# -*- coding: utf-8 -*-

import logging

from optparse import make_option

from django.core.management import BaseCommand

from django.db import reset_queries, transaction

from rdflib import BNode

from p4l.mapping.constants import get_empty_graph, IIEP

from p4l.mapping.parsers import RecordParser, QueryCache

from p4l.utils import show_progress

import xml.etree.cElementTree as ET

from django.conf import settings

logger = logging.getLogger(__name__)

DEFAULT_LANGUAGE_URI = "http://psi.oasis-open.org/iso/639/#eng"

DEFAULT_LANGUAGE_QUERY =  """SELECT ( COALESCE(?lang, ?other_lang) as ?main_lang) WHERE {

    OPTIONAL { ?s dct:language ?lang }.

    OPTIONAL { ?s iiep:otherLanguage ?other_lang }.

}"""

class Command(BaseCommand):

    args = "record_url ..."

    help = "Import p4l record rdf format"

    option_list = BaseCommand.option_list + (

        make_option('-b', '--batch-size',

            dest= 'batch_size',

            type='int',

            default= 50,

            help= 'number of object to import in bulk operations' 

        ),

        make_option('-p', '--preserve',

            dest= 'preserve',

            action='store_true',

            default=False,

            help= 'preserve existing record' 

        ),

        make_option('-i', '--index',

            dest= 'index',

            action='store_true',

            default=False,

            help= 'index while importing' 

        ),

    )

    def __init__(self, *args, **kwargs):

        super(Command, self).__init__(*args, **kwargs)

        self.record_parser = RecordParser(query_cache=QueryCache())

    def filter_node(self, node, graph, res_graph):

        for p,o in graph[node]:

            res_graph.add((node,p,o))

            if isinstance(o, BNode):

                self.filter_node(o, graph, res_graph)

    def calculate_records_nb(self, records_url):

        context = ET.iterparse(records_url, events=("end",))

        i = 0

        for _,elem in context:

            if elem.tag == "{%s}Record" % IIEP:

                i += 1

        return i

    def process_url(self, records_url, options):

        total_records = self.calculate_records_nb(records_url)

        writer = None

        errors=[]

        context = ET.iterparse(records_url, events=("end",))

        i = 0

        for _,elem in context:

            if elem.tag == "{%s}Record" % IIEP:

                i += 1

                writer = show_progress(i, total_records, "Processing record nb %d " % i, 50, writer=writer)

                try:

                    record_graph = get_empty_graph()

                    record_graph.parse(data=ET.tostring(elem, encoding='utf-8'), format='xml')                    

                    self.record_parser.build_record(record_graph, delete=(not self.preserve))                    

                except Exception as e:

                    transaction.rollback()

                    msg = "Error processing resource %d in %s : %s" % (i, records_url, repr(e))

                    logger.exception(msg)

                    errors.append((i, records_url, msg))

                else:

                    transaction.commit()

                if i%self.batch_size == 0:                    

                    reset_queries()

        return errors

    # def process_url(self, records_url, options):

    #     #open graph with rdflib

    #             

    #     g = Graph()

    #     print("Loading %s" % records_url)

    #     g.parse(records_url)

    #     print("Parsing %s done" % records_url)

    #     for i,record_uri in enumerate(g[:RDF.type:IIEP.Record]):

    #         print(i, repr(record_uri))

    #         record_graph = self.get_empty_graph()

    #         self.filter_node(record_uri, g, record_graph)

    #         self.build_record(record_graph)

    #         if i > 3:

    #             break

    def handle(self, *args, **options):

        self.batch_size = options.get('batch_size', 50)

        self.preserve = options.get("preserve", False)

        self.index = options.get("index", False)

        if not self.index:

            #this is not recommended by the django manual, but in case of management command it seems to work

        transaction.enter_transaction_management()

        transaction.managed(True)

        for records_url in args:

            print("Processing %s" % records_url)

            errors = self.process_url(records_url, options)

            print("Processing %s Done" % records_url)

            if errors:

                print("%d error(s) when processing %s, check your log file." % (len(errors), records_url))

        transaction.leave_transaction_management()