diff --git a/web/app/libs/uoj-html-lib.php b/web/app/libs/uoj-html-lib.php
new file mode 100644
index 0000000..40cd787
--- /dev/null
+++ b/web/app/libs/uoj-html-lib.php
@@ -0,0 +1,18 @@
+<?php
+
+function renderMarkdown($content_md) {
+    $purifier = HTML::pruifier();
+
+    try {
+        $v8 = new V8Js();
+        $v8->content_md = $content_md;
+        $v8->executeString(file_get_contents($_SERVER['DOCUMENT_ROOT'] . '/js/marked.js'), 'marked.js');
+        $content = $v8->executeString('marked(PHP.content_md)');
+    } catch (V8JsException $e) {
+        throw new Exception('V8Js error: ' . $e->getMessage());
+    }
+
+    $content = $purifier->purify($content);
+
+    return $content;
+}
diff --git a/web/app/libs/uoj-luogu-lib.php b/web/app/libs/uoj-luogu-lib.php
new file mode 100644
index 0000000..220a074
--- /dev/null
+++ b/web/app/libs/uoj-luogu-lib.php
@@ -0,0 +1,75 @@
+<?php
+
+define('LUOGU_BASE_URL', 'https://www.luogu.com.cn');
+define('LUOGU_API_BASEURL', 'https://open-v1.lgapi.cn');
+define('LUOGU_SUPPORTED_LANGUAGES', ['C', 'C++', 'C++11', 'Java8', 'Pascal', 'Python2', 'Python3']);
+define('LUOGU_USER_AGENT', 'UniversalOJ/1.0 UOJ-Luogu-RemoteJudge/1.0 ( https://github.com/renbaoshuo/UOJ-Luogu-RemoteJudge )');
+
+function parseLuoguProblemData($problem) {
+    if (!$problem) return null;
+
+    $statement = '';
+
+    if ($problem['background']) {
+        $statement .= "\n### 题目背景\n\n";
+        $statement .= $problem['background'] . "\n";
+    }
+
+    $statement .= "\n### 题目描述\n\n";
+    $statement .= $problem['description'] . "\n";
+
+    if (isset($problem['translation']) && $problem['translation']) {
+        $statement .= "\n### 题意翻译\n\n";
+        $statement .= $problem['translation'] . "\n";
+    }
+
+    $statement .= "\n### 输入格式\n\n";
+    $statement .= $problem['inputFormat'] . "\n";
+
+    $statement .= "\n### 输出格式\n\n";
+    $statement .= $problem['outputFormat'] . "\n";
+
+    $statement .= "\n### 输入输出样例\n\n";
+
+    foreach ($problem['samples'] as $id => $sample) {
+        $display_sample_id = $id + 1;
+
+        $statement .= "\n#### 样例输入 #{$display_sample_id}\n\n";
+        $statement .= "\n```text\n{$sample[0]}\n```\n\n";
+
+        $statement .= "\n#### 样例输出 #{$display_sample_id}\n\n";
+        $statement .= "\n```text\n{$sample[1]}\n```\n\n";
+    }
+
+    $statement .= "\n### 说明/提示\n\n";
+    $statement .= $problem['hint'] . "\n";
+
+    return [
+        'title' => "【洛谷 {$problem['pid']}】{$problem['title']}",
+        'time_limit' => (float)max($problem['limits']['time']) / 1000.0,
+        'memory_limit' => (float)max($problem['limits']['memory']) / 1024.0,
+        'statement' => renderMarkdown($statement),
+    ];
+}
+
+function fetchLuoguProblemBasicInfo($pid) {
+    // ensure validateLuoguProblemId($pid) is true
+
+    $curl = Curl::init();
+
+    $curl->set('CURLOPT_HTTPHEADER', [
+        'User-Agent: ' . LUOGU_USER_AGENT,
+        'Content-Type: application/json',
+        'Accept: application/json',
+    ]);
+
+    $curl->url(LUOGU_BASE_URL . '/problem/' . $pid . '?_contentOnly=1');
+
+    if ($curl->error()) {
+        throw new Exception('Curl error: ' . $curl->message());
+    }
+
+    $data = json_decode($curl->data(), true);
+
+    return parseLuoguProblemData($data['currentData']['problem']);
+}
diff --git a/web/app/libs/uoj-validate-lib.php b/web/app/libs/uoj-validate-lib.php
new file mode 100644
index 0000000..21cf3b0
--- /dev/null
+++ b/web/app/libs/uoj-validate-lib.php
@@ -0,0 +1,5 @@
+<?php
+
+function validateLuoguProblemId($str) {
+	return preg_match('/^P[1-9][0-9]{3,5}$/', $str);
+}
diff --git a/web/app/models/Curl.php b/web/app/models/Curl.php
new file mode 100644
index 0000000..d8386b4
--- /dev/null
+++ b/web/app/models/Curl.php
@@ -0,0 +1,249 @@
+<?php
+
+// from https://github.com/wenpeng/curl
+// requires php-curl module
+
+use Exception;
+
+class Curl {
+    private $post;
+    private $retry = 0;
+    private $custom = array();
+    private $option = array(
+        'CURLOPT_HEADER'         => 0,
+        'CURLOPT_TIMEOUT'        => 30,
+        'CURLOPT_ENCODING'       => '',
+        'CURLOPT_IPRESOLVE'      => 1,
+        'CURLOPT_RETURNTRANSFER' => true,
+        'CURLOPT_SSL_VERIFYPEER' => false,
+        'CURLOPT_CONNECTTIMEOUT' => 10,
+    );
+
+    private $info;
+    private $data;
+    private $error;
+    private $message;
+
+    private static $instance;
+
+    /**
+     * Instance
+     * @return self
+     */
+    public static function init() {
+        if (self::$instance === null) {
+            self::$instance = new self;
+        }
+
+        return self::$instance;
+    }
+
+    /**
+     * Task info
+     *
+     * @return array
+     */
+    public function info() {
