// gKeyMapper - GTK4 GUI for remapping the G keys (G1-G9) of the Logitech G910
// GUI only for now. Mappings are stored as a simple text file.

#include <gtk/gtk.h>

#include <algorithm>
#include <cctype>
#include <fstream>
#include <iostream>
#include <locale.h>
#include <libintl.h>
#include <set>
#include <string>
#include <vector>

#ifndef PACKAGE
#define PACKAGE "gkeymapper"
#endif

#ifndef LOCALEDIR
#define LOCALEDIR "/usr/local/share/locale"
#endif

#define _(s) gettext(s)
#define N_(s) (s)

namespace {
constexpr int NUM_KEYS = 9;

struct KeyRow {
    int index;                 // 0..8 -> G1..G9
    GtkWidget* keyLabel = nullptr;
    GtkWidget* typeDrop = nullptr;
    GtkWidget* targetEntry = nullptr;
    GtkWidget* captureButton = nullptr;
};

std::vector<KeyRow> rows;

static void on_pick_file_response(GtkDialog* dialog, int response, gpointer userData) {
    if (response == GTK_RESPONSE_ACCEPT) {
        KeyRow* row = static_cast<KeyRow*>(userData);
        GtkFileChooser* chooser = GTK_FILE_CHOOSER(dialog);
        g_autoptr(GFile) file = gtk_file_chooser_get_file(chooser);
        char* path = g_file_get_path(file);
        if (path) {
            gtk_editable_set_text(GTK_EDITABLE(row->targetEntry), path);
            g_free(path);
        }
    }
    gtk_window_destroy(GTK_WINDOW(dialog));
}

static void pick_command_file(KeyRow* row, GtkWindow* parent) {
    GtkWidget* dialog = gtk_file_chooser_dialog_new(_("Choose file"),
                                                   parent,
                                                   GTK_FILE_CHOOSER_ACTION_OPEN,
                                                   _("_Cancel"), GTK_RESPONSE_CANCEL,
                                                   _("_Open"), GTK_RESPONSE_ACCEPT,
                                                   NULL);
    g_signal_connect(dialog, "response", G_CALLBACK(on_pick_file_response), row);
    gtk_window_present(GTK_WINDOW(dialog));
}

struct CaptureSession {
    KeyRow* row = nullptr;
    GtkWidget* displayLabel = nullptr;
    std::vector<std::string> steps;
    std::set<guint> heldKeys; // non-modifier keyvals currently held (ignores auto-repeat)
};

static bool is_modifier_keyval(guint keyval) {
    switch (keyval) {
        case GDK_KEY_Control_L:
        case GDK_KEY_Control_R:
        case GDK_KEY_Alt_L:
        case GDK_KEY_Alt_R:
        case GDK_KEY_Shift_L:
        case GDK_KEY_Shift_R:
        case GDK_KEY_Super_L:
        case GDK_KEY_Super_R:
        case GDK_KEY_Meta_L:
        case GDK_KEY_Meta_R:
        case GDK_KEY_ISO_Level3_Shift: // AltGr
            return true;
        default:
            return false;
    }
}

// Format one step like the reference project: modifiers joined with '+',
// e.g. "ctrl+shift+t". Multiple steps are joined with ',' ("ctrl+c,ctrl+v").
static std::string format_capture_step(GdkModifierType state, guint keyval) {
    std::string step;
    if (state & GDK_CONTROL_MASK) {
        step += "ctrl+";
    }
    if (state & GDK_ALT_MASK) {
        step += "alt+";
    }
    if (state & GDK_SHIFT_MASK) {
        step += "shift+";
    }
    if (state & (GDK_SUPER_MASK | GDK_META_MASK)) {
        step += "super+";
    }
    const char* name = gdk_keyval_name(keyval);
    std::string key = name ? name : "?";
    std::transform(key.begin(), key.end(), key.begin(),
                   [](unsigned char c) { return std::tolower(c); });
    step += key;
    return step;
}

