<?php
// $Id: twitter_pull.module,v 1.1.2.7 2011/01/11 04:08:04 inadarei Exp $

/**
 * @file
 * Twitter Pull module.
 */

require_once (dirname(__FILE__) . '/twitter_pull.class.inc');

define ('TWITTER_PULL_NUM_ITEMS', 5);
define ('TWITTER_PULL_CACHE_LENGTH', 20); //-- cache for 20 minutes
define ('TWITTER_PULL_EMPTY_MESSAGE', 'No Tweets');
define ('TWITTER_PULL_CACHE_TABLE', 'cache_pulled_tweets');

function twitter_pull_num_items() {
  return variable_get('twitter_pull_num_items', TWITTER_PULL_NUM_ITEMS);
}

function twitter_pull_cache_length() {
  return variable_get('twitter_pull_cache_length', TWITTER_PULL_CACHE_LENGTH);
}

function twitter_pull_empty_message() {
  return variable_get('twitter_pull_empty_message', TWITTER_PULL_EMPTY_MESSAGE);
}

/**
 * Implementation of hook_flush_caches().
 */
function twitter_pull_flush_caches() {
  return array(TWITTER_PULL_CACHE_TABLE);
}

/**
 * Implementation of hook_init().
 */
function twitter_pull_init() {
  $css_path = drupal_get_path('module', 'twitter_pull') . '/twitter-pull-listing.css';
  drupal_add_css($css_path);
}

/**
 * Retrieves appropriate tweets (by username, hashkey or search term)
 * and passes over to the theming function with $themekey key passing
 * tweets array along.
 *
 * The rest of this module needs to make sure that corresponding theming
 * functions exist, exist tweets array and perform desired theming.
 *
 * @param $twitkey
 *     Twitter key, which can be a username (prepended with @), hashtag
 *     (prepended with #), or a search term.
 * @param $title
 *     Title passed to the theme template.
 * @param $num_items
 *     Number of tweets to retrieve from Twitter. Can't be more than 200.
 * @param $themekey
 *     Theme key name to use for theming the output of Twitter API.
 */
function twitter_pull_render($twitkey, $title = NULL, $num_items = NULL, $themekey = NULL) {
  //-- Set defaults if empty arguments were passed
  $title = (empty($title) && $title != FALSE ) ? t('Related Tweets') : $title;
  $themekey = empty($themekey) ? 'twitter_pull_listing' : $themekey;
  $num_items = empty($num_items) ? twitter_pull_num_items() : $num_items;

  $tweets = twitter_pull_retrieve($twitkey, $num_items);

  $ret = theme($themekey, $tweets, $twitkey, $title);

  if (empty($ret) && !empty($tweets)) {
    $errmsg = t("Non-empty list of tweets returned blank space after applying theme function. Most probably you are passing invalid/unregistered theme key or tpl file corresponding to the theme key does not yet exist. Please fix the problem.");
    watchdog('Twitter Pull', $errmsg, array(), WATCHDOG_WARNING);
    $ret = t('Errors occured while trying to retrieve tweets. Please check Watchdog log messages.');
  }

  return $ret;
}

/**
 * Retrieves tweets by username, hashkey or search term.
 *
 * @param $twitkey
 *     Twitter key, which can be a username (prepended with @), hashtag
 *     (prepended with #), or a search term.
 * @param $num_items
 *     Number of tweets to retrieve from Twitter. Can't be more than 200.
 */
function twitter_pull_retrieve($twitkey, $num_items = NULL) {
  // If $num_items is not set, use the default value.
  // This value is checked more rigorously in twitter_puller->check_arguments().
  $num_items = (intval($num_items) > 0) ? intval($num_items) : twitter_pull_num_items();

  // Cached value is specific to the Twitter key and number of tweets retrieved.
  $cache_key = $twitkey . '::' . $num_items;
  $cache = cache_get($cache_key, TWITTER_PULL_CACHE_TABLE);

