<?php

/**
 * @file
 *
 * This api renders includes/graph.inc data structures into visual graphs.
 *
 * The module makes use of the HTML5 canvas and adds
 * new HTML tags <edges> and <edge>
 *
 * $g['node']['data'] = your data
 * $g['node']['data']['title'] = simple label
 * $g['node']['data']['content'] = html contents used for rendering
 * $g['node']['edges']['node-to']['data'] = your link data
 */

/**
 * Implements hook_menu().
 */
function graphapi_menu() {
  return array(
    'admin/config/system/graphapi' => array(
      'title' => 'Graph API',
      'description' => 'Graph API and engines settings.',
      'page callback' => 'drupal_get_form',
      'page arguments' => array('graphapi_engines_form'),
      'access arguments' => array('administer site configuration'),
    ),
    'admin/config/system/graphapi/engines' => array(
      'title' => 'Engines overview',
      'description' => 'Show and adjust the engines',
      'page callback' => 'drupal_get_form',
      'page arguments' => array('graphapi_engines_form'),
      'access arguments' => array('administer site configuration'),
      'type' => MENU_LOCAL_TASK,
    ),
  );
}

/**
 * Helper function to remove the views oriented default values.
 *
 * @param array $values
 *
 * @return array
 *   A tree of key/value pairs
 *
 * @see hook_graphapi_settings_form()
 * @see views_plugin_style::option_definition()
 */
function _graphapi_remove_views_defaults($values = array()) {
  $result = array();
  foreach ($values as $key => $value) {
    if (isset($value['contains'])) {
      $result[$key] = _graphapi_remove_views_defaults($value['contains']);
    }
    else {
      $result[$key] = $value['default'];
    }
  }
  return $result;
}

function graphapi_engines_form() {
  $form = array();

  $form_state = array();
  $form = graphapi_settings_form($form, $form_state);

  $engines = graphapi_views_formats();
  foreach ($engines as $engine => $data) {
    // we need to extract the views structure :(
    $settings = module_invoke($engine, 'graphapi_default_settings');
    if (!isset($settings)) {
      $defaults = array($engine => array());
    }
    else {
      $defaults = _graphapi_remove_views_defaults($settings);
    }
    $config = $defaults[$engine];
    $config['id'] = $engine;
    $config['engine'] = $engine;
    $config += array(
      'height' => 300,
      'width' => 400,
    );
    $setup = array(
      'graph' => _graphapi_demo_graph(),
      'config' => $config,
    );
    $result = theme('graphapi_dispatch', $setup);
    $form[$engine]['demo'] = array(
      '#type' => 'fieldset',
      '#title' => check_plain($data),
      '#description' => t("This is a graph rendered with the defaults from the engine."),
    );
    $form[$engine]['demo']['content'] = array(
      '#prefix' => '<div>',
      '#markup' => $result,
      '#suffix' => '</div>',
      '#weight' => -1,
    );
    $form[$engine]['#collapsed'] = FALSE;
  }

  return $form;
}

function _graphapi_demo_graph() {
  $graph = graphapi_new_graph();
  graphapi_add_link($graph, "graphapi_relation", "relation");
  graphapi_add_link($graph, "graphapi_relation", "graphapi");
  graphapi_add_link($graph, "graphapi", "views");
  graphapi_add_link($graph, "php", "graphapi");
  graphapi_add_link($graph, "graphapi", "graph_phyz");
  graphapi_add_link($graph, "graphapi", "graphviz_filter");
  graphapi_add_link($graph, "graphapi", "thejit");
  graphapi_add_link($graph, "thejit", "thejit_spacetree");
  graphapi_add_link($graph, "thejit", "thejit_forcedirected");
  graphapi_add_link($graph, "thejit", "thejit_x");
  return $graph;
}

/**
 * Creates a new empty graph array.
 */
function graphapi_new_graph() {
  return array();
}

