from __future__ import annotations

import argparse
import json
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
from pathlib import Path
from urllib.parse import parse_qs, urlparse

from .api import build_dashboard_payload

ROOT = Path(__file__).resolve().parent.parent
UI_DIR = ROOT / "ui"

UI_CONTENT_TYPES = {
    ".css": "text/css",
    ".js": "application/javascript",
    ".json": "application/json",
    ".html": "text/html; charset=utf-8",
}


class ObservatoryHandler(BaseHTTPRequestHandler):
    data_dir: Path = ROOT / "data"

    def _send(self, status: int, body: bytes, content_type: str) -> None:
        self.send_response(status)
        self.send_header("Content-Type", content_type)
        self.send_header("Access-Control-Allow-Origin", "*")
        self.end_headers()
        self.wfile.write(body)

    def do_GET(self) -> None:
        parsed = urlparse(self.path)
        if parsed.path == "/api/dashboard":
            query = parse_qs(parsed.query)
            period = query.get("period", [None])[0]
            payload = build_dashboard_payload(self.data_dir, period)
            self._send(200, json.dumps(payload).encode("utf-8"), "application/json")
            return

        if parsed.path == "/":
            return self._serve_file(UI_DIR / "index.html", "text/html; charset=utf-8")

        if parsed.path.startswith("/ui/"):
            relative = parsed.path.removeprefix("/ui/")
            target = UI_DIR / relative
            if target.exists() and target.is_file():
                content_type = UI_CONTENT_TYPES.get(target.suffix, "application/octet-stream")
                if "charset" not in content_type:
                    content_type = f"{content_type}; charset=utf-8"
                return self._serve_file(target, content_type)

        self._send(404, b"Not found", "text/plain")

    def _serve_file(self, path: Path, content_type: str) -> None:
        self._send(200, path.read_bytes(), content_type)

    def log_message(self, format: str, *args) -> None:
        return


def main(argv: list[str] | None = None) -> int:
    parser = argparse.ArgumentParser(description="Coulomb Economic Observatory UI server")
    parser.add_argument("--host", default="127.0.0.1")
    parser.add_argument("--port", type=int, default=8765)
    parser.add_argument("--data-dir", type=Path, default=ROOT / "data")
    args = parser.parse_args(argv)

    ObservatoryHandler.data_dir = args.data_dir
    server = ThreadingHTTPServer((args.host, args.port), ObservatoryHandler)
    print(f"Economic Observatory UI: http://{args.host}:{args.port}/")
    print(f"API: http://{args.host}:{args.port}/api/dashboard")
    try:
        server.serve_forever()
    except KeyboardInterrupt:
        print("\nStopped.")
    return 0


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