#!/usr/bin/env python3

import datetime
import sys
import lxml.etree as ET

from decimal import Decimal, getcontext
getcontext().prec = 6


TEMPLATE_DATE = '%Y-%m-%dT%H:%M:%S'
NS_CFDI = {
    'cfdi': 'http://www.sat.gob.mx/cfd/3',
    'tfd': 'http://www.sat.gob.mx/TimbreFiscalDigital',
    'nomina12': 'http://www.sat.gob.mx/nomina12',
}
PRE = '/cfdi:Comprobante'
CADENA = "||{Version}|{UUID}|{FechaTimbrado}|{SelloCFD}|{NoCertificadoSAT}||"


class CfdiToDic(object):

    def __init__(self):
        self._data = {}
        self.complements = True

    def parse(self, source):
        # ~ recovering_parser = ET.XMLParser(recover=True)
        # ~ tree = ET.fromstring(xml, parser=recovering_parser)
        self._tree = ET.fromstring(source)
        self._data['comprobante'] = dict(self._tree.attrib)
        self._data['comprobante']['Total'] = \
            self._str_to_decimal(self._data['comprobante']['Total'])
        self._data['comprobante']['Fecha'] = \
            self._str_to_date(self._data['comprobante']['Fecha'])

        attr = self._get_attr(f'{PRE}/cfdi:Complemento/tfd:TimbreFiscalDigital')
        self._data['timbre'] = attr

        attr = self._get_attr(f'{PRE}/cfdi:Emisor')
        self._data['emisor'] = attr

        attr = self._get_attr(f'{PRE}/cfdi:Receptor')
        self._data['receptor'] = attr

        self._parse_details()
        self._parse_taxes()
        self._parse_nomina()
        self._complements()
        return

    def _parse_details(self):
        name = f'{PRE}/cfdi:Conceptos/cfdi:Concepto'
        details = self._tree.xpath(name, namespaces=NS_CFDI)
        rows = []
        for detail in details:
            row = dict(detail.attrib)
            for k, v in row.items():
                if k in ('Cantidad', 'ValorUnitario', 'Descuento', 'Importe'):
                    row[k] = self._str_to_decimal(v)
            row['taxes'] = self._get_taxes(detail)
            rows.append(row)
        self._data['conceptos'] = rows
        return

    def _get_taxes(self, node):
        data = {'traslados': [], 'retenciones': []}
        for n in node.iter():
            row = {}
            if n.tag.endswith('Traslado') or n.tag.endswith('Retencion'):
                row = dict(n.attrib)
            if row:
                row['Base'] = self._str_to_decimal(row['Base'])
                row['TasaOCuota'] = self._str_to_decimal(row['TasaOCuota'])
                row['Importe'] = self._str_to_decimal(row['Importe'])
                if n.tag.endswith('Traslado'):
                    data['traslados'].append(row)
                else:
                    data['retenciones'].append(row)
        return data

    def _parse_taxes(self):
        attr = self._get_attr(f'{PRE}/cfdi:Impuestos')
        self._data['impuestos'] = attr
        fields = ('TotalImpuestosTrasladados', 'TotalImpuestosRetenidos')
        k = 'impuestos'
        for f in fields:
            if f in self._data[k]:
                self._data[k][f] = self._str_to_decimal(self._data[k][f])

        name = f'{PRE}/cfdi:Impuestos/cfdi:Traslados/cfdi:Traslado'
        taxes = self._tree.xpath(name, namespaces=NS_CFDI)
        if taxes:
            data = []
            for t in taxes:
                values = dict(t.attrib)
                values['TasaOCuota'] = self._str_to_decimal(values['TasaOCuota'])
                values['Importe'] = self._str_to_decimal(values['Importe'])
                data.append(values)
            self._data['impuestos']['traslados'] = data

        name = f'{PRE}/cfdi:Impuestos/cfdi:Retenciones/cfdi:Retencion'
        taxes = self._tree.xpath(name, namespaces=NS_CFDI)
        if taxes:
            data = []
            for t in taxes:
                values = dict(t.attrib)
                values['Importe'] = self._str_to_decimal(values['Importe'])
                data.append(values)
            self._data['impuestos']['retenciones'] = data

        return

    def _parse_nomina(self):
        node_name = '//cfdi:Complemento/nomina12:Nomina'
        node = self._tree.xpath(node_name, namespaces=NS_CFDI)
        if not node:
            return

        node = node[0]
        attr = dict(node.attrib)
        # ~ self._data['version_nomina'] = attr['version']
        self._data['nomina'] = attr

        node_name = '//nomina12:Emisor'
        attr = self._get_attr(node_name, node)
        self._data['emisor'].update(attr)

        node_name = '//nomina12:Receptor'
        attr = self._get_attr(node_name, node)
        self._data['receptor'].update(attr)

        node_name = '//nomina12:Percepciones'
        self._data['percepciones'] = self._get_attr(node_name, node)

        node_name = '//nomina12:Percepcion'
        percepciones = node.xpath(node_name, namespaces=NS_CFDI)
        self._data['percepciones']['percepciones'] = [
            dict(n.attrib) for n in percepciones]

        node_name = '//nomina12:Deducciones'
        self._data['deducciones'] = self._get_attr(node_name, node)

        node_name = '//nomina12:Deduccion'
        deducciones = node.xpath(node_name, namespaces=NS_CFDI)
        self._data['deducciones']['deducciones'] = [
            dict(n.attrib) for n in deducciones]

        return

    def _complements(self):
        if not self.complements:
            self._data['comprobante']['xml'] = self.xml
            return

        self._data['comprobante']['Certificado'] = ''
        self._data['comprobante']['cadenaoriginal'] = \
            CADENA.format(**self._data['timbre'])
        return

    def _get_attr(self, node_name, node=None):
        if node is None:
            new_node = self._tree.xpath(node_name, namespaces=NS_CFDI)[0]
        else:
            new_node = node.xpath(node_name, namespaces=NS_CFDI)[0]
        attr = dict(new_node.attrib)
        return attr

    def _str_to_date(self, str_date, template=TEMPLATE_DATE):
        return datetime.datetime.strptime(str_date, template)

    def _str_to_decimal(self, value):
        d = Decimal(value)
        return d

    def __str__(self):
        return str(self._data)

    @property
    def xml(self):
        data = ET.tostring(self._tree,
            pretty_print=True,
            xml_declaration=True,
            encoding='utf-8').decode()
        return data

    @property
    def data(self):
        return self._data


def main(path):
    with open(path, 'rb') as f:
        data = f.read()
    cfdi = CfdiToDic(data)
    print(cfdi)
    return


if __name__ == '__main__':
    main(sys.argv[1])