/**
 * Adds a graph node to an existing graph array, if it doesn't already exist.
 *
 * @param $graph
 *   Graph array, passed by reference.
 * @param $id
 *   Id of the node to add.
 */
function graphapi_add_node(&$graph, $id) {
  if (!isset($graph[$id])) {
    $graph[$id]['edges'] = array();
    $graph[$id]['data'] = array();
    // Set the graph title to the $id, incase it isn't set later.
    $graph[$id]['data']['title'] = $id;
  }
}

/**
 * Adds data to a graph node.
 *
 * @param $graph
 *   Graph array, passed by reference.
 * @param $id
 *   Id of the node to add data to.
 * @param $data
 *   Graph node data associative array, containing:
 *   - 'title': title of the graph node.
 *   - 'uri': URI of the graph node.
 *   - 'content': HTML string of body content of the graph node.
 */
function graphapi_set_node_data(&$graph, $id, $data) {
  graphapi_add_node($graph, $id);
  $current_data = $graph[$id]['data'];
  // Merge with current data.
  if (is_array($current_data)) {
    //  Latest data is more important
    $data = $data + $current_data;
  }
  $graph[$id]['data'] = $data;
}

/**
 * Sets the title of a graph node.
 *
 * @param $graph
 *   Graph array, passed by reference.
 * @param $id
 *   Id of the node for which to set the title.
 * @param $title
 *   Title string.
 */
function graphapi_set_node_title(&$graph, $id, $title) {
  graphapi_add_node($graph, $id);
  $graph[$id]['data']['title'] = $title;
}

/**
 * Sets the uri of a graph node, to which the graph will link.
 *
 * @param $graph
 *   Graph array, passed by reference.
 * @param $id
 *   Id of the node for which to set the title.
 * @param $uri
 *   URI string.
 */
function graphapi_set_node_uri(&$graph, $id, $uri) {
  graphapi_add_node($graph, $id);
  $graph[$id]['data']['uri'] = $uri;
}

/**
 * Sets the uri of a graph node, to which the graph will link.
 *
 * @param $graph
 *   Graph array, passed by reference.
 * @param $id
 *   Id of the node for which to set the title.
 * @param $content
 *   HTML string of body content.
 */
function graphapi_set_node_content(&$graph, $id, $content) {
  graphapi_add_node($graph, $id);
  $graph[$id]['data']['content'] = $content;
}

/**
 * Adds a directed edge to the graph.
 *
 * @param $graph
 *   Graph array, passed by reference.
 * @param $from_id
 *   Id of the source graph node for the edge.
 * @param $to_id
 *   Id of the target graph not for the edge.
 */
function graphapi_add_link(&$graph, $from_id, $to_id) {
  graphapi_add_node($graph, $from_id);
  graphapi_add_node($graph, $to_id);
  if (!isset($graph[$from_id]['edges'][$to_id])) {
    $graph[$from_id]['edges'][$to_id] = array();
  }
}

/**
 * Adds a title to an existing edge in the graph.
 *
 * @param $graph
 *   Graph array, passed by reference.
 * @param $from_id
 *   Id of the source graph node for the edge.
 * @param $to_id
 *   Id of the target graph not for the edge.
 * @param $title
 *   Title string.
 */
function graphapi_set_link_title(&$graph, $from_id, $to_id, $title) {
  graphapi_add_link($graph, $from_id, $to_id);
  $graph[$from_id]['edges'][$to_id]['title'] = $title;
}

/**
 * Adds data to a graph node.
 *
 * @param $graph
 *   Graph array, passed by reference.
 * @param $from_id
 *   Id of the source graph node for the edge.
 * @param $to_id
 *   Id of the target graph not for the edge.
 * @param $data
 *   Graph node data associative array, containing:
 *   - 'title': title of the graph edge.
 */
function graphapi_set_link_data(&$graph, $from_id, $to_id, $data) {
  graphapi_add_link($graph, $from_id, $to_id);
  $graph[$from_id]['edges'][$to_id]['data'] = $data;
}

