# UGE / L2 / Intro to relational databases / Python project prototype
# Author: Pacien TRAN-GIRARD
# Licence: EUPL-1.2

from decimal import Decimal

from fastapi import APIRouter, Form, Depends, status

from embrace.exceptions import IntegrityError
from psycopg2.errors import CheckViolation
from psycopg2.extensions import ISOLATION_LEVEL_SERIALIZABLE

from app_sessions import UserSession
from app_database import db_transaction


router = APIRouter()


# TODO: add paging for the transaction history
@router.get('/wallet')
def wallet(
    session: UserSession=Depends(UserSession.authenticated),
):
    with db_transaction() as tx:
        history = tx.fetch_transactions(user_id=session.get_user_id())
        return list(history)


@router.post('/wallet/transfer')
def wallet_transfer(
    session: UserSession=Depends(UserSession.authenticated),
    recipient: str=Form(...),
    amount: Decimal=Form(...),
):
    if amount <= 0:
        return 'error: Invalid transaction amount.'

    try:
        with db_transaction(ISOLATION_LEVEL_SERIALIZABLE) as tx:
            recipient_user = tx.fetch_account_username(username=recipient)
            if recipient_user is None:
                raise LookupError('Could not find recipient')

            tx.transfer(
                from_user_id=session.get_user_id(),
                to_user_id=recipient_user.id,
                amount=amount,
                fee=amount * Decimal(0.10))

        return 'Your business is appreciated.'

    except LookupError as exception:
        return 'error: ' + str(exception)

    except IntegrityError as exception:
        if isinstance(exception.__cause__, CheckViolation):
            return 'error: Insufficient funds.'
        else:
            raise exception


@router.post('/wallet/deposit')
def wallet_deposit(
    session: UserSession=Depends(UserSession.authenticated),
    amount: Decimal=Form(...),
):
    if amount <= 0:
        return 'error: Invalid transaction amount.'

    with db_transaction(ISOLATION_LEVEL_SERIALIZABLE) as tx:
        tx.deposit(user_id=session.get_user_id(), amount=amount)

    return 'Your business is appreciated.'


@router.post('/wallet/withdraw')
def wallet_withdraw(
    session: UserSession=Depends(UserSession.authenticated),
    amount: Decimal=Form(...),
):
    if amount <= 0:
        return 'error: Invalid transaction amount.'

    try:
        with db_transaction(ISOLATION_LEVEL_SERIALIZABLE) as tx:
            tx.withdraw(user_id=session.get_user_id(), amount=amount)

        return 'Annnnnd... It\'s gone.'

    except IntegrityError as exception:
        if isinstance(exception.__cause__, CheckViolation):
            return 'error: Insufficient funds.'
        else:
            raise exception