/*
 * Copyright (c) 2020, Andreas Kling <andreas@ladybird.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/Debug.h>
#include <AK/IDAllocator.h>
#include <ImageDecoder/ConnectionFromClient.h>
#include <ImageDecoder/ImageDecoderClientEndpoint.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/ImageFormats/ImageDecoder.h>
#include <LibGfx/ImageFormats/TIFFMetadata.h>

namespace ImageDecoder {

static HashMap<int, RefPtr<ConnectionFromClient>> s_connections;
static IDAllocator s_client_ids;

ConnectionFromClient::ConnectionFromClient(IPC::Transport transport)
    : IPC::ConnectionFromClient<ImageDecoderClientEndpoint, ImageDecoderServerEndpoint>(*this, move(transport), s_client_ids.allocate())
{
    s_connections.set(client_id(), *this);
}

void ConnectionFromClient::die()
{
    for (auto& [_, job] : m_pending_jobs) {
        job->cancel();
    }
    m_pending_jobs.clear();

    auto client_id = this->client_id();
    s_connections.remove(client_id);
    s_client_ids.deallocate(client_id);

    if (s_connections.is_empty()) {
        Threading::quit_background_thread();
        Core::EventLoop::current().quit(0);
    }
}

ErrorOr<IPC::File> ConnectionFromClient::connect_new_client()
{
    int socket_fds[2] {};
    if (auto err = Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, socket_fds); err.is_error())
        return err.release_error();

    auto client_socket_or_error = Core::LocalSocket::adopt_fd(socket_fds[0]);
    if (client_socket_or_error.is_error()) {
        close(socket_fds[0]);
        close(socket_fds[1]);
        return client_socket_or_error.release_error();
    }

    auto client_socket = client_socket_or_error.release_value();
    // Note: A ref is stored in the static s_connections map
    auto client = adopt_ref(*new ConnectionFromClient(IPC::Transport(move(client_socket))));

    return IPC::File::adopt_fd(socket_fds[1]);
}

Messages::ImageDecoderServer::ConnectNewClientsResponse ConnectionFromClient::connect_new_clients(size_t count)
{
    Vector<IPC::File> files;
    files.ensure_capacity(count);
    for (size_t i = 0; i < count; ++i) {
        auto file_or_error = connect_new_client();
        if (file_or_error.is_error()) {
            dbgln("Failed to connect new client: {}", file_or_error.error());
            return Vector<IPC::File> {};
        }
        files.unchecked_append(file_or_error.release_value());
    }
    return files;
}

static void decode_image_to_bitmaps_and_durations_with_decoder(Gfx::ImageDecoder const& decoder, Optional<Gfx::IntSize> ideal_size, Vector<Optional<NonnullRefPtr<Gfx::Bitmap>>>& bitmaps, Vector<u32>& durations)
{
    for (size_t i = 0; i < decoder.frame_count(); ++i) {
        auto frame_or_error = decoder.frame(i, ideal_size);
        if (frame_or_error.is_error()) {
            bitmaps.append({});
            durations.append(0);
        } else {
            auto frame = frame_or_error.release_value();
            bitmaps.append(frame.image.release_nonnull());
            durations.append(frame.duration);
        }
    }
}

static ErrorOr<ConnectionFromClient::DecodeResult> decode_image_to_details(Core::AnonymousBuffer const& encoded_buffer, Optional<Gfx::IntSize> ideal_size, Optional<ByteString> const& known_mime_type)
{
    auto decoder = TRY(Gfx::ImageDecoder::try_create_for_raw_bytes(ReadonlyBytes { encoded_buffer.data<u8>(), encoded_buffer.size() }, known_mime_type));

    if (!decoder)
        return Error::from_string_literal("Could not find suitable image decoder plugin for data");

    if (!decoder->frame_count())
        return Error::from_string_literal("Could not decode image from encoded data");

    ConnectionFromClient::DecodeResult result;
    result.is_animated = decoder->is_animated();
    result.loop_count = decoder->loop_count();

    if (auto maybe_icc_data = decoder->color_space(); !maybe_icc_data.is_error())
        result.color_profile = maybe_icc_data.value();

    Vector<Optional<NonnullRefPtr<Gfx::Bitmap>>> bitmaps;

    if (auto maybe_metadata = decoder->metadata(); maybe_metadata.has_value() && is<Gfx::ExifMetadata>(*maybe_metadata)) {
        auto const& exif = static_cast<Gfx::ExifMetadata const&>(maybe_metadata.value());
        if (exif.x_resolution().has_value() && exif.y_resolution().has_value()) {
            auto const x_resolution = exif.x_resolution()->as_double();
            auto const y_resolution = exif.y_resolution()->as_double();
            if (x_resolution < y_resolution)
                result.scale.set_y(x_resolution / y_resolution);
            else
                result.scale.set_x(y_resolution / x_resolution);
        }
    }

    decode_image_to_bitmaps_and_durations_with_decoder(*decoder, move(ideal_size), bitmaps, result.durations);

    if (bitmaps.is_empty())
        return Error::from_string_literal("Could not decode image");

    result.bitmaps = Gfx::BitmapSequence { bitmaps };

    return result;
}

NonnullRefPtr<ConnectionFromClient::Job> ConnectionFromClient::make_decode_image_job(i64 image_id, Core::AnonymousBuffer encoded_buffer, Optional<Gfx::IntSize> ideal_size, Optional<ByteString> mime_type)
{
    return Job::construct(
        [encoded_buffer = move(encoded_buffer), ideal_size = move(ideal_size), mime_type = move(mime_type)](auto&) -> ErrorOr<DecodeResult> {
            return TRY(decode_image_to_details(encoded_buffer, ideal_size, mime_type));
        },
        [strong_this = NonnullRefPtr(*this), image_id](DecodeResult result) -> ErrorOr<void> {
            strong_this->async_did_decode_image(image_id, result.is_animated, result.loop_count, result.bitmaps, result.durations, result.scale, result.color_profile);
            strong_this->m_pending_jobs.remove(image_id);
            return {};
        },
        [strong_this = NonnullRefPtr(*this), image_id](Error error) -> void {
            if (strong_this->is_open())
                strong_this->async_did_fail_to_decode_image(image_id, MUST(String::formatted("Decoding failed: {}", error)));
            strong_this->m_pending_jobs.remove(image_id);
        });
}

Messages::ImageDecoderServer::DecodeImageResponse ConnectionFromClient::decode_image(Core::AnonymousBuffer const& encoded_buffer, Optional<Gfx::IntSize> const& ideal_size, Optional<ByteString> const& mime_type)
{
    auto image_id = m_next_image_id++;

    if (!encoded_buffer.is_valid()) {
        dbgln_if(IMAGE_DECODER_DEBUG, "Encoded data is invalid");
        async_did_fail_to_decode_image(image_id, "Encoded data is invalid"_string);
        return image_id;
    }

    m_pending_jobs.set(image_id, make_decode_image_job(image_id, encoded_buffer, ideal_size, mime_type));

    return image_id;
}

void ConnectionFromClient::cancel_decoding(i64 image_id)
{
    if (auto job = m_pending_jobs.take(image_id); job.has_value()) {
        job.value()->cancel();
    }
}

}