"""
    This file is part of Accountant.

    Accountant is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Foobar is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with Accountant.  If not, see <http://www.gnu.org/licenses/>.
"""
from .. import api
from ..model import db, session_scope
from ..model.accounts import Account
from ..model.entries import Entry
from ..model.operations import Operation
from flask import json, request
from sqlalchemy import func, case, cast, extract, distinct

@api.route("/accounts", methods=["GET"])
def get_accounts():
    """
    Returns accounts with their solds.
    """
    with session_scope() as session:
        query = session.query(
          Account.id.label("id"),
          Account.name.label("name"),
          Account.authorized_overdraft.label("authorized_overdraft"),
          func.sum(Entry.value).label("future"),
          func.sum(case([(Entry.pointed, Entry.value,)], else_=cast(0, db.Numeric(15, 2)))).label("pointed"),
          func.sum(case([(Entry.operation_date < func.now(), Entry.value,)], else_=cast(0, db.Numeric(15, 2)))).label("current")
        ).outerjoin(Entry).group_by(Account.id).order_by(Account.id)

        return json.dumps([{
            "id": i.id,
            "name": i.name,
            "authorized_overdraft": i.authorized_overdraft,
            "current": str(i.current),
            "pointed": str(i.pointed),
            "future": str(i.future)
        } for i in query.all()])

@api.route("/accounts/<account_id>/<year>/<month>/")
def get_account_status(account_id, year, month):
    with session_scope() as session:
        query = session.query(
            func.sum(case([(func.sign(Operation.value) == -1, Operation.value)], else_=0)).label("expenses"),
            func.sum(case([(func.sign(Operation.value) == 1, Operation.value)], else_=0)).label("revenues"),
            func.sum(Operation.value).label("balance")
        ).filter(
            Operation.account_id == account_id
        ).filter(
            func.date_trunc('month', Operation.operation_date) == "%s-%s-01" % (year, month)
        ).group_by(Operation.account_id)

        if query.count() == 1:
            result = query.one()
            revenues = result.revenues
            expenses = result.expenses
            balance = result.balance
        else:
            revenues = 0.0
            expenses = 0.0
            balance = 0.0

        return json.dumps({
            "expenses": str(expenses),
            "revenues": str(revenues),
            "balance": str(balance)
        })

@api.route("/accounts/<account_id>/months")
def get_months(account_id):
    with session_scope() as session:
        query = session.query(
          distinct(func.lpad(cast(extract("year", Entry.operation_date), db.String), 4, '0')).label("year"),
          func.lpad(cast(extract("month", Entry.operation_date), db.String), 2, '0').label("month")
        ).filter(Entry.account_id == account_id).order_by("year", "month")

        return json.dumps([{
            "year": i.year,
            "month": i.month.rjust(2, '0')
        } for i in query.all()])

@api.route("/accounts", methods=["PUT"])
def add_account():
    with session_scope() as session:
        account = Account(request.json['name'], request.json['authorized_overdraft'])

        session.add(account)

        return json.dumps("Account added.")


@api.route("/accounts/<account_id>", methods=["PUT"])
def update_account(account_id):
    with session_scope() as session:
        account = session.query(Account).filter(Account.id == account_id).first()

        account.name = request.json['name']
        account.authorized_overdraft = request.json['authorized_overdraft']

        session.merge(account)

        return json.dumps("Account #%s updated." % account_id)

@api.route("/accounts/<account_id>", methods=["DELETE"])
def delete_account(account_id):
    with session_scope() as session:
        account = session.query(Account).filter(Account.id == account_id).first()

        session.delete(account)

        return json.dumps("Account #%s deleted." % account_id)