<?php
// $Id: rdfproxy.module,v 1.2 2009/06/21 12:05:28 scor Exp $

/**
 * Implementation of hook_init().
 */
function rdfproxy_init() {

}

/**
 * Implementation of hook_perm().
 */
function rdfproxy_perm() {
  return array(
    'import via RDF proxy',
    'administer RDF proxy',
  );
}

/**
 * Implementation of hook_menu().
 */
function rdfproxy_menu() {
  return array(
    'rdfproxy/lookup/%rdfproxy_profile' => array(
      'title' => 'RDF proxy lookup',
      'type' => MENU_CALLBACK,
      'access callback' => 'user_access',
      'access arguments' => array('import via RDF proxy'),
      'page callback' => 'rdfproxy_lookup_redirect',
      'page arguments' => array(2),
    ),
    'admin/build/rdfproxy/add' => array(
      'title' => 'Create new RDF proxy profile',
      'type' => MENU_CALLBACK,
      'access callback' => 'user_access',
      'access arguments' => array('administer RDF proxy'),
      'page callback' => 'drupal_get_form',
      'page arguments' => array(rdfproxy_add_profile_form),  
    ),
    'admin/build/rdfproxy/edit/%rdfproxy_profile' => array(
      'title' => 'RDF proxy edit',
      'type' => MENU_CALLBACK,
      'access callback' => 'user_access',
      'access arguments' => array('administer RDF proxy'),
      'page callback' => 'drupal_get_form',
      'page arguments' => array(rdfproxy_add_profile_form, 4),  
    ),
  );
}
function rdfproxy_lookup_redirect($profile) {
	$node = rdfproxy_lookup($profile,$_GET['uri']);
	if ($node->nid) drupal_goto('node/'.$node->nid);
	return 'Unable to find information for provided uri';
}

/**
 * Specialized menu callback to load an RDF proxy profile.
 */
function rdfproxy_profile_load($name) {
  $profile = rdfproxy_get_profile($name);
  if (empty($profile)) {
    return FALSE;
  }
  else {
    return $profile;
  }
}

/**
 * Lookup function which fetches RDF data from a SPARQL endpoint.
 */
function rdfproxy_lookup($profile,$uri=null, $default_values = array()) {
//  echo 'lookup';
//  var_dump($profile);
//global $rdf_namespaces;
//var_dump(rdf_get_namespaces());
  //var_dump($_GET['uri']);

  // Check if the instance is already in the system.
  $properties = db_query(db_rewrite_sql("SELECT * FROM {evoc_rdf_properties}"));

  while ($item = db_fetch_object($properties)) {
    $term_curie = $item->prefix . ':' . $item->id;
    $properties_options[$term_curie] = $term_curie;
  }
  
  
  if (!$uri) {
    drupal_set_message('The RDF proxy lookup requires an URI to be provided', 'error');
    return FALSE;
  }
  
  // FIXME in sparql module.
  require_once drupal_get_path('module', 'sparql') . '/sparql.client.inc';
  $query = str_replace('%uri', '<' . $uri . '>', $profile->sparql_query);
  $sparql_res = sparql_request($profile->sparql_endpoint, $query);
  //var_dump($sparql_res);
  
  // Instances to be added/updated.
  $instances = array();
  
  // Build a node based on the RDF graph.
  // Get the content type to be created.
  foreach ($sparql_res as $triple) {
    if ($triple[1] == rdf_qname_to_uri('rdf:type')) {
      $found = preg_match('/.*#(.*)/', $triple[2], $matches);
      if (isset($matches[1])) {
        $content_type_name = strtolower($matches[1]);
        $instances["$triple[0]"]['type'] = $content_type_name;
      }
      else {
        drupal_set_message('The RDF proxy lookup was not able to find a suitable local content type.', 'error');
        return FALSE;
      }
    }
  }

  // Get values of the instances and their associated field name.
  // TODO embed these values in RDF CCK instead of guessing them here.
  $values = array();
  foreach ($sparql_res as $triple) {
    // TODO add check on the site ns.
    //var_dump($triple);
    $found = preg_match('/.*#[a-z_]*([A-Z])(.*)/', $triple[1], $matches);
    if ($matches[2]) {
      $field_name = strtolower($matches[1] . $matches[2]);
      $field_name = ($field_name == 'title' || $field_name == 'body') ? $field_name : 'field_' . $field_name;
      $value = rdf_val_to_str($triple[2]);
      $instances["$triple[0]"]['values']["$field_name"][] = $value;
    }
  }
  /*
  	Field might not actually show up in the sparql_res, so add default values here
  */
  foreach($default_values as $field_name => $val) {
  	if (! $instances["$triple[0]"]['values']["$field_name"])
  		 $instances["$triple[0]"]['values']["$field_name"] = $val;
  }
//var_dump($instances);
//var_dump($values);
  foreach ($instances as $uri => $instance) {
    $nodes[] = _rdfproxy_node_save($uri, $instance['type'], $instance['values'], $profile);
  }
   return array_pop($nodes);
}