+        return $this->info;
+    }
+
+    /**
+     * Result Data
+     *
+     * @return string
+     */
+    public function data() {
+        return $this->data;
+    }
+
+    /**
+     * Error status
+     *
+     * @return integer
+     */
+    public function error() {
+        return $this->error;
+    }
+
+    /**
+     * Error message
+     *
+     * @return string
+     */
+    public function message() {
+        return $this->message;
+    }
+
+    /**
+     * Set POST data
+     * @param array|string  $data
+     * @param null|string   $value
+     * @return self
+     */
+    public function post($data, $value = null) {
+        if (is_array($data)) {
+            foreach ($data as $key => $val) {
+                $this->post[$key] = $val;
+            }
+        } else {
+            if ($value === null) {
+                $this->post = $data;
+            } else {
+                $this->post[$data] = $value;
+            }
+        }
+
+        return $this;
+    }
+
+    /**
+     * File upload
+     * @param string $field
+     * @param string $path
+     * @param string $type
+     * @param string $name
+     * @return self
+     */
+    public function file($field, $path, $type, $name) {
+        $name = basename($name);
+
+        if (class_exists('CURLFile')) {
+            $this->set('CURLOPT_SAFE_UPLOAD', true);
+            $file = curl_file_create($path, $type, $name);
+        } else {
+            $file = "@{$path};type={$type};filename={$name}";
+        }
+
+        return $this->post($field, $file);
+    }
+
+    /**
+     * Save file
+     * @param string $path
+     * @return self
+     * @throws Exception
+     */
+    public function save($path) {
+        if ($this->error) {
+            throw new Exception($this->message, $this->error);
+        }
+
+        $fp = @fopen($path, 'w');
+
+        if ($fp === false) {
+            throw new Exception('Failed to save the content', 500);
+        }
+
+        fwrite($fp, $this->data);
+        fclose($fp);
+
+        return $this;
+    }
+
+    /**
+     * Request URL
+     * @param string $url
+     * @return self
+     * @throws Exception
+     */
+    public function url($url) {
+        if (filter_var($url, FILTER_VALIDATE_URL)) {
+            return $this->set('CURLOPT_URL', $url)->process();
+        }
+
+        throw new Exception('Target URL is required.', 500);
+    }
+
+    /**
+     * Set option
+     * @param array|string  $item
+     * @param null|string   $value
+     * @return self
+     */
+    public function set($item, $value = null) {
+        if (is_array($item)) {
+            foreach ($item as $key => $val) {
+                $this->custom[$key] = $val;
+            }
+        } else {
+            $this->custom[$item] = $value;
+        }
+
+        return $this;
+    }
+
+    /**
+     * Set retry times
+     * @param int $times
+     * @return self
+     */
+    public function retry($times = 0) {
+        $this->retry = $times;
+
+        return $this;
+    }
+
+    /**
+     * Task process
+     * @param int $retry
+     * @return self
+     */
+    private function process($retry = 0) {
+        $ch = curl_init();
+
+        $option = array_merge($this->option, $this->custom);
+
+        foreach ($option as $key => $val) {
+            if (is_string($key)) {
+                $key = constant(strtoupper($key));
+            }
+            curl_setopt($ch, $key, $val);
+        }
+
+        if ($this->post) {
+            curl_setopt($ch, CURLOPT_POST, true);
+            curl_setopt($ch, CURLOPT_POSTFIELDS, $this->convert($this->post));
+        }
+
+        $this->data = (string)curl_exec($ch);
+        $this->info = curl_getinfo($ch);
+        $this->error = curl_errno($ch);
+        $this->message = $this->error ? curl_error($ch) : '';
+
+        curl_close($ch);
+
+        if ($this->error && $retry < $this->retry) {
+            $this->process($retry + 1);
+        }
+
+        $this->post = array();
+        $this->retry = 0;
+
+        return $this;
+    }
+
+    /**
+     * Convert array
+     * @param array  $input
+     * @param string $pre
+     * @return array
+     */
+    private function convert($input, $pre = null) {
+        if (is_array($input)) {
+            $output = array();
+
+            foreach ($input as $key => $value) {
+                $index = is_null($pre) ? $key : "{$pre}[{$key}]";
+                if (is_array($value)) {
+                    $output = array_merge($output, $this->convert($value, $index));
+                } else {
+                    $output[$index] = $value;
+                }
+            }
+
+            return $output;
+        }
+
+        return $input;
+    }
+}