import json
import os
import signal
import sys
import time

from tui_gateway.server import _CRASH_LOG, dispatch, resolve_skin, write_json

signal.signal(signal.SIGPIPE, signal.SIG_DFL)
signal.signal(signal.SIGINT, signal.SIG_IGN)


def _log_exit(reason: str) -> None:
    """Record why the gateway subprocess is shutting down.

    Three exit paths (startup write fail, parse-error-response write fail,
    dispatch-response write fail, stdin EOF) all collapse into a silent
    sys.exit(0) here.  Without this trail the TUI shows "gateway exited"
    with no actionable clue about WHICH broken pipe or WHICH message
    triggered it — the main reason voice-mode turns look like phantom
    crashes when the real story is "TUI read pipe closed on this event".
    """
    try:
        os.makedirs(os.path.dirname(_CRASH_LOG), exist_ok=True)
        with open(_CRASH_LOG, "a", encoding="utf-8") as f:
            f.write(
                f"\n=== gateway exit · {time.strftime('%Y-%m-%d %H:%M:%S')} "
                f"· reason={reason} ===\n"
            )
    except Exception:
        pass
    print(f"[gateway-exit] {reason}", file=sys.stderr, flush=True)


def main():
    if not write_json({
        "jsonrpc": "2.0",
        "method": "event",
        "params": {"type": "gateway.ready", "payload": {"skin": resolve_skin()}},
    }):
        _log_exit("startup write failed (broken stdout pipe before first event)")
        sys.exit(0)

    for raw in sys.stdin:
        line = raw.strip()
        if not line:
            continue

        try:
            req = json.loads(line)
        except json.JSONDecodeError:
            if not write_json({"jsonrpc": "2.0", "error": {"code": -32700, "message": "parse error"}, "id": None}):
                _log_exit("parse-error-response write failed (broken stdout pipe)")
                sys.exit(0)
            continue

        method = req.get("method") if isinstance(req, dict) else None
        resp = dispatch(req)
        if resp is not None:
            if not write_json(resp):
                _log_exit(f"response write failed for method={method!r} (broken stdout pipe)")
                sys.exit(0)

    _log_exit("stdin EOF (TUI closed the command pipe)")


if __name__ == "__main__":
    main()