/**
 * Create or update a node from the RDF proxy item
 */
function _rdfproxy_node_save($uri, $content_type_name, $values, $profile, $settings = array()) {
//  $uri = isset($_GET['uri']) ? $_GET['uri'] : $uri;
  $uri = $uri;
  $profile_name = $profile->name;
  
  module_load_include('inc', 'node', 'node.pages');

  // Check if the instance is already in the system.
  $local_instances = db_query("SELECT id, expires FROM {rdfproxy_instances} WHERE uri = '%s' AND profile = '%s'", $uri, $profile_name);
  $item = db_fetch_object($local_instances);
  if ($item) {
    $expires = $item->expires;
    $nid = $item->id;
    // If the instance is still valid, go to its page.
//var_dump($nid);
//var_dump($expire);
    if ($expires > time()) {
//      drupal_goto('node/' . $nid);
       return node_load($nid);
    }
    
  }
  
  // Constructs the node object.
  $node = new stdClass();
  if (isset($nid)) {
    $node->nid = $nid;
    $node->vid = db_result(db_query("SELECT vid FROM {node_revisions} WHERE nid = %d", $node->nid));
  }
  // Determines the node type.
  $node->type = $content_type_name;
      
  // Get the default options from the cont
  $options = variable_get('node_options_'. $node->type, FALSE);
  if (is_array($options)) {
    $node->status = in_array('status', $options) ? 1 : 0;
    $node->promote = in_array('promote', $options) ? 1 : 0;
    $node->sticky = in_array('sticky', $options) ? 1 : 0;
  }
  else {
    $node->status = 1;
  }


  // Multiple values mushing.
  foreach ($values as $k => $v) {
    if (is_array($v)) {
      $values["$k"] = implode(', ', $v);
    }
  }

  // Fill the node object with the given values
  if (isset($values['title']) && $values['title']) {
    $node->title = $values['title'];  
    unset($values['title']);
  }
  else {
    // TODO generate a better title from the other values?
    $node->title = 'no title';
  }
  if (isset($values['body']) && $values['body']) {
    $node->title = $values['body'];
    unset($values['body']);  
  }
  
  // CCK fields values.
  foreach ($values as $field => $value) {
    $type = content_types($node->type);
    switch ($type['fields']["$field"]['type']) {
      case 'link' :
      $node->{$field}[0]['url'] = $value;
        break;
      case 'content_taxonomy':
			// change to tid
			$possibilities = taxonomy_get_term_by_name($value);
	        $typed_term_tid = NULL; // tid match, if any.
	        foreach ($possibilities as $possibility) {
	          if ($possibility->vid == $type['fields']["$field"]['vid']) {
	            $typed_term_tid = $possibility->tid;
	          }
	        }
			
	        if (!$typed_term_tid) {
	          $edit = array('vid' => $type['fields']["$field"]['vid'], 'name' => $value);
	          $status = taxonomy_save_term($edit);
	          $typed_term_tid = $edit['tid'];
	        }
			$value =$typed_term_tid;
      default:
        $node->{$field}[0]['value'] = $value;
    }
  }
//  $node->teaser = node_teaser();
  $node->created = time();
  $node->uid = 1;
  node_object_prepare($node);
  
  node_save($node);
  
  // Store the saved instance in the rdfproxy_instances table.
  $instance = new stdClass();
  $instance->id = $node->nid;
  $instance->type = 'node';
  $instance->profile = $profile_name;
  // FIXME pass this information as well.
  $instance->uri = $uri;
  $instance->expires = time() + $profile->expires_after;
  //var_dump($instance);
  
  if (isset($nid)) {
    drupal_write_record('rdfproxy_instances', $instance, 'id');
    drupal_set_message('The RDF proxy instance has been updated');
  }
  else {
    drupal_write_record('rdfproxy_instances', $instance);
    drupal_set_message('The RDF proxy instance has been created');
  }

  // Go to the instance now that it's been created/refreshed.
//  drupal_goto('node/' . $node->nid);
  