static std::string join_capture_steps(const std::vector<std::string>& steps) {
    std::string out;
    for (size_t i = 0; i < steps.size(); ++i) {
        if (i > 0) {
            out += ",";
        }
        out += steps[i];
    }
    return out;
}

static void update_capture_display(CaptureSession* session) {
    std::string text = join_capture_steps(session->steps);
    if (text.empty()) {
        text = _("No keys recorded yet");
    }
    gtk_label_set_text(GTK_LABEL(session->displayLabel), text.c_str());
}

static gboolean on_capture_key_pressed(GtkEventControllerKey* /*controller*/,
                                       guint keyval, guint /*keycode*/,
                                       GdkModifierType state, gpointer userData) {
    auto* session = static_cast<CaptureSession*>(userData);
    if (is_modifier_keyval(keyval)) {
        return TRUE; // modifiers are recorded as part of the next real key
    }
    if (session->heldKeys.count(keyval)) {
        return TRUE; // ignore auto-repeat while the key is held down
    }
    session->heldKeys.insert(keyval);
    constexpr GdkModifierType kModMask = static_cast<GdkModifierType>(
        GDK_SHIFT_MASK | GDK_CONTROL_MASK | GDK_ALT_MASK |
        GDK_SUPER_MASK | GDK_META_MASK);
    session->steps.push_back(format_capture_step(
        static_cast<GdkModifierType>(state & kModMask), keyval));
    update_capture_display(session);
    return TRUE;
}

static gboolean on_capture_key_released(GtkEventControllerKey* /*controller*/,
                                        guint keyval, guint /*keycode*/,
                                        GdkModifierType /*state*/, gpointer userData) {
    auto* session = static_cast<CaptureSession*>(userData);
    session->heldKeys.erase(keyval);
    return TRUE;
}

static void on_capture_session_destroy(GtkWidget* /*widget*/, gpointer userData) {
    delete static_cast<CaptureSession*>(userData);
}

static void on_capture_done_clicked(GtkButton* btn, gpointer userData) {
    auto* session = static_cast<CaptureSession*>(userData);
    if (!session->steps.empty()) {
        gtk_editable_set_text(GTK_EDITABLE(session->row->targetEntry),
                              join_capture_steps(session->steps).c_str());
    }
    GtkWindow* window = GTK_WINDOW(gtk_widget_get_root(GTK_WIDGET(btn)));
    gtk_window_destroy(window); // triggers session cleanup via "destroy"
}

static void on_capture_cancel_clicked(GtkButton* btn, gpointer /*userData*/) {
    GtkWindow* window = GTK_WINDOW(gtk_widget_get_root(GTK_WIDGET(btn)));
    gtk_window_destroy(window); // triggers session cleanup via "destroy"
}

static void on_capture_clear_clicked(GtkButton* /*btn*/, gpointer userData) {
    auto* session = static_cast<CaptureSession*>(userData);
    session->steps.clear();
    session->heldKeys.clear();
    update_capture_display(session);
}

static void open_key_capture_dialog(KeyRow* row, GtkWindow* parent) {
    auto* session = new CaptureSession();
    session->row = row;

    GtkWidget* dialog = gtk_window_new();
    gtk_window_set_title(GTK_WINDOW(dialog), _("Capture key sequence"));
    gtk_window_set_transient_for(GTK_WINDOW(dialog), parent);
    gtk_window_set_modal(GTK_WINDOW(dialog), TRUE);
    gtk_window_set_resizable(GTK_WINDOW(dialog), FALSE);
    gtk_window_set_default_size(GTK_WINDOW(dialog), 540, 300);
    g_signal_connect(dialog, "destroy", G_CALLBACK(on_capture_session_destroy), session);

