import os
import lxml.builder
from lxml import etree
from lxml.builder import E
from StringIO import StringIO

from django.conf import settings as djsettings
from django.utils import timezone
from django.utils.translation import ugettext_lazy as _
from django_iban.validators import IBANValidator, IBAN_COUNTRY_CODE_LENGTH
from rest_framework import serializers

from orchestra.utils import plugins

from . import settings
from .forms import DirectDebitForm, CreditCardForm


class PaymentMethod(plugins.Plugin):
    label_field = 'label'
    number_field = 'number'
    
    __metaclass__ = plugins.PluginMount
    
    def get_form(self):
        self.form.plugin = self
        return self.form
    
    def get_serializer(self):
        self.serializer.plugin = self
        return self.serializer
    
    def get_label(self, data):
        return data[self.label_field]
    
    def get_number(self, data):
        return data[self.number_field]


class DirectDebitSerializer(serializers.Serializer):
    iban = serializers.CharField(label='IBAN', validators=[IBANValidator()],
            min_length=min(IBAN_COUNTRY_CODE_LENGTH.values()), max_length=34)
    name = serializers.CharField(label=_("Name"), max_length=128)


class CreditCardSerializer(serializers.Serializer):
    pass


class DirectDebit(PaymentMethod):
    verbose_name = _("Direct debit")
    label_field = 'name'
    number_field = 'iban'
    form = DirectDebitForm
    serializer = DirectDebitSerializer
    
    def _process_transactions(self, transactions):
        for transaction in transactions:
            self.object.transactions.add(transaction)
            # TODO transaction.account
            account = transaction.bill.account
            # FIXME
            data = account.payment_sources.first().data
            transaction.state = transaction.WAITTING_CONFIRMATION
            transaction.save()
            yield E.DrctDbtTxInf(                           # Direct Debit Transaction Info
                E.PmtId(                                    # Payment Id
                    E.EndToEndId(str(transaction.id))       # Payment Id/End to End
                ),
                E.InstdAmt(                                 # Instructed Amount
                    str(transaction.amount),
                    Ccy=transaction.currency.upper()
                ),
                E.DrctDbtTx(                                # Direct Debit Transaction
                    E.MndtRltdInf(                          # Mandate Related Info
                        E.MndtId(str(account.id)),          # Mandate Id
                        E.DtOfSgntr(                        # Date of Signature
                            account.register_date.strftime("%Y-%m-%d")
                        )
                    )
                ),
                E.DbtrAgt(                                  # Debtor Agent
                    E.FinInstnId(                           # Financial Institution Id
                        E.Othr(
                            E.Id('NOTPROVIDED')
                        )
                    )
                ),
                E.Dbtr(                                     # Debtor
                    E.Nm(account.name),                     # Name
                ),
                E.DbtrAcct(                                 # Debtor Account
                    E.Id(
                        E.IBAN(data['iban'])
                    ),
                ),
            )
    
    def process(self, transactions):
        from .models import PaymentProcess
        self.object = PaymentProcess.objects.create()
        creditor_name = settings.PAYMENTS_DD_CREDITOR_NAME
        creditor_iban = settings.PAYMENTS_DD_CREDITOR_IBAN
        creditor_bic = settings.PAYMENTS_DD_CREDITOR_BIC
        creditor_at02_id = settings.PAYMENTS_DD_CREDITOR_AT02_ID
        now = timezone.now()
        total = str(sum([transaction.amount for transaction in transactions]))
        sepa = lxml.builder.ElementMaker(
             nsmap = {
                 'xsi': "http://www.w3.org/2001/XMLSchema-instance",
                 None: "urn:iso:std:iso:20022:tech:xsd:pain.008.001.02",
             }
        )
        sepa = sepa.Document(
            E.CstmrDrctDbtInitn(
                E.GrpHdr(                                   # Group Header
                    E.MsgId(str(self.object.id)),         # Message Id
                    E.CreDtTm(now.strftime("%Y-%m-%dT%H:%M:%S")), # Creation Date Time
                    E.NbOfTxs(str(len(transactions))),      # Number of Transactions
                    E.CtrlSum(total),                       # Control Sum
                    E.InitgPty(                             # Initiating Party
                        E.Nm(creditor_name),                # Name
                        E.Id(                               # Identification
                            E.OrgId(                        # Organisation Id
                                E.Othr(
                                    E.Id(creditor_at02_id)
                                )
                            )
                        )
                    )
                ),
                E.PmtInf(                                   # Payment Info
                    E.PmtInfId(str(self.object.id)),        # Payment Id
                    E.PmtMtd("DD"),                         # Payment Method
                    E.NbOfTxs(str(len(transactions))),      # Number of Transactions
                    E.CtrlSum(total),                       # Control Sum
                    E.PmtTpInf(                             # Payment Type Info
                        E.SvcLvl(                           # Service Level
                            E.Cd("SEPA")                    # Code
                        ),
                        E.LclInstrm(                        # Local Instrument
                            E.Cd("CORE")                    # Code
                        ),
                        E.SeqTp("RCUR")                     # Sequence Type
                    ),
                    E.ReqdColltnDt(now.strftime("%Y-%m-%d")), # Requested Collection Date
                    E.Cdtr(                                 # Creditor
                        E.Nm(creditor_name)
                    ),
                    E.CdtrAcct(                             # Creditor Account
                        E.Id(
                            E.IBAN(creditor_iban)
                        )
                    ),
                    E.CdtrAgt(                              # Creditor Agent
                        E.FinInstnId(                       # Financial Institution Id
                            E.BIC(creditor_bic)
                        )
                    ),
                *list(self._process_transactions(transactions))   # Transactions
                )
            )
        )
        # http://www.iso20022.org/documents/messages/1_0_version/pain/schemas/pain.008.001.02.zip
        path = os.path.dirname(os.path.realpath(__file__))
        xsd_path = os.path.join(path, 'pain.008.001.02.xsd')
        schema_doc = etree.parse(xsd_path)
        schema = etree.XMLSchema(schema_doc)
        sepa = etree.parse(StringIO(etree.tostring(sepa)))
        schema.assertValid(sepa)
        base_path = self.object.file.field.upload_to or djsettings.MEDIA_ROOT
        file_name = 'payment-process-%i.xml' % self.object.id
        file_path = os.path.join(base_path, file_name)
        sepa.write(file_path,
                   pretty_print=True,
                   xml_declaration=True,
                   encoding='UTF-8')
        self.object.file = file_name
        self.object.save()


class CreditCard(PaymentMethod):
    verbose_name = _("Credit card")
    form = CreditCardForm
    serializer = CreditCardSerializer