#!/usr/bin/env python3
"""Serial HTTP/SSE fixture for the authentic prefill-cancellation runner."""

import argparse
import http.server
import json
import time


class Handler(http.server.BaseHTTPRequestHandler):
    cancellation_started = False

    def do_GET(self):
        if self.path != "/health":
            self.send_response(404)
            self.end_headers()
            return
        self.send_response(200)
        self.send_header("Content-Type", "application/json")
        self.end_headers()
        self.wfile.write(b'{"status":"ok"}')

    def do_POST(self):
        if self.path != "/v1/chat/completions":
            self.send_response(404)
            self.end_headers()
            return
        length = int(self.headers.get("Content-Length", "0"))
        try:
            request = json.loads(self.rfile.read(length))
            assert request["stream"] is True
        except (AssertionError, KeyError, json.JSONDecodeError):
            self.send_response(400)
            self.end_headers()
            return

        self.send_response(200)
        self.send_header("Content-Type", "text/event-stream")
        self.send_header("Cache-Control", "no-cache")
        self.end_headers()
        if not Handler.cancellation_started:
            Handler.cancellation_started = True
            self.wfile.write(b": keepalive\n\n")
            self.wfile.flush()
            time.sleep(2.0)
            try:
                self.wfile.write(b": keepalive\n\n")
                self.wfile.flush()
            except (BrokenPipeError, ConnectionResetError):
                pass
            return

        time.sleep(0.05)
        self.wfile.write(
            b'data: {"choices":[{"delta":{"content":"OK"},'
            b'"finish_reason":null}]}\n\n'
        )
        self.wfile.write(
            b'data: {"choices":[{"delta":{},"finish_reason":"stop"}],'
            b'"usage":{"prompt_tokens":3,"completion_tokens":2,"total_tokens":5}}\n\n'
        )
        self.wfile.write(b"data: [DONE]\n\n")
        self.wfile.flush()

    def log_message(self, _format, *_args):
        pass


parser = argparse.ArgumentParser(add_help=False)
parser.add_argument("--port", type=int, required=True)
arguments, _ = parser.parse_known_args()
http.server.HTTPServer(("127.0.0.1", arguments.port), Handler).serve_forever()