"""Entry point for the AI sidebar application."""

from __future__ import annotations

import os
import sys

import gi

gi.require_version("Gtk", "4.0")
from gi.repository import Gtk  # noqa: E402

from sidebar_window import SidebarWindow  # noqa: E402

HEADLESS_ENV_VAR = "AI_SIDEBAR_HEADLESS"
_STARTUP_FAILED = False


def main(argv: list[str] | None = None) -> int:
    """Launch the GTK application and return the exit status."""
    args = argv or sys.argv

    if os.environ.get(HEADLESS_ENV_VAR) == "1":
        print("Headless mode enabled; skipping GTK startup.")
        return 0

    if not Gtk.init_check():
        print(
            "Failed to initialize GTK. Ensure a display server is available.",
            file=sys.stderr,
        )
        return 1

    if not (os.environ.get("WAYLAND_DISPLAY") or os.environ.get("DISPLAY")):
        print(
            "No Wayland or X11 display detected. Launch this app inside a graphical session.",
            file=sys.stderr,
        )
        return 1

    # Warn if GDK_BACKEND is set to X11 on Wayland systems
    if os.environ.get("WAYLAND_DISPLAY") and os.environ.get("GDK_BACKEND") == "x11":
        print(
            "Warning: GDK_BACKEND is set to 'x11' but you're on Wayland.",
            file=sys.stderr,
        )
        print(
            "GTK4 Layer Shell requires native Wayland. Use './run.sh' instead.",
            file=sys.stderr,
        )

    app = Gtk.Application(application_id="ai.sidebar")
    app.connect("activate", _on_activate)
    status = app.run(args)
    return 1 if _STARTUP_FAILED else status


def _on_activate(app: Gtk.Application) -> None:
    """Create and present the main sidebar window when the app activates."""
    try:
        window = SidebarWindow(application=app)
    except RuntimeError as exc:
        if "Gtk couldn't be initialized" in str(exc):
            print(
                "Failed to initialize GTK. Ensure a display server is available.",
                file=sys.stderr,
            )
            global _STARTUP_FAILED
            _STARTUP_FAILED = True
            app.quit()
            return
        raise

    window.present()


if __name__ == "__main__":
    raise SystemExit(main())