from datetime import datetime

from flask import json

from accounting.models import Amount, Transaction, Posting, Account

class AccountingEncoder(json.JSONEncoder):

    def default(self, o):

        if isinstance(o, Account):

            return dict(

                __type__=o.__class__.__name__,

                name=o.name,

                amounts=o.amounts,

                accounts=o.accounts

            )

        elif isinstance(o, Transaction):

            return dict(

                __type__=o.__class__.__name__,

                date=o.date.strftime('%Y-%m-%d'),

                payee=o.payee,

                postings=o.postings,

                metadata=o.metadata

            )

        elif isinstance(o, Posting):

                __type__=o.__class__.__name__,

                args=o.args

            )

        return json.JSONEncoder.default(self, o)

class AccountingDecoder(json.JSONDecoder):

    def __init__(self):

        json.JSONDecoder.__init__(self, object_hook=self.dict_to_object)

    def dict_to_object(self, d):

        if '__type__' not in d:

            return d

        _type = d.pop('__type__')

        if _type == 'Transaction':

            d['date'] = datetime.strptime(d['date'], '%Y-%m-%d')