ladybird/Userland/Applications/TextEditor/TextEditorWidget.cpp

/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "TextEditorWidget.h"
#include <AK/JsonObject.h>
#include <AK/JsonValue.h>
#include <AK/Optional.h>
#include <AK/StringBuilder.h>
#include <AK/URL.h>
#include <Applications/TextEditor/TextEditorWindowGML.h>
#include <LibCore/ConfigFile.h>
#include <LibCore/File.h>
#include <LibCore/MimeData.h>
#include <LibCpp/SyntaxHighlighter.h>
#include <LibDesktop/Launcher.h>
#include <LibGUI/Action.h>
#include <LibGUI/ActionGroup.h>
#include <LibGUI/BoxLayout.h>
#include <LibGUI/Button.h>
#include <LibGUI/FilePicker.h>
#include <LibGUI/FontPicker.h>
#include <LibGUI/GMLSyntaxHighlighter.h>
#include <LibGUI/INISyntaxHighlighter.h>
#include <LibGUI/Menu.h>
#include <LibGUI/MenuBar.h>
#include <LibGUI/MessageBox.h>
#include <LibGUI/RegularEditingEngine.h>
#include <LibGUI/Splitter.h>
#include <LibGUI/StatusBar.h>
#include <LibGUI/TextBox.h>
#include <LibGUI/TextEditor.h>
#include <LibGUI/ToolBar.h>
#include <LibGUI/ToolBarContainer.h>
#include <LibGUI/VimEditingEngine.h>
#include <LibGfx/Font.h>
#include <LibJS/SyntaxHighlighter.h>
#include <LibMarkdown/Document.h>
#include <LibWeb/OutOfProcessWebView.h>
#include <Shell/SyntaxHighlighter.h>
#include <string.h>

TextEditorWidget::TextEditorWidget()
{
    load_from_gml(text_editor_window_gml);

    m_config = Core::ConfigFile::get_for_app("TextEditor");

    auto& toolbar = *find_descendant_of_type_named<GUI::ToolBar>("toolbar");
    auto& toolbar_container = *find_descendant_of_type_named<GUI::ToolBarContainer>("toolbar_container");

    m_editor = *find_descendant_of_type_named<GUI::TextEditor>("editor");
    m_editor->set_ruler_visible(true);
    m_editor->set_automatic_indentation_enabled(true);
    m_editor->set_editing_engine(make<GUI::RegularEditingEngine>());

    m_editor->on_change = [this] {
        update_preview();

        // Do not mark as dirty on the first change (When document is first opened.)
        if (m_document_opening) {
            m_document_opening = false;
            return;
        }

        bool was_dirty = m_document_dirty;
        m_document_dirty = true;
        if (!was_dirty)
            update_title();
    };

    m_page_view = *find_descendant_of_type_named<Web::OutOfProcessWebView>("webview");
    m_page_view->on_link_hover = [this](auto& url) {
        if (url.is_valid())
            m_statusbar->set_text(url.to_string());
        else
            update_statusbar_cursor_position();
    };
    m_page_view->on_link_click = [&](auto& url, auto&, unsigned) {
        if (!Desktop::Launcher::open(url)) {
            GUI::MessageBox::show(
                window(),
                String::formatted("The link to '{}' could not be opened.", url),
                "Failed to open link",
                GUI::MessageBox::Type::Error);
        }
    };

    m_find_replace_widget = *find_descendant_of_type_named<GUI::Widget>("find_replace_widget");

    m_find_widget = *find_descendant_of_type_named<GUI::Widget>("find_widget");

    m_replace_widget = *find_descendant_of_type_named<GUI::Widget>("replace_widget");

    m_find_textbox = m_find_widget->add<GUI::TextBox>();
    m_replace_textbox = m_replace_widget->add<GUI::TextBox>();

    m_find_next_action = GUI::Action::create("Find next", { Mod_Ctrl, Key_G }, Gfx::Bitmap::load_from_file("/res/icons/16x16/find-next.png"), [&](auto&) {
        auto needle = m_find_textbox->text();
        if (needle.is_empty()) {
            dbgln("find_next(\"\")");
            return;
        }

