/*
 * Copyright (c) 2021, Hunter Salyer <thefalsehonesty@gmail.com>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/ByteBuffer.h>
#include <AK/FlyString.h>
#include <AK/HashMap.h>
#include <AK/NonnullOwnPtrVector.h>
#include <AK/OwnPtr.h>
#include <AK/String.h>
#include <AK/Utf8View.h>

namespace Video {

struct EBMLHeader {
    String doc_type;
    u32 doc_type_version;
};

class SegmentInformation {
public:
    u64 timestamp_scale() const { return m_timestamp_scale; }
    void set_timestamp_scale(u64 timestamp_scale) { m_timestamp_scale = timestamp_scale; }
    Utf8View muxing_app() const { return Utf8View(m_muxing_app); }
    void set_muxing_app(String muxing_app) { m_muxing_app = move(muxing_app); }
    Utf8View writing_app() const { return Utf8View(m_writing_app); }
    void set_writing_app(String writing_app) { m_writing_app = move(writing_app); }

private:
    u64 m_timestamp_scale { 1'000'000 };
    String m_muxing_app;
    String m_writing_app;
};

class TrackEntry {
public:
    enum TrackType : u8 {
        Invalid = 0,
        Video = 1,
        Audio = 2,
        Complex = 3,
        Logo = 16,
        Subtitle = 17,
        Buttons = 18,
        Control = 32,
        Metadata = 33,
    };

    struct VideoTrack {
        u64 pixel_width;
        u64 pixel_height;
    };

    struct AudioTrack {
        u64 channels;
        u64 bit_depth;
    };

    u64 track_number() const { return m_track_number; }
    void set_track_number(u64 track_number) { m_track_number = track_number; }
    u64 track_uid() const { return m_track_uid; }
    void set_track_uid(u64 track_uid) { m_track_uid = track_uid; }
    TrackType track_type() const { return m_track_type; }
    void set_track_type(TrackType track_type) { m_track_type = track_type; }
    FlyString language() const { return m_language; }
    void set_language(FlyString const& language) { m_language = language; }
    FlyString codec_id() const { return m_codec_id; }
    void set_codec_id(FlyString const& codec_id) { m_codec_id = codec_id; }
    Optional<VideoTrack> video_track() const
    {
        if (track_type() != Video)
            return {};
        return m_video_track;
    }
    void set_video_track(VideoTrack video_track) { m_video_track = video_track; }
    Optional<AudioTrack> audio_track() const
    {
        if (track_type() != Audio)
            return {};
        return m_audio_track;
    }
    void set_audio_track(AudioTrack audio_track) { m_audio_track = audio_track; }

private:
    u64 m_track_number { 0 };
    u64 m_track_uid { 0 };
    TrackType m_track_type { Invalid };
    FlyString m_language = "eng";
    FlyString m_codec_id;

    union {
        VideoTrack m_video_track;
        AudioTrack m_audio_track;
    };
};

class Block {
public:
    enum Lacing : u8 {
        None = 0b00,
        XIPH = 0b01,
        FixedSize = 0b10,
        EBML = 0b11,
    };

    Block() = default;

    u64 track_number() const { return m_track_number; }
    void set_track_number(u64 track_number) { m_track_number = track_number; }
    i16 timestamp() const { return m_timestamp; }
    void set_timestamp(i16 timestamp) { m_timestamp = timestamp; }
    bool only_keyframes() const { return m_only_keyframes; }
    void set_only_keyframes(bool only_keyframes) { m_only_keyframes = only_keyframes; }
    bool invisible() const { return m_invisible; }
    void set_invisible(bool invisible) { m_invisible = invisible; }
    Lacing lacing() const { return m_lacing; }
    void set_lacing(Lacing lacing) { m_lacing = lacing; }
    bool discardable() const { return m_discardable; }
    void set_discardable(bool discardable) { m_discardable = discardable; }
    u64 frame_count() const { return m_frames.size(); }
    Vector<ByteBuffer> const& frames() const { return m_frames; }
    ByteBuffer const& frame(size_t index) const { return frames()[index]; }
    void add_frame(ByteBuffer frame) { m_frames.append(move(frame)); }

private:
    u64 m_track_number { 0 };
    i16 m_timestamp { 0 };
    bool m_only_keyframes { false };
    bool m_invisible { false };
    Lacing m_lacing { None };
    bool m_discardable { true };
    Vector<ByteBuffer> m_frames;
};

class Cluster {
public:
    u64 timestamp() const { return m_timestamp; }
    void set_timestamp(u64 timestamp) { m_timestamp = timestamp; }
    NonnullOwnPtrVector<Block>& blocks() { return m_blocks; }
    NonnullOwnPtrVector<Block> const& blocks() const { return m_blocks; }

private:
    u64 m_timestamp { 0 };
    NonnullOwnPtrVector<Block> m_blocks;
};

class MatroskaDocument {
public:
    explicit MatroskaDocument(EBMLHeader m_header)
        : m_header(move(m_header))
    {
    }

    EBMLHeader const& header() const { return m_header; }

    Optional<SegmentInformation> segment_information() const
    {
        if (!m_segment_information)
            return {};
        return *m_segment_information;
    }
    void set_segment_information(OwnPtr<SegmentInformation> segment_information) { m_segment_information = move(segment_information); }
    HashMap<u64, NonnullOwnPtr<TrackEntry>> const& tracks() const { return m_tracks; }
    Optional<TrackEntry> track_for_track_number(u64 track_number) const
    {
        auto track = m_tracks.get(track_number);
        if (!track.has_value())
            return {};
        return *track.value();
    }
    Optional<TrackEntry> track_for_track_type(TrackEntry::TrackType type) const
    {
        for (auto& track_entry : m_tracks) {
            if (track_entry.value->track_type() == type)
                return *track_entry.value;
        }
        return {};
    }
    void add_track(u64 track_number, NonnullOwnPtr<TrackEntry> track)
    {
        m_tracks.set(track_number, move(track));
    }
    NonnullOwnPtrVector<Cluster>& clusters() { return m_clusters; }

private:
    EBMLHeader m_header;
    OwnPtr<SegmentInformation> m_segment_information;
    HashMap<u64, NonnullOwnPtr<TrackEntry>> m_tracks;
    NonnullOwnPtrVector<Cluster> m_clusters;
};

}