from typing import Sequence, Optional
from sqlalchemy import select, desc, func
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import joinedload
from datetime import date

from app.domain.models import Appointment


class AppointmentsRepository:
    def __init__(self, db: AsyncSession):
        self.db = db

    async def get_all(self, start_date: date | None = None, end_date: date | None = None) -> Sequence[Appointment]:
        stmt = (
            select(Appointment)
            .options(joinedload(Appointment.type))
            .options(joinedload(Appointment.patient))
            .options(joinedload(Appointment.doctor))
            .order_by(desc(Appointment.appointment_datetime))
        )
        if start_date:
            stmt = stmt.filter(Appointment.appointment_datetime >= start_date)
        if end_date:
            stmt = stmt.filter(Appointment.appointment_datetime <= end_date)
        result = await self.db.execute(stmt)
        return result.scalars().all()

    async def get_by_doctor_id(self, doctor_id: int, start_date: date | None = None, end_date: date | None = None) -> \
            Sequence[Appointment]:
        stmt = (
            select(Appointment)
            .options(joinedload(Appointment.type))
            .options(joinedload(Appointment.patient))
            .options(joinedload(Appointment.doctor))
            .filter_by(doctor_id=doctor_id)
            .order_by(desc(Appointment.appointment_datetime))
        )
        if start_date:
            stmt = stmt.filter(Appointment.appointment_datetime >= start_date)
        if end_date:
            stmt = stmt.filter(Appointment.appointment_datetime <= end_date)
        result = await self.db.execute(stmt)
        return result.scalars().all()

    async def get_upcoming_by_doctor_id(self, doctor_id: int) -> Sequence[Appointment]:
        stmt = (
            select(Appointment)
            .options(joinedload(Appointment.type))
            .options(joinedload(Appointment.patient))
            .options(joinedload(Appointment.doctor))
            .filter_by(doctor_id=doctor_id)
            .filter(Appointment.appointment_datetime >= func.now())
            .order_by(Appointment.appointment_datetime)
            .limit(5)
        )
        result = await self.db.execute(stmt)
        return result.scalars().all()

    async def get_by_patient_id(self, patient_id: int, start_date: date | None = None, end_date: date | None = None) -> \
            Sequence[Appointment]:
        stmt = (
            select(Appointment)
            .options(joinedload(Appointment.type))
            .options(joinedload(Appointment.patient))
            .options(joinedload(Appointment.doctor))
            .filter_by(patient_id=patient_id)
            .order_by(desc(Appointment.appointment_datetime))
        )
        if start_date:
            stmt = stmt.filter(Appointment.appointment_datetime >= start_date)
        if end_date:
            stmt = stmt.filter(Appointment.appointment_datetime <= end_date)
        result = await self.db.execute(stmt)
        return result.scalars().all()

    async def get_by_id(self, appointment_id: int) -> Optional[Appointment]:
        stmt = (
            select(Appointment)
            .options(joinedload(Appointment.type))
            .options(joinedload(Appointment.patient))
            .options(joinedload(Appointment.doctor))
            .filter_by(id=appointment_id)
        )
        result = await self.db.execute(stmt)
        return result.scalars().first()

    async def create(self, appointment: Appointment) -> Appointment:
        self.db.add(appointment)
        await self.db.commit()
        await self.db.refresh(appointment)
        return appointment

    async def update(self, appointment: Appointment) -> Appointment:
        await self.db.merge(appointment)
        await self.db.commit()
        return appointment

    async def delete(self, appointment) -> Appointment:
        await self.db.delete(appointment)
        await self.db.commit()
        return appointment