        if (m_find_use_regex)
            m_editor->document().update_regex_matches(needle);

        auto found_range = m_editor->document().find_next(needle, m_editor->normalized_selection().end(), GUI::TextDocument::SearchShouldWrap::Yes, m_find_use_regex);
        dbgln("find_next('{}') returned {}", needle, found_range);
        if (found_range.is_valid()) {
            m_editor->set_selection(found_range);
        } else {
            GUI::MessageBox::show(window(),
                String::formatted("Not found: \"{}\"", needle),
                "Not found",
                GUI::MessageBox::Type::Information);
        }
    });

    m_find_regex_action = GUI::Action::create("Find regex", { Mod_Ctrl | Mod_Shift, Key_R }, [&](auto&) {
        m_find_regex_button->set_checked(!m_find_regex_button->is_checked());
        m_find_use_regex = m_find_regex_button->is_checked();
    });

    m_find_previous_action = GUI::Action::create("Find previous", { Mod_Ctrl | Mod_Shift, Key_G }, [&](auto&) {
        auto needle = m_find_textbox->text();
        if (needle.is_empty()) {
            dbgln("find_prev(\"\")");
            return;
        }

        auto selection_start = m_editor->normalized_selection().start();
        if (!selection_start.is_valid())
            selection_start = m_editor->normalized_selection().end();

        if (m_find_use_regex)
            m_editor->document().update_regex_matches(needle);

        auto found_range = m_editor->document().find_previous(needle, selection_start, GUI::TextDocument::SearchShouldWrap::Yes, m_find_use_regex);

        dbgln("find_prev(\"{}\") returned {}", needle, found_range);
        if (found_range.is_valid()) {
            m_editor->set_selection(found_range);
        } else {
            GUI::MessageBox::show(window(),
                String::formatted("Not found: \"{}\"", needle),
                "Not found",
                GUI::MessageBox::Type::Information);
        }
    });

    m_replace_next_action = GUI::Action::create("Replace next", { Mod_Ctrl, Key_F1 }, [&](auto&) {
        auto needle = m_find_textbox->text();
        auto substitute = m_replace_textbox->text();

        if (needle.is_empty())
            return;

        auto selection_start = m_editor->normalized_selection().start();
        if (!selection_start.is_valid())
            selection_start = m_editor->normalized_selection().start();

        if (m_find_use_regex)
            m_editor->document().update_regex_matches(needle);

        auto found_range = m_editor->document().find_next(needle, selection_start, GUI::TextDocument::SearchShouldWrap::Yes, m_find_use_regex);

        if (found_range.is_valid()) {
            m_editor->set_selection(found_range);
            m_editor->insert_at_cursor_or_replace_selection(substitute);
        } else {
            GUI::MessageBox::show(window(),
                String::formatted("Not found: \"{}\"", needle),
                "Not found",
                GUI::MessageBox::Type::Information);
        }
    });

    m_replace_previous_action = GUI::Action::create("Replace previous", { Mod_Ctrl | Mod_Shift, Key_F1 }, [&](auto&) {
        auto needle = m_find_textbox->text();
        auto substitute = m_replace_textbox->text();
        if (needle.is_empty())
            return;

        auto selection_start = m_editor->normalized_selection().start();
        if (!selection_start.is_valid())
            selection_start = m_editor->normalized_selection().start();

        if (m_find_use_regex)
            m_editor->document().update_regex_matches(needle);

        auto found_range = m_editor->document().find_previous(needle, selection_start);

        if (found_range.is_valid()) {
            m_editor->set_selection(found_range);
            m_editor->insert_at_cursor_or_replace_selection(substitute);
        } else {
            GUI::MessageBox::show(window(),
                String::formatted("Not found: \"{}\"", needle),
                "Not found",
                GUI::MessageBox::Type::Information);
        }
    });

