"""FastAPI routes for agent communication with Go backend."""

import json
import logging
import time
from typing import Any, AsyncGenerator

from fastapi import APIRouter, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel

logger = logging.getLogger(__name__)

router = APIRouter()


# Request/Response models - aligned with Go backend
class ChatRequest(BaseModel):
    """Chat request from Go backend.

    Fields aligned with server/internal/service/agent_service.go::AgentChatRequest
    """
    agent_id: int
    message: str
    user_id: int = 0
    session_id: str | None = None
    model_id: str | None = None
    model_name: str | None = None
    model_provider: str | None = None
    api_key: str | None = None
    base_url: str | None = None
    use_xbot: bool = False


class ChatResponse(BaseModel):
    """Chat response to Go backend.

    Fields aligned with server/internal/service/agent_service.go::AgentChatResponse
    """
    agent_id: int
    response: str
    tool_calls: list = []
    tokens_used: int = 0
    duration_ms: int = 0
    session_id: str


class TeamChatRequest(BaseModel):
    """Team chat request from Go backend.

    Fields aligned with server/internal/service/agent_service.go::TeamChatRequest
    """
    supervisor_agent_id: int
    member_agent_ids: list[int]
    message: str
    user_id: int = 0
    session_id: str | None = None
    strategy: str = "parallel"


class TeamChatResponse(BaseModel):
    """Team chat response to Go backend.

    Fields aligned with server/internal/service/agent_service.go::TeamChatResponse
    """
    supervisor_agent_id: int
    response: str
    subtask_results: list = []
    strategy: str = "parallel"
    duration_ms: int = 0
    session_id: str


class HealthResponse(BaseModel):
    """Health check response."""
    status: str
    version: str = "0.1.0"


# Global agent instance (to be initialized by main)
_agent = None
_team_agent = None


def set_agent(agent: Any) -> None:
    """Set the global agent instance.

    Args:
        agent: Agent loop instance
    """
    global _agent
    _agent = agent


def set_team_agent(team_agent: Any) -> None:
    """Set the global team agent instance.

    Args:
        team_agent: Team agent instance
    """
    global _team_agent
    _team_agent = team_agent


def add_cors(app) -> None:
    """Add CORS middleware to allow Go backend cross-origin requests.

    Args:
        app: FastAPI application instance
    """
    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )


@router.get("/health", response_model=HealthResponse)
async def health_check() -> HealthResponse:
    """Health check endpoint."""
    return HealthResponse(status="ok")


@router.post("/agent/chat", response_model=ChatResponse)
async def chat(request: ChatRequest) -> ChatResponse:
    """Handle chat requests from Go backend.

    Path: POST /agent/chat
    Aligned with Go backend server/internal/service/agent_service.go

    Args:
        request: Chat request with agent_id, message, user_id, etc.

    Returns:
        Chat response with agent_id, response, tool_calls, tokens_used, duration_ms, session_id

    Raises:
        HTTPException: If agent is not initialized or processing fails
    """
    if _agent is None:
        raise HTTPException(status_code=500, detail="Agent not initialized")

    start_time = time.time()
    session_id = request.session_id or f"session_{request.agent_id}_{int(start_time)}"

    try:
        # Prepare kwargs for agent.chat()
        kwargs = {
            "message": request.message,
            "session_key": session_id,
        }

        # Add optional model configuration
        if request.model_id:
            kwargs["model_id"] = request.model_id
        if request.model_name:
            kwargs["model_name"] = request.model_name
        if request.model_provider:
            kwargs["model_provider"] = request.model_provider
        if request.api_key:
            kwargs["api_key"] = request.api_key
        if request.base_url:
            kwargs["base_url"] = request.base_url
        if request.use_xbot:
            kwargs["use_xbot"] = request.use_xbot

        # Process the message
        logger.info(f"[chat] kwargs: model_provider={kwargs.get('model_provider')}, model_name={kwargs.get('model_name')}, api_key={'set' if kwargs.get('api_key') else 'not set'}")
        result = await _agent.chat(**kwargs)
        logger.info(f"[chat] result type={type(result).__name__}, content={str(result)[:100]}")

