature->info['spaces']['settings'] as $id => $setting) {
          $valid_settings[$id] = $setting;
        }
      }
    }
    foreach ($space->settings as $setting => $value) {
      if (isset($valid_settings[$setting]) && !empty($value)) {
        $value = serialize($value);
        $values = array($space->sid, $space->type, $setting, $value);
        db_query('INSERT INTO {spaces_settings} (sid, type, id, value) VALUES (%d, "%s", "%s", "%s")', $values);
      }
    }

    // Update preset & customizer
    $exists = db_result(db_query("SELECT count(sid) FROM {spaces} WHERE sid = %d AND type = '%s'", $space->sid, $space->type));
    if ($exists) {
      db_query("UPDATE {spaces} SET preset = '%s', customizer = '%s' WHERE sid = %d AND type = '%s'", $space->preset, serialize($space->customizer), $space->sid, $space->type);
    }
    else {
      db_query("INSERT INTO {spaces} (sid, type, preset, customizer) VALUES(%d, '%s', '%s', '%s')", $space->sid, $space->type, $space->preset, serialize($space->customizer));
    }

    // Save context prefix if space type allows prefix customization
    $types = spaces_types();
    $save_purl = isset($types[$space->type]['custom purl']) && $types[$space->type]['custom purl'];
    if ($space->purl && $save_purl) {
      // We need to concatenate the type/sid so that collisions between space types do not occur.
      $modifier = array(
        'provider' => 'spaces_'. $space->type,
        'id' => $space->sid,
        'value' => $space->purl,
      );
      purl_save($modifier);
    }

    // Allow space type to do its own saving
    $space->save();

    return true;
  }
  return false;
}

/**
 * Deletes a space object's records in the database.
 *
 * @param $space
 *   The space object to delete.
 *
 * @return
 *   Returns TRUE for now.
 */
function spaces_delete($space) {
  // Remove all features and settings
  db_query("DELETE FROM {spaces} WHERE sid = %d AND type = '%s'", $space->sid, $space->type);
  db_query("DELETE FROM {spaces_features} WHERE sid = %d AND type = '%s'", $space->sid, $space->type);
  db_query("DELETE FROM {spaces_settings} WHERE sid = %d AND type = '%s'", $space->sid, $space->type);

  // Delete the purl modifier
  $modifier = array('provider' => 'spaces_'. $space->type, 'id'   => $space->sid);
  purl_delete($modifier);

  // Allow space type to do its own deleting
  $space->delete();

  return true;
}

/**
 * Enforces a spaces preset.
 */
function spaces_preset_enforce(&$space) {
  $presets = spaces_presets($space->type);
  if (isset($space->preset) && isset($presets[$space->preset])) {
    $preset = $presets[$space->preset]['preset'];

    // Enforce features, settings, customizer
    $keys = array('features', 'settings', 'customizer');
    foreach ($keys as $key) {
      if (isset($preset[$key]) && is_array($preset[$key])) {
        foreach ($preset[$key] as $k => $v) {
          if ($preset['locked'][$key][$k] || !isset($space->{$key}[$k])) {
            $space->{$key}[$k] = $v;
          }
        }
      }
    }

    // Type-specific presets
    $space->preset_enforce($preset);
  }
}

/**
 * Invokes hook_spaces_types() to gather an array of space types and
 * associated classes.
 *
 * Implementing modules should provide an associate array in
 * hook_spaces_types() of the following format:
 *
 * return array(
 *   $id => array(
 *     'class' => $space_class,
 *     'title' => $space_type_name,
 *     'purl modifier' => $bool,
 *   ),
 * );
 *
 * Where:
 *
 * $id: A unique string identifier for this space type. e.g. "og"
 * $space_class: The PHP class to construct for this space. e.g. "spaces_og"
 * $space_type_name: The human-readable name of your space type. e.g. "Group space"
 * $bool: TRUE or FALSE for whether spaces should provide a UI for
 *   users to provide a custom URL modifier for each space. If FALSE,
 *   the implementing module should implement
 *   hook_purl_modifiers() in order to provide PURL modifiers programatically.
 *
 * @param $reset
 *   Optional reset flag for clearing the static cache.
 *
 * @return
 *   An array of space types where $key => $value corresponds to the space type => space class.
 */
function spaces_types($reset = false) {
  static $spaces_types;
  if (!isset($spaces_types) || $reset) {
    $spaces_types = module_invoke_all('spaces_types');
  }
  return $spaces_types;
}