    m_replace_all_action = GUI::Action::create("Replace all", { Mod_Ctrl, Key_F2 }, [&](auto&) {
        auto needle = m_find_textbox->text();
        auto substitute = m_replace_textbox->text();
        if (needle.is_empty())
            return;
        if (m_find_use_regex)
            m_editor->document().update_regex_matches(needle);

        auto found_range = m_editor->document().find_next(needle, {}, GUI::TextDocument::SearchShouldWrap::Yes, m_find_use_regex);
        while (found_range.is_valid()) {
            m_editor->set_selection(found_range);
            m_editor->insert_at_cursor_or_replace_selection(substitute);
            found_range = m_editor->document().find_next(needle, {}, GUI::TextDocument::SearchShouldWrap::Yes, m_find_use_regex);
        }
    });

    m_find_previous_button = *find_descendant_of_type_named<GUI::Button>("find_previous_button");
    m_find_previous_button->set_action(*m_find_previous_action);

    m_find_next_button = *find_descendant_of_type_named<GUI::Button>("find_next_button");
    m_find_next_button->set_action(*m_find_next_action);

    m_find_textbox->on_return_pressed = [this] {
        m_find_next_button->click();
    };

    m_find_regex_button = m_find_widget->add<GUI::Button>(".*");
    m_find_regex_button->set_fixed_width(20);
    m_find_regex_button->set_action(*m_find_regex_action);

    m_find_textbox->on_escape_pressed = [this] {
        m_find_replace_widget->set_visible(false);
        m_editor->set_focus(true);
    };

    m_replace_previous_button = *find_descendant_of_type_named<GUI::Button>("replace_previous_button");
    m_replace_previous_button->set_action(*m_replace_previous_action);

    m_replace_next_button = *find_descendant_of_type_named<GUI::Button>("replace_next_button");
    m_replace_next_button->set_action(*m_replace_next_action);

    m_replace_all_button = *find_descendant_of_type_named<GUI::Button>("replace_all_button");
    m_replace_all_button->set_action(*m_replace_all_action);

    m_replace_textbox->on_return_pressed = [this] {
        m_replace_next_button->click();
    };

    m_replace_textbox->on_escape_pressed = [this] {
        m_find_replace_widget->set_visible(false);
        m_editor->set_focus(true);
    };

    m_vim_emulation_setting_action = GUI::Action::create_checkable("Vim emulation", { Mod_Ctrl | Mod_Shift | Mod_Alt, Key_V }, [&](auto& action) {
        if (action.is_checked())
            m_editor->set_editing_engine(make<GUI::VimEditingEngine>());
        else
            m_editor->set_editing_engine(make<GUI::RegularEditingEngine>());
    });
    m_vim_emulation_setting_action->set_checked(false);

    m_find_replace_action = GUI::Action::create("Find/Replace...", { Mod_Ctrl, Key_F }, Gfx::Bitmap::load_from_file("/res/icons/16x16/find.png"), [this](auto&) {
        m_find_replace_widget->set_visible(true);
        m_find_widget->set_visible(true);
        m_replace_widget->set_visible(true);
        m_find_textbox->set_focus(true);

        if (m_editor->has_selection()) {
            auto selected_text = m_editor->document().text_in_range(m_editor->normalized_selection());
            m_find_textbox->set_text(selected_text);
        }
        m_find_textbox->select_all();
    });

    m_editor->add_custom_context_menu_action(*m_find_replace_action);
    m_editor->add_custom_context_menu_action(*m_find_next_action);
    m_editor->add_custom_context_menu_action(*m_find_previous_action);

    m_statusbar = *find_descendant_of_type_named<GUI::StatusBar>("statusbar");

    m_editor->on_cursor_change = [this] { update_statusbar_cursor_position(); };