//var_dump($node);
   return $node;
}


/**
 * Specialized menu callback to load an RDF proxy profile.
 */
function rdfproxy_get_profile($name) {
  $fields = drupal_schema_fields_sql('rdfproxy_profiles', 'p');
  $fields = implode(', ', $fields);
  $profile = db_fetch_object(db_query("SELECT $fields FROM {rdfproxy_profiles} p WHERE p.name = '%s'", $name));
  return $profile;
}

/**
 * Add/edit RDF proxy profile form.
 */
function rdfproxy_add_profile_form(&$form_state, $profile = NULL) {
//  var_dump($profile);
  $form = array();
  if (!$profile) {
    // A new profile is being created, remember it for the next FAPI steps.
    $form['name'] = array(
      '#type' => 'textfield',
      '#title' => t('RDF proxy profile name'),
      '#description' => t('This is the unique name of the profile. It must contain only alphanumeric characters and underscores.'),
      '#required' => TRUE,
      '#maxlength' => 32,
      '#default_value' => $profile ? $profile->name : '',
    );    
  }
  else {
    drupal_set_title(t('Edit %profile RDF proxy profile', array('%profile' => $profile->name)));
    $form['rpid'] = array('#type' => 'value', '#value' => $profile->rpid);
    $form['name'] = array('#type' => 'value', '#value' => $profile->name);
  }

  $form['description'] = array(
    '#type' => 'textfield',
    '#title' => t('Profile description'),
    '#description' => t('This description will appear on the RDF proxy administrative UI to tell you what the profile is about.'),
    '#default_value' => $profile ? $profile->description : '',
  );

//  $form['tag'] = array(
//    '#type' => 'textfield',
//    '#title' => t('View tag'),
//    '#description' => t('Enter an optional tag for this view; it is used only to help sort views on the administrative page.'),
//    '#default_value' => $view ? $view->tag : '',
//    '#autocomplete_path' => 'admin/views/ajax/autocomplete/tag',
//  );

  $form['sparql_endpoint'] = array(
    '#type' => 'textfield',
    '#title' => t('SPARQL endpoint'),
    '#description' => t(''),
    '#required' => TRUE,
    '#default_value' => $profile ? $profile->sparql_endpoint : '',
  );
  $form['sparql_query'] = array(
    '#type' => 'textarea',
    '#title' => t('SPARQL query'),
    '#rows' => 10,
    '#required' => TRUE,
    '#description' => t('This CONSTRUCT SPARQL query will be used to map the schema of RDF data to the local schema.'),
    '#default_value' => $profile ? $profile->sparql_query : '',
  );
  $form['expires_after'] = array(
    '#type' => 'select',
    '#title' => t('Expiration time'),
    '#options' => array(
      '60' => t('1 minute'),
      '3600' => t('1 hour'),
      '86400' => t('1 day'),
      '0' => t('Never')
    ),
    '#default_value' => $profile ? $profile->expires_after : '3600',
    '#description' => t('Duration after which a RDF proxy instance should be refreshed.')
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save'),
  );
  
  return $form;

}

/**
 * Validate the add view form.
 */
function rdfproxy_add_profile_form_validate($form, &$form_state) {
  $name = $form_state['values']['name'];

  // Profile name must be alphanumeric or underscores, no other punctuation.
  if (preg_match('/[^a-zA-Z0-9_]/', $name)) {
    form_error($form['name'], t('Profile name must be alphanumeric or underscores only.'));
  }

  // Profile name must already exist.

  if ($view && $view->type != t('Default')) {
    form_error($form['name'], t('You must use a unique name for this profile.'));
  }
}

/**
 * Process the add view form
 */
function rdfproxy_add_profile_form_submit($form, &$form_state) {
  $profile = (object) $form_state['values'];
  if ($profile->rpid) {
    drupal_write_record('rdfproxy_profiles', $profile, 'rpid');
    drupal_set_message(t('The profile %profile has been udpated.', array('%profile' => $profile->name)));
  }
  else {
    drupal_write_record('rdfproxy_profiles', $profile);
    drupal_set_message(t('The profile %profile has been created.', array('%profile' => $profile->name)));
    $form_state['redirect'] = 'admin/build/rdfproxy/edit/' . $profile->name;
  }
}


/**
 * Implementation of hook_nodeapi().
 */
function rdfproxy_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL) {
  switch ($op) {
    case 'load':
      // TODO
      break;
    case 'delete':
      db_query("DELETE FROM {rdfproxy_instances} WHERE id = %d", $node->nid);      
      break;
  }
}