"""
    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
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.
    """
    session = db.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):
    session = db.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):
    session = db.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():
    session = db.session

    try:
        account = Account(request.json['name'], request.json['authorized_overdraft'])

        session.add(account)
        session.commit()

        return json.dumps("Account added.")
    except:
        session.rollback()
        raise


@api.route("/accounts/<account_id>", methods=["PUT"])
def update_account(account_id):
    session = db.session

    try:
        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)
        session.commit()

        return json.dumps("Account #%s updated." % account_id)
    except:
        session.rollback()
        raise

@api.route("/accounts/<account_id>", methods=["DELETE"])
def delete_account(account_id):
    session = db.session

    try:
        account = session.query(Account).filter(Account.id == account_id).first()

        session.delete(account)
        session.commit()

        return json.dumps("Account #%s deleted." % account_id)
    except:
        session.rollback()
        raise