    GtkWidget* outer = gtk_box_new(GTK_ORIENTATION_VERTICAL, 16);
    gtk_widget_set_margin_top(outer, 20);
    gtk_widget_set_margin_bottom(outer, 20);
    gtk_widget_set_margin_start(outer, 20);
    gtk_widget_set_margin_end(outer, 20);
    gtk_window_set_child(GTK_WINDOW(dialog), outer);

    GtkWidget* title = gtk_label_new(nullptr);
    gtk_label_set_markup(GTK_LABEL(title),
                         g_strdup_printf("<span size='large' weight='bold'>%s</span>",
                                         _("Capture key sequence")));
    gtk_label_set_xalign(GTK_LABEL(title), 0.0f);
    gtk_box_append(GTK_BOX(outer), title);

    GtkWidget* info = gtk_label_new(_("Press keys in order (modifiers like Ctrl, Alt, Shift and Super are recorded too). Click Done to apply or Cancel to discard."));
    gtk_label_set_wrap(GTK_LABEL(info), TRUE);
    gtk_label_set_xalign(GTK_LABEL(info), 0.0f);
    gtk_widget_add_css_class(info, "dim-label");
    gtk_box_append(GTK_BOX(outer), info);

    session->displayLabel = gtk_label_new(_("No keys recorded yet"));
    gtk_label_set_xalign(GTK_LABEL(session->displayLabel), 0.0f);
    gtk_label_set_ellipsize(GTK_LABEL(session->displayLabel), PANGO_ELLIPSIZE_MIDDLE);
    gtk_widget_add_css_class(session->displayLabel, "monospace");
    gtk_widget_set_margin_top(session->displayLabel, 12);
    gtk_widget_set_margin_bottom(session->displayLabel, 12);
    gtk_widget_set_margin_start(session->displayLabel, 12);
    gtk_widget_set_margin_end(session->displayLabel, 12);
    GtkWidget* frame = gtk_frame_new(nullptr);
    gtk_frame_set_child(GTK_FRAME(frame), session->displayLabel);
    gtk_widget_set_size_request(frame, -1, 64);
    gtk_widget_set_vexpand(frame, TRUE);
    gtk_box_append(GTK_BOX(outer), frame);

    gtk_box_append(GTK_BOX(outer), gtk_separator_new(GTK_ORIENTATION_HORIZONTAL));

    // Buttons: Clear on the left, Cancel/Done grouped on the right.
    GtkWidget* buttonRow = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
    gtk_box_append(GTK_BOX(outer), buttonRow);

    GtkWidget* clearBtn = gtk_button_new_with_label(_("Clear"));
    gtk_widget_set_size_request(clearBtn, 110, -1);
    g_signal_connect(clearBtn, "clicked", G_CALLBACK(on_capture_clear_clicked), session);
    gtk_box_append(GTK_BOX(buttonRow), clearBtn);

    GtkWidget* spacer = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
    gtk_widget_set_hexpand(spacer, TRUE);
    gtk_box_append(GTK_BOX(buttonRow), spacer);

    GtkWidget* endBox = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 8);
    gtk_box_append(GTK_BOX(buttonRow), endBox);

    GtkWidget* cancelBtn = gtk_button_new_with_label(_("Cancel"));
    gtk_widget_set_size_request(cancelBtn, 110, -1);
    g_signal_connect(cancelBtn, "clicked", G_CALLBACK(on_capture_cancel_clicked), nullptr);
    gtk_box_append(GTK_BOX(endBox), cancelBtn);

    GtkWidget* doneBtn = gtk_button_new_with_label(_("Done"));
    gtk_widget_set_size_request(doneBtn, 110, -1);
    g_signal_connect(doneBtn, "clicked", G_CALLBACK(on_capture_done_clicked), session);
    gtk_box_append(GTK_BOX(endBox), doneBtn);

