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

from ..model import Category, SingleExpense, CatExpense, MonthExpense
from ..forms import ExpenseForm

import datetime, decimal
from sqlalchemy import sql, func

mod = Blueprint('expenses', __name__)

def expense_form(obj=None):
    form = ExpenseForm(obj=obj)
    form.category.query = Category.of(current_user).order_by(Category.name)
    return form

def calc_month_exp(year, month):
    ssum = func.sum(SingleExpense.expense)
    query = SingleExpense.of_month(current_user, month, year)

    result = query.group_by(SingleExpense.category_id).\
             values(SingleExpense.category_id, ssum)

    exps = [CatExpense(Category.query.get(c), s, query.filter(SingleExpense.category_id == c)) for c,s in result]

    return MonthExpense(current_user, datetime.date(year, month, 1), exps)

def pie_stuff(exp):
    expenses = {}
    for c in exp.catexps:
        expenses[c.cat.name] = float(c.expense)

    for c in Category.of(current_user).order_by(Category.name).all():
        yield (c.name, expenses.get(c.name, 0.0))

def calc_month_and_pie(year, month):
    exp = calc_month_exp(year,month)
    pie = pie_stuff(exp)
    return (exp, dict(pie))

@mod.app_template_filter()
def prev_date(exp):
    if exp.date.month == 1:
        return exp.date.replace(year = exp.date.year - 1, month = 12)
    else:
        return exp.date.replace(month = exp.date.month - 1)

@mod.app_template_filter()
def next_date(exp):
    if exp.date.month == 12:
        return exp.date.replace(year = exp.date.year + 1, month = 1)
    else:
        return exp.date.replace(month = exp.date.month + 1)

@mod.app_template_test("last_date")
def is_last(exp):
    return exp.date >= datetime.date.today().replace(day = 1)

@mod.route("/<int(fixed_digits=4):year>/<int(fixed_digits=2):month>")
@login_required
@templated(".show")
def show_date(year, month):
    c,p = calc_month_and_pie(year, month)
    return { 'exps' : [c], 'pies' : [p] }

mod.add_url_rule("/<path:p>", endpoint = "show_date_str", build_only = True)

@mod.route("/")
@login_required
@templated()
def show():
    d = datetime.date.today()
            
    first, pfirst = calc_month_and_pie(d.year, d.month)
    if d.month == 1:
        second, psecond = calc_month_and_pie(d.year - 1, 12)
    else:
        second, psecond = calc_month_and_pie(d.year, d.month - 1)

    return { 'exps' : [first, second], 'pies': [pfirst, psecond] }

@mod.route("/edit/<int:id>", methods=("GET", "POST"))
@login_required
@templated()
def edit(id):
    exp = SingleExpense.get(id)
    form = expense_form(exp)

    if request.method == "POST":
        if "deleteB" in request.form:
            db.session.delete(exp)

        elif form.validate(): # change
            form.populate_obj(exp)

        else:
            return { 'form': form }

        db.session.commit()
        return redirect("index")

    return { 'form': form }

@mod.route("/add/", methods=("GET", "POST"))
@login_required
@templated()
def add():
    form = expense_form()

    if form.validate_on_submit():
        exp = SingleExpense()

        form.populate_obj(exp)
        exp.user = current_user

        db.session.add(exp)
        db.session.commit()

        return redirect(".add")

    return { 'form': form }