<?php

// Uncomment to test
// $_GET['name'] = 'FragmentManager.BackStackEntry';

$baseUrl = 'http://developer.android.com';
$classesPath = '/reference/classes.html';

$cacheFile = 'cache.xml';
$cacheTTL = 14400;

// Converts all blocks of whitespace to a single SP
function space($str)
{
    return preg_replace('/\s{2,}/', ' ', $str);
}

// Attempts to converts a DOMElement to sensible markdown
function dom_to_markdown(DOMElement $el, $baseUrl, $trim = 0)
{
    $result = '';

    foreach ($el->childNodes as $child) {
        if ($child instanceof DOMText) {
            $result .= space($child->data);
        } else if ($child instanceof DOMElement) {
            if (strtolower($child->tagName) === 'em' || strtolower($child->tagName) === 'emb') {
                $result = '*' . dom_to_markdown($child, $baseUrl, 2) . '*';
            } else if (strtolower($child->tagName) === 'i') {
                $result .= '*' . space($child->firstChild->data) . '*';
            } else if (strtolower($child->tagName) === 'b' || strtolower($child->tagName) === 'strong') {
                $result .= '**' . space($child->firstChild->data) . '**';
            } else if (strtolower($child->tagName) === 'p') {
                $result = space($result . dom_to_markdown($child, $baseUrl));
            } else if (strtolower($child->tagName) === 'tt' || strtolower($child->tagName) === 'blockquote') {
                $result .= '`' . space($child->firstChild->data) . '`';
            } else if (strtolower($child->tagName) === 'br') {
                $result = space($result . ' ');
            } else if (strtolower($child->tagName) === 'code') {
                if ($child->firstChild instanceof DOMText) {
                    $result .= '`' . space($child->firstChild->data) . '`';
                } else if ($child->firstChild instanceof DOMElement && strtolower($child->firstChild->tagName) === 'a' && $child->firstChild->firstChild instanceof DOMText) {
                    $result .= '[`' . space($child->firstChild->firstChild->data) . '`](' . $baseUrl . $child->firstChild->getAttribute('href') . ')';
                }
            } else if (strtolower($child->tagName) === 'a' && $child->firstChild instanceof DOMText) {
                $result .= '[' . space($child->firstChild->data) . '](' . $baseUrl . $child->getAttribute('href') . ')';
            }
        }
    }

    return substr(trim($result, " \t\r\n\x00\xC2\xA0"), 0, 350 - $trim);
}

error_reporting(0);

if (!isset($_GET['name'])) {
    header('HTTP/1.1 400 Bad Request');
    exit('No class specified');
}
$class = basename($_GET['name']);

$cache = new DOMDocument('1.0', 'utf-8');

if (!file_exists($cacheFile) || filemtime($cacheFile) < time() - $cacheTTL) {
    // Rebuild cache file
    $remote = new DOMDocument;
    @$remote->loadHTMLFile($baseUrl . $classesPath);
    $remoteXPath = new DOMXPath($remote);

    $cacheRoot = $cache->appendChild($cache->createElement('root'));

    $result = $remoteXPath->query("//td[@class='jd-linkcol']/a");
    foreach ($result as $match) {
        $el = $cache->createElement(strtolower($match->firstChild->data));
        $el->setAttribute('name', $match->firstChild->data);
        $el->setAttribute('href', $baseUrl . $match->getAttribute('href'));
        $desc = $remoteXPath->query("./td[@class='jd-descrcol']", $match->parentNode->parentNode)->item(0);
        $el->setAttribute('desc', dom_to_markdown($desc, $baseUrl));
        $cacheRoot->appendChild($el);
    }

    unset($remote, $remoteXPath, $result, $match, $cacheRoot, $el);

    $cache->save($cacheFile);
} else {
    // Load cache
    $cache->load($cacheFile);
}

// Find the class we want
$xpath = new DOMXPath($cache);
if (!$result = $xpath->query('/root/' . strtolower($class))->item(0)) {
    header('HTTP/1.1 404 Not Found');
    exit("Unable to locate class {$class}");
}

// Create the markdown
$result = '[`' . $result->getAttribute('name') . '`](' . $result->getAttribute('href') . ') - ' . $result->getAttribute('desc');

// JSONP-ify if required
if (isset($_GET['callback'])) {
    $result =  $_GET['callback'] . '(' . json_encode(array('src' => $result)) . ')';
}

echo $result;