    // Key events go to the dialog; buttons must not steal Space/Return.
    GtkEventController* keyCtrl = gtk_event_controller_key_new();
    g_signal_connect(keyCtrl, "key-pressed", G_CALLBACK(on_capture_key_pressed), session);
    g_signal_connect(keyCtrl, "key-released", G_CALLBACK(on_capture_key_released), session);
    gtk_widget_add_controller(dialog, keyCtrl);
    gtk_widget_set_focusable(clearBtn, FALSE);
    gtk_widget_set_focusable(cancelBtn, FALSE);
    gtk_widget_set_focusable(doneBtn, FALSE);

    gtk_window_present(GTK_WINDOW(dialog));
}

void on_capture_clicked(GtkButton* btn, gpointer userData) {
    auto* row = static_cast<KeyRow*>(userData);
    guint sel = gtk_drop_down_get_selected(GTK_DROP_DOWN(row->typeDrop));

    GtkWindow* window = GTK_WINDOW(gtk_widget_get_root(GTK_WIDGET(btn)));
    if (sel == 1) {
        pick_command_file(row, window);
        return;
    }

    if (sel == 0) {
        open_key_capture_dialog(row, window);
    }
}

static void update_row_state(KeyRow* row) {
    guint sel = gtk_drop_down_get_selected(GTK_DROP_DOWN(row->typeDrop));
    gboolean enabled = (sel != 2);
    gtk_widget_set_sensitive(row->targetEntry, enabled);
    gtk_widget_set_sensitive(row->captureButton, enabled);

    if (sel == 1) {
        gtk_button_set_label(GTK_BUTTON(row->captureButton), _("Choose file..."));
        gtk_entry_set_placeholder_text(GTK_ENTRY(row->targetEntry),
                                       _("e.g. /usr/bin/firefox or custom command"));
    } else {
        gtk_button_set_label(GTK_BUTTON(row->captureButton), _("Capture"));
        gtk_entry_set_placeholder_text(GTK_ENTRY(row->targetEntry),
                                       _("e.g. ctrl+c, ctrl+v"));
    }
    gtk_widget_set_size_request(row->captureButton, 180, -1);
}

static void on_type_changed(GObject* /*object*/, GParamSpec* /*pspec*/, gpointer userData) {
    update_row_state(static_cast<KeyRow*>(userData));
}

static bool write_mappings_to_file(const std::string& path) {
    std::ofstream out(path);
    if (!out) {
        return false;
    }

    out << "# gKeyMapper mappings (G1..G9)\n";
    for (const auto& row : rows) {
        const char* type = "disabled";
        switch (gtk_drop_down_get_selected(GTK_DROP_DOWN(row.typeDrop))) {
            case 0: type = "key"; break;
            case 1: type = "command"; break;
            default: type = "disabled"; break;
        }
        const char* target = gtk_editable_get_text(GTK_EDITABLE(row.targetEntry));
        out << "G" << (row.index + 1) << "=" << type << ":" << (target ? target : "") << "\n";
    }
    out.close();
    return true;
}

void on_save_clicked(GtkButton* /*btn*/, gpointer /*userData*/) {
    const char* home = g_get_home_dir();
    std::string dir = std::string(home) + "/.config/gKeyMapper";
    g_mkdir_with_parents(dir.c_str(), 0755);
    std::string path = dir + "/mappings.conf";

    if (!write_mappings_to_file(path)) {
        g_printerr(_("Could not save %s.\n"), path.c_str());
        return;
    }

    std::cout << _("Mappings saved to ") << path << "\n";
}

static void import_mappings_from_file(const std::string& path) {
    std::ifstream in(path);
    if (!in) {
        g_printerr(_("Could not open %s.\n"), path.c_str());
        return;
    }

    std::string line;
    while (std::getline(in, line)) {
        if (line.empty() || line[0] == '#') {
            continue;
        }
        auto eq = line.find('=');
        if (eq == std::string::npos) {
            continue;
        }
        std::string key = line.substr(0, eq);
        if (key.size() < 2 || key[0] != 'G') {
            continue;
        }
        int n = 0;
        try {
            n = std::stoi(key.substr(1)) - 1;
        } catch (...) {
            continue;
        }
        if (n < 0 || n >= (int)rows.size()) {
            continue;
        }

