from pymarc import XmlHandler, parse_xml, MARCReader
from marcdb.db import connect, commit
from marcdb.models import *

class Loader:

  def __init__(self, uri, verbose=False):
    self.verbose = verbose
    self.db = connect(uri)

  def load_xml(self, xml_file):
    handler = DatabaseHandler(verbose=self.verbose)
    parse_xml(xml_file, handler)
    commit()

  def load(self, marc_file):
    handler = DatabaseHandler(verbose=self.verbose)
    for record in MARCReader(file(marc_file)):
      handler.process_record(record)
    commit()

class DatabaseHandler (XmlHandler):
  """
  Subclass of pymarc's XmlHandler to stream Record objects
  into the database using the process_record override.
  """

  def __init__(self, verbose=False):
    self._record_count = 0
    self.verbose = verbose

  def process_record(self, marc_record):
    self._record_count += 1
    if self.verbose:
      print self._record_count

    r = Record()
    r.leader = marc_record.leader
    field_position = -1
    for marc_field in marc_record:
      field_position += 1
      if marc_field.is_control_field():
        f = ControlField()
        f.tag = marc_field.tag
        f.value = marc_field.data
        f.position = field_position
        r.control_fields.append(f)
      else:
        f = DataField()
        f.tag = marc_field.tag
        f.indicator1 = marc_field.indicators[0]
        f.indicator2 = marc_field.indicators[1]
        f.position = field_position
        subfield_position = -1
        for marc_subfield in marc_field:
          subfield_position += 1
          sf = Subfield()
          sf.code=marc_subfield[0]
          sf.value=marc_subfield[1]
          sf.position = subfield_position
          f.subfields.append(sf)
        r.data_fields.append(f)

    if self._record_count % 1000 == 0:
      commit()