/**
 * Gather an array of spaces presets from the DB.
 *
 * @param $type
 *   Optional space type to filter results by.
 * @param $include_disabled
 *   Optional flag to return all presets, including disabled ones.
 * @param $reset
 *   Optional reset flag for clearing the static cache.
 *
 * @return
 *   An array of space types where $key => $value corresponds to the space type => space class.
 */
function spaces_presets($type = NULL, $include_disabled = FALSE, $reset = FALSE) {
  static $presets;
  if (!isset($presets)) {
    $presets = array();
    $disabled = variable_get('spaces_disabled_presets', array());

    // Collect presets provided by modules in code
    foreach(module_implements('spaces_presets') as $module) {
      $items = call_user_func($module .'_spaces_presets');
      foreach($items as $id => $preset) {
        $preset['disabled'] = isset($disabled[$preset['type']][$id]);
        $presets[$preset['type']][$id] = $preset;
      }
    }
    $result = db_query("SELECT * FROM {spaces_presets}");
    while ($row = db_fetch_object($result)) {
      $presets[$row->type][$row->id] = array(
        'name' => $row->name,
        'description' => $row->description,
        'preset' => unserialize($row->value),
        'disabled' => isset($disabled[$row->type][$row->id]),
      );
    }
  }
  // Move filtering outside main condition in order to hit the DB only once
  $return = $presets;
  if (!$include_disabled) {
    foreach (array_keys($return) as $preset_type) {
      foreach ($return[$preset_type] as $id => $preset) {
        if ($preset['disabled']) {
          unset($return[$preset_type][$id]);
        }
      }
    }
  }
  if ($type) {
    return isset($return[$type]) ? $return[$type] : array();
  }
  return $return;
}

/**
 * Wrapper function around spaces_set_space(). Retrieves the current
 * active space.
 */
function spaces_get_space() {
  return spaces_set_space();
}

/**
 * Sets the specified space as the current active space. Returns the
 * active space if no space is provided.
 *
 * @param $space
 *   The space object to set as the active space. Optional.
 * @param $reset
 *   Optional flag to reset the static cache.
 *
 * @return
 *   The active space object or FALSE if there is no active space.
 */
function spaces_set_space($space = NULL, $reset = FALSE) {
  static $current_space;
  if (!isset($current_space) || $reset) {
    $current_space = $space;

    if ($space) {
      // Context integration with spaces_type setter.
      context_set_by_condition('spaces_type', $space->type);
    }
  }
  return $current_space ? $current_space : FALSE;
}

/**
 * Wrapper around implementations of $space->router. Provides
 * additional intelligence, including a global killswitch and routing
 * when no spaces are active.
 *
 * @param $op
 *   The current "hook" or "hook op" identifier for the $space->router
 *   to act on.
 * @param $object
 *   Optional object to pass to the $space->router.
 */
function spaces_router($op, $object = NULL) {
  // Check global killswitch
  if (spaces_router_get()) {
    $access = true;
    $types = spaces_types();
    // Run the router for the active space
    if ($space = spaces_get_space()) {
      $access = $access && $space->router($op, $object);
      unset($types[$space->type]);
    }
    // Run each non-active space type's router
    foreach ($types as $type => $info) {
      $access = $access && call_user_func(array($info['class'], 'router'), $op, $object, FALSE);
    }
    if (!$access && !user_access('administer spaces')) {
      // We use a menu callback here rather than drupal_access_denied()
      // because spaces_router() is called at times from hook_init().
      // Using drupal_access_denied() can terminate the page request before
      // bootstrap completes, leading to all sorts of havoc.
      menu_set_active_item('spaces-access-denied');
    }
  }
}

