"""
Claude Chat API Routes

Provides endpoints for AI-powered chat within the Atomizer dashboard.

Two approaches:
1. Session-based: Persistent sessions with MCP tools (new)
2. Legacy: Stateless CLI calls (backwards compatible)
"""

from fastapi import APIRouter, HTTPException, WebSocket, WebSocketDisconnect
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
from typing import Optional, List, Dict, Any, Literal
import json

router = APIRouter()


# ========== Request/Response Models ==========

class ChatMessage(BaseModel):
    role: str  # "user" or "assistant"
    content: str


class ChatRequest(BaseModel):
    message: str
    study_id: Optional[str] = None
    conversation_history: Optional[List[Dict[str, Any]]] = None


class ChatResponse(BaseModel):
    response: str
    tool_calls: Optional[List[Dict[str, Any]]] = None
    study_id: Optional[str] = None


class CreateSessionRequest(BaseModel):
    mode: Literal["user", "power"] = "user"
    study_id: Optional[str] = None
    resume_session_id: Optional[str] = None


class SwitchModeRequest(BaseModel):
    mode: Literal["user", "power"]


# Store active conversations (legacy, in production use database)
_conversations: Dict[str, List[Dict[str, Any]]] = {}


# ========== Session Manager Access ==========

_session_manager = None


def get_session_manager():
    """Lazy import to avoid circular dependencies"""
    global _session_manager
    if _session_manager is None:
        from api.services.session_manager import SessionManager
        _session_manager = SessionManager()
    return _session_manager


# ========== NEW: Session-based Endpoints ==========

@router.post("/sessions")
async def create_session(request: CreateSessionRequest):
    """
    Create or resume a Claude session with MCP tools.

    Args:
        mode: "user" for safe operations, "power" for full access
        study_id: Optional study to provide context
        resume_session_id: Optional session ID to resume

    Returns:
        Session info including session_id, mode, study_id
    """
    try:
        manager = get_session_manager()
        session = await manager.create_session(
            mode=request.mode,
            study_id=request.study_id,
            resume_session_id=request.resume_session_id,
        )
        return {
            "session_id": session.session_id,
            "mode": session.mode,
            "study_id": session.study_id,
            "is_alive": session.is_alive(),
        }
    except Exception as e:
        import traceback
        error_msg = f"{type(e).__name__}: {str(e) or 'No message'}"
        traceback.print_exc()
        raise HTTPException(status_code=500, detail=error_msg)


@router.get("/sessions/{session_id}")
async def get_session(session_id: str):
    """Get session info"""
    manager = get_session_manager()
    info = manager.get_session_info(session_id)
    if not info:
        raise HTTPException(status_code=404, detail="Session not found")
    return info


@router.post("/sessions/{session_id}/mode")
async def switch_session_mode(session_id: str, request: SwitchModeRequest):
    """
    Switch session mode (requires session restart).

    Args:
        session_id: Session to update
        mode: New mode ("user" or "power")
    """
    try:
        manager = get_session_manager()
        session = await manager.switch_mode(session_id, request.mode)
        return {
            "session_id": session.session_id,
            "mode": session.mode,
            "message": f"Mode switched to {request.mode}",
        }
    except ValueError as e:
        raise HTTPException(status_code=404, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/sessions/{session_id}/study")
async def set_session_study(session_id: str, study_id: str):
    """Update study context for a session"""
    try:
        manager = get_session_manager()
        await manager.set_study_context(session_id, study_id)
        return {"message": f"Study context updated to {study_id}"}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.websocket("/sessions/{session_id}/ws")
async def session_websocket(websocket: WebSocket, session_id: str):
    """
    WebSocket for real-time chat with a session.

    Message formats (client -> server):
        {"type": "message", "content": "user message", "canvas_state": {...}}
        {"type": "set_study", "study_id": "study_name"}
        {"type": "set_canvas", "canvas_state": {...}}
        {"type": "ping"}

    Message formats (server -> client):
        {"type": "text", "content": "..."}
        {"type": "tool_call", "tool": {...}}
        {"type": "tool_result", "result": {...}}
        {"type": "done", "tool_calls": [...]}
        {"type": "error", "message": "..."}
        {"type": "pong"}
        {"type": "context_updated", "study_id": "..."}
        {"type": "canvas_updated", "canvas_state": {...}}
    """
    await websocket.accept()

    manager = get_session_manager()
    session = manager.get_session(session_id)

    if not session:
        await websocket.send_json({"type": "error", "message": "Session not found"})
        await websocket.close()
        return

    # Track current canvas state for this connection
    current_canvas_state: Dict[str, Any] = {}

    try:
        while True:
            data = await websocket.receive_json()

            if data.get("type") == "message":
                content = data.get("content", "")
                if not content:
                    continue

                # Get canvas state from message or use stored state
                canvas_state = data.get("canvas_state") or current_canvas_state

                async for chunk in manager.send_message(
                    session_id,
                    content,
                    canvas_state=canvas_state if canvas_state else None,
                ):
                    await websocket.send_json(chunk)

            elif data.get("type") == "set_study":
                study_id = data.get("study_id")
                if study_id:
                    await manager.set_study_context(session_id, study_id)
                    await websocket.send_json({
                        "type": "context_updated",
                        "study_id": study_id,
                    })

            elif data.get("type") == "set_canvas":
                # Update canvas state for this connection
                current_canvas_state = data.get("canvas_state", {})
                await websocket.send_json({
                    "type": "canvas_updated",
                    "canvas_state": current_canvas_state,
                })

            elif data.get("type") == "ping":
                await websocket.send_json({"type": "pong"})

    except WebSocketDisconnect:
        pass
    except Exception as e:
        try:
            await websocket.send_json({"type": "error", "message": str(e)})
        except:
            pass


