from . import Blueprint, flash, db, \
        current_user, login_required, \
        assert_authorisation, templated, redirect, request, \
        today

from .. import forms as F
from ..model import ConstExpense, SingleExpense
import sqlalchemy as sql
import calendar
from collections import defaultdict
from datetime import date
from flask import jsonify

mod = Blueprint('stats', __name__)

def next_date(d):
    if d.month == 12:
        return d.replace(year = d.year + 1, month = 1)
    else:
        return d.replace(month = d.month + 1)

def date_to_ms(d):
    return calendar.timegm(d.timetuple()) * 1000

@mod.route('/_const/<int(fixed_digits=4):year>/<int(fixed_digits=2):month>')
@login_required
@templated
def const_dialog(year,month):
    consts = ConstExpense.of_month(current_user, month, year).order_by(ConstExpense.description)

    return { 'consts': consts }


@mod.route('/')
@login_required
@templated
def show():
    # easy way: fetch them all and then do some computation
    consts = defaultdict(int)
    t = today().replace(day = 1)
    for e in ConstExpense.of(current_user):
        cur = e.start
        end = min(e.end, t)
        while cur <= end:
            consts[date_to_ms(cur)] += e.monthly
            cur = next_date(cur)

    consts = list(sorted(consts.items()))

    expQuery = SingleExpense.of(current_user)\
            .group_by(SingleExpense.year, SingleExpense.month)\
            .values(SingleExpense.year, SingleExpense.month, sql.func.sum(SingleExpense.expense))

    expenses = list(sorted((date_to_ms(date(year,month,1)), exp) for (year, month, exp) in expQuery))

    return { 'consts': consts, 'expenses' : expenses }