"""Stub node HTTP server for the Distributed Inference Network."""

import http.server
import json
import threading


class _StubHandler(http.server.BaseHTTPRequestHandler):
    def log_message(self, fmt, *args):  # noqa: suppress request logs in tests
        pass

    def do_POST(self):
        if self.path == "/v1/infer":
            length = int(self.headers.get("Content-Length", 0))
            body = json.loads(self.rfile.read(length))
            messages = body.get("messages", [])
            last_content = messages[-1]["content"] if messages else ""
            payload = json.dumps({"text": f"stub response to: {last_content}"}).encode()
            self.send_response(200)
            self.send_header("Content-Type", "application/json")
            self.send_header("Content-Length", str(len(payload)))
            self.end_headers()
            self.wfile.write(payload)
        else:
            self.send_response(404)
            self.end_headers()


class StubNodeServer:
    """Single-process stub node that returns fixed inference responses."""

    def __init__(self, host: str = "127.0.0.1", port: int = 0):
        self._host = host
        self._requested_port = port
        self._server: http.server.HTTPServer | None = None
        self._thread: threading.Thread | None = None
        self.port: int | None = None

    def start(self) -> int:
        if self._server is not None:
            raise RuntimeError("StubNodeServer is already running")

        self._server = http.server.HTTPServer((self._host, self._requested_port), _StubHandler)
        self.port = self._server.server_address[1]
        self._thread = threading.Thread(target=self._server.serve_forever, daemon=True)
        self._thread.start()
        return self.port

    def stop(self) -> None:
        if self._server is None:
            return

        self._server.shutdown()
        self._server.server_close()
        if self._thread is not None:
            self._thread.join(timeout=1)
        self._server = None
        self._thread = None
        self.port = None