/**
 * Wrapper around spaces_router_get().
 */
function spaces_router_set($status) {
  return spaces_router_get($status, TRUE);
}

/**
 * Sets a static variable that is used to disable spaces routing
 * altogether -- e.g. for install/update scripts, migrations, etc.
 *
 * @param $enabled
 *   Optional boolean for enabling/disabling spaces routing.
 * @param $reset
 *   Optional boolean for resetting the static cache.
 *
 * @return
 *   Returns a boolean for whether routing is enabled/disabled.
 */
function spaces_router_get($enabled = 1, $reset = FALSE) {
  static $status;
  if (!isset($status) || $reset) {
    $status = $enabled;
  }
  return $status;
}

/**
 * Retrieve all available features.
 *
 * @param $type
 *   Optional type flag by which to filter available features.
 * @param $reset
 *   Optional boolean flag for resetting the static cache.
 *
 * @return
 *   Keyed array of potential features.
 */
function spaces_features($type = NULL, $reset = FALSE) {
  static $spaces_features;
  if (!isset($spaces_features) || $reset) {
    $spaces_features = array('all' => array(), 'common' => array());
    $features = features_get_features();
    foreach ($features as $feature) {
      if (!empty($feature->info['spaces'])) {
        if (!empty($feature->info['spaces']['types']) && is_array($feature->info['spaces']['types'])) {
          foreach ($feature->info['spaces']['types'] as $t) {
            $spaces_features[$t][$feature->name] = $feature;
          }
        }
        else {
          $spaces_features['common'][$feature->name] = $feature;
        }
        $spaces_features['all'][$feature->name] = $feature;
      }
    }
    foreach (array_keys($spaces_features) as $t) {
      if ($t != 'all' && $t != 'common') {
        $spaces_features[$t] = array_merge($spaces_features[$t], $spaces_features['common']);
      }
    }
  }
  if ($type) {
    return !empty($spaces_features[$type]) ? $spaces_features[$type] : $spaces_features['common'];
  }
  return $spaces_features['all'];
}

/**
 * Retrieve all available settings.
 *
 * @param $type
 *   Optional space type to return a subset of settings that only apply
 *   to the given space type.
 * @param $reset
 *   Optional boolean flag for resetting the static cache.
 *
 * @return
 *   Keyed array of potential settings.
 */
function spaces_settings($type = NULL, $reset = FALSE) {
  static $spaces_settings;
  if (!isset($spaces_settings) || $reset) {
    $spaces_settings = array('all' => array(), 'common' => array());
    $settings = module_invoke_all('spaces_settings');
    foreach ($settings as $setting_name => $class) {
      $setting = new $class();
      if (!empty($setting->types)) {
        foreach ($setting->types as $t) {
          if (!isset($spaces_settings[$t])) {
            $spaces_settings[$t] = array();
          }
          $spaces_settings[$t][$setting_name] = $setting;
        }
      }
      else {
        $spaces_settings['common'][$setting_name] = $setting;
      }
      $spaces_settings['all'][$setting_name] = $setting;
    }
    foreach (array_keys($spaces_settings) as $t) {
      if ($t != 'all' && $t != 'common') {
        $spaces_settings[$t] = array_merge($spaces_settings[$t], $spaces_settings['common']);
      }
    }
  }
  if ($type) {
    return !empty($spaces_settings[$type]) ? $spaces_settings[$type] : $spaces_settings['common'];
  }
  return $spaces_settings['all'];
}

/**
 * Retrieve all available customizers.
 *
 * @param $reset
 *   Optional boolean flag for resetting the static cache.
 *
 * @return
 *   Keyed array of customizers.
 */
function spaces_customizers($reset = FALSE) {
  static $spaces_customizers;
  if (!isset($spaces_customizers) || $reset) {
    $customizers = module_invoke_all('spaces_customizers');
    foreach ($customizers as $customizer_name => $class) {
      $spaces_customizers[$customizer_name] = new $class();
    }
  }
  return $spaces_customizers;
}

