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

#include "PreviewWidget.h"
#include <AK/StringView.h>
#include <LibCore/MimeData.h>
#include <LibFileSystemAccessClient/Client.h>
#include <LibGUI/BoxLayout.h>
#include <LibGUI/Button.h>
#include <LibGUI/CheckBox.h>
#include <LibGUI/MessageBox.h>
#include <LibGUI/Painter.h>
#include <LibGUI/RadioButton.h>
#include <LibGUI/Statusbar.h>
#include <LibGUI/TextEditor.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/WindowTheme.h>

namespace ThemeEditor {

class MiniWidgetGallery final : public GUI::Widget {
    C_OBJECT(MiniWidgetGallery);

public:
    void set_preview_palette(const Gfx::Palette& palette)
    {
        set_palette(palette);
        Function<void(GUI::Widget&)> recurse = [&](GUI::Widget& parent_widget) {
            parent_widget.for_each_child_widget([&](auto& widget) {
                widget.set_palette(palette);
                recurse(widget);
                return IterationDecision::Continue;
            });
        };
        recurse(*this);
    }

private:
    MiniWidgetGallery()
    {
        set_fill_with_background_color(true);
        m_button = add<GUI::Button>();
        m_button->set_text("Button");
        m_checkbox = add<GUI::CheckBox>();
        m_checkbox->set_text("Check box");
        m_radio = add<GUI::RadioButton>();
        m_radio->set_text("Radio button");
        m_statusbar = add<GUI::Statusbar>();
        m_statusbar->set_text("Status bar");
        m_editor = add<GUI::TextEditor>();
        m_editor->set_text("Text editor\nwith multiple\nlines.");

        for_each_child_widget([](auto& child) {
            child.set_focus_policy(GUI::FocusPolicy::NoFocus);
            return IterationDecision::Continue;
        });
    }

    virtual void resize_event(GUI::ResizeEvent&) override
    {
        m_editor->set_relative_rect(10, 70, 200, 140);
        m_button->set_relative_rect(10, 10, 200, 20);
        m_checkbox->set_relative_rect(10, 30, 200, 20);
        m_radio->set_relative_rect(10, 50, 200, 20);
        m_statusbar->set_relative_rect(0, height() - 16, width(), 16);
    }

    RefPtr<GUI::TextEditor> m_editor;
    RefPtr<GUI::Button> m_button;
    RefPtr<GUI::CheckBox> m_checkbox;
    RefPtr<GUI::RadioButton> m_radio;
    RefPtr<GUI::Statusbar> m_statusbar;
};

PreviewWidget::PreviewWidget(const Gfx::Palette& preview_palette)
    : m_preview_palette(preview_palette)
{
    m_active_window_icon = Gfx::Bitmap::try_load_from_file("/res/icons/16x16/window.png");
    m_inactive_window_icon = Gfx::Bitmap::try_load_from_file("/res/icons/16x16/window.png");

    m_close_bitmap = Gfx::Bitmap::try_load_from_file("/res/icons/16x16/window-close.png");
    m_maximize_bitmap = Gfx::Bitmap::try_load_from_file("/res/icons/16x16/upward-triangle.png");
    m_minimize_bitmap = Gfx::Bitmap::try_load_from_file("/res/icons/16x16/downward-triangle.png");

    m_gallery = add<MiniWidgetGallery>();
    set_greedy_for_hits(true);
}

PreviewWidget::~PreviewWidget()
{
}

void PreviewWidget::set_preview_palette(const Gfx::Palette& palette)
{
    m_preview_palette = palette;
    m_gallery->set_preview_palette(palette);
    update();
}

void PreviewWidget::set_theme_from_file(String const& path, int fd)
{
    auto file = Core::ConfigFile::open(path, fd);
    auto theme = Gfx::load_system_theme(file);
    VERIFY(theme.is_valid());

    m_preview_palette = Gfx::Palette(Gfx::PaletteImpl::create_with_anonymous_buffer(theme));
    set_preview_palette(m_preview_palette);
    if (on_theme_load_from_file)
        on_theme_load_from_file(path);
}

void PreviewWidget::paint_event(GUI::PaintEvent& event)
{
    GUI::Frame::paint_event(event);
    GUI::Painter painter(*this);

    painter.add_clip_rect(event.rect());
    painter.add_clip_rect(frame_inner_rect());

    painter.fill_rect(frame_inner_rect(), m_preview_palette.desktop_background());

    struct Button {
        Gfx::IntRect rect;
        RefPtr<Gfx::Bitmap> bitmap;
    };

    auto paint_window = [&](auto& title, const Gfx::IntRect& rect, auto state, const Gfx::Bitmap& icon) {
        int window_button_width = m_preview_palette.window_title_button_width();
        int window_button_height = m_preview_palette.window_title_button_height();
        auto titlebar_text_rect = Gfx::WindowTheme::current().titlebar_text_rect(Gfx::WindowTheme::WindowType::Normal, rect, m_preview_palette);
        int pos = titlebar_text_rect.right() + 1;

        Vector<Button> buttons;
        buttons.append(Button { {}, m_close_bitmap });
        buttons.append(Button { {}, m_maximize_bitmap });
        buttons.append(Button { {}, m_minimize_bitmap });

        for (auto& button : buttons) {
            pos -= window_button_width;
            Gfx::IntRect rect { pos, 0, window_button_width, window_button_height };
            rect.center_vertically_within(titlebar_text_rect);
            button.rect = rect;
        }

        auto frame_rect = Gfx::WindowTheme::current().frame_rect_for_window(Gfx::WindowTheme::WindowType::Normal, rect, m_preview_palette, 0);
        Gfx::PainterStateSaver saver(painter);
        painter.translate(frame_rect.location());
        Gfx::WindowTheme::current().paint_normal_frame(painter, state, rect, title, icon, m_preview_palette, buttons.last().rect, 0, false);

        for (auto& button : buttons) {
            Gfx::StylePainter::paint_button(painter, button.rect, m_preview_palette, Gfx::ButtonStyle::Normal, false);
            auto bitmap_rect = button.bitmap->rect().centered_within(button.rect);
            painter.blit(bitmap_rect.location(), *button.bitmap, button.bitmap->rect());
        }
    };

    auto active_rect = Gfx::IntRect(0, 0, 320, 240).centered_within(frame_inner_rect());
    auto inactive_rect = active_rect.translated(-20, -20);

    paint_window("Inactive window", inactive_rect, Gfx::WindowTheme::WindowState::Inactive, *m_active_window_icon);
    paint_window("Active window", active_rect, Gfx::WindowTheme::WindowState::Active, *m_inactive_window_icon);
}

void PreviewWidget::resize_event(GUI::ResizeEvent&)
{
    m_gallery->set_relative_rect(Gfx::IntRect(0, 0, 320, 240).centered_within(rect()));
}

void PreviewWidget::drop_event(GUI::DropEvent& event)
{
    event.accept();
    window()->move_to_front();

    if (event.mime_data().has_urls()) {
        auto urls = event.mime_data().urls();
        if (urls.is_empty())
            return;
        if (urls.size() > 1) {
            GUI::MessageBox::show(window(), "ThemeEditor can only open one file at a time!", "One at a time please!", GUI::MessageBox::Type::Error);
            return;
        }

        auto result = FileSystemAccessClient::Client::the().request_file(window()->window_id(), urls.first().path(), Core::OpenMode::ReadOnly);
        if (result.error != 0)
            return;

        set_theme_from_file(urls.first().path(), *result.fd);
    }
}

}