import asyncio
import json
import logging
from typing import Dict, List, Any, Optional, AsyncGenerator

from aiostream import stream
from fastapi import APIRouter, Request
from fastapi.responses import StreamingResponse
from llama_index.core import BaseCallbackHandler
from llama_index.core.base.llms.types import ChatMessage
from llama_index.core.callbacks import CBEventType
from llama_index.core.chat_engine.types import StreamingAgentChatResponse
from llama_index.core.tools import ToolOutput
from pydantic import BaseModel

from app.api.routers.events import EventCallbackHandler
from app.api.routers.request.base import userMng, conversations
from app.api.routers.request.models import ChatRequestData
from app.engine import get_chat_engine

logger = logging.getLogger("uvicorn")

v1_router = v = APIRouter()


class ChatCallbackEvent(BaseModel):
    event_type: CBEventType
    payload: Optional[Dict[str, Any]] = None
    event_id: str = ""

    def get_retrieval_message(self) -> dict | None:
        if self.payload:
            nodes = self.payload.get("nodes")
            if nodes:
                msg = f"根据查询检索到 {len(nodes)} 源文件"
            else:
                msg = f"查询检索中: '{self.payload.get('query_str')}'"
            return {
                "type": "events",
                "data": {"title": msg},
            }
        else:
            return None

    def get_tool_message(self) -> dict | None:
        func_call_args = self.payload.get("function_call")
        if func_call_args is not None and "tool" in self.payload:
            tool = self.payload.get("tool")
            return {
                "type": "events",
                "data": {
                    "title": f"调用工具 {tool.name} ，参数: {func_call_args}",
                },
            }

    def _is_output_serializable(self, output: Any) -> bool:
        try:
            json.dumps(output)
            return True
        except TypeError:
            return False

    def get_agent_tool_response(self) -> dict | None:
        response = self.payload.get("response")
        if response is not None:
            sources = response.sources
            for source in sources:
                # Return the tool response here to include the toolCall information
                if isinstance(source, ToolOutput):
                    if self._is_output_serializable(source.raw_output):
                        output = source.raw_output
                    else:
                        output = source.content

                    return {
                        "type": "tools",
                        "data": {
                            "toolOutput": {
                                "output": output,
                                "isError": source.is_error,
                            },
                            "toolCall": {
                                "id": None,  # There is no tool id in the ToolOutput
                                "name": source.tool_name,
                                "input": source.raw_input,
                            },
                        },
                    }

    def to_response(self):
        try:
            match self.event_type:
                case "retrieve":
                    return self.get_retrieval_message()
                case "function_call":
                    return self.get_tool_message()
                case "agent_step":
                    return self.get_agent_tool_response()
                case _:
                    return None
        except Exception as e:
            logger.error(f"转换回应时间时发生错误，原因: {e}")
            return None


class ChatEventCallbackHandler(BaseCallbackHandler):
    _aqueue: asyncio.Queue
    is_done: bool = False

    def __init__(
            self,
    ):
        """Initialize the base callback handler."""
        ignored_events = [
            CBEventType.CHUNKING,
            CBEventType.NODE_PARSING,
            CBEventType.EMBEDDING,
            CBEventType.LLM,
            CBEventType.TEMPLATING,
        ]
        super().__init__(ignored_events, ignored_events)
        self._aqueue = asyncio.Queue()

    def on_event_start(
            self,
            event_type: CBEventType,
            payload: Optional[Dict[str, Any]] = None,
            event_id: str = "",
            **kwargs: Any,
    ) -> str:
        event = ChatCallbackEvent(event_id=event_id, event_type=event_type, payload=payload)
        if event.to_response() is not None:
            self._aqueue.put_nowait(event)

    def on_event_end(
            self,
            event_type: CBEventType,
            payload: Optional[Dict[str, Any]] = None,
            event_id: str = "",
            **kwargs: Any,
    ) -> None:
        event = ChatCallbackEvent(event_id=event_id, event_type=event_type, payload=payload)
        if event.to_response() is not None:
            self._aqueue.put_nowait(event)

    def start_trace(self, trace_id: Optional[str] = None) -> None:
        """No-op."""