/**
 * Returns default graph settings.
 */
function graphapi_default_config() {
  $temp = graphapi_settings_defaults();
  $result = $temp['settings']['graph'];
  $result['id'] = 'default';

  return $result;
}

/**
 * Provide default setup values
 *
 * @return type
 */
function graphapi_settings_defaults() {
  $result = array(
    'label' => t('Graph'),
    'settings' => array(
      'global' => array(
        'use_global' => FALSE,
      ),
      'graph' => array(
        'animate' => TRUE,
        'background-color' => 'grey',
        'height' => '800',
        'menu' => TRUE,
        'randomize' => TRUE,
        'rankType' => 'TopBottom',
        'rankDepth' => 2,
        'showLinks' => FALSE,
        'width' => '800',
      ),
      'physics' => array(
        'showForces' => FALSE,
        'applyAttractToCenter' => TRUE,
        'applyBoundingBox' => FALSE,
        'applyBoxOverlap' => FALSE,
        'applyCoulombsLaw' => TRUE,
        'applyDamping' => TRUE,
        'applyHookesLaw' => TRUE,
        'applyCompass' => FALSE,
      ),
      'links' => array(),
    ),
  );
  return $result;
}

/**
 * Renders the HTML for the given graph containing the canvas and divs
 *
 * @param $graph
 *   Graph array.
 * @param $config
 *   Graph config array (see graphapi_default_config() for details).
 */
function graphapi_container($graph, $config = array()) {
  $config+= graphapi_default_config();
  $config['id'] = 'graphapi-' . $config['id'];
  $config['canvas-id'] = $config['id'] . '-canvas';

  $styles = array(
    'width' => $config['width'] . 'px',
    'height' => $config['height'] . 'px',
    'background-color' => $config['background-color'],
    '-webkit-user-select' => 'none',
    '-moz-user-select' => 'none',
    'overflow' => 'hidden',
    'position' => 'relative',
  );
  $s = '';
  foreach ($styles as $style => $value) {
    $s .= "$style: $value; ";
  }
  $attributes = array(
    'id' => $config['id'],
    'class' => 'graphapi',
    'style' => $s,
  );
  $a = drupal_attributes($attributes);
  $nl = "\n";
  $result = '';
  $result.= '<div ' . $a . '>';
  $result.= $nl . '<noscript>' . t('This page element requires JavaScript to be enabled.') . '</noscript>';
  $result.= $nl . theme('graphapi_links', array('graph' => $graph, 'config' => $config));
  $result.= $nl . '<div class="graphapi-nodes">';
  $nodes = array();
  foreach ($graph as $id => $data) {
    $dom_id = _graphapi_uniform_id($config, $id);
    if (!(isset($data['data']) && isset($data['data']['title']))) {
      $data['data']['title'] = $id;
    }
    $result .= $nl . theme('graphapi_node', array('dom_id' => $dom_id, 'data' => $data['data'], 'config' => $config));
  }
  $result .= $nl . '</div>';
  $result .= $nl . '</div>';
  _graphapi_add_graph($graph, $config);
  return $result;
}

/**
 * Implements hook_theme()
 */
function graphapi_theme() {
  return array(
    'graphapi_container' => array(
      'variables' => array(
        'graph' => NULL,
        'config' => NULL,
      ),
    ),
    'graphapi_links' => array(
      'variables' => array(
        'graph' => NULL,
        'config' => NULL,
      ),
    ),
    'graphapi_node' => array(
      'variables' => array(
        'dom_id' => NULL,
        'data' => NULL,
        'config' => NULL,
      ),
    ),
    'graphapi_title' => array(
      'variables' => array(
        'title' => NULL,
        'data' => NULL,
      ),
    ),
    'graphapi_link' => array(
      'variables' => array(
        'to_id' => NULL,
        'from_id' => NULL,
        'title' => NULL,
        'data' => NULL,
      ),
    ),
    'graphapi_dispatch' => array(
      'variables' => array(
        'graph' => NULL,
        'config' => NULL,
      ),
    ),
    'graphapi_graphviz_filter_graphapi' => array(
      'variables' => array(
        'graph' => NULL,
        'config' => NULL,
      ),
    ),
    'graphapi_raw_data_graphapi' => array(
      'variables' => array(
        'graph' => NULL,
        'config' => NULL,
      ),
    ),
  );
}