/**
 * Caches a map of feature component => feature name
 */
function spaces_features_map($type = NULL, $reset = FALSE) {
  static $map;
  if (!isset($map) || $reset) {
    $map = array();
    $cache = cache_get('spaces_map', 'cache');

    if ($cache && !$reset) {
      $map = $cache->data;
    }
    else {
      $features = spaces_features();
      foreach ($features as $feature) {
        foreach ($feature->info['features'] as $component => $items) {
          if (is_array($items)) {
            foreach ($items as $item) {
              $map[$component][$item] = $feature->name;
            }
          }
        }
      }
      // Go through contexts and add relevant context components in as well
      $contexts = context_enabled_contexts();
      $components = array('node', 'views');
      foreach ($map['context'] as $identifier => $feature_name) {
        $context = $contexts[$identifier];
        if (!empty($context)) {
          foreach ($components as $component) {
            if (!empty($context->{$component})) {
              foreach ($context->{$component} as $item) {
                $map[$component][$item] = $feature_name;
              }
            }
          }
        }
      }
      cache_set('spaces_map', $map, 'cache');
    }
  }
  if (!empty($type)) {
    return isset($map[$type]) ? $map[$type] : array();
  }
  return $map;
}

/**
 * Returns an array of items of a given type that belong to a given feature.
 */
function spaces_features_items($type, $feature) {
  $features = spaces_features();
  if (!empty($features[$feature]) && !empty($features[$feature]->info['features'][$type])) {
    return $features[$feature]->info['features'][$type];
  }
  return array();
}

/**
 * Implementation of hook_features_menu_links_alter().
 */
function spaces_features_menu_links_alter(&$links) {
  $space = empty($space) ? spaces_get_space() : $space;

  // Sanity check on our space object.
  if ($space && !empty($space->sid)) {
    // Load up the spaces menu links
    space_customizer_menu::customize($space, $links);

    // Retrieve the menu cache for a path to feature mapping
    $map = spaces_features_map('menu');

    // Sort the menu by feature weight & hide any items for features
    // that are not available (this **should**) be handled by access
    // control on the links' respective menu callbacks, but awkward
    // permissioning (e.g. user 1)  makes it nice for these to be
    // hidden manually.
    $weights = array_flip(array_keys($space->features));
    $weighted = array();
    foreach ($links as $k => $item) {
      $feature = '';
      if (!empty($map[$item['href']])) {
        $feature = $map[$item['href']];
      }
      if (!empty($feature) && $space->feature_access($feature)) {
        // Retrieve path > feature > weight
        $links[$k]['#weight'] = $weights[$feature];
      }
      else {
        unset($links[$k]);
      }
    }
    uasort($links, 'element_sort');
  }
}

/**
 * Preset options form that can be reused by implementing modules.
 *
 * @param $space
 *   A space object.
 *
 * @return
 *   A FormAPI array structure.
 */
function spaces_form_presets($space) {
  $presets = spaces_presets($space->type);
  if ($presets) {
    $default_presets = variable_get('spaces_default_presets', array());
    if (isset($space->preset) && !empty($presets[$space->preset])) {
      $default_preset = $space->preset;
    }
    else if (isset($default_presets[$space->type])) {
      $default_preset = $default_presets[$space->type];
    }
    else {
      $default_preset = NULL;
    }

    // Radios for presets
    $form = array(
      '#tree' => false,
      '#theme' => 'spaces_form_presets',
    );
    $form['preset'] = array(
      '#title' => t('Preset'),
      '#type' => 'radios',
      '#required' => true,
      '#options' => array(),
      '#default_value' => $default_preset,
    );    
    $form['info'] = array();
    foreach ($presets as $id => $preset) {
      $form['preset']['#options'][$id] = $preset['name'];
      $form['info'][$id] = array(
        '#type' => 'item',
        '#title' => $preset['name'],
        '#description' => $preset['description'],
      );
    }
    return $form;
  }
  return array();
}

