import asyncio
import json
import random
import uuid
from typing import Dict, Any

import aiohttp
import websockets
from aiohttp import ClientTimeout

from workflow_service.config import Settings, ComfyUIServer

settings = Settings()


# [新增] 定义一个自定义异常，用于封装来自ComfyUI的执行错误
class ComfyUIExecutionError(Exception):
    def __init__(self, error_data: dict):
        self.error_data = error_data
        # 创建一个对开发者友好的异常消息
        message = (
            f"ComfyUI节点执行失败。节点ID: {error_data.get('node_id')}, "
            f"节点类型: {error_data.get('node_type')}. "
            f"错误: {error_data.get('exception_message', 'N/A')}"
        )
        super().__init__(message)


async def get_server_status(
    server: ComfyUIServer, session: aiohttp.ClientSession
) -> Dict[str, Any]:
    """
    检查单个ComfyUI服务器的详细状态。
    返回一个包含可达性、队列状态和详细队列内容的字典。
    """
    # [BUG修复] 确保初始字典结构与成功时的结构一致，以满足Pydantic模型
    status_info = {
        "is_reachable": False,
        "is_free": False,
        "queue_details": {"running_count": 0, "pending_count": 0},
    }
    try:
        queue_url = f"{server.http_url}/queue"
        async with session.get(queue_url, timeout=60) as response:
            response.raise_for_status()
            queue_data = await response.json()

            status_info["is_reachable"] = True

            running_count = len(queue_data.get("queue_running", []))
            pending_count = len(queue_data.get("queue_pending", []))

            status_info["queue_details"] = {
                "running_count": running_count,
                "pending_count": pending_count,
            }

            status_info["is_free"] = running_count == 0 and pending_count == 0

    except Exception as e:
        # 当请求失败时，将返回上面定义的、结构正确的初始 status_info
        print(f"警告: 无法检查服务器 {server.http_url} 的队列状态: {e}")

    return status_info


async def select_server_for_execution() -> ComfyUIServer:
    """
    智能选择一个ComfyUI服务器。
    优先选择一个空闲的服务器，如果所有服务器都忙，则随机选择一个。
    """
    servers = settings.SERVERS
    if not servers:
        raise ValueError("没有在 COMFYUI_SERVERS_JSON 中配置任何服务器。")
    if len(servers) == 1:
        return servers[0]

    async with aiohttp.ClientSession() as session:
        tasks = [get_server_status(server, session) for server in servers]
        results = await asyncio.gather(*tasks)

    free_servers = [servers[i] for i, status in enumerate(results) if status["is_free"]]

    if free_servers:
        selected_server = random.choice(free_servers)
        print(
            f"发现 {len(free_servers)} 个空闲服务器。已选择: {selected_server.http_url}"
        )
        return selected_server
    else:
        # 后备方案：选择一个可达的服务器，即使它很忙
        reachable_servers = [
            servers[i] for i, status in enumerate(results) if status["is_reachable"]
        ]
        if reachable_servers:
            selected_server = random.choice(reachable_servers)
            print(
                f"所有服务器当前都在忙。从可达服务器中随机选择: {selected_server.http_url}"
            )
            return selected_server
        else:
            # 最坏情况：所有服务器都不可达，抛出异常
            raise ConnectionError("所有配置的ComfyUI服务器都不可达。")


async def execute_prompt_on_server(prompt: Dict, server: ComfyUIServer) -> Dict:
    """
    在指定的服务器上执行一个准备好的prompt。
    """
    client_id = str(uuid.uuid4())
    prompt_id = await _queue_prompt(prompt, client_id, server.http_url)
    print(f"工作流已在 {server.http_url} 上入队，Prompt ID: {prompt_id}")
    results = await _get_execution_results(prompt_id, client_id, server.ws_url)
    return results


async def _queue_prompt(prompt: dict, client_id: str, http_url: str) -> str:
    """通过HTTP POST将工作流任务提交到指定的ComfyUI服务器。"""
    for node_id in prompt:
        prompt[node_id]["inputs"][f"cache_buster_{uuid.uuid4().hex}"] = random.random()
    payload = {"prompt": prompt, "client_id": client_id}
    async with aiohttp.ClientSession(timeout=ClientTimeout(total=90)) as session:
        prompt_url = f"{http_url}/prompt"
        async with session.post(prompt_url, json=payload) as response:
            response.raise_for_status()
            result = await response.json()
            if "prompt_id" not in result:
                raise Exception(f"从 ComfyUI /prompt 端点返回的响应无效: {result}")
            return result["prompt_id"]


async def _get_execution_results(prompt_id: str, client_id: str, ws_url: str) -> dict:
    """
    通过WebSocket连接到指定的ComfyUI服务器，聚合执行结果。
    [核心改动] 新增对 'execution_error' 消息的处理。
    """
    full_ws_url = f"{ws_url}?clientId={client_id}"
    aggregated_outputs = {}

    try:
        async with websockets.connect(full_ws_url) as websocket:
            while True:
                try:
                    out = await websocket.recv()
                    if not isinstance(out, str):
                        continue

                    message = json.loads(out)
                    msg_type = message.get("type")
                    data = message.get("data")

                    if not (data and data.get("prompt_id") == prompt_id):
                        continue

                    # [核心改动] 捕获并处理执行错误
                    if msg_type == "execution_error":
                        print(f"ComfyUI执行错误 (Prompt ID: {prompt_id}): {data}")
                        # 抛出自定义异常，将错误详情传递出去
                        raise ComfyUIExecutionError(data)

                    if msg_type == "executed":
                        node_id = data.get("node")
                        output_data = data.get("output")
                        if node_id and output_data:
                            aggregated_outputs[node_id] = output_data
                            print(f"收到节点 {node_id} 的输出 (Prompt ID: {prompt_id})")

                    elif msg_type == "executing" and data.get("node") is None:
                        print(f"Prompt ID: {prompt_id} 执行完成。")
                        return aggregated_outputs

                except websockets.exceptions.ConnectionClosed as e:
                    print(f"WebSocket 连接已关闭 (Prompt ID: {prompt_id})。错误: {e}")
                    return aggregated_outputs
                except Exception as e:
                    # 重新抛出我们自己的异常，或者处理其他意外错误
                    if not isinstance(e, ComfyUIExecutionError):
                        print(f"处理 prompt {prompt_id} 时发生意外错误: {e}")
                    raise e

    except websockets.exceptions.InvalidURI as e:
        print(
            f"错误: 尝试连接的WebSocket URI无效: '{full_ws_url}'. 原始URL: '{ws_url}'. 错误: {e}"
        )
        raise e

    return aggregated_outputs