"""
Server HTTP minimal untuk NER test — berjalan di http://127.0.0.1:8001

Endpoint:
    GET  /api/status   — health-check, kembalikan status model
    POST /api/ner      — deteksi entitas dari {"text": "..."}

Jalankan:
    python src/ner_server.py
    python src/ner_server.py --port 8001 --model cahya/xlm-roberta-base-indonesian-NER
"""

from __future__ import annotations

import argparse
import json
import logging
import sys
import threading
from http.server import BaseHTTPRequestHandler, HTTPServer
from pathlib import Path

# Pastikan src/ ada di sys.path agar ner_detector bisa diimpor langsung
sys.path.insert(0, str(Path(__file__).parent))
sys.path.insert(0, str(Path(__file__).parent.parent))
from core.language import detect_language
from ner_detector import IndonesianNER

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s  %(levelname)-7s  %(message)s",
    datefmt="%H:%M:%S",
)
logger = logging.getLogger(__name__)

# State global

_ner: IndonesianNER | None = None
_model_loading = threading.Event()   # di-set saat load selesai (berhasil atau gagal)
_load_success  = False


def _load_model_background(model_name: str | None) -> None:
    """Muat model di thread terpisah agar server bisa langsung merespons /api/status."""
    global _ner, _load_success
    _ner = IndonesianNER(model_name=model_name)
    _load_success = _ner.load()
    if not _load_success:
        logger.error("Gagal memuat model: %s", _ner.load_error)
    _model_loading.set()


# Request handler

class NERHandler(BaseHTTPRequestHandler):

    # CORS: izinkan semua origin agar bisa dipanggil dari file://

    def _send_cors_headers(self) -> None:
        self.send_header("Access-Control-Allow-Origin", "*")
        self.send_header("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
        self.send_header("Access-Control-Allow-Headers", "Content-Type")

    def do_OPTIONS(self) -> None:  # preflight
        self.send_response(204)
        self._send_cors_headers()
        self.end_headers()

    # Helpers

    def _json_response(self, status: int, body: object) -> None:
        payload = json.dumps(body, ensure_ascii=False).encode()
        self.send_response(status)
        self.send_header("Content-Type", "application/json; charset=utf-8")
        self.send_header("Content-Length", str(len(payload)))
        self._send_cors_headers()
        self.end_headers()
        self.wfile.write(payload)

    def _read_json_body(self) -> dict | None:
        length = int(self.headers.get("Content-Length", 0))
        if length == 0:
            return {}
        try:
            return json.loads(self.rfile.read(length))
        except (json.JSONDecodeError, ValueError):
            return None

    def log_message(self, fmt: str, *args) -> None:
        logger.info("%-6s %s", args[0] if args else "", args[1] if len(args) > 1 else "")

    # GET

    def do_GET(self) -> None:
        if self.path == "/api/status":
            loaded = _load_success and _ner is not None and _ner.is_loaded
            self._json_response(200, {
                "model_loaded": loaded,
                "model": _ner.loaded_model if (loaded and _ner) else None,
                "loading": not _model_loading.is_set(),
            })
        else:
            self._json_response(404, {"error": "Not found"})

    # POST

    def do_POST(self) -> None:
        if self.path != "/api/ner":
            self._json_response(404, {"error": "Not found"})
            return

        body = self._read_json_body()
        if body is None:
            self._json_response(400, {"error": "Body bukan JSON yang valid."})
            return

        text = str(body.get("text", "")).strip()
        if not text:
            self._json_response(400, {"error": "Field 'text' kosong atau tidak ada."})
            return

        if not (_ner and _ner.is_loaded):
            self._json_response(503, {
                "error": "Model belum selesai dimuat. Coba lagi dalam beberapa detik.",
                "loading": not _model_loading.is_set(),
            })
            return

        language = str(body.get("language") or detect_language(text).language)
        entities = _ner.predict(text, language=language)
        self._json_response(200, {
            "text": text,
            "entities": [
                {
                    "word":   e.word,
                    "label":  e.label,
                    "score":  round(e.score, 4),
                    "start":  e.start,
                    "end":    e.end,
                    "source": e.source,
                }
                for e in entities
            ],
            "model": _ner.loaded_model,
        })


# Entrypoint

def main() -> None:
    parser = argparse.ArgumentParser(description="Server NER Bahasa Indonesia")
    parser.add_argument("--port",  type=int, default=8001)
    parser.add_argument("--host",  default="127.0.0.1")
    parser.add_argument("--model", default=None,
                        help="ID model HuggingFace atau path lokal. "
                             "Default: cascade otomatis (xlm-roberta-large → base → bert).")
    args = parser.parse_args()

    # Muat model di background agar server langsung bisa dijangkau
    logger.info("Memuat model NER di background…")
    t = threading.Thread(target=_load_model_background, args=(args.model,), daemon=True)
    t.start()

    server = HTTPServer((args.host, args.port), NERHandler)
    logger.info("Server berjalan di http://%s:%d", args.host, args.port)
    logger.info("  GET  http://%s:%d/api/status", args.host, args.port)
    logger.info("  POST http://%s:%d/api/ner", args.host, args.port)
    logger.info("Buka web/ner-test.html di browser untuk memulai pengujian.")
    logger.info("Tekan Ctrl+C untuk menghentikan server.")

    try:
        server.serve_forever()
    except KeyboardInterrupt:
        logger.info("Server dihentikan.")
        server.server_close()


if __name__ == "__main__":
    main()