import uuid
from typing import Optional, List

from fastapi import HTTPException
from sqlalchemy import func
from sqlalchemy.orm import Session
from starlette import status

from barker.models import (
    VoucherType,
    Settlement,
    SettleOption,
    Voucher,
    Overview,
    GuestBook,
)

from barker.schemas.receive_payment import ReceivePaymentItem as SettleSchema


def get_tax(tax, voucher_type):
    if voucher_type in [VoucherType.STAFF, VoucherType.NO_CHARGE]:
        return 0
    elif voucher_type in [VoucherType.KOT, VoucherType.REGULAR_BILL]:
        return tax
    else:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="Unexpected Voucher Type",
        )


def get_bill_id(voucher_type, db):
    if voucher_type == VoucherType.KOT:
        return None
    bill_id = (
        db.query(func.coalesce(func.max(Voucher.bill_id), 0) + 1)
        .filter(Voucher.voucher_type == voucher_type.value)
        .scalar()
    )
    if voucher_type == VoucherType.REGULAR_BILL and bill_id % 10000 == 0:
        bill_id += 1
    return bill_id


def do_update_table(item: Voucher, guest_book: Optional[GuestBook], db: Session):
    status_ = "running" if item.voucher_type == VoucherType.KOT else "printed"
    if item.status is None:
        item.status = Overview(
            voucher_id=item.id,
            food_table_id=item.food_table_id,
            guest_book_id=guest_book.id if guest_book is not None else None,
            status=status_,
        )
        db.add(item.status)
    else:
        item.status.status = status_


def check_permissions(item: Optional[Voucher], voucher_type: VoucherType, permissions: List[str]):
    if voucher_type == VoucherType.KOT and "print-kot" not in permissions:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN, detail="You are not allowed to print a kot",
        )
    if voucher_type != VoucherType.KOT and "print-bill" not in permissions:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN, detail="You are not allowed to print bill",
        )

    if item is None:
        return
    if item.voucher_type != VoucherType.KOT and "edit-printed-bill" not in permissions:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN, detail="You are not allowed to edit a printed bill",
        )

    if item.voucher_type != VoucherType.KOT and voucher_type == VoucherType.KOT:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN, detail="This Bill is already printed\nCannot add a Kot to it.",
        )

    if item.voucher_type == VoucherType.VOID:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN, detail=f"This Bill is already void.\nReason: {item.reason}",
        )


def get_guest_book(id_: uuid.UUID, db: Session):
    if id_ is None:
        return id_
    return db.query(GuestBook).filter(GuestBook.id == id_).first()


def do_update_settlements(voucher: Voucher, others: List[SettleSchema], db: Session):
    settlements: List[SettleSchema] = []
    settlements += others
    total_amount = voucher.amount
    settlements.append(SettleSchema(id=SettleOption.AMOUNT(), amount=-total_amount))
    round_off = round(total_amount) - total_amount
    if round_off != 0:
        settlements.append(SettleSchema(id=SettleOption.ROUND_OFF(), amount=-round_off))
    unsettled = sum(x.amount for x in settlements)
    if len(others) and unsettled != 0:  # This should not be allowed
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="Payment received is not equal to bill amount",
        )
    if unsettled != 0:
        settlements.append(SettleSchema(id=SettleOption.UNSETTLED(), amount=unsettled))

    for i in settlements:
        old = [s for s in voucher.settlements if s.settled == i.id_]
        if len(old) == 1:
            old[0].amount = i.amount
        else:
            s = Settlement(voucher.id, i.id_, i.amount)
            voucher.settlements.append(s)
            db.add(s)

    for i in (i for i in voucher.settlements if i.settled not in [x.id_ for x in settlements]):
        voucher.settlements.remove(i)
        db.delete(i)