        std::string rest = line.substr(eq + 1);
        auto col = rest.find(':');
        std::string typeToken = (col == std::string::npos) ? rest : rest.substr(0, col);
        std::string target = (col == std::string::npos) ? std::string() : rest.substr(col + 1);

        guint idx = 2;
        if (typeToken == "key") {
            idx = 0;
        } else if (typeToken == "command") {
            idx = 1;
        } else if (typeToken == "disabled") {
            idx = 2;
        }
        gtk_drop_down_set_selected(GTK_DROP_DOWN(rows[n].typeDrop), idx);
        gtk_editable_set_text(GTK_EDITABLE(rows[n].targetEntry), target.c_str());
    }
}

static void on_export_response(GtkDialog* dialog, int response, gpointer /*userData*/) {
    if (response == GTK_RESPONSE_ACCEPT) {
        GtkFileChooser* chooser = GTK_FILE_CHOOSER(dialog);
        g_autoptr(GFile) file = gtk_file_chooser_get_file(chooser);
        char* path = g_file_get_path(file);
        if (path) {
            if (!write_mappings_to_file(path)) {
                g_printerr(_("Could not export mappings.\n"));
            }
            g_free(path);
        }
    }
    gtk_window_destroy(GTK_WINDOW(dialog));
}

static void on_import_response(GtkDialog* dialog, int response, gpointer /*userData*/) {
    if (response == GTK_RESPONSE_ACCEPT) {
        GtkFileChooser* chooser = GTK_FILE_CHOOSER(dialog);
        g_autoptr(GFile) file = gtk_file_chooser_get_file(chooser);
        char* path = g_file_get_path(file);
        if (path) {
            import_mappings_from_file(path);
            g_free(path);
        }
    }
    gtk_window_destroy(GTK_WINDOW(dialog));
}

static std::string find_asset(const std::string& name);

static void show_about_dialog(GtkWindow* parent) {
    GtkWidget* dialog = gtk_about_dialog_new();
    gtk_about_dialog_set_program_name(GTK_ABOUT_DIALOG(dialog), _("gKeyMapper"));
    gtk_about_dialog_set_version(GTK_ABOUT_DIALOG(dialog), "0.1.0");
    gtk_about_dialog_set_comments(GTK_ABOUT_DIALOG(dialog),
                                 _("G-Key mapper for the Logitech G910 (GTK4)."));
    gtk_about_dialog_set_website(GTK_ABOUT_DIALOG(dialog), "https://rager.dev");
    gtk_about_dialog_set_website_label(GTK_ABOUT_DIALOG(dialog), "Thomas Rager - rager.dev");

    std::string iconPath = find_asset("icon.png");
    GError* error = nullptr;
    GdkTexture* texture = gdk_texture_new_from_filename(iconPath.c_str(), &error);
    if (texture) {
        gtk_about_dialog_set_logo(GTK_ABOUT_DIALOG(dialog), GDK_PAINTABLE(texture));
        g_object_unref(texture);
    } else if (error) {
        g_printerr("Could not load icon: %s\n", error->message);
        g_error_free(error);
    }
    gtk_window_set_transient_for(GTK_WINDOW(dialog), parent);
    g_signal_connect(dialog, "response", G_CALLBACK(gtk_window_destroy), NULL);
    gtk_window_present(GTK_WINDOW(dialog));
}

static void do_export(GtkWindow* parent) {
    GtkWidget* dialog = gtk_file_chooser_dialog_new(_("Export configuration"),
                                                   parent,
                                                   GTK_FILE_CHOOSER_ACTION_SAVE,
                                                   _("_Cancel"), GTK_RESPONSE_CANCEL,
                                                   _("_Save"), GTK_RESPONSE_ACCEPT,
                                                   NULL);
    gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(dialog), "gkeymapper.conf");
    g_signal_connect(dialog, "response", G_CALLBACK(on_export_response), NULL);
    gtk_window_present(GTK_WINDOW(dialog));
}

