from typing import List, Optional
from sqlalchemy.orm import Session
from sqlalchemy import and_, or_, func, desc
from datetime import date, datetime
from app.models.ppr import PPRRecord, PPRStatus
from app.schemas.ppr import PPRCreate, PPRUpdate


class CRUDPPR:
    def get(self, db: Session, ppr_id: int) -> Optional[PPRRecord]:
        return db.query(PPRRecord).filter(PPRRecord.id == ppr_id).first()

    def get_multi(
        self, 
        db: Session, 
        skip: int = 0, 
        limit: int = 100,
        status: Optional[PPRStatus] = None,
        date_from: Optional[date] = None,
        date_to: Optional[date] = None
    ) -> List[PPRRecord]:
        query = db.query(PPRRecord)
        
        if status:
            query = query.filter(PPRRecord.status == status)
        
        if date_from:
            query = query.filter(
                or_(
                    func.date(PPRRecord.eta) >= date_from,
                    func.date(PPRRecord.etd) >= date_from
                )
            )
            
        if date_to:
            query = query.filter(
                or_(
                    func.date(PPRRecord.eta) <= date_to,
                    func.date(PPRRecord.etd) <= date_to
                )
            )
        
        return query.order_by(desc(PPRRecord.submitted_dt)).offset(skip).limit(limit).all()

    def get_arrivals_today(self, db: Session) -> List[PPRRecord]:
        """Get today's arrivals"""
        today = date.today()
        return db.query(PPRRecord).filter(
            and_(
                func.date(PPRRecord.eta) == today,
                PPRRecord.status == PPRStatus.NEW
            )
        ).order_by(PPRRecord.eta).all()

    def get_departures_today(self, db: Session) -> List[PPRRecord]:
        """Get today's departures"""
        today = date.today()
        return db.query(PPRRecord).filter(
            and_(
                func.date(PPRRecord.etd) == today,
                PPRRecord.status == PPRStatus.LANDED
            )
        ).order_by(PPRRecord.etd).all()

    def create(self, db: Session, obj_in: PPRCreate, created_by: str) -> PPRRecord:
        db_obj = PPRRecord(
            **obj_in.dict(),
            created_by=created_by,
            status=PPRStatus.NEW
        )
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    def update(self, db: Session, db_obj: PPRRecord, obj_in: PPRUpdate) -> PPRRecord:
        update_data = obj_in.dict(exclude_unset=True)
        for field, value in update_data.items():
            setattr(db_obj, field, value)
        
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    def update_status(
        self, 
        db: Session, 
        ppr_id: int, 
        status: PPRStatus
    ) -> Optional[PPRRecord]:
        db_obj = self.get(db, ppr_id)
        if not db_obj:
            return None
        
        db_obj.status = status
        
        # Set timestamps based on status
        if status == PPRStatus.LANDED:
            db_obj.landed_dt = datetime.utcnow()
        elif status == PPRStatus.DEPARTED:
            db_obj.departed_dt = datetime.utcnow()
        
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    def delete(self, db: Session, ppr_id: int) -> Optional[PPRRecord]:
        db_obj = self.get(db, ppr_id)
        if db_obj:
            # Soft delete by setting status
            db_obj.status = PPRStatus.DELETED
            db.add(db_obj)
            db.commit()
            db.refresh(db_obj)
        return db_obj


ppr = CRUDPPR()