/*
 * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
 * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
 * Copyright (c) 2021, Mohsan Ali <mohsan0073@gmail.com>
 * Copyright (c) 2022, Mustafa Quraish <mustafa@serenityos.org>
 * Copyright (c) 2022, the SerenityOS developers.
 * Copyright (c) 2023, Caoimhe Byrne <caoimhebyrne06@gmail.com>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "ViewWidget.h"
#include <AK/LexicalPath.h>
#include <AK/StringBuilder.h>
#include <LibCore/Directory.h>
#include <LibCore/MappedFile.h>
#include <LibCore/MimeData.h>
#include <LibCore/Timer.h>
#include <LibFileSystemAccessClient/Client.h>
#include <LibGUI/Application.h>
#include <LibGUI/MessageBox.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/Orientation.h>
#include <LibGfx/Palette.h>
#include <LibImageDecoderClient/Client.h>

namespace ImageViewer {

ViewWidget::ViewWidget()
    : m_timer(Core::Timer::try_create().release_value_but_fixme_should_propagate_errors())
{
    set_fill_with_background_color(false);
}

void ViewWidget::clear()
{
    m_timer->stop();
    m_decoded_image.clear();
    m_bitmap = nullptr;
    if (on_image_change)
        on_image_change(m_bitmap);
    set_original_rect({});
    m_path = {};

    reset_view();
    update();
}

void ViewWidget::flip(Gfx::Orientation orientation)
{
    m_bitmap = m_bitmap->flipped(orientation).release_value_but_fixme_should_propagate_errors();
    scale_image_for_window();
}

void ViewWidget::rotate(Gfx::RotationDirection rotation_direction)
{
    m_bitmap = m_bitmap->rotated(rotation_direction).release_value_but_fixme_should_propagate_errors();
    scale_image_for_window();
}

bool ViewWidget::is_next_available() const
{
    if (m_current_index.has_value())
        return m_current_index.value() + 1 < m_files_in_same_dir.size();
    return false;
}

bool ViewWidget::is_previous_available() const
{
    if (m_current_index.has_value())
        return m_current_index.value() > 0;
    return false;
}

// FIXME: Convert to `String` & use LibFileSystemAccessClient + `Core::System::unveil(nullptr, nullptr)`
//        - Converting to String is not super-trivial due to the LexicalPath usage, while we can do a bunch of
//          String::from_deprecated_string() and String.to_deprecated_string(), it is quite ugly to read and
//          probably not the best approach.
//
//        - If we go full-unveil (`Core::System::unveil(nullptr, nullptr)`) this functionality does not work,
//          we can not access the list of contents of a directory through LibFileSystemAccessClient at the moment.
Vector<DeprecatedString> ViewWidget::load_files_from_directory(DeprecatedString const& path) const
{
    Vector<DeprecatedString> files_in_directory;

    auto current_dir = LexicalPath(path).parent().string();
    // FIXME: Propagate errors
    (void)Core::Directory::for_each_entry(current_dir, Core::DirIterator::Flags::SkipDots, [&](auto const& entry, auto const& directory) -> ErrorOr<IterationDecision> {
        auto full_path = LexicalPath::join(directory.path().string(), entry.name).string();
        if (Gfx::Bitmap::is_path_a_supported_image_format(full_path))
            files_in_directory.append(full_path);
        return IterationDecision::Continue;
    });
    return files_in_directory;
}

void ViewWidget::set_path(String const& path)
{
    m_path = path;
    m_files_in_same_dir = load_files_from_directory(path.to_deprecated_string());
    m_current_index = m_files_in_same_dir.find_first_index(path.to_deprecated_string());
}

void ViewWidget::navigate(Directions direction)
{
    if (!m_current_index.has_value()) {
        return;
    }

    auto index = m_current_index.value();
    if (direction == Directions::Back) {
        index--;
    } else if (direction == Directions::Forward) {
        index++;
    } else if (direction == Directions::First) {
        index = 0;
    } else if (direction == Directions::Last) {
        index = m_files_in_same_dir.size() - 1;
    }

    auto result = FileSystemAccessClient::Client::the().request_file_read_only_approved(window(), m_files_in_same_dir.at(index));
    if (result.is_error())
        return;

    m_current_index = index;

    auto value = result.release_value();
    open_file(value.filename(), value.stream());
}

void ViewWidget::doubleclick_event(GUI::MouseEvent&)
{
    on_doubleclick();
}

void ViewWidget::paint_event(GUI::PaintEvent& event)
{
    Frame::paint_event(event);

    GUI::Painter painter(*this);
    painter.add_clip_rect(event.rect());
    painter.add_clip_rect(frame_inner_rect());