# ========== LEGACY: Stateless Endpoints (backwards compatible) ==========


@router.get("/status")
async def get_claude_status():
    """
    Check if Claude CLI is available

    Returns:
        JSON with CLI status
    """
    import shutil
    claude_available = shutil.which("claude") is not None

    return {
        "available": claude_available,
        "message": "Claude CLI is available" if claude_available else "Claude CLI not found in PATH",
        "mode": "cli"  # Indicate we're using CLI mode
    }


@router.post("/chat", response_model=ChatResponse)
async def chat_with_claude(request: ChatRequest):
    """
    Send a message to Claude via CLI with Atomizer context

    Args:
        request: ChatRequest with message, optional study_id, and conversation history

    Returns:
        ChatResponse with Claude's response
    """
    try:
        from api.services.claude_cli_agent import AtomizerCLIAgent

        # Create agent with study context
        agent = AtomizerCLIAgent(study_id=request.study_id)

        # Convert conversation history format if needed
        history = []
        if request.conversation_history:
            for msg in request.conversation_history:
                if isinstance(msg.get('content'), str):
                    history.append(msg)

        # Get response
        result = await agent.chat(request.message, history)

        return ChatResponse(
            response=result["response"],
            tool_calls=result.get("tool_calls"),
            study_id=request.study_id
        )

    except Exception as e:
        raise HTTPException(
            status_code=500,
            detail=f"Chat error: {str(e)}"
        )


@router.post("/chat/stream")
async def chat_stream(request: ChatRequest):
    """
    Stream a response from Claude CLI token by token

    Args:
        request: ChatRequest with message and optional context

    Returns:
        StreamingResponse with text/event-stream
    """
    async def generate():
        try:
            from api.services.claude_cli_agent import AtomizerCLIAgent

            agent = AtomizerCLIAgent(study_id=request.study_id)

            # Convert history
            history = []
            if request.conversation_history:
                for msg in request.conversation_history:
                    if isinstance(msg.get('content'), str):
                        history.append(msg)

            # Stream response
            async for token in agent.chat_stream(request.message, history):
                yield f"data: {json.dumps({'token': token})}\n\n"

            yield f"data: {json.dumps({'done': True})}\n\n"

        except Exception as e:
            yield f"data: {json.dumps({'error': str(e)})}\n\n"

    return StreamingResponse(
        generate(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
        }
    )


@router.websocket("/chat/ws")
async def websocket_chat(websocket: WebSocket):
    """
    WebSocket endpoint for real-time chat

    Message format (client -> server):
        {"type": "message", "content": "user message", "study_id": "optional"}

    Message format (server -> client):
        {"type": "token", "content": "..."}
        {"type": "done", "tool_calls": [...]}
        {"type": "error", "message": "..."}
    """
    await websocket.accept()

    conversation_history = []

    try:
        from api.services.claude_cli_agent import AtomizerCLIAgent

        while True:
            # Receive message from client
            data = await websocket.receive_json()

            if data.get("type") == "message":
                content = data.get("content", "")
                study_id = data.get("study_id")

                if not content:
                    continue

                # Create agent
                agent = AtomizerCLIAgent(study_id=study_id)

                try:
                    # Use non-streaming chat
                    result = await agent.chat(content, conversation_history)

                    # Send response
                    await websocket.send_json({
                        "type": "response",
                        "content": result["response"],
                        "tool_calls": result.get("tool_calls", [])
                    })

                    # Update history
                    conversation_history.append({"role": "user", "content": content})
                    conversation_history.append({"role": "assistant", "content": result["response"]})

                except Exception as e:
                    await websocket.send_json({
                        "type": "error",
                        "message": str(e)
                    })

            elif data.get("type") == "clear":
                # Clear conversation history
                conversation_history = []
                await websocket.send_json({"type": "cleared"})

    except WebSocketDisconnect:
        pass
    except Exception as e:
        try:
            await websocket.send_json({
                "type": "error",
                "message": str(e)
            })
        except:
            pass


@router.get("/suggestions")
async def get_chat_suggestions(study_id: Optional[str] = None):
    """
    Get contextual chat suggestions based on current study

    Args:
        study_id: Optional study to get suggestions for

    Returns:
        List of suggested prompts
    """
    base_suggestions = [
        "What's the status of my optimization?",
        "Show me the best designs found",
        "Compare the top 3 trials",
        "What parameters have the most impact?",
        "Explain the convergence behavior"
    ]

    if study_id:
        # Add study-specific suggestions
        return {
            "suggestions": [
                f"Summarize the {study_id} study",
                "What's the current best objective value?",
                "Are there any failed trials? Why?",
                "Show parameter sensitivity analysis",
                "What should I try next to improve results?"
            ] + base_suggestions[:3]
        }

    return {
        "suggestions": [
            "List all available studies",
            "Help me create a new study",
            "What can you help me with?"
        ] + base_suggestions[:3]
    }