import re
from uuid import UUID, uuid4
from fastapi import APIRouter, Depends
from sqlalchemy.ext.asyncio import AsyncSession
from schemas import TripCreate
from models import Item, Trip, TripItem
from database import get_db
from sqlalchemy import select
from sqlalchemy.orm import selectinload
from config import FIXED_USER_ID

router = APIRouter()

@router.post("/trips/")
async def create_trip(trip: TripCreate, db: AsyncSession = Depends(get_db)):
    user_id = FIXED_USER_ID

    db_trip = Trip(
        id=uuid4(),
        name=trip.name,
        user_id=user_id,
        start_date=trip.start_date,
        end_date=trip.end_date,
        selected_tags=trip.selected_tags,
        marked_tags=trip.marked_tags
    )

    await db.commit()  # damit ID vorhanden ist
    db.add(db_trip)

    # Tage berechnen
    days = (trip.end_date - trip.start_date).days + 1
    nights = days - 1

    # relevante Items
    result = await db.execute(select(Item).where(Item.user_id == user_id))
    all_items = result.scalars().all()

    trip_items = []

    for item in all_items:
        item_tag_names = [tag.name for tag in item.tags]

        if not set(item_tag_names).issubset(set(trip.selected_tags)):
            continue

        item_text = replace_placeholders(item.name, days, nights)

        # markierte Tags matchen?
        matching_marked = set(item_tag_names) & set(trip.marked_tags)

        if matching_marked:
            for tag in matching_marked:
                trip_items.append(TripItem(
                    id=uuid4(),
                    trip_id=db_trip.id,
                    item_id=item.id,
                    tag=tag,
                    name=item.name,
                    calculated_label=item_text,
                    checked=False
                ))
        else:
            trip_items.append(TripItem(
                id=uuid4(),
                trip_id=db_trip.id,
                item_id=item.id,
                tag=None,
                name=item.name,
                calculated_label=item_text,
                checked=False
            ))

    db.add_all(trip_items)
    await db.commit()
    return {"status": "trip created", "trip_id": str(db_trip.id)}


@router.get("/trips/{trip_id}/items")
async def get_trip_items(trip_id: UUID, db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(TripItem).where(TripItem.trip_id == trip_id))
    items = result.scalars().all()
    return [
        {
            "label": item.calculated_label,
            "tag": item.tag,
            "checked": item.checked
        } for item in items
    ]

@router.get("/trips/")
async def get_trips(db: AsyncSession = Depends(get_db)):
    user_id = FIXED_USER_ID
    result = await db.execute(select(Trip).where(Trip.user_id == user_id))
    trips = result.scalars().all()
    return [
        {
            "id": str(trip.id),
            "name": trip.name,
            "start_date": trip.start_date,
            "end_date": trip.end_date,
            "selected_tags": trip.selected_tags,
            "marked_tags": trip.marked_tags
        } for trip in trips
    ]

def replace_placeholders(text: str, days: int, nights: int) -> str:
    def replacer(match):
        expr = match.group(1)
        expr = expr.replace("days", str(days)).replace("nights", str(nights))
        try:
            return str(eval(expr))
        except:
            return match.group(0)

    return re.sub(r"{(.*?)}", replacer, text)