/**
 * Menu admin access wrapper.
 */
function spaces_admin_access($type = NULL, $op = NULL) {
  $return = false;
  $space = spaces_get_space();
  if ($space && $type == $space->type) {
    $return = $space->admin_access();
  }
  if ($op == 'features') {
    return $return && (user_access('administer spaces') || user_access('configure spaces features'));
  }
  return $return;
}

/**
 * Menu feature access wrapper.
 */
function spaces_feature_access($feature = NULL) {
  if (user_access('administer spaces')) {
    return TRUE;
  }
  else if ($space = spaces_get_space()) {
    return $space->feature_access($feature);
  }
  return user_access('access content');
}

/**
 * A mild abstraction of hook_menu() items that can be used by
 * implementing modules to embed/graft relevant spaces items into the
 * menu tree. Should only be used when the $may_cache argument of
 * hook_menu() is false.
 *
 * @param $space
 *   A space object.
 * @param $local_tasks
 *   Optional boolean flag for whether the items are fully rendered as
 *   local tasks.
 * @param $path_prefix
 *   A path to prefix the menu item paths by.
 *
 * @return
 *   An array of menu items.
 */
function spaces_active_space_menu($type, $local_tasks = FALSE, $path_prefix = '') {
  $types = spaces_types();
  $path_prefix = !empty($path_prefix) ? $path_prefix .'/' : '';
  $spaces_path = drupal_get_path('module', 'spaces');

  if ($local_tasks == FALSE) {
    $items[$path_prefix. 'spaces'] = array(
      'title' => t('!space_type settings', array('!space_type' => $types[$type]['title'])),
      'page arguments' => array('spaces_basic_form'),
      'access arguments' => array($type),
      'type' => MENU_NORMAL_ITEM,
    );
  }
  else {
    $items[$path_prefix. 'spaces'] = array(
      'title' => t('Spaces'),
      'page arguments' => array('spaces_basic_form'),
      'access arguments' => array($type),
      'type' => MENU_LOCAL_TASK,
      'weight' => 1,
    );
  }
  $items[$path_prefix. 'spaces/setup'] = array(
    'title' => t('Basic setup'),
    'page arguments' => array('spaces_basic_form'),
    'access arguments' => array($type),
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => 0,
  );
  $items[$path_prefix. 'spaces/features'] = array(
    'title' => t('Features'),
    'page arguments' => array('spaces_features_form'),
    'access arguments' => array($type, 'features'),
    'type' => MENU_LOCAL_TASK,
    'weight' => 1,
  );
  $items[$path_prefix. 'spaces/features/%'] = array(
    'title' => t('Features'),
    'page arguments' => array('spaces_customize_form', NULL, 2),
    'access arguments' => array($type, 'features'),
    'type' => MENU_LOCAL_TASK,
    'weight' => 1,
  );
  foreach ($items as $path => $item) {
    $items[$path]['page callback'] = 'drupal_get_form';
    $items[$path]['access callback'] = 'spaces_admin_access';
    $items[$path]['file'] = 'spaces_admin.inc';
    $items[$path]['file path'] = $spaces_path;
  }
  return $items;
}

/**
 * THEME FUNCTIONS ====================================================
 */

/**
 * Generates an array of utility links for the current space suitable
 * for use in theme_links().
 */
function spaces_space_links() {
  $links = array();
  if ($space = spaces_get_space()) {
    $space->links($links);
    drupal_alter('space_links', $links);
  }
  return $links;
}

/**
 * theme_block() preprocessor.
 */
function spaces_preprocess_block(&$vars) {
  $space = spaces_get_space();
  if (!empty($vars['block'])) {
    space_customizer_block::customize_subject($space, $vars['block']);
  }
}