"""Targets router (spec §3.4). Thin handlers — business logic in services/targets.py."""

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session

from database import get_db
from schemas import TargetCreate, TargetRead, TargetUpdate
from services import targets as svc

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


@router.get("", response_model=list[TargetRead])
def list_targets(db: Session = Depends(get_db)):
    return svc.list_targets(db)


@router.get("/current", response_model=TargetRead)
def current_target(db: Session = Depends(get_db)):
    target = svc.get_current_target(db)
    if target is None:
        raise HTTPException(status_code=404, detail="No active target")
    return target


@router.post("", response_model=TargetRead, status_code=201)
def create_target(data: TargetCreate, db: Session = Depends(get_db)):
    """Create a new target. Auto-closes the previous active target."""
    try:
        return svc.create_target(db, data)
    except ValueError as e:
        raise HTTPException(status_code=422, detail=str(e))


@router.put("/{target_id}", response_model=TargetRead)
def update_target(target_id: int, data: TargetUpdate, db: Session = Depends(get_db)):
    """Update a target's values and/or date range.
    The single-active-target invariant is preserved."""
    try:
        result = svc.update_target(db, target_id, data)
    except ValueError as e:
        raise HTTPException(status_code=422, detail=str(e))
    except svc.ActiveTargetConflictError as e:
        raise HTTPException(status_code=409, detail=str(e))

    if result is None:
        raise HTTPException(status_code=404, detail="Target not found")
    return result