static void do_import(GtkWindow* parent) {
    GtkWidget* dialog = gtk_file_chooser_dialog_new(_("Import configuration"),
                                                   parent,
                                                   GTK_FILE_CHOOSER_ACTION_OPEN,
                                                   _("_Cancel"), GTK_RESPONSE_CANCEL,
                                                   _("_Open"), GTK_RESPONSE_ACCEPT,
                                                   NULL);
    g_signal_connect(dialog, "response", G_CALLBACK(on_import_response), NULL);
    gtk_window_present(GTK_WINDOW(dialog));
}

static void action_export(GSimpleAction* /*action*/, GVariant* /*parameter*/, gpointer userData) {
    GtkApplication* app = GTK_APPLICATION(userData);
    GtkWindow* window = gtk_application_get_active_window(app);
    if (window) {
        do_export(window);
    }
}

static void action_import(GSimpleAction* /*action*/, GVariant* /*parameter*/, gpointer userData) {
    GtkApplication* app = GTK_APPLICATION(userData);
    GtkWindow* window = gtk_application_get_active_window(app);
    if (window) {
        do_import(window);
    }
}

static void action_about(GSimpleAction* /*action*/, GVariant* /*parameter*/, gpointer userData) {
    GtkApplication* app = GTK_APPLICATION(userData);
    GtkWindow* window = gtk_application_get_active_window(app);
    if (window) {
        show_about_dialog(window);
    }
}

static std::string find_asset(const std::string& name) {
    const char* env = g_getenv("GKEYMAPPER_ASSETS_DIR");
    if (env && *env) {
        std::string path = std::string(env) + "/" + name;
        if (g_file_test(path.c_str(), G_FILE_TEST_EXISTS)) {
            return path;
        }
    }

    std::string local = std::string("./assets/") + name;
    if (g_file_test(local.c_str(), G_FILE_TEST_EXISTS)) {
        return local;
    }

#ifndef ASSETS_DIR
#define ASSETS_DIR "/usr/local/share/gkeymapper/assets"
#endif
    std::string installed = std::string(ASSETS_DIR) + "/" + name;
    if (g_file_test(installed.c_str(), G_FILE_TEST_EXISTS)) {
        return installed;
    }
    return local;
}

void build_ui(GtkApplication* app) {
    GtkWidget* window = gtk_application_window_new(app);
    gtk_window_set_title(GTK_WINDOW(window), _("gKeyMapper – Logitech G910"));
    gtk_window_set_resizable(GTK_WINDOW(window), FALSE);

    GtkWidget* headerBar = gtk_header_bar_new();
    gtk_window_set_titlebar(GTK_WINDOW(window), headerBar);
    gtk_window_set_icon_name(GTK_WINDOW(window), "gkeymapper");

    GtkWidget* titleBox = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 8);
    GtkWidget* iconImage = gtk_image_new_from_file(find_asset("icon.png").c_str());
    gtk_image_set_pixel_size(GTK_IMAGE(iconImage), 24);
    gtk_box_append(GTK_BOX(titleBox), iconImage);
    gtk_box_append(GTK_BOX(titleBox), gtk_label_new(_("gKeyMapper")));
    gtk_header_bar_set_title_widget(GTK_HEADER_BAR(headerBar), titleBox);

    GMenu* menu = g_menu_new();
    g_menu_append(menu, _("Export configuration..."), "app.export-config");
    g_menu_append(menu, _("Import configuration..."), "app.import-config");

    GMenu* helpSection = g_menu_new();
    g_menu_append(helpSection, _("About"), "app.about");
    g_menu_append_section(menu, NULL, G_MENU_MODEL(helpSection));

