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

from ..model import Category, ConstExpense
from ..forms import ConstForm, today

import datetime
from sqlalchemy import sql
from functools import partial

assert_authorisation = partial(assert_authorisation, ConstExpense.get)

mod = Blueprint('consts', __name__)

def const_form(cur=None, obj=None):
    obj = cur if obj is None else obj
    form = ConstForm(obj=obj)
    form.category.query = Category.of(current_user).order_by(Category.name)

    # init prev_list
    CE = ConstExpense

    filter = (CE.next == None)

    if cur and cur.id is not None: # not empty
        filter = sql.or_(CE.next == cur, filter)
        filter = sql.and_(filter, CE.id != cur.id)

    form.prev.query = CE.of(current_user).filter(filter).order_by(CE.description)

    return form

@mod.route('/')
@login_required
@templated()
def list ():
    d = today()

    expenses = ConstExpense.of(current_user).order_by(ConstExpense.description).all()

    current = []
    old = []
    future = []

    for e in expenses:
        if e.start <= d:
            if e.end >= d:
                current.append(e)
            else:
                old.append(e)
        else:
            future.append(e)

    return { 'current': current, 'old': old, 'future': future }

@mod.route('/<int:id>')
@login_required
@assert_authorisation('id')
@templated()
def show(id):
    return { 'exp': ConstExpense.get(id) }

@mod.route('/edit/<int:id>', methods=('GET', 'POST'))
@login_required
@assert_authorisation('id')
@templated()
def edit(id):
    exp = ConstExpense.get(id)
    form = const_form(exp)

    if form.is_submitted():
        if 'deleteB' in request.form:
            db.session.delete(exp)
            db.session.commit()
            return redirect('.list')

        elif form.validate(): # change
            form.populate_obj(exp)
            db.session.commit()
            return redirect('.show', id = id)

    return { 'form': form }

@mod.route('/add/from/<int:other>')
@login_required
@assert_authorisation('other')
@templated('.add')
def add_from(other):
    exp = ConstExpense() # needed to initialize 'CE.next'

    other = ConstExpense.get(other)

    # get form with data from other
    form = const_form(obj = other)

    # replace some fields to be more meaningful
    start = max(form.end.data, today())
    form.start.data = start
    form.end.data = start.replace(year = start.year + 1)
    if not other.next: form.prev.data = other

    return { 'form': form }

@mod.route('/add/', methods=('GET', 'POST'))
@login_required
@templated()
def add ():
    exp = ConstExpense()

    form = const_form()

    if form.validate_on_submit():
        form.populate_obj(exp)
        exp.user = current_user
        db.session.add(exp)
        db.session.commit()
        return redirect('.show', id = exp.id)

    return { 'form': form }