    m_new_action = GUI::Action::create("New", { Mod_Ctrl, Key_N }, Gfx::Bitmap::load_from_file("/res/icons/16x16/new.png"), [this](const GUI::Action&) {
        if (m_document_dirty) {
            auto save_document_first_result = GUI::MessageBox::show(window(), "Save changes to current document first?", "Warning", GUI::MessageBox::Type::Warning, GUI::MessageBox::InputType::YesNoCancel);
            if (save_document_first_result == GUI::Dialog::ExecResult::ExecYes)
                m_save_action->activate();
            if (save_document_first_result == GUI::Dialog::ExecResult::ExecCancel)
                return;
        }

        m_document_dirty = false;
        m_editor->set_text(StringView());
        set_path(LexicalPath());
        update_title();
    });

    m_open_action = GUI::CommonActions::make_open_action([this](auto&) {
        Optional<String> open_path = GUI::FilePicker::get_open_filepath(window());

        if (!open_path.has_value())
            return;

        if (m_document_dirty) {
            auto save_document_first_result = GUI::MessageBox::show(window(), "Save changes to current document first?", "Warning", GUI::MessageBox::Type::Warning, GUI::MessageBox::InputType::YesNoCancel);
            if (save_document_first_result == GUI::Dialog::ExecResult::ExecYes)
                m_save_action->activate();
            if (save_document_first_result == GUI::Dialog::ExecResult::ExecCancel)
                return;
        }

        open_sesame(open_path.value());
    });

    m_save_as_action = GUI::CommonActions::make_save_as_action([&](auto&) {
        Optional<String> save_path = GUI::FilePicker::get_save_filepath(window(), m_name.is_null() ? "Untitled" : m_name, m_extension.is_null() ? "txt" : m_extension);
        if (!save_path.has_value())
            return;

        if (!m_editor->write_to_file(save_path.value())) {
            GUI::MessageBox::show(window(), "Unable to save file.\n", "Error", GUI::MessageBox::Type::Error);
            return;
        }

        m_document_dirty = false;
        set_path(LexicalPath(save_path.value()));
        dbgln("Wrote document to {}", save_path.value());
    });

    m_save_action = GUI::CommonActions::make_save_action([&](auto&) {
        if (!m_path.is_empty()) {
            if (!m_editor->write_to_file(m_path)) {
                GUI::MessageBox::show(window(), "Unable to save file.\n", "Error", GUI::MessageBox::Type::Error);
            } else {
                m_document_dirty = false;
                update_title();
            }
            return;
        }

        m_save_as_action->activate();
    });

    auto menubar = GUI::MenuBar::construct();
    auto& app_menu = menubar->add_menu("Text Editor");
    app_menu.add_action(*m_new_action);
    app_menu.add_action(*m_open_action);
    app_menu.add_action(*m_save_action);
    app_menu.add_action(*m_save_as_action);
    app_menu.add_separator();
    app_menu.add_action(GUI::CommonActions::make_quit_action([this](auto&) {
        if (!request_close())
            return;
        GUI::Application::the()->quit();
    }));

    auto& edit_menu = menubar->add_menu("Edit");
    edit_menu.add_action(m_editor->undo_action());
    edit_menu.add_action(m_editor->redo_action());
    edit_menu.add_separator();
    edit_menu.add_action(m_editor->cut_action());
    edit_menu.add_action(m_editor->copy_action());
    edit_menu.add_action(m_editor->paste_action());
    edit_menu.add_action(m_editor->delete_action());
    edit_menu.add_separator();
    edit_menu.add_action(*m_vim_emulation_setting_action);
    edit_menu.add_separator();
    edit_menu.add_action(*m_find_replace_action);
    edit_menu.add_action(*m_find_next_action);
    edit_menu.add_action(*m_find_regex_action);
    edit_menu.add_action(*m_find_previous_action);
    edit_menu.add_action(*m_replace_next_action);
    edit_menu.add_action(*m_replace_previous_action);
    edit_menu.add_action(*m_replace_all_action);

    m_no_preview_action = GUI::Action::create_checkable(
        "No preview", [this](auto&) {
            set_preview_mode(PreviewMode::None);
        });

    m_markdown_preview_action = GUI::Action::create_checkable(
        "Markdown preview", [this](auto&) {
            set_preview_mode(PreviewMode::Markdown);
        },
        this);