    GtkWidget* menuButton = gtk_menu_button_new();
    gtk_menu_button_set_icon_name(GTK_MENU_BUTTON(menuButton), "open-menu-symbolic");
    gtk_menu_button_set_menu_model(GTK_MENU_BUTTON(menuButton), G_MENU_MODEL(menu));
    gtk_header_bar_pack_end(GTK_HEADER_BAR(headerBar), menuButton);

    GtkWidget* outer = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
    gtk_window_set_child(GTK_WINDOW(window), outer);

    // Title / subtitle
    GtkWidget* headerBox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 2);
    gtk_widget_set_margin_top(headerBox, 16);
    gtk_widget_set_margin_bottom(headerBox, 8);
    gtk_widget_set_margin_start(headerBox, 16);
    gtk_widget_set_margin_end(headerBox, 16);
    gtk_box_append(GTK_BOX(outer), headerBox);

    GtkWidget* title = gtk_label_new(nullptr);
    gtk_label_set_markup(GTK_LABEL(title), "<span size='x-large' weight='bold'>G-Key Mapper</span>");
    gtk_label_set_xalign(GTK_LABEL(title), 0.0f);
    gtk_box_append(GTK_BOX(headerBox), title);

    GtkWidget* subtitle = gtk_label_new(_("G1 to G9 of the Logitech G910 remapped to keys or commands"));
    gtk_label_set_xalign(GTK_LABEL(subtitle), 0.0f);
    gtk_widget_add_css_class(subtitle, "dim-label");
    gtk_box_append(GTK_BOX(headerBox), subtitle);

    // Table with all nine G keys (no scrolling needed, everything stays visible)
    GtkWidget* grid = gtk_grid_new();
    gtk_grid_set_row_spacing(GTK_GRID(grid), 6);
    gtk_grid_set_column_spacing(GTK_GRID(grid), 8);
    gtk_widget_set_margin_top(grid, 8);
    gtk_widget_set_margin_bottom(grid, 4);
    gtk_widget_set_margin_start(grid, 16);
    gtk_widget_set_margin_end(grid, 16);
    gtk_widget_set_hexpand(grid, TRUE);
    gtk_box_append(GTK_BOX(outer), grid);

    // Column headers
    const char* headers[] = { _("G-Key"), _("Type"), _("Target (Key/Command)"), _("Action") };
    for (int c = 0; c < 4; ++c) {
        GtkWidget* h = gtk_label_new(headers[c]);
        gtk_label_set_markup(GTK_LABEL(h), g_strdup_printf("<b>%s</b>", headers[c]));
        gtk_widget_add_css_class(h, "dim-label");
        gtk_grid_attach(GTK_GRID(grid), h, c, 0, 1, 1);
    }

    const char* typeOptions[] = { _("Key"), _("Command"), _("Disabled"), nullptr };

    rows.resize(NUM_KEYS);
    for (int i = 0; i < NUM_KEYS; ++i) {
        rows[i].index = i;

        // G key label
        GtkWidget* keyLabel = gtk_label_new(g_strdup_printf("G%d", i + 1));
        gtk_label_set_markup(GTK_LABEL(keyLabel), g_strdup_printf("<b>G%d</b>", i + 1));
        gtk_grid_attach(GTK_GRID(grid), keyLabel, 0, i + 1, 1, 1);
        rows[i].keyLabel = keyLabel;

        // Type dropdown (fixed width so rows don't jump between languages)
        GtkWidget* drop = gtk_drop_down_new_from_strings(typeOptions);
        gtk_drop_down_set_selected(GTK_DROP_DOWN(drop), 0);
        gtk_widget_set_size_request(drop, 150, -1);
        gtk_grid_attach(GTK_GRID(grid), drop, 1, i + 1, 1, 1);
        rows[i].typeDrop = drop;

        g_signal_connect(drop, "notify::selected", G_CALLBACK(on_type_changed), &rows[i]);

