#!/usr/bin/env python3
"""SSE 通道演示脚本：证明"服务器主动推、客户端用 HTTP 发"这一对方向都通。

它同时是一个"外部客户端"的样板——完全不知道游戏内部结构，只知道协议：

    连上 /api/stream → 收 welcome（含状态）→ 用 HTTP 发一个动作 → 收 state 推送

只用标准库（urllib 流式读长连接），所以任何有 Python 的环境都能跑。

用法：
    python tools/sse_demo.py --url http://127.0.0.1:8765 --farm demo --seconds 8
"""

from __future__ import annotations

import argparse
import json
import os
import sys
import time
import urllib.parse
import urllib.request

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from farm import net


def stream_url(endpoint: str, farm: str, token: str | None) -> str:
    base = endpoint if "://" in endpoint else "http://" + endpoint
    query = {"farm": farm, "name": "sse-demo"}
    if token:
        query["token"] = token
    return f"{base.rstrip('/')}/api/stream?{urllib.parse.urlencode(query)}"


def action_url(endpoint: str, farm: str, token: str | None) -> str:
    base = endpoint if "://" in endpoint else "http://" + endpoint
    query = {"farm": farm}
    if token:
        query["token"] = token
    return f"{base.rstrip('/')}/api/actions?{urllib.parse.urlencode(query)}"


def post_action(url: str, action: str, params: dict | None = None) -> dict:
    """用普通 HTTP POST 提交动作——上行不占用实时通道。"""
    body = json.dumps({"action": action, "params": params or {}}).encode("utf-8")
    request = urllib.request.Request(
        url, data=body, method="POST", headers={"Content-Type": "application/json"}
    )
    with net.open_url(request, timeout=8.0) as response:
        return json.loads(response.read().decode("utf-8"))


def run(endpoint: str, farm: str, token: str | None, seconds: float) -> int:
    url = stream_url(endpoint, farm, token)
    print(f"连接 {url}")
    request = urllib.request.Request(url, headers={"Accept": "text/event-stream"})

    counts: dict[str, int] = {}
    acted = False
    deadline = time.time() + seconds

    # 读超时必须比服务器心跳（15 秒）宽裕，否则空闲时会被自己的超时打断
    with net.open_url(request, timeout=45.0) as response:
        while True:
            try:
                raw_line = response.readline()
            except (TimeoutError, OSError) as exc:
                print(f"（读超时：{exc}）")
                break
            if not raw_line:
                print("（服务器关闭了长连接）")
                break
            line = raw_line.decode("utf-8", errors="replace").strip()
            if not line or line.startswith(":"):
                continue
            if not line.startswith("data:"):
                continue
            message = json.loads(line[len("data:") :].strip())
            kind = message.get("type", "?")
            counts[kind] = counts.get(kind, 0) + 1

            if kind == "welcome":
                state = message.get("state", {})
                print(
                    f"← welcome：牧场 {message.get('farm')} · 第 {state.get('day')} 天 · "
                    f"金币 {state.get('gold')} · 候选动作 {len(message.get('actions', []))} 个"
                )
                # welcome 里就带着当前合法动作，挑第一个执行，
                # 验证"两条通道改的是同一个引擎"
                candidates = message.get("actions") or []
                if candidates:
                    pick = candidates[0]
                    reply = post_action(
                        action_url(endpoint, farm, token),
                        pick["action"],
                        pick.get("params") or {},
                    )
                    acted = True
                    print(
                        f"→ POST /api/actions {pick['action']} "
                        f"{pick.get('params') or {}}：{reply.get('message')}"
                    )
            elif kind == "state":
                snapshot = message.get("state", {})
                print(
                    f"← state(seq={message.get('seq')})：第 {snapshot.get('day')} 天 · "
                    f"金币 {snapshot.get('gold')} · "
                    f"在线 {message.get('online')}"
                )
                if acted:
                    # 收到了动作触发的推送，两条路都验证完了
                    break
            elif kind == "day":
                print(f"← day：进入第 {message.get('day')} 天，事件 {message.get('events')}")
            elif kind == "notice":
                print(f"← notice：{message.get('text')}")
            else:
                print(f"← {kind}")

            if time.time() >= deadline:
                break

    print(f"\n消息统计：{counts}")
    if counts.get("welcome", 0) < 1:
        print("✗ 没有收到 welcome，SSE 长连接可能没建立")
        return 1
    if counts.get("state", 0) < 1:
        print("✗ 动作之后没有收到 state 推送（引擎与推送线程之间可能断了）")
        return 1
    print("✓ SSE 通道正常：状态会主动下行，动作经由 HTTP 上行")
    return 0


def main() -> int:
    parser = argparse.ArgumentParser(description="SSE 通道演示")
    parser.add_argument("--url", default="http://127.0.0.1:8765")
    parser.add_argument("--farm", default="sse-demo")
    parser.add_argument("--token", default=None)
    parser.add_argument("--seconds", type=float, default=8.0)
    args = parser.parse_args()
    return run(args.url, args.farm, args.token, args.seconds)


if __name__ == "__main__":
    sys.exit(main())