import datetime

import brewman.schemas.reports as schemas

from fastapi import APIRouter, Depends, Request, Security
from sqlalchemy.orm import Session
from sqlalchemy.orm.util import aliased
from sqlalchemy.sql.expression import desc, func

from ...core.security import get_current_active_user as get_user
from ...core.session import get_finish_date, get_start_date, set_period
from ...db.session import SessionLocal
from ...models.master import AccountBase, AccountType
from ...models.voucher import Journal, Voucher, VoucherType
from ...schemas.auth import UserToken


router = APIRouter()


# Dependency
def get_db() -> Session:
    try:
        db = SessionLocal()
        yield db
    finally:
        db.close()


@router.get("", response_model=schemas.CashFlow)
def report_blank(
    request: Request,
    user: UserToken = Security(get_user, scopes=["cash-flow"]),
):
    return {
        "startDate": get_start_date(request.session),
        "finishDate": get_finish_date(request.session),
        "body": {"operating": [], "investing": [], "financing": [], "details": []},
        "footer": None,
    }


@router.get("/data")
def report_data(
    request: Request,
    s: str = None,
    f: str = None,
    db: Session = Depends(get_db),
    user: UserToken = Security(get_user, scopes=["cash-flow"]),
):
    body, footer = build_report(s, f, db)
    set_period(s, f, request.session)
    return {
        "startDate": s,
        "finishDate": f,
        "body": body,
        "footer": footer,
    }


@router.get("/{id_}")
def report_id(
    id_: int,
    request: Request,
    s: str = None,
    f: str = None,
    db: Session = Depends(get_db),
    user: UserToken = Security(get_user, scopes=["cash-flow"]),
):
    details, footer = build_report_id(id_, s, f, db)
    set_period(s, f, request.session)
    return {
        "startDate": s,
        "finishDate": f,
        "body": {"details": details},
        "footer": footer,
    }


def build_report(start_date, finish_date, db):
    sub_voucher = aliased(Voucher)
    sub_journal = aliased(Journal)
    sub_account = aliased(AccountBase)

    sub_query = (
        db.query(sub_voucher.id)
        .join(sub_journal, sub_voucher.journals)
        .join(sub_account, sub_journal.account)
        .filter(sub_account.type == AccountType.by_name("Cash").id)
        .filter(sub_voucher.date >= datetime.datetime.strptime(start_date, "%d-%b-%Y"))
        .filter(sub_voucher.date <= datetime.datetime.strptime(finish_date, "%d-%b-%Y"))
        .subquery()
    )

    query = (
        db.query(AccountBase.type, func.sum(Journal.signed_amount))
        .join(Journal, Voucher.journals)
        .join(AccountBase, Journal.account)
        .filter(Voucher.id.in_(sub_query))
        .filter(AccountBase.type != AccountType.by_name("Cash").id)
        .group_by(AccountBase.type)
        .order_by(func.sum(Journal.signed_amount))
        .all()
    )

    total_amount = 0
    cf = {"operating": [], "investing": [], "financing": []}
    for account_type, amount in query:
        lt = AccountType.by_id(account_type)
        total_amount += amount * -1
        cf[lt.cash_flow_classification.lower()].append(
            {
                "name": lt.name,
                "url": ["/", "cash-flow", str(lt.id)],
                "amount": amount * -1,
            }
        )

    opening = (
        db.query(func.sum(Journal.amount * Journal.debit))
        .join(Journal.voucher)
        .join(Journal.account)
        .filter(Voucher.date < start_date)
        .filter(Voucher.type != VoucherType.by_name("Issue").id)
        .filter(AccountBase.type == AccountType.by_name("Cash").id)
        .scalar()
    )

    closing = (
        db.query(func.sum(Journal.amount * Journal.debit))
        .join(Journal.voucher)
        .join(Journal.account)
        .filter(Voucher.date <= finish_date)
        .filter(Voucher.type != VoucherType.by_name("Issue").id)
        .filter(AccountBase.type == AccountType.by_name("Cash").id)
        .scalar()
    )

    return (
        cf,
        [
            {
                "name": "Net increase in cash and cash equivalents",
                "amount": total_amount,
            },
            {
                "name": "Cash and cash equivalents at beginning of period",
                "amount": opening,
            },
            {"name": "Cash and cash equivalents at end of period", "amount": closing},
        ],
    )


def build_report_id(account_type, start_date, finish_date, db):
    details = []
    sub_voucher = aliased(Voucher)
    sub_journal = aliased(Journal)
    sub_account = aliased(AccountBase)

    sub_query = (
        db.query(sub_voucher.id)
        .join(sub_journal, sub_voucher.journals)
        .join(sub_account, sub_journal.account)
        .filter(sub_account.type == AccountType.by_name("Cash").id)
        .filter(sub_voucher.date >= datetime.datetime.strptime(start_date, "%d-%b-%Y"))
        .filter(sub_voucher.date <= datetime.datetime.strptime(finish_date, "%d-%b-%Y"))
        .subquery()
    )

    query = (
        db.query(AccountBase, func.sum(Journal.signed_amount))
        .join(Journal, Voucher.journals)
        .join(AccountBase, Journal.account)
        .filter(Voucher.id.in_(sub_query))
        .filter(AccountBase.type == account_type)
        .group_by(AccountBase)
        .order_by(desc(func.sum(Journal.amount)))
        .all()
    )

    total_amount = 0
    for account, amount in query:
        total_amount += amount * -1
        details.append(
            {
                "name": account.name,
                "url": ["/", "ledger", str(account.id)],
                "amount": amount * -1,
            }
        )

    return details, [{"name": "total", "amount": total_amount}]