        # Extract response content
        if isinstance(result, dict):
            response_text = result.get("response", result.get("content", str(result)))
            tool_calls = result.get("tool_calls", [])
            tokens_used = result.get("tokens_used", 0)
        else:
            response_text = str(result)
            tool_calls = []
            tokens_used = 0

        duration_ms = int((time.time() - start_time) * 1000)

        return ChatResponse(
            agent_id=request.agent_id,
            response=response_text,
            tool_calls=tool_calls,
            tokens_used=tokens_used,
            duration_ms=duration_ms,
            session_id=session_id,
        )
    except Exception as e:
        logger.exception(f"Error processing chat: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/agent/chat/stream")
async def chat_stream(request: ChatRequest):
    """Handle streaming chat requests from Go backend.

    Path: POST /agent/chat/stream
    Returns streaming response using SSE format.

    Args:
        request: Chat request with agent_id, message, user_id, etc.

    Yields:
        Streaming response chunks in SSE format
    """
    if _agent is None:
        raise HTTPException(status_code=500, detail="Agent not initialized")

    session_id = request.session_id or f"session_{request.agent_id}_{int(time.time())}"

    async def generate() -> AsyncGenerator[str, None]:
        """Generate streaming response."""
        try:
            # Prepare kwargs for agent.chat()
            kwargs = {
                "message": request.message,
                "session_key": session_id,
            }

            if request.model_id:
                kwargs["model_id"] = request.model_id
            if request.model_name:
                kwargs["model_name"] = request.model_name
            if request.model_provider:
                kwargs["model_provider"] = request.model_provider
            if request.api_key:
                kwargs["api_key"] = request.api_key
            if request.base_url:
                kwargs["base_url"] = request.base_url
            if request.use_xbot:
                kwargs["use_xbot"] = request.use_xbot

            # Process with streaming
            async for chunk in _agent.chat_stream(**kwargs):
                # SSE format: "data: <json>\n\n"
                yield f"data: {json.dumps(chunk)}\n\n"

            # Send final message
            yield f"data: {json.dumps({'done': True, 'session_id': session_id})}\n\n"

        except Exception as e:
            logger.exception(f"Error in streaming chat: {e}")
            yield f"data: {json.dumps({'error': str(e)})}\n\n"

    from fastapi.responses import StreamingResponse

    return StreamingResponse(
        generate(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
            "X-Accel-Buffering": "no-cache",  # Disable nginx buffering
        },
    )


@router.post("/agent/team/chat", response_model=TeamChatResponse)
async def team_chat(request: TeamChatRequest) -> TeamChatResponse:
    """Handle team chat requests from Go backend.

    Path: POST /agent/team/chat
    Aligned with Go backend server/internal/service/agent_service.go::TeamChat

    Args:
        request: Team chat request with supervisor_agent_id, member_agent_ids, message, etc.

    Returns:
        Team chat response with supervisor_agent_id, response, subtask_results, strategy, duration_ms, session_id

    Raises:
        HTTPException: If team agent is not initialized or processing fails
    """
    if _team_agent is None:
        raise HTTPException(status_code=500, detail="Team agent not initialized")

    start_time = time.time()
    session_id = request.session_id or f"team_session_{request.supervisor_agent_id}_{int(start_time)}"

    try:
        # Process the team chat message
        result = await _team_agent.chat(
            message=request.message,
            session_id=session_id,
            supervisor_agent_id=request.supervisor_agent_id,
            member_agent_ids=request.member_agent_ids,
            strategy=request.strategy,
        )

        # Extract response content
        if isinstance(result, dict):
            response_text = result.get("response", str(result))
            subtask_results = result.get("subtask_results", [])
        else:
            response_text = str(result)
            subtask_results = []

        duration_ms = int((time.time() - start_time) * 1000)

        return TeamChatResponse(
            supervisor_agent_id=request.supervisor_agent_id,
            response=response_text,
            subtask_results=subtask_results,
            strategy=request.strategy,
            duration_ms=duration_ms,
            session_id=session_id,
        )
    except Exception as e:
        logger.exception(f"Error processing team chat: {e}")
        raise HTTPException(status_code=500, detail=str(e))