    m_html_preview_action = GUI::Action::create_checkable(
        "HTML preview", [this](auto&) {
            set_preview_mode(PreviewMode::HTML);
        },
        this);

    m_preview_actions.add_action(*m_no_preview_action);
    m_preview_actions.add_action(*m_markdown_preview_action);
    m_preview_actions.add_action(*m_html_preview_action);
    m_preview_actions.set_exclusive(true);

    m_layout_toolbar_action = GUI::Action::create_checkable("Toolbar", [&](auto& action) {
        action.is_checked() ? toolbar_container.set_visible(true) : toolbar_container.set_visible(false);
        m_config->write_bool_entry("Layout", "ShowToolbar", action.is_checked());
        m_config->sync();
    });
    auto show_toolbar = m_config->read_bool_entry("Layout", "ShowToolbar", true);
    m_layout_toolbar_action->set_checked(show_toolbar);
    toolbar_container.set_visible(show_toolbar);

    m_layout_statusbar_action = GUI::Action::create_checkable("Status bar", [&](auto& action) {
        action.is_checked() ? m_statusbar->set_visible(true) : m_statusbar->set_visible(false);
        m_config->write_bool_entry("Layout", "ShowStatusBar", action.is_checked());
        m_config->sync();
    });
    auto show_statusbar = m_config->read_bool_entry("Layout", "ShowStatusBar", true);
    m_layout_statusbar_action->set_checked(show_statusbar);
    m_statusbar->set_visible(show_statusbar);

    m_layout_ruler_action = GUI::Action::create_checkable("Ruler", [&](auto& action) {
        action.is_checked() ? m_editor->set_ruler_visible(true) : m_editor->set_ruler_visible(false);
        m_config->write_bool_entry("Layout", "ShowRuler", action.is_checked());
        m_config->sync();
    });
    auto show_ruler = m_config->read_bool_entry("Layout", "ShowRuler", true);
    m_layout_ruler_action->set_checked(show_ruler);
    m_editor->set_ruler_visible(show_ruler);

    auto& view_menu = menubar->add_menu("View");
    auto& layout_menu = view_menu.add_submenu("Layout");
    layout_menu.add_action(*m_layout_toolbar_action);
    layout_menu.add_action(*m_layout_statusbar_action);
    layout_menu.add_action(*m_layout_ruler_action);

    view_menu.add_separator();

    view_menu.add_action(GUI::Action::create("Editor font...", Gfx::Bitmap::load_from_file("/res/icons/16x16/app-font-editor.png"),
        [&](auto&) {
            auto picker = GUI::FontPicker::construct(window(), &m_editor->font(), false);
            if (picker->exec() == GUI::Dialog::ExecOK) {
                dbgln("setting font {}", picker->font()->qualified_name());
                m_editor->set_font(picker->font());
            }
        }));

    view_menu.add_separator();

    m_wrapping_mode_actions.set_exclusive(true);
    auto& wrapping_mode_menu = view_menu.add_submenu("Wrapping mode");
    m_no_wrapping_action = GUI::Action::create_checkable("No wrapping", [&](auto&) {
        m_editor->set_wrapping_mode(GUI::TextEditor::WrappingMode::NoWrap);
    });
    m_wrap_anywhere_action = GUI::Action::create_checkable("Wrap anywhere", [&](auto&) {
        m_editor->set_wrapping_mode(GUI::TextEditor::WrappingMode::WrapAnywhere);
    });
    m_wrap_at_words_action = GUI::Action::create_checkable("Wrap at words", [&](auto&) {
        m_editor->set_wrapping_mode(GUI::TextEditor::WrappingMode::WrapAtWords);
    });

    m_wrapping_mode_actions.add_action(*m_no_wrapping_action);
    m_wrapping_mode_actions.add_action(*m_wrap_anywhere_action);
    m_wrapping_mode_actions.add_action(*m_wrap_at_words_action);