    def end_trace(
            self,
            trace_id: Optional[str] = None,
            trace_map: Optional[Dict[str, List[str]]] = None,
    ) -> None:
        """No-op."""

    async def async_event_gen(self) -> AsyncGenerator[ChatCallbackEvent, None]:
        while not self._aqueue.empty() or not self.is_done:
            try:
                yield await asyncio.wait_for(self._aqueue.get(), timeout=0.1)
            except asyncio.TimeoutError:
                pass

class ChatStreamResponse(StreamingResponse):
    TEXT_PREFIX = "data:"
    DATA_PREFIX = "data:"

    @classmethod
    def convert_text(cls, token: str):
        # Escape newlines and double quotes to avoid breaking the stream
        token = json.dumps(token)

        #return f"data: {{"event": "message", "conversation_id": "80d85523-de92-4b9d-aca0-c48a5eacb068", "message_id": "16a06b1b-a89b-49c0-bc15-123bd999f6d6", "created_at": 1724406492, "task_id": "802f3064-030d-42ac-a882-0e1293712d04", "id": "16a06b1b-a89b-49c0-bc15-123bd999f6d6", "answer": "{token}"}}"
        return ""

    @classmethod
    def convert_data(cls, data: dict):
        data_str = json.dumps(data)
        return f"{cls.DATA_PREFIX}{data_str}\n"

    def __init__(
            self,
            request: Request,
            event_handler: EventCallbackHandler,
            response: StreamingAgentChatResponse,
            data: ChatRequestData
    ):
        content = ChatStreamResponse.content_generator(
            request, event_handler, response, data
        )
        super().__init__(content=content)

    @classmethod
    async def content_generator(
            cls,
            request: Request,
            event_handler: EventCallbackHandler,
            response: StreamingAgentChatResponse,
            data: ChatRequestData
    ):
        # Yield the text response
        async def _chat_response_generator():
            final_response = ""
            async for token in response.async_response_gen():
                final_response += token
                yield ChatStreamResponse.convert_text(token)


            # 存储消息历史
            #message = Message(data.conversation_id, data.query, answer=final_response)
            #messageManager.addmessage(message)

            # the text_generator is the leading stream, once it's finished, also finish the event stream
            event_handler.is_done = True

        # Yield the events from the event handler
        async def _event_generator():
            async for event in event_handler.async_event_gen():
                event_response = event.to_response()
                if event_response is not None:
                    yield ChatStreamResponse.convert_data(event_response)

        combine = stream.merge(_chat_response_generator(), _event_generator())
        is_stream_started = False
        async with combine.stream() as streamer:
            async for output in streamer:
                if not is_stream_started:
                    is_stream_started = True
                    # Stream a blank message to start the stream
                    yield ChatStreamResponse.convert_text("")

                yield output

                if await request.is_disconnected():
                    break

@v.post("/chat-messages")
async def post_conversations(request: Request, data: ChatRequestData):
    userMng.findNoExistCreate(data.user)
    
    conversaObj = conversations()
    conversationinfo = conversaObj.get(data.user, data.conversation_id)
    if conversationinfo is None:
        conversationinfo = conversaObj.add(data.user, "新建会话", data.conversation_id)

    # 生成聊天参数
    last_message_content = ChatMessage.from_str(data.query)
    filters = None
    params = data.inputs or {}

    # 获取聊天引擎对象
    chat_engine = get_chat_engine(filters=filters, params=params)

    # 启动聊天事件监听
    event_handler = EventCallbackHandler()
    chat_engine.callback_manager.handlers.append(event_handler)  # type: ignore

    # 执行异步聊天
    response = await chat_engine.astream_chat(data.query)

    # 返回异步消息回应
    return ChatStreamResponse(request, event_handler, response, data)

@v.get("/messages")
async def query_messages(user:str, conversation_id:str):
    pass

@v.post("/conversations/{itemid}/name")
async def post_conversations(user:str):
    pass

@v.get("/conversations")
async def query_conversations(user:str):
    user_id = '' if user is None else user
    userMng.findNoExistCreate(user_id)

    return {
        "limit": 20,
        "has_more": False,
        "data": conversations().gets(user_id)
    }