    Gfx::StylePainter::paint_transparency_grid(painter, frame_inner_rect(), palette());

    if (!m_bitmap.is_null())
        painter.draw_scaled_bitmap(content_rect(), *m_bitmap, m_bitmap->rect(), 1.0f, m_scaling_mode);
}

void ViewWidget::mousedown_event(GUI::MouseEvent& event)
{
    if (event.button() == GUI::MouseButton::Primary)
        start_panning(event.position());
    GUI::AbstractZoomPanWidget::mousedown_event(event);
}

void ViewWidget::mouseup_event(GUI::MouseEvent& event)
{
    if (event.button() == GUI::MouseButton::Primary)
        stop_panning();
    GUI::AbstractZoomPanWidget::mouseup_event(event);
}

void ViewWidget::open_file(String const& path, Core::File& file)
{
    auto open_result = try_open_file(path, file);
    if (open_result.is_error()) {
        auto error = open_result.release_error();
        auto user_error_message = String::formatted("Failed to open the image: {}.", error).release_value_but_fixme_should_propagate_errors();

        GUI::MessageBox::show_error(nullptr, user_error_message);
    }
}

ErrorOr<void> ViewWidget::try_open_file(String const& path, Core::File& file)
{
    // Spawn a new ImageDecoder service process and connect to it.
    auto client = TRY(ImageDecoderClient::Client::try_create());
    auto mime_type = Core::guess_mime_type_based_on_filename(path);
    auto decoded_image_or_none = client->decode_image(TRY(file.read_until_eof()), mime_type);
    if (!decoded_image_or_none.has_value()) {
        return Error::from_string_literal("Failed to decode image");
    }

    m_decoded_image = decoded_image_or_none.release_value();
    m_bitmap = m_decoded_image->frames[0].bitmap;
    if (m_bitmap.is_null()) {
        return Error::from_string_literal("Image didn't contain a bitmap");
    }

    set_original_rect(m_bitmap->rect());

    if (m_decoded_image->is_animated && m_decoded_image->frames.size() > 1) {
        auto const& first_frame = m_decoded_image->frames[0];
        m_timer->set_interval(first_frame.duration);
        m_timer->on_timeout = [this] { animate(); };
        m_timer->start();
    } else {
        m_timer->stop();
    }

    set_path(path);
    GUI::Application::the()->set_most_recently_open_file(path);

    if (on_image_change)
        on_image_change(m_bitmap);

    if (scaled_for_first_image())
        scale_image_for_window();
    else
        reset_view();

    return {};
}

void ViewWidget::drag_enter_event(GUI::DragEvent& event)
{
    auto const& mime_types = event.mime_types();
    if (mime_types.contains_slow("text/uri-list"))
        event.accept();
}

void ViewWidget::drop_event(GUI::DropEvent& event)
{
    event.accept();
    if (on_drop)
        on_drop(event);
}

void ViewWidget::resize_event(GUI::ResizeEvent& event)
{
    event.accept();
    scale_image_for_window();
}

void ViewWidget::scale_image_for_window()
{
    if (!m_bitmap)
        return;

    set_original_rect(m_bitmap->rect());
    fit_content_to_view(GUI::AbstractZoomPanWidget::FitType::Both);
}

void ViewWidget::resize_window()
{
    if (window()->is_fullscreen() || window()->is_maximized())
        return;

    auto absolute_bitmap_rect = content_rect();
    absolute_bitmap_rect.translate_by(window()->rect().top_left());

    if (!m_bitmap)
        return;

    auto new_size = content_rect().size();

    if (new_size.width() < 300)
        new_size.set_width(300);
    if (new_size.height() < 200)
        new_size.set_height(200);

    if (new_size.width() > 500)
        new_size = { 500, 500 * absolute_bitmap_rect.height() / absolute_bitmap_rect.width() };
    if (new_size.height() > 500)
        new_size = { 500 * absolute_bitmap_rect.width() / absolute_bitmap_rect.height(), 500 };

    new_size.set_height(new_size.height() + m_toolbar_height);
    window()->resize(new_size);
    scale_image_for_window();
}

void ViewWidget::set_bitmap(Gfx::Bitmap const* bitmap)
{
    if (m_bitmap == bitmap)
        return;
    m_bitmap = bitmap;
    set_original_rect(m_bitmap->rect());
    update();
}

// Same as ImageWidget::animate(), you probably want to keep any changes in sync
void ViewWidget::animate()
{
    if (!m_decoded_image.has_value())
        return;

    m_current_frame_index = (m_current_frame_index + 1) % m_decoded_image->frames.size();

    auto const& current_frame = m_decoded_image->frames[m_current_frame_index];
    set_bitmap(current_frame.bitmap);

    if ((int)current_frame.duration != m_timer->interval()) {
        m_timer->restart(current_frame.duration);
    }

    if (m_current_frame_index == m_decoded_image->frames.size() - 1) {
        ++m_loops_completed;
        if (m_loops_completed > 0 && m_loops_completed == m_decoded_image->loop_count) {
            m_timer->stop();
        }
    }
}

void ViewWidget::set_scaling_mode(Gfx::Painter::ScalingMode scaling_mode)
{
    m_scaling_mode = scaling_mode;
    update();
}

}