/**
 * Dispatch the graph to the correct engine
 * 
 * @param type $vars
 * @return type 
 */
function theme_graphapi_dispatch($vars) {
  $engines = graphapi_views_formats();
  $engine = '';
  if (isset($vars['config']['engine'])) {
    $engine = $vars['config']['engine'];
  }
  if (isset($engines[$engine])) {
    $theme = $engine . "_graphapi";
    return theme($theme, $vars);
  }
  else {
    if (!empty($engine)) {
      return t("Graph API render engine !engine not found.", array('!engine' => $engine));
    }
    else {
      return t("No Graph API render engines enabled. Check your modules page for a Graph API render engine");
    }
  }
}

/**
 * Rendering a graph from views
 * 
 * @param array $vars 
 */
function template_preprocess_views_graphapi_style_graphapi(&$vars) {
  _views_graphapi_style_build_graph_data($vars);
  //dsm(func_get_args(), __FUNCTION__);
  $config = $vars['graph-config'];
  $vars["xml"] = theme('graphapi_dispatch', array('graph' => $vars['graph'], 'config' => $config));
}

//TODO: move theme_functions to graph_phyz.module

/**
 * Theme implementation, returns GraphAPI container as HTML.
 */
function theme_graphapi_container($variables) {
  return graphapi_container($variables['graph'], $variables['config']);
}

/**
 * Theme implementation, returns graph title as HTML.
 */
function theme_graphapi_title($variables) {
  $title = $variables['title'];
  $data = $variables['data'];

  $attributes = array(
    'class' => 'graphapi-title',
  );
  if (isset($data['background-color'])) {
    $attributes['style'] = 'background-color: ' . $data['background-color'] . ';';
  }
  $a = drupal_attributes($attributes);

  if (isset($data['uri'])) {
    $title = '<a href="' . $data['uri'] . '">' . $title . '</a>';
  }
  return '<div ' . $a . '>' . $title . '</div>';
}

/**
 * Theme implementation, returns graph node as HTML.
 */
function theme_graphapi_node($variables) {
  $dom_id = $variables['dom_id'];
  $data = $variables['data'];
  $config = $variables['config'];

  $attributes = array(
    'id' => $dom_id,
    'class' => 'graphapi-node',
  );
  // We always add a rank ... all ranks <= 0 are not used for layout
  $attributes['rank'] = isset($data['rank']) ? $data['rank'] : 0;
  $a = drupal_attributes($attributes);

  if (isset($data['content'])) {
    $content = '<div class="graphapi-content" title="' . $data['title'] . '">' . $data['content'] . '</div>';
  }
  else {
    $content = '';
  }
  return '<div ' . $a . '>'
      . theme('graphapi_title', array('title' => $data['title'], 'data' => $data))
      . $content . '</div>';
}

/**
 * Theme implementation, returns graph edge as HTML.
 */
function theme_graphapi_link($variables) {
  $html = '<edge';
  $html.= ' from="' . $variables['from'] . '"';
  $html.= ' to="' . $variables['to'] . '"';
  if (isset($link['data']['type'])) {
    $html.= ' type="' . $variables['data']['type'] . '"';
  }
  if (isset($variables['data']['color'])) {
    $html.= ' color="' . $variables['data']['color'] . '"';
  }
  if (isset($variables['data']['classes'])) {
    $classes = $variables['data']['classes'];
    $class = join(" ", $classes);
    $html.= ' class="' . $class . '"';
  }
  $html.= '>';
  if (isset($variables['title'])) {
    $html.= '<a href="#" title="' . $variables['title'] . '">&curren;</a>';
  }
  $html.='</edge>';

