<?php

require_once 'config.php';
$instance = $config['mastodon-instance'];
$uid = $config['user-id'];
$searchurl = $config['search-url'];
$search = isset($_GET['search']) ? $_GET['search'] : '';
$debug_on = true;
/* cache files */
$dbt = "cache-toots.json";

/* Exit if search empty */
if (empty($search)) {
  debug("No proper search given");
  die();
}

/* MISC FUNCTIONS */
function debug($data) {
  global $debug_on;
  if ($debug_on === true) {
    error_log("[getcomments.php] " . print_r($data, TRUE));
  }
}

/* CACHE FUNCTIONS */
/* write data to file */
function write_db($db, $data) {
  // encode and write file
  $encoded = json_encode($data, JSON_PRETTY_PRINT);
  file_put_contents($db, $encoded, LOCK_EX);
}
/* access data from file */
function read_db($db, &$data) {
  // if DB does not exist, create it with empty array
  if (! file_exists($db)) {
    touch($db);
    write_db($db, array());
  }
  $file = file_get_contents($db, true);
  $data = json_decode($file, true);
}

/* TOOT FUNCTIONS */
function collectToots($instance, $uid, $min_id, $searchurl) {
  $raw = file_get_contents("$instance/api/v1/accounts/$uid/statuses?exclude_reblogs=true&exclude_replies=true&limit=50&min_id=$min_id");
  $json_complete = json_decode($raw, true);
  $json = array();
  foreach ($json_complete as $toot) {
    $json[] = array('id' => $toot['id'], 'date' => $toot['created_at'] ,'url' => analyzeToot($instance, $toot['id'], $searchurl));
  }
  return($json);
}
/* Find out if a toot contains the searched URL */
function analyzeToot($instance, $id, $searchurl) {
  debug("Searching for $searchurl in $id");
  $raw = file_get_contents("$instance/api/v1/statuses/$id");
  $json = json_decode($raw, true);

  preg_match("|$searchurl.+?(?=\")|i", $json['content'], $matches);

  if(!empty($matches)) {
    return(strtolower($matches[0]));
  } else {
    return("");
  }
}


/* Collect all the toots */
/* get id of latest cached toot, and set as $min_id */
read_db($dbt, $toots);
$toots_cached = $toots;
if (!empty($toots['0']['id'])) {
  $min_id_cached = $toots['0']['id'];
  $min_id = $min_id_cached;
} else {
  /* if cached toots do not exist, start from oldest toot */
  $min_id = "0";
  $min_id_cached = "0";
}

/* test whether there are new toots available */
// Search for toots older than the cached latest toot ID ($min_id)
$uptodate = false;
while ($uptodate === false) {
  $toots = array_merge(collectToots($instance, $uid, $min_id, $searchurl), $toots);
  $min_id_new = $toots['0']['id']; // the latest ID of the recent search
  if ($min_id_new === $min_id) {
    // min_id is the latest, let's write the new DB and end this loop
    $uptodate = true;
    debug("Rewrite cache DB.");
    write_db($dbt, $toots);
  } else {
    // next round looks for toots newer than the newly found ID
    debug("Newer toots than in cache found. Starting another search for new toots");
    $min_id = $min_id_new;
  }
}

/* check if URL from $search exists in $toots */
// if multiple exist, take the oldest one (highest array position)
$id = array_keys(array_column($toots, 'url'), strtolower($search));
if (empty($id)) {
  debug("Blog URL \"$search\" has not been found");
  die();
}
$id = $toots[end($id)]['id'];

/* Extract comments and stats from toot */
$result = ['comments' => [], 'stats' => ['reblogs' => 0, 'favs' => 0, 'replies' => 0, 'url' => '', 'root' => 0]];

function filterComments($descendants, $root, &$result) {
  foreach ($descendants as $d) {
    $result['comments'][$d['id']] = [
      'author' => [
        'display_name' => $d['account']['display_name'] ? $d['account']['display_name'] : $d['account']['username'],
        'avatar' => $d['account']['avatar_static'],
        'url' => $d['account']['url']
      ],
      'toot' => $d['content'],
      'date' => $d['created_at'],
      'url' => $d['uri'],
      'reply_to' => $d['in_reply_to_id'],
      'root' => $root,
    ];
  }
  return $result;
}

function tootContext($instance, $id, &$result) {
  $raw = file_get_contents("$instance/api/v1/statuses/$id/context");
  $json = json_decode($raw, true);
  filterComments($json['descendants'], $id, $result);
}

function filterStats($stats) {
  $result = [
    'reblogs' => (int)$stats['reblogs_count'],
    'favs' => (int)$stats['favourites_count'],
    'replies' => (int)$stats['replies_count'],
    'url' => $stats['url']
  ];
  return $result;
}

function tootStats($instance, $id, &$result) {
  debug("Checking ID $id");
  $raw = file_get_contents("$instance/api/v1/statuses/$id");
  $json = json_decode($raw, true);
  $newStats = filterStats($json);
  $result['stats']['reblogs'] += $newStats['reblogs'];
  $result['stats']['favs'] += $newStats['favs'];
  $result['stats']['replies'] += $newStats['replies'];
  if (empty($result['stats']['url'])) {
    $result['stats']['url'] = $newStats['url'];
  }
}

// FIXME: At the moment the API doesn't return the correct replies count so I count it manually
$result['stats']['replies'] = count($result['comments']);
$result['stats']['root'] = $id;
tootContext($instance, $id, $result);
tootStats($instance, $id, $result);


// headers for not caching the results
header('Cache-Control: no-cache, must-revalidate');
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');

// headers to tell that result is JSON
header('Content-type: application/json');

echo json_encode($result);

?>