/*
 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
 * Copyright (c) 2021, Sergey Bugaev <bugaevc@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include "DNSAnswer.h"
#include "DNSQuestion.h"
#include <AK/Optional.h>
#include <AK/Types.h>
#include <AK/Vector.h>

#define T_A 1
#define T_NS 2
#define T_CNAME 5
#define T_SOA 6
#define T_PTR 12
#define T_MX 15

#define C_IN 1

namespace LookupServer {

enum class ShouldRandomizeCase {
    No = 0,
    Yes
};

class DNSPacket {
public:
    DNSPacket() { }

    static Optional<DNSPacket> from_raw_packet(const u8*, size_t);
    ByteBuffer to_byte_buffer() const;

    bool is_query() const { return !m_query_or_response; }
    bool is_response() const { return m_query_or_response; }
    void set_is_query() { m_query_or_response = false; }
    void set_is_response() { m_query_or_response = true; }

    u16 id() const { return m_id; }
    void set_id(u16 id) { m_id = id; }

    const Vector<DNSQuestion>& questions() const { return m_questions; }
    const Vector<DNSAnswer>& answers() const { return m_answers; }

    u16 question_count() const
    {
        VERIFY(m_questions.size() <= UINT16_MAX);
        return m_questions.size();
    }

    u16 answer_count() const
    {
        VERIFY(m_answers.size() <= UINT16_MAX);
        return m_answers.size();
    }

    void add_question(const DNSQuestion&);
    void add_answer(const DNSAnswer&);

    enum class Code : u8 {
        NOERROR = 0,
        FORMERR = 1,
        SERVFAIL = 2,
        NXDOMAIN = 3,
        NOTIMP = 4,
        REFUSED = 5,
        YXDOMAIN = 6,
        XRRSET = 7,
        NOTAUTH = 8,
        NOTZONE = 9,
    };

    Code code() const { return (Code)m_code; }
    void set_code(Code code) { m_code = (u8)code; }

private:
    u16 m_id { 0 };
    u8 m_code { 0 };
    bool m_query_or_response { false };
    Vector<DNSQuestion> m_questions;
    Vector<DNSAnswer> m_answers;
};

}