"""
..
  Copyright 2018 The University of Sydney
  This file is part of entrezpy.

  Entrezpy is free software: you can redistribute it and/or modify it under the
  terms of the GNU Lesser General Public License as published by the Free
  Software Foundation, either version 3 of the License, or (at your option) any
  later version.

  Entrezpy is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with entrezpy.  If not, see <https://www.gnu.org/licenses/>.

.. module:: entrezpy.efetch.efetcher
  :synopsis: Exports class Efetcher implementing entrezpy Efetch queries to
    NCBI EUtils Efetch

.. moduleauthor:: Jan P Buchmann <jan.buchmann@sydney.edu.au>
"""


import json

import entrezpy.base.query
import entrezpy.efetch.efetch_parameter
import entrezpy.efetch.efetch_request
import entrezpy.efetch.efetch_analyzer
import entrezpy.log.logger


class Efetcher(entrezpy.base.query.EutilsQuery):
  """Efetcher implements Efetch E-Utilities queries [0]. It implements
  :meth:`entrezpy.base.query.EutilsQuery.inquire` to fetch data from NCBI
  Entrez servers.
  [0]: https://www.ncbi.nlm.nih.gov/books/NBK25499/#chapter4.EFetch
  [1]: https://www.ncbi.nlm.nih.gov/books/NBK25497/table/
  chapter2.T._entrez_unique_identifiers_ui/?report=objectonly
  """

  def __init__(self, tool, email, apikey=None, apikey_var=None, threads=None, qid=None):
    """:ivar result: :class:`entrezpy.base.result.EutilsResult`"""
    super().__init__('efetch.fcgi', tool, email, apikey=apikey, threads=threads, qid=qid)
    self.logger = entrezpy.log.logger.get_class_logger(Efetcher)
    self.logger.debug(json.dumps({'init':self.dump()}))

  def inquire(self, parameter, analyzer=entrezpy.efetch.efetch_analyzer.EfetchAnalyzer()):
    """
    Implements :meth:`entrezpy.base.query.EutilsQuery.inquire` and configures
    fetch.

    .. note :: Efetch prefers to know the number of UIDs to fetch, i.e. number
      of UIDs or retmax. If this information is missing, the max number
      of UIDs for the specific retmode and rettype are fetched.

    :param dict parameter: EFetch parameter
    :param analyzer: analyzer for Efetch results
    :type analyzer: :class:`entrezpy.base.analyzer.EutilsAnalyzer`
    :return: analyzer instance or None if request errors have been encountered
    :rtype: :class:`entrezpy.base.analyzer.EutilsAnalyzer` or None
    """
    param = entrezpy.efetch.efetch_parameter.EfetchParameter(parameter)
    self.logger.debug(json.dumps({'parameter':param.dump()}))
    self.monitor_start(param)
    req_size = param.reqsize
    for i in range(param.expected_requests):
      if i * req_size + req_size > param.retmax:
        req_size = param.retmax % param.reqsize
      self.add_request(entrezpy.efetch.efetch_request.EfetchRequest(
        self.eutil, param, (i*param.reqsize), req_size), analyzer)
    self.request_pool.drain()
    self.monitor_stop()
    if self.isGoodQuery():
      return analyzer
    return None