# Copyright 2018 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""This module is used to go from raw data to a csv dataset to build models for
   component prediction.
"""
from __future__ import print_function
from __future__ import division
from __future__ import absolute_import

import argparse
import string
import sys
import csv
import re
import logging
import random
import time
import os
import settings
from framework import sql

if not settings.unit_test_mode:
  import MySQLdb as mdb
ISSUE_LIMIT = 7000
ISSUES_PER_RUN = 50
COMPONENT_PREDICTOR_PROJECT = 16

def build_component_dataset(issue, csv_file):
  """Main function to build dataset for training models.

  Args:
    issue: The issue service with set up data.
    csv_file: The csv file path to store the dataset.
  """

  logging.info('Building dataset')
  con = sql.MonorailConnection()

  csv_writer = csv.writer(csv_file)

  logging.info('Downloading the dataset from database.')

  issue_table = sql.SQLTableManager('Issue')
  issue_component_table = sql.SQLTableManager('Issue2Component')
  closed_index_table = sql.SQLTableManager('ComponentIssueClosedIndex')

  close = closed_index_table.SelectValue(con, col='closed_index')

  last_close = issue_table.Select(con,
                                  cols=['closed'],
                                  where=[('closed > %s', [str(close)]),
                                         ('project_id = %s',
                                          [str(COMPONENT_PREDICTOR_PROJECT)])],
                                  order_by=[('closed', [])],
                                  limit=ISSUE_LIMIT)[-1][0]

  issue_ids = issue_table.Select(con,
                              cols=['id'],
                              where=[('closed > %s', [str(close)]),
                                     ('closed <= %s', [str(last_close)]),
                                     ('project_id = %s',
                                      [str(COMPONENT_PREDICTOR_PROJECT)])])


  logging.info('Close: ' + str(close))
  logging.info('Last close: ' + str(last_close))

  # Get the comments and components for 50 issues at a time so as to not
  # overwhelm a single shard with all 7000 issues at once
  for i in range(0, len(issue_ids), ISSUES_PER_RUN):
    issue_list = [str(x[0]) for x in issue_ids[i:i+ISSUES_PER_RUN]]

    comments = issue.GetCommentsForIssues(con, issue_list, content_only=True)

    shard_id = random.randint(0, settings.num_logical_shards - 1)

    components = issue_component_table.Select(con,
                                        cols=['issue_id',
                                              'GROUP_CONCAT(component_id '
                                              + 'SEPARATOR \',\')'],
                                        joins=[('ComponentDef ON '
                                                'ComponentDef.id = '
                                                'Issue2Component.component_id',
                                                [])],
                                        where=[('(deprecated = %s OR deprecated'
                                                ' IS NULL)', [False]),
                                                ('is_deleted = %s', [False])],
                                        group_by=['issue_id'],
                                        shard_id=shard_id,
                                        issue_id=issue_list)

    for issue_id, component_ids in components:
      comment_string = ' '.join(
          [comment.content for comment in comments[issue_id]])

      final_text = CleanText(comment_string)

      final_issue = component_ids, final_text
      csv_writer.writerow(final_issue)

  closed_index_table.Update(con, delta={'closed_index' : last_close})

  return csv_file


def CleanText(text):
  """Cleans provided text by lower casing words, removing punctuation, and
  normalizing spacing so that there is exactly one space between each word.

  Args:
    text: Raw text to be cleaned.

  Returns:
    Cleaned version of text.

  """

  pretty_issue = text.lower().strip()

  quoteless_issue = re.sub('\'', '', pretty_issue)
  no_punctuation_issue = re.sub(r'[^\w\s]|_+', ' ', quoteless_issue)
  one_space_issue = ' '.join(no_punctuation_issue.split())

  return one_space_issue