from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session, joinedload
from uuid import UUID
from database import get_db
import models
from schemas import TripCreate, TripOut, TripUpdate, TripRegenerationResult
from crud import generate_trip_items

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

@router.get("/", response_model=list[TripOut])
def list_trips(db: Session = Depends(get_db)):
    trips = (
        db.query(models.Trip)
        .options(
            joinedload(models.Trip.selected_tags).joinedload(models.TripTagSelected.tag),
            joinedload(models.Trip.marked_tags).joinedload(models.TripTagMarked.tag),
        )
        .all()
    )
    return [
        TripOut(
            id=t.id,
            name=t.name,
            start_date=t.start_date,
            end_date=t.end_date,
            selected_tags=[st.tag for st in t.selected_tags],
            marked_tags=[mt.tag for mt in t.marked_tags],
        )
        for t in trips
    ]

@router.post("/", response_model=TripOut)
def create_trip(payload: TripCreate, db: Session = Depends(get_db)):
    user = db.query(models.User).first()
    if not user:
        from uuid import uuid4
        user = models.User(id=uuid4(), name="Demo")
        db.add(user)
        db.flush()

    trip = models.Trip(user_id=user.id, name=payload.name, start_date=payload.start_date, end_date=payload.end_date)
    db.add(trip)
    db.flush()

    # attach selected & marked
    if payload.selected_tag_ids:
        for tid in payload.selected_tag_ids:
            db.add(models.TripTagSelected(trip_id=trip.id, tag_id=tid))
    if payload.marked_tag_ids:
        for tid in payload.marked_tag_ids:
            db.add(models.TripTagMarked(trip_id=trip.id, tag_id=tid))

    db.flush()

    # generate items per rules
    created_ids, _ = generate_trip_items(
        db,
        trip=trip,
        selected_tag_ids=payload.selected_tag_ids,
        marked_tag_ids=payload.marked_tag_ids,
    )

    db.commit()

    # reload with relationships
    trip = (
        db.query(models.Trip)
        .options(
            joinedload(models.Trip.selected_tags).joinedload(models.TripTagSelected.tag),
            joinedload(models.Trip.marked_tags).joinedload(models.TripTagMarked.tag),
        )
        .get(trip.id)
    )
    return TripOut(
        id=trip.id,
        name=trip.name,
        start_date=trip.start_date,
        end_date=trip.end_date,
        selected_tags=[st.tag for st in trip.selected_tags],
        marked_tags=[mt.tag for mt in trip.marked_tags],
    )

@router.put("/{trip_id}/reconfigure", response_model=TripRegenerationResult)
def reconfigure_trip(trip_id: UUID, payload: TripUpdate, db: Session = Depends(get_db)):
    trip = db.get(models.Trip, trip_id)
    if not trip:
        raise HTTPException(status_code=404, detail="Trip not found")

    # update base fields
    if payload.name is not None:
        trip.name = payload.name
    if payload.start_date is not None:
        trip.start_date = payload.start_date
    if payload.end_date is not None:
        trip.end_date = payload.end_date
    db.flush()

    # update selected/marked join tables if provided
    if payload.selected_tag_ids is not None:
        # replace all
        db.query(models.TripTagSelected).filter_by(trip_id=trip.id).delete()
        for tid in payload.selected_tag_ids:
            db.add(models.TripTagSelected(trip_id=trip.id, tag_id=tid))
    if payload.marked_tag_ids is not None:
        db.query(models.TripTagMarked).filter_by(trip_id=trip.id).delete()
        for tid in payload.marked_tag_ids:
            db.add(models.TripTagMarked(trip_id=trip.id, tag_id=tid))
    db.flush()

    # read back lists
    sel_ids = [row.tag_id for row in db.query(models.TripTagSelected).filter_by(trip_id=trip.id).all()]
    mrk_ids = [row.tag_id for row in db.query(models.TripTagMarked).filter_by(trip_id=trip.id).all()]

    created_ids, deleted_checked = generate_trip_items(
        db, trip=trip, selected_tag_ids=sel_ids, marked_tag_ids=mrk_ids
    )
    db.commit()
    return {
        "trip_id": trip.id,
        "deleted_checked_trip_item_ids": deleted_checked,
        "created_trip_item_ids": created_ids,
    }