  return $html;
}

/**
 * Returns the <edge> canvas node for the given graph.
 *
 * @param $graph
 *   Graph array.
 * @param $config
 *   Graph config array (see graphapi_default_config() for details).
 */
function theme_graphapi_links($variables) {
  $graph = $variables['graph'];
  $config = $variables['config'];
  $result = '<edges>';
  foreach ($graph as $from => $data) {
    foreach ($data['edges'] as $to => $link_data) {
      $link = array(
        'from' => _graphapi_uniform_id($config, $from),
        'to' => _graphapi_uniform_id($config, $to),
      );
      if (isset($link_data['title'])) {
        $link['title'] = $link_data['title'];
      }
      if (isset($link_data['data'])) {
        $link['data'] = $link_data['data'];
      }
      $result.= theme('graphapi_link', $link);
    }
  }
  $result.= '</edges>';
  return $result;
}

/**
 * Helper function. Returns unique id for each node id.
 */
function _graphapi_uniform_id($config, $id) {
  return $config['id'] . '-' . md5($id);
}

/**
 * Helper function. Adds javascript and css on to drupal pages.
 */
function _graphapi_add_graph($graph, $config) {
  $dom_prefix = $config['id'];
  $path = drupal_get_path('module', 'graphapi');
  drupal_add_library('system', 'ui.dialog');
  drupal_add_library('system', 'ui.draggable');
  drupal_add_library('system', 'ui.droppable');
  drupal_add_js($path . '/js/jquery-graphapi.js');
  drupal_add_js($path . '/js/graphapi.js');
  drupal_add_css($path . '/css/graphapi.css');
  $conf = drupal_json_encode($config);
  $id = '#' . $config['id'];
  drupal_add_js('jQuery(document).ready( function() {'
      . "\n" . '  var config = ' . $conf . ';'
      . "\n" . '  jQuery("' . $id . '").graphapi(config);'
      . "\n" . '});'
      , 'inline');

  return;
}

/**
 * Reverses all edges on a graph.
 *
 * @param $graph
 *   Graph array.
 * @param $keep_link_data
 *   boolean: whether to keep the old link data (not yet implemented).
 *
 * @return
 *   $graph array with edges in opposite direction to original.
 */
function graphapi_reverse($graph, $keep_link_data = FALSE) {
  $result = $graph;
  foreach ($result as $key => $value) {
    $result[$key]['edges'] = array();
  }
  foreach ($graph as $key => $value) {
    foreach ($graph[$key]['edges'] as $link => $link_data) {
      $result[$link]['edges'][$key] = 1;
    }
  }
  return $result;
}

// TODO move this to graphviz_filter.module
function graphapi_to_dot($graph) {
  $dot = array();
  $dot[] = "digraph {";
  foreach ($graph as $id => $node) {
    $dot[] = '  ' . $id . ' [';

    $dot[] = '    label = "' . $node['data']['title'] . '"';
    $dot[] = '  ]';
  }

  foreach ($graph as $id => $node) {
    foreach ($node['edges'] as $eid => $edge) {
      $dot[] = "  $id -> $eid";
    }
  }
  $dot[] = '}';

  return join("\n", $dot);
}

function graphapi_views_api() {
  return array(
    'api' => 3.0,
    'path' => drupal_get_path('module', 'graphapi') . '/views',
  );
}

/**
 * Return list of all hook_graphapi_formats
 */
function graphapi_views_formats() {
  return module_invoke_all('graphapi_formats');
}

/**
 * Implements hook_graphapi_formats().
 *
 * TODO: move to seperate modules
 */
function graphapi_graphapi_formats() {
  return array(
    'graphapi_graphviz_filter' => 'Graphviz Filter',
  );
}

/**
 * Implements theme_ENGINE_graphapi().
 */
function theme_graphapi_graphviz_filter_graphapi($vars) {
  $config = $vars['config'];
  return '<xmp>' . graphapi_to_dot($vars['graph']) . '</xmp>';
}

/**
 * Implements hook_graphapi_default_settings().
 */
function graphapi_graphapi_default_settings() {
  $engine = 'graphapi';
  foreach (graphapi_global_settings() as $setting => $value) {
    if (!is_array($value)) {
      $settings[$engine]['contains'][$setting] = array('default' => $value);
    }
    else {
      foreach ($value as $key => $val) {
        $settings[$engine]['contains'][$setting]['contains'][$key] = array('default' => $val);
      }
    }
  }
  return $settings;
}

