from __future__ import with_statement

import web
from web import form
from web.form import Validator

from model import *
from helper import appdir
from renderer import render

import datetime, decimal
import itertools as iter
import operator as op
from sqlalchemy import sql

class Form (form.Form):
    """Make sure we return utf-8 stuff."""

    def render_utf8 (self, *args):
        return form.Form.render(self, *args).decode("utf-8")

class Show:
    def GET(self, year = '', month = ''):
        if year:
            c = self.calc(year, month)
            return self.render([c], self.is_last(c))
        else:
            d = datetime.date.today()
            
            first = self.calc(d.year, d.month)
            if d.month == 1:
                second = self.calc(d.year - 1, 12)
            else:
                second = self.calc(d.year, d.month - 1)

            return self.render([first, second], self.is_last(first))

    def calc(self, year, month):

        year = int(year)
        month = int(month)

        ssum = sql.functions.sum(SingleExpense.expense)
        query = SingleExpense.of_month(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(datetime.date(int(year), int(month), 1), exps)

    def is_last(self, exp):
        return exp.date >= datetime.date.today().replace(day = 1)

    def render(self, exps, is_last):
        return render("show", exps = exps, is_last = is_last)

class Add:

    dformat = "%d.%m.%Y"
    template = "add"

    def GET(self):
        return self.render(self.form())

    def POST(self):
        f = self.form()
        if f.validates():
            category = Category.get_by(name = f.category.value)
            
            e = self.get_expense()
            e.category = category
            e.date = datetime.datetime.strptime(f.date.value, self.dformat)
            e.expense = decimal.Decimal(f.expense.value)
            e.description = f.description.value

            self.return_()
        else:
            return self.render(f)

    def get_expense(self):
        return SingleExpense()

    def render(self, f):
        return render(self.template, form = f)

    def return_(self):
        raise web.seeother("/add")

    def form(self):
        return Form(
                form.Textbox(
                    "date",
                    form.notnull,
                    Validator("Date Format does not match", lambda v: datetime.datetime.strptime(v, self.dformat)),
                    value = datetime.date.today().strftime(self.dformat)
                    ),
                form.Textbox(
                    "expense",
                    form.notnull,
                    Validator("Not a valid decimal", decimal.Decimal),
                    ),
                form.Textbox(
                    "description",
                    form.notnull
                    ),
                form.Dropdown(
                    "category",
                    map(op.itemgetter(0), sorted(Category.query.values(Category.name)))
                    )
                )

class Edit (Add):

    template = "edit"

    def GET(self, id):
        exp = SingleExpense.get(id)
        self.get_expense = lambda *x: exp
        
        fvalues = { "date" : exp.date.strftime(self.dformat), "expense" : str(exp.expense), "description" : exp.description, "category" : exp.category.name }
        f = self.form()
        f.fill(fvalues)

        return self.render(f)

    def POST(self, id):
        exp = SingleExpense.get(id)
        self.get_expense = lambda *x: exp

        return Add.POST(self)

    def return_(self):
        raise web.seeother("/")

class Const:
    dformat = "%m.%Y"
    def GET(self, id=None):
        if id is None:           
            d = datetime.date.today()

            current = ConstExpense.of_month(d.month, d.year)
            
            csub = current.subquery()
            
            # if only mysql would allow "EXCEPT" -.-
            old = ConstExpense.query.outerjoin((csub, csub.c.id == ConstExpense.id)).filter(csub.c.id == None)
            old = old.order_by(ConstExpense.start)

            return render("constlist", current = current.order_by(ConstExpense.start).all(), old = old.all())
        
        else:
            exp = ConstExpense.get(id)
            return render("const", exp = exp, dformat = lambda x: x.strftime(self.dformat))

class ConstAdd:
    template = "constadd"
    dformat = "%m.%Y"

    def GET(self):
        return render(self.template, form = self.form())

    def POST(self):
        f = self.form()
        if f.validates():
            category = Category.get_by(name = f.category.value)
            
            e = self.get_expense()
            e.category = category
            e.start = datetime.datetime.strptime(f.start.value, self.dformat)
            e.end = datetime.datetime.strptime(f.end.value, self.dformat)
            e.months = f.months.value
            e.expense = decimal.Decimal(f.expense.value)
            e.description = f.description.value

            if int(f.prev.value) != -1:
                e.prev = ConstExpense.get(f.prev.value)
            else:
                e.prev = None

            raise web.seeother("/const/%s" % e.id)
        else:
            return render(self.template, form = f)

    def get_expense(self):
        return ConstExpense()

    def form(self):
        CE = ConstExpense

        # get the list of 'previous' expenses
        filter = (CE.next == None)
        cur = self.get_expense()

        if cur.id is None: # empty
            session.expunge(cur)
        else:
            filter = sql.or_(CE.next == cur, filter)
            filter = sql.and_(filter, CE.id != cur.id)

        prev_list = CE.query.filter(filter).order_by(CE.description).values(CE.id, CE.description)

        return Form(
                form.Textbox(
                    "start",
                    form.notnull,
                    Validator("Date Format does not match", lambda v: datetime.datetime.strptime(v, self.dformat)),
                    value = datetime.date.today().strftime(self.dformat)
                    ),
                form.Textbox(
                    "end",
                    form.notnull,
                    Validator("Date Format does not match", lambda v: datetime.datetime.strptime(v, self.dformat)),
                    value = datetime.date.today().strftime(self.dformat)
                    ),
                form.Textbox(
                    "months",
                    form.notnull,
                    Validator("Not an integer > 0", lambda v: int(v) > 0),
                    value = "12",
                    description = "Number of Months"
                    ),
                form.Textbox(
                    "expense",
                    form.notnull,
                    Validator("Not a valid decimal", decimal.Decimal),
                    ),
                form.Textbox(
                    "description",
                    form.notnull
                    ),
                form.Dropdown(
                    "category",
                    map(op.itemgetter(0), sorted(Category.query.values(Category.name)))
                    ),
                form.Dropdown(
                    "prev",
                    iter.chain([(-1, '')], prev_list)
                    )
                )

class ConstEdit (ConstAdd):
    template = "constedit"
    
    def GET(self, id, fromId = None):

        if id == "from":
            fromC = ConstExpense.get(fromId)
            
            exp = ConstExpense()
            exp.from_dict(fromC.to_dict(exclude=["id", "prev", "next"]))
            exp.prev = fromC
            session.commit()
        else:    
            exp = ConstExpense.get(id)
        
        self.get_expense = lambda *x: exp
        
        fvalues = {
                "start" : exp.start.strftime(self.dformat),
                "end" : exp.end.strftime(self.dformat),
                "months" : str(exp.months),
                "expense" : str(exp.expense),
                "description" : exp.description,
                "category" : exp.category.name,
                "prev" : exp.prev.id if exp.prev else str(-1)
                }
        f = self.form()
        f.fill(fvalues)

        return render(self.template, form = f)

    def POST(self, id, fromId = None):
        if id == "from":
            id = fromId

        exp = ConstExpense.get(id)
        self.get_expense = lambda *x: exp
        return ConstAdd.POST(self)

class Cat:
    def GET(self):
        categories = Category.query.order_by(Category.name).all()

        return render("cats", cats = categories)

    def POST(self):
        for id, name in web.input().iteritems():
            if id.startswith("n-"):
                Category(name = name)
            else:
                Category.get(id).name = name

        raise web.seeother("/")

class FourOhFour:
    """
    404 error page.
    """

    def GET (self, p):
        raise self.catch(p)

    @staticmethod
    def catch (page = "?"):
        return web.notfound(render("404", level = "", page = page))