"""
    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 auth
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
from forms.accounts import AccountIdForm, AccountForm

@api.route("/accounts", methods=["GET"])
@auth.login_required
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>/")
@auth.login_required
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")
@auth.login_required
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"])
@auth.login_required
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"])
@auth.login_required
def update_account(account_id):
    account_form = AccountForm()

    if account_form.validate():
        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)
    else:
        return json.dumps({'ok': False, 'error_type': 'validation', 'errors': account_form.errors})

@api.route("/accounts/<account_id>", methods=["DELETE"])
@auth.login_required
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)