    wrapping_mode_menu.add_action(*m_no_wrapping_action);
    wrapping_mode_menu.add_action(*m_wrap_anywhere_action);
    wrapping_mode_menu.add_action(*m_wrap_at_words_action);

    m_no_wrapping_action->set_checked(true);

    view_menu.add_separator();
    view_menu.add_action(*m_no_preview_action);
    view_menu.add_action(*m_markdown_preview_action);
    view_menu.add_action(*m_html_preview_action);
    m_no_preview_action->set_checked(true);
    view_menu.add_separator();

    syntax_actions.set_exclusive(true);

    auto& syntax_menu = view_menu.add_submenu("Syntax");
    m_plain_text_highlight = GUI::Action::create_checkable("Plain text", [&](auto&) {
        m_editor->set_syntax_highlighter({});
        m_editor->update();
    });
    m_plain_text_highlight->set_checked(true);
    syntax_actions.add_action(*m_plain_text_highlight);
    syntax_menu.add_action(*m_plain_text_highlight);

    m_cpp_highlight = GUI::Action::create_checkable("C++", [&](auto&) {
        m_editor->set_syntax_highlighter(make<Cpp::SyntaxHighlighter>());
        m_editor->update();
    });
    syntax_actions.add_action(*m_cpp_highlight);
    syntax_menu.add_action(*m_cpp_highlight);

    m_js_highlight = GUI::Action::create_checkable("JavaScript", [&](auto&) {
        m_editor->set_syntax_highlighter(make<JS::SyntaxHighlighter>());
        m_editor->update();
    });
    syntax_actions.add_action(*m_js_highlight);
    syntax_menu.add_action(*m_js_highlight);

    m_gml_highlight = GUI::Action::create_checkable("GML", [&](auto&) {
        m_editor->set_syntax_highlighter(make<GUI::GMLSyntaxHighlighter>());
        m_editor->update();
    });
    syntax_actions.add_action(*m_gml_highlight);
    syntax_menu.add_action(*m_gml_highlight);

    m_ini_highlight = GUI::Action::create_checkable("INI File", [&](auto&) {
        m_editor->set_syntax_highlighter(make<GUI::IniSyntaxHighlighter>());
        m_editor->update();
    });
    syntax_actions.add_action(*m_ini_highlight);
    syntax_menu.add_action(*m_ini_highlight);

    m_shell_highlight = GUI::Action::create_checkable("Shell File", [&](auto&) {
        m_editor->set_syntax_highlighter(make<Shell::SyntaxHighlighter>());
        m_editor->update();
    });
    syntax_actions.add_action(*m_shell_highlight);
    syntax_menu.add_action(*m_shell_highlight);

    auto& help_menu = menubar->add_menu("Help");
    help_menu.add_action(GUI::CommonActions::make_help_action([](auto&) {
        Desktop::Launcher::open(URL::create_with_file_protocol("/usr/share/man/man1/TextEditor.md"), "/bin/Help");
    }));
    help_menu.add_action(GUI::CommonActions::make_about_action("Text Editor", GUI::Icon::default_icon("app-text-editor"), window()));

    GUI::Application::the()->set_menubar(move(menubar));

    toolbar.add_action(*m_new_action);
    toolbar.add_action(*m_open_action);
    toolbar.add_action(*m_save_action);

    toolbar.add_separator();

    toolbar.add_action(m_editor->cut_action());
    toolbar.add_action(m_editor->copy_action());
    toolbar.add_action(m_editor->paste_action());
    toolbar.add_action(m_editor->delete_action());

    toolbar.add_separator();

    toolbar.add_action(m_editor->undo_action());
    toolbar.add_action(m_editor->redo_action());
}

