/*
 * Copyright (c) 2021-2022, the SerenityOS developers.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "WelcomeWidget.h"
#include <AK/Random.h>
#include <AK/String.h>
#include <Applications/Welcome/WelcomeWindowGML.h>
#include <LibConfig/Client.h>
#include <LibCore/StandardPaths.h>
#include <LibCore/Stream.h>
#include <LibGUI/Application.h>
#include <LibGUI/Button.h>
#include <LibGUI/CheckBox.h>
#include <LibGUI/Frame.h>
#include <LibGUI/Label.h>
#include <LibGUI/Painter.h>
#include <LibGUI/Process.h>
#include <LibGfx/Palette.h>

ErrorOr<NonnullRefPtr<WelcomeWidget>> WelcomeWidget::try_create()
{
    auto welcome_widget = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) WelcomeWidget()));
    TRY(welcome_widget->create_widgets());

    return welcome_widget;
}

ErrorOr<void> WelcomeWidget::create_widgets()
{
    TRY(load_from_gml(welcome_window_gml));

    m_banner_widget = find_descendant_of_type_named<GUI::Widget>("welcome_banner");
    m_banner_font = TRY(Gfx::BitmapFont::try_load_from_file("/res/fonts/MarietaRegular24.font"sv));

    m_web_view = find_descendant_of_type_named<WebView::OutOfProcessWebView>("web_view");
    auto path = TRY(String::formatted("{}/README.md", Core::StandardPaths::home_directory()));
    m_web_view->load(URL::create_with_file_scheme(path.to_deprecated_string()));

    m_tip_label = find_descendant_of_type_named<GUI::Label>("tip_label");
    m_tip_frame = find_descendant_of_type_named<GUI::Frame>("tip_frame");

    m_next_button = find_descendant_of_type_named<GUI::Button>("next_button");
    m_next_button->on_click = [&](auto) {
        m_web_view->set_visible(false);
        m_tip_frame->set_visible(true);
        if (m_tips.is_empty())
            return;
        m_tip_index++;
        if (m_tip_index >= m_tips.size())
            m_tip_index = 0;
        m_tip_label->set_text(m_tips[m_tip_index].to_deprecated_string());
    };

    m_help_button = find_descendant_of_type_named<GUI::Button>("help_button");
    m_help_button->on_click = [&](auto) {
        GUI::Process::spawn_or_show_error(window(), "/bin/Help"sv);
    };

    m_new_button = find_descendant_of_type_named<GUI::Button>("new_button");
    m_new_button->on_click = [&](auto) {
        m_web_view->set_visible(!m_web_view->is_visible());
        m_tip_frame->set_visible(!m_tip_frame->is_visible());
    };

    m_close_button = find_descendant_of_type_named<GUI::Button>("close_button");
    m_close_button->on_click = [](auto) {
        GUI::Application::the()->quit();
    };

    auto welcome = Config::list_groups("SystemServer"sv).first_matching([](auto& group) { return group == "Welcome"sv; });
    m_startup_checkbox = find_descendant_of_type_named<GUI::CheckBox>("startup_checkbox");
    m_startup_checkbox->set_checked(welcome.has_value());
    m_startup_checkbox->on_checked = [](bool is_checked) {
        if (is_checked)
            Config::add_group("SystemServer"sv, "Welcome"sv);
        else
            Config::remove_group("SystemServer"sv, "Welcome"sv);
    };

    if (auto result = open_and_parse_tips_file(); result.is_error()) {
        auto path = TRY(String::formatted("{}/tips.txt", Core::StandardPaths::documents_directory()));
        auto error = TRY(String::formatted("Opening \"{}\" failed: {}", path, result.error()));
        m_tip_label->set_text(error.to_deprecated_string());
        warnln(error);
    }

    set_random_tip();

    return {};
}

ErrorOr<void> WelcomeWidget::open_and_parse_tips_file()
{
    auto path = TRY(String::formatted("{}/tips.txt", Core::StandardPaths::documents_directory()));
    auto file = TRY(Core::Stream::File::open(path, Core::Stream::OpenMode::Read));
    auto buffered_file = TRY(Core::Stream::BufferedFile::create(move(file)));
    Array<u8, PAGE_SIZE> buffer;

    while (TRY(buffered_file->can_read_line())) {
        auto line = TRY(buffered_file->read_line(buffer));
        if (line.starts_with('#') || line.is_empty())
            continue;
        TRY(m_tips.try_append(TRY(String::from_utf8(line))));
    }

    return {};
}

void WelcomeWidget::set_random_tip()
{
    if (m_tips.is_empty())
        return;

    m_tip_index = get_random_uniform(m_tips.size());
    m_tip_label->set_text(m_tips[m_tip_index].to_deprecated_string());
}

void WelcomeWidget::paint_event(GUI::PaintEvent& event)
{
    GUI::Painter painter(*this);
    painter.add_clip_rect(event.rect());

    auto rect = m_banner_widget->relative_rect();
    painter.draw_text(rect, "Welcome to "sv, *m_banner_font, Gfx::TextAlignment::CenterLeft, palette().base_text());
    rect.set_x(rect.x() + static_cast<int>(ceilf(m_banner_font->width("Welcome to "sv))));
    painter.draw_text(rect, "Serenity"sv, m_banner_font->bold_variant(), Gfx::TextAlignment::CenterLeft, palette().base_text());
    rect.set_x(rect.x() + static_cast<int>(ceilf(m_banner_font->bold_variant().width("Serenity"sv))));
    painter.draw_text(rect, "OS"sv, m_banner_font->bold_variant(), Gfx::TextAlignment::CenterLeft, palette().tray_text());
}