# modules/nlp/api.py
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from typing import List

from core.database import get_db

from modules.auth.dependencies import get_current_user
from modules.auth.models import User
from modules.nlp.service import process_request, ask_ai
# Import the response schema
from modules.nlp.schemas import ProcessCommandRequest, ProcessCommandResponse
from modules.calendar.service import create_calendar_event, get_calendar_events, update_calendar_event, delete_calendar_event
# Import the CalendarEvent *model* for type hinting
from modules.calendar.models import CalendarEvent
# Import the CalendarEvent Pydantic schemas for data validation
from modules.calendar.schemas import CalendarEventCreate, CalendarEventUpdate

router = APIRouter(prefix="/nlp", tags=["nlp"])

# Helper to format calendar events (expects list of CalendarEvent models)
def format_calendar_events(events: List[CalendarEvent]) -> List[str]:
    if not events:
        return ["You have no events matching that criteria."]
    formatted = ["Here are the events:"]
    for event in events:
        # Access attributes directly from the model instance
        start_str = event.start.strftime("%Y-%m-%d %H:%M") if event.start else "No start time"
        end_str = event.end.strftime("%H:%M") if event.end else ""
        title = event.title or "Untitled Event"
        formatted.append(f"- {title} ({start_str}{' - ' + end_str if end_str else ''})")
    return formatted

# Update the response model for the endpoint
@router.post("/process-command", response_model=ProcessCommandResponse)
def process_command(request_data: ProcessCommandRequest, current_user: User = Depends(get_current_user), db: Session = Depends(get_db)):
    """
    Process the user command, execute the action, and return user-friendly responses.
    """
    user_input = request_data.user_input
    command_data = process_request(user_input)
    intent = command_data["intent"]
    params = command_data["params"]
    response_text = command_data["response_text"]

    responses = [response_text] # Start with the initial response

    if intent == "error":
        raise HTTPException(status_code=400, detail=response_text)

    if intent == "clarification_needed" or intent == "unknown":
        return ProcessCommandResponse(responses=responses)

    try:
        match intent:
            case "ask_ai":
                ai_answer = ask_ai(**params)
                responses.append(ai_answer)
                return ProcessCommandResponse(responses=responses)

            case "get_calendar_events":
                # get_calendar_events returns List[CalendarEvent models]
                events: List[CalendarEvent] = get_calendar_events(db, current_user.id, **params)
                responses.extend(format_calendar_events(events))
                return ProcessCommandResponse(responses=responses)

            case "add_calendar_event":
                # Validate input with Pydantic schema
                event_data = CalendarEventCreate(**params)
                created_event = create_calendar_event(db, current_user.id, event_data)
                start_str = created_event.start.strftime("%Y-%m-%d %H:%M") if created_event.start else "No start time"
                title = created_event.title or "Untitled Event"
                responses.append(f"Added: {title} starting at {start_str}.")
                return ProcessCommandResponse(responses=responses)

            case "update_calendar_event":
                event_id = params.pop('event_id', None)
                if event_id is None:
                    raise HTTPException(status_code=400, detail="Event ID is required for update.")
                # Validate input with Pydantic schema
                event_data = CalendarEventUpdate(**params)
                updated_event = update_calendar_event(db, current_user.id, event_id, event_data=event_data)
                title = updated_event.title or "Untitled Event"
                responses.append(f"Updated event ID {updated_event.id}: {title}.")
                return ProcessCommandResponse(responses=responses)

            case "delete_calendar_event":
                event_id = params.get('event_id')
                if event_id is None:
                    raise HTTPException(status_code=400, detail="Event ID is required for delete.")
                delete_calendar_event(db, current_user.id, event_id)
                responses.append(f"Deleted event ID {event_id}.")
                return ProcessCommandResponse(responses=responses)

            case _: 
                print(f"Warning: Unhandled intent '{intent}' reached api.py match statement.")
                return ProcessCommandResponse(responses=responses)

    except HTTPException as http_exc:
        raise http_exc
    except Exception as e:
        print(f"Error executing intent '{intent}': {e}")
        return ProcessCommandResponse(responses=["Sorry, I encountered an error while trying to perform that action."])