from typing import Dict, List, Optional
from uuid import UUID

from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.responses import StreamingResponse
from flowsint_core.core.models import Profile
from flowsint_core.core.postgre_db import get_db
from flowsint_core.core.services import (
    NotFoundError,
    create_chat_service,
)
from pydantic import BaseModel
from sqlalchemy.orm import Session

from app.api.deps import get_current_user
from app.api.schemas.chat import ChatCreate, ChatRead

router = APIRouter()


class ChatRequest(BaseModel):
    prompt: str
    context: Optional[List[str]] = None


@router.get("", response_model=List[ChatRead])
def get_chats(
    db: Session = Depends(get_db), current_user: Profile = Depends(get_current_user)
):
    service = create_chat_service(db)
    return service.get_chats_for_user(current_user.id)


@router.get("/investigation/{investigation_id}", response_model=List[ChatRead])
def get_chats_by_investigation(
    investigation_id: UUID,
    db: Session = Depends(get_db),
    current_user: Profile = Depends(get_current_user),
):
    service = create_chat_service(db)
    return service.get_by_investigation(investigation_id, current_user.id)


@router.post("/stream/{chat_id}")
async def stream_chat(
    chat_id: UUID,
    payload: ChatRequest,
    db: Session = Depends(get_db),
    current_user: Profile = Depends(get_current_user),
):
    service = create_chat_service(db)

    try:
        chat = service.get_by_id(chat_id, current_user.id)
    except NotFoundError:
        raise HTTPException(status_code=404, detail="Chat not found")

    service.add_user_message(chat_id, current_user.id, payload.prompt, payload.context)

    ai_context = service.prepare_ai_context(chat, payload.prompt, payload.context)
    llm_messages = service.build_llm_messages(ai_context)

    try:
        provider = service.get_llm_provider(current_user.id)
    except ValueError as e:
        raise HTTPException(status_code=500, detail=str(e))

    return StreamingResponse(
        service.stream_response(chat_id, llm_messages, provider),
        media_type="text/event-stream",
        headers={"x-vercel-ai-ui-message-stream": "v1"},
    )


@router.post("/create", response_model=ChatRead, status_code=status.HTTP_201_CREATED)
def create_chat(
    payload: ChatCreate,
    db: Session = Depends(get_db),
    current_user: Profile = Depends(get_current_user),
):
    service = create_chat_service(db)
    return service.create(
        title=payload.title,
        description=payload.description,
        investigation_id=payload.investigation_id,
        owner_id=current_user.id,
    )


@router.get("/{chat_id}", response_model=ChatRead)
def get_chat_by_id(
    chat_id: UUID,
    db: Session = Depends(get_db),
    current_user: Profile = Depends(get_current_user),
):
    service = create_chat_service(db)
    try:
        return service.get_by_id(chat_id, current_user.id)
    except NotFoundError:
        raise HTTPException(status_code=404, detail="Chat not found")


@router.delete("/{chat_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_chat(
    chat_id: UUID,
    db: Session = Depends(get_db),
    current_user: Profile = Depends(get_current_user),
):
    service = create_chat_service(db)
    try:
        service.delete(chat_id, current_user.id)
        return None
    except NotFoundError:
        raise HTTPException(status_code=404, detail="Chat not found")