# -*- coding: utf-8 -*-
"""control_server.py — 远程控制通道 (port 5000). 重构自旧 colab_server 协议.

Endpoints:
  POST /execute_stream  {"code": "..."}  -> SSE: {type: stdout|stderr|error|complete}
  GET  /health          -> {"ok": true}

注意: 这是无鉴权的任意代码执行端点, 仅用于开发调试, URL 为随机子域名不可枚举,
用完建议关掉 Colab 会话.
"""
import json
import queue
import sys
import threading
import traceback

from flask import Flask, Response, jsonify, request

app = Flask(__name__)


class _StreamToQ:
    def __init__(self, q, tag):
        self.q, self.tag = q, tag

    def write(self, s):
        if s:
            self.q.put((self.tag, s))
        return len(s)

    def flush(self):
        pass

    def writelines(self, lines):
        for s in lines:
            self.write(s)

    def isatty(self):
        return False


@app.route("/health")
def health():
    return jsonify({"ok": True, "service": "samai-control"})


@app.route("/execute_stream", methods=["POST"])
def execute_stream():
    code = (request.get_json(force=True) or {}).get("code", "")
    q = queue.Queue()

    def worker():
        g = {"__name__": "__main__"}
        old = sys.stdout, sys.stderr
        sys.stdout = _StreamToQ(q, "stdout")
        sys.stderr = _StreamToQ(q, "stderr")
        try:
            exec(compile(code, "<remote>", "exec"), g)  # noqa: S102
            q.put(("complete", "ok"))
        except BaseException:  # noqa: BLE001
            q.put(("error", traceback.format_exc()))
            q.put(("complete", "error"))
        finally:
            sys.stdout, sys.stderr = old

    threading.Thread(target=worker, daemon=True).start()

    def gen():
        while True:
            t, c = q.get()
            yield f"data: {json.dumps({'type': t, 'content': c})}\n\n"
            if t == "complete":
                break

    return Response(gen(), mimetype="text/event-stream",
                    headers={"Cache-Control": "no-cache",
                             "X-Accel-Buffering": "no"})


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, threaded=True)