"""Disconnect-safe HTTP serving for the AI usage exporter."""

from __future__ import annotations

from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
from typing import Any


def make_handler(collector: Any, poller: Any) -> type[BaseHTTPRequestHandler]:
    """Build an HTTP handler bound to one collector and polling engine."""

    class Handler(BaseHTTPRequestHandler):
        def _respond(self, status: int, payload: bytes, content_type: str) -> None:
            self.send_response(status)
            self.send_header("Content-Type", content_type)
            self.send_header("Content-Length", str(len(payload)))
            self.end_headers()
            self.wfile.write(payload)

        def do_GET(self) -> None:  # noqa: N802
            try:
                if self.path == "/metrics":
                    self._respond(
                        200,
                        collector.render(),
                        "text/plain; version=0.0.4",
                    )
                elif self.path == "/healthz":
                    healthy = poller.is_healthy()
                    self._respond(
                        200 if healthy else 503,
                        b"ok\n" if healthy else b"poller unhealthy\n",
                        "text/plain; charset=utf-8",
                    )
                else:
                    self.send_error(404)
            except (BrokenPipeError, ConnectionResetError):
                return

        def log_message(self, _format: str, *_args: object) -> None:
            return

    return Handler


class Server(ThreadingHTTPServer):
    """Threaded metrics server that does not retain disconnected clients."""

    daemon_threads = True