#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright 2010 Timu Eren

import time
from cassandra.ttypes import *

from connections import Connection
from fields import *
from sinexceptions import *
from utils import timestamp

class ModelType(type):
  def __new__(cls, classname, bases, attrs):

      fields = dict()
      _key_field = None
      instance = type.__new__(cls, classname, bases, attrs)

      for name, value in attrs.iteritems():
        if isinstance(value, Field):
          fields[name] = value

        if isinstance(value, KeyField):
          _key_field = value

      if not _key_field:
        raise ErrorKeyFieldNotFound("")



      instance._key_field = _key_field
      if len(fields):
        instance._fields = fields
      return instance

class Model(dict):
  __metaclass__ = ModelType

  __changed_columns__ = set()

  def _get_cas(self):
      """Return the cassandra client."""
      if keyspace not in self._clients:
          self._clients[self.__keyspace__] = connection.get_pool(self.__keyspace__)

      return self._clients[self.__keyspace__]

  def __init__(self):
      self._clients = {}

  """put changed rows to cassandra"""
  def save(self, consistency_level=None):
    """put changed rows to cassandra"""
    """
      Parameters:
      - consistency_level
    """

    """has any changed column?"""
    if self.__changed_columns__:
      _key_field = self._key_field.get()
      __column_family__ = self.__column_family__

      mutate_map = {_key_field: {
          __column_family__:list()
        }
      }
      columns = list()
      for c in self.__changed_columns__:
        column = Column(c, self._fields[c].get(), timestamp())
        if not self._key_field.is_super():
          mutate_map[_key_field][self.__column_family__].append(Mutation(ColumnOrSuperColumn(
                column=column
              )
            )
          )
        else:
          columns.append(column)

      if self._key_field.is_super():
        mutate_map[_key_field][self.__column_family__].append(Mutation(ColumnOrSuperColumn(
              super_column=SuperColumn(self._key_field.super_column, columns=columns)
            )
          )
        )
      Connection.instance().batch_mutate(self.__keyspace__, mutate_map, consistency_level)

  def __getitem__(self, k):
    if k not in self._fields:
      raise ErrorFieldNotFound(k)
    return self._fields[k].get()

  def __setitem__(self, k, v):
    if k not in self._fields:
      raise ErrorFieldNotFound(k)

    if self._fields[k].get() != v :
      self.__changed_columns__.add(k)
    self._fields[k].set(v)

if __name__ == '__main__':

  class UserModel(Model):
    __keyspace__ = 'Test'
    __column_family__ = 'SuperColumnTest'

    username = KeyField(super_column='information')
    password = StringField(default=None)


  u = UserModel()
  u['username'] = 'test'
  u['password'] = 'test'
  u.save()