        // Target input (wide: commands and file paths need room)
        GtkWidget* entry = gtk_entry_new();
        gtk_entry_set_placeholder_text(GTK_ENTRY(entry), _("e.g. ctrl+c, ctrl+v"));
        gtk_widget_set_size_request(entry, 440, -1);
        gtk_widget_set_hexpand(entry, TRUE);
        gtk_grid_attach(GTK_GRID(grid), entry, 2, i + 1, 1, 1);
        rows[i].targetEntry = entry;

        // Capture button
        GtkWidget* capture = gtk_button_new_with_label(_("Capture"));
        gtk_widget_set_size_request(capture, 180, -1);
        g_signal_connect(capture, "clicked", G_CALLBACK(on_capture_clicked), &rows[i]);
        gtk_grid_attach(GTK_GRID(grid), capture, 3, i + 1, 1, 1);
        rows[i].captureButton = capture;

        update_row_state(&rows[i]);
    }

    // Footer with save button
    GtkWidget* footer = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 8);
    gtk_widget_set_margin_top(footer, 8);
    gtk_widget_set_margin_bottom(footer, 16);
    gtk_widget_set_margin_start(footer, 16);
    gtk_widget_set_margin_end(footer, 16);
    gtk_box_append(GTK_BOX(outer), footer);

    GtkWidget* saveBtn = gtk_button_new_with_label(_("Save mappings"));
    // No "suggested-action" class on purpose: it gets a strong accent color
    // (e.g. Mint-Y green) that clashes with the rest of the layout. The plain
    // button follows the system theme like everything else.
    g_signal_connect(saveBtn, "clicked", G_CALLBACK(on_save_clicked), nullptr);
    gtk_box_append(GTK_BOX(footer), saveBtn);

    GtkWidget* hint = gtk_label_new(_("Saved to ~/.config/gKeyMapper/mappings.conf"));
    gtk_widget_add_css_class(hint, "dim-label");
    gtk_widget_set_halign(hint, GTK_ALIGN_END);
    gtk_widget_set_hexpand(hint, TRUE);
    gtk_box_append(GTK_BOX(footer), hint);

    gtk_window_present(GTK_WINDOW(window));
}

static void on_activate(GtkApplication* app, gpointer /*user_data*/) {
    GSimpleAction* exportAction = g_simple_action_new("export-config", NULL);
    g_signal_connect(exportAction, "activate", G_CALLBACK(action_export), app);
    g_action_map_add_action(G_ACTION_MAP(app), G_ACTION(exportAction));

    GSimpleAction* importAction = g_simple_action_new("import-config", NULL);
    g_signal_connect(importAction, "activate", G_CALLBACK(action_import), app);
    g_action_map_add_action(G_ACTION_MAP(app), G_ACTION(importAction));

    GSimpleAction* aboutAction = g_simple_action_new("about", NULL);
    g_signal_connect(aboutAction, "activate", G_CALLBACK(action_about), app);
    g_action_map_add_action(G_ACTION_MAP(app), G_ACTION(aboutAction));

    build_ui(app);
}
} // namespace

int main(int argc, char** argv) {
    setlocale(LC_ALL, "");

    const char* localedir = g_getenv("GKEYMAPPER_LOCALEDIR");
    if (!localedir || !*localedir) {
        localedir = LOCALEDIR;
    }
    bindtextdomain(PACKAGE, localedir);
    bind_textdomain_codeset(PACKAGE, "UTF-8");
    textdomain(PACKAGE);

    GtkApplication* app = gtk_application_new("com.example.gkeymapper",
                                              G_APPLICATION_FLAGS_NONE);
    g_signal_connect(app, "activate", G_CALLBACK(on_activate), nullptr);
    int status = g_application_run(G_APPLICATION(app), argc, argv);
    g_object_unref(app);
    return status;
}