TextEditorWidget::~TextEditorWidget()
{
}

void TextEditorWidget::set_path(const LexicalPath& lexical_path)
{
    m_path = lexical_path.string();
    m_name = lexical_path.title();
    m_extension = lexical_path.extension();

    if (m_extension == "c" || m_extension == "cc" || m_extension == "cxx" || m_extension == "cpp" || m_extension == "h") {
        m_cpp_highlight->activate();
    } else if (m_extension == "js" || m_extension == "json") {
        m_js_highlight->activate();
    } else if (m_extension == "gml") {
        m_gml_highlight->activate();
    } else if (m_extension == "ini") {
        m_ini_highlight->activate();
    } else {
        m_plain_text_highlight->activate();
    }

    if (m_auto_detect_preview_mode) {
        if (m_extension == "md")
            set_preview_mode(PreviewMode::Markdown);
        else if (m_extension == "html")
            set_preview_mode(PreviewMode::HTML);
        else
            set_preview_mode(PreviewMode::None);
    }

    update_title();
}

void TextEditorWidget::update_title()
{
    StringBuilder builder;
    if (m_path.is_empty())
        builder.append("Untitled");
    else
        builder.append(m_path);
    if (m_document_dirty)
        builder.append(" (*)");
    builder.append(" - Text Editor");
    window()->set_title(builder.to_string());
}

void TextEditorWidget::open_sesame(const String& path)
{
    auto file = Core::File::construct(path);
    if (!file->open(Core::IODevice::ReadOnly) && file->error() != ENOENT) {
        GUI::MessageBox::show(window(), String::formatted("Opening \"{}\" failed: {}", path, strerror(errno)), "Error", GUI::MessageBox::Type::Error);
        return;
    }

    m_editor->set_text(file->read_all());
    m_document_dirty = false;
    m_document_opening = true;

    set_path(LexicalPath(path));

    m_editor->set_focus(true);
}

bool TextEditorWidget::request_close()
{
    if (!m_document_dirty)
        return true;
    auto result = GUI::MessageBox::show(window(), "The document has been modified. Would you like to save?", "Unsaved changes", GUI::MessageBox::Type::Warning, GUI::MessageBox::InputType::YesNoCancel);

    if (result == GUI::MessageBox::ExecYes) {
        m_save_action->activate();
        return true;
    }

    if (result == GUI::MessageBox::ExecNo)
        return true;

    return false;
}

void TextEditorWidget::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(), "TextEditor can only open one file at a time!", "One at a time please!", GUI::MessageBox::Type::Error);
            return;
        }
        open_sesame(urls.first().path());
    }
}

void TextEditorWidget::set_preview_mode(PreviewMode mode)
{
    if (m_preview_mode == mode)
        return;
    m_preview_mode = mode;

    if (m_preview_mode == PreviewMode::HTML) {
        m_html_preview_action->set_checked(true);
        m_page_view->set_visible(true);
        update_html_preview();
    } else if (m_preview_mode == PreviewMode::Markdown) {
        m_markdown_preview_action->set_checked(true);
        m_page_view->set_visible(true);
        update_markdown_preview();
    } else {
        m_no_preview_action->set_checked(true);
        m_page_view->set_visible(false);
    }
}

void TextEditorWidget::update_preview()
{
    switch (m_preview_mode) {
    case PreviewMode::Markdown:
        update_markdown_preview();
        break;
    case PreviewMode::HTML:
        update_html_preview();
        break;
    default:
        break;
    }
}

void TextEditorWidget::update_markdown_preview()
{
    auto document = Markdown::Document::parse(m_editor->text());
    if (document) {
        auto html = document->render_to_html();
        auto current_scroll_pos = m_page_view->visible_content_rect();
        m_page_view->load_html(html, URL::create_with_file_protocol(m_path));
        m_page_view->scroll_into_view(current_scroll_pos, true, true);
    }
}

void TextEditorWidget::update_html_preview()
{
    auto current_scroll_pos = m_page_view->visible_content_rect();
    m_page_view->load_html(m_editor->text(), URL::create_with_file_protocol(m_path));
    m_page_view->scroll_into_view(current_scroll_pos, true, true);
}

void TextEditorWidget::update_statusbar_cursor_position()
{
    StringBuilder builder;
    builder.appendff("Line: {}, Column: {}", m_editor->cursor().line() + 1, m_editor->cursor().column());
    m_statusbar->set_text(builder.to_string());
}