/**
 * Convert a settings array to a views compatible one.
 *
 * @param $engine
 * @param $values
 *
 * @see views_plugin_style::option_definition()
 */
function graphapi_settings_to_views($engine, $values) {
  $result = array(
    $engine => _graphapi_settings_to_views($values),
  );
  return $result;
}

function _graphapi_settings_to_views($value) {
  if (!is_array($value)) {
    $result = array('default' => $value);
  }
  else {
    $result = array();
    foreach ($value as $key => $val) {
      $result['contains'][$key] = _graphapi_settings_to_views($val);
    }
  }
  return $result;
}

function graphapi_global_settings() {
  return array(
    'width' => 400,
    'height' => 300,
    'background-color' => 'yellow',
    'cascade' => '',
  );
}

/**
 * Provide general settings
 */
function graphapi_global_settings_form($values) {
  $values += graphapi_global_settings();

  // This is our 'global' engine
  $engine = 'graphapi';
  $form[$engine] = array(
    '#title' => t('Global settings'),
    '#type' => 'fieldset',
    '#collapsed' => FALSE,
    '#collapsible' => TRUE,
  );
  $form[$engine]['width'] = array(
    '#title' => t('Width'),
    '#type' => 'textfield',
    '#default_value' => $values['width'],
  );
  $form[$engine]['height'] = array(
    '#title' => t('Height'),
    '#type' => 'textfield',
    '#default_value' => $values['height'],
  );
  $form[$engine]['background-color'] = array(
    '#title' => t('Background color'),
    '#type' => 'textfield',
    '#default_value' => $values['background-color'],
  );

  return $form;
}

/**
 * Gathers all relevant settings for all engines
 *
 * Each engine form is a fieldset containing it's specific settings
 * 
 * Ie width, height, background-color are graphapi settings
 * Ie show_menu or node_color is engine specific.
 * 
 * @see graphapi_global_settings_form().
 * @see graph_phyz_settings_form().
 */
function graphapi_settings_form($form, &$form_state) {
  $values = isset($form_state['values']) ? $form_state['values'] : array();
  if (!isset($values['graphapi'])) {
    $values['graphapi'] = array();
  }

  $form += graphapi_global_settings_form($values['graphapi']);

  $engines = graphapi_views_formats();
  $implementations = module_implements('graphapi_settings_form');
  $order = 1;
  foreach ($engines as $engine => $title) {
    if (in_array($engine, $implementations)) {
      $form += _graphapi_engine_form($engine, $values);
      $form[$engine]['#weight'] = $order++;
    }
    else {
      $no_settings = array();
      $no_settings[$engine] = array(
        '#title' => t('No settings for') . ': ' . $title,
        '#type' => 'fieldset',
        '#collapsed' => TRUE,
        '#collapsible' => FALSE,
      );
      $no_settings[$engine]['dummy'] = array(
        '#markup' => 'The module does not yet support a graphapi settings form. You could check the issue queue for that module.',
      );
      $form += $no_settings;
      $form[$engine]['#weight'] = count($engines);
    }
    $form[$engine]['#collapsible'] = TRUE;
  }
  return $form;
}

/**
 * Helper function to get engine subforms
 */
function _graphapi_engine_form($engine, $values) {
  if (!isset($values[$engine])) {
    $values[$engine] = array();
  }
  $values = $values[$engine];
  $function = $engine . "_graphapi_settings_form";
  return call_user_func($function, $values);
}

function graphapi_demo_engines($engine = 'graph_phyz') {
  $graph = _graphapi_demo_graph();

  $config = array(
    'engine' => $engine,
    'width' => 400,
    'height' => 300,
    'background-color' => '#AAA',
    'duration' => 400,
  );
  return theme('graphapi_dispatch', array('graph' => $graph, 'config' => $config));
}