  $tweets = array();

  if (!empty($cache) && !empty($cache->data)) {
    $tweets =  $cache->data;
  }
  else {
    try {
      $puller = new twitter_puller($twitkey, $num_items);
      $puller->get_items();
      $tweets = $puller->tweets;
    }
    catch (Exception $e) {
      watchdog('Twitter Pull', $e->getMessage(), array(), WATCHDOG_WARNING);
      return twitter_pull_empty_message();
    }

    if (!empty($tweets) && is_array($tweets)) {
      $cache_length = twitter_pull_cache_length() * 60; //-- in the settings we indicate length in minutes, here we need seconds.
      cache_set($cache_key, $tweets, TWITTER_PULL_CACHE_TABLE, time() + $cache_length);
    }
  }

  return $tweets;
}

/**
 * Automatically add links to URLs and Twitter usernames in a tweet.
 */
function twitter_pull_add_links($text) {
  $pattern = '#(https?)://([^\s\(\)\,]+)#ims';
  $repl = '<a href="$1://$2" rel="nofollow" title="$1://$2">$2</a>';
  $text = preg_replace($pattern, $repl, $text);

  $pattern = '#@(\w+)#ims';
  $repl = '@<a href="http://twitter.com/$1" rel="nofollow" title="@$1">$1</a>';
  $text = preg_replace($pattern, $repl, $text);

  $pattern = '/[#]+([A-Za-z0-9-_]+)/';
  $repl = '#<a href="http://twitter.com/#!/search?q=%23$1" title="#$1" rel="nofollow">$1</a>';
  $text = preg_replace($pattern, $repl, $text);  

  return $text;
}

/**
 * Sample theme definitions that can be applied to tweets.
 */
function twitter_pull_theme() {
  return array(
    'twitter_pull_listing' => array(
      'arguments' => array('tweets' => NULL, 'twitkey' => NULL, 'title' => NULL),
      'template' => 'twitter-pull-listing',
    ),
  );
}

/**
 * Implementation of hook_block()
 * Note we are getting info about blocks from the 
 * twitter_pull_block_data function 
 * if at some time this data is store in the db (currently
 * it is just in code) then we would want to add the config 
 * options in a $op = configure
 */
function twitter_pull_block($op = 'list', $delta = 0, $edit = array()) {
  $info = twitter_pull_block_data();
  switch($op) {
    case 'list' :
      return  array_map(create_function('$a', 'return array("info"=>$a->name);'),$info);
      break;
    case 'view' :
      $b_info = $info["$delta"];
      $content = twitter_pull_render($b_info->tweetkey, $b_info->title, $b_info->number_of_items, $b_info->theme_key);
      return array("subject"=>"", "content"=>$content);
      break;
  }
}


/* 
 * data hook for twitter_pull blocks.  
 * RETURN an array of data object with the following properties
 *   delta (unique for all blocks)
 *   name
 *   title - optional, defaults to name
 *   tweetkey
 *   number_of_items - optional, defaults to 5
 *   theme_key - optional, defaults to twitter_pull_listing. if you set anything else you have to implement corresponding theme in hook_theme()!
 */
function twitter_pull_block_data() {
  static $data;
  
  //-- Static cache;
  if (!empty($data)) return $data;
  
  $data = module_invoke_all('twitter_pull_blocks');
  drupal_alter('twitter_pull_data', $data);
  
  //-- Do some cleanup
  if (!empty($data) && is_array($data)) {
    foreach ($data as &$block) {
      //-- assign defaults
      $block->title = (empty($block->title)) ? $block->name : $block->title;     
      $block->number_of_items = (empty($block->number_of_items)) ? 5 : $block->number_of_items;      
      $block->theme_key = (empty($block->theme_key)) ? 'twitter_pull_listing' : $block->theme_key;            
    }  
  }
  else {
    $data = array();
  }
  
  return $data;
}


/****** FOR TESTING ONLY. KEEP DISABLED AT ALL TIMES UNLESS DEBUGGING ******/

/*
function twitter_pull_menu() {
  $items = array();

  $items['twitter/pull/test'] = array(
    'title' => 'Twitter Pull Test',
    'page callback' => 'twitter_pull_test',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  return $items;
}

function twitter_pull_test() {
  return twitter_pull_render('@inadarei');
}
*/