from apiclient.discovery import build
from oauth2client.service_account import ServiceAccountCredentials
import pandas as pd
from pandas.io.json import json_normalize

SCOPES = ['https://www.googleapis.com/auth/analytics.readonly']
KEY_FILE_LOCATION = './key.json'
VIEW_ID = #secret


def initialize_analyticsreporting():
  credentials = ServiceAccountCredentials.from_json_keyfile_name(
      KEY_FILE_LOCATION, SCOPES)

  # Build the service object.
  analytics = build('analyticsreporting', 'v4', credentials=credentials)

  return analytics


def get_report(analytics):
  return analytics.reports().batchGet(
      body={
        'reportRequests': [
            {
            'viewId': VIEW_ID,
            'dateRanges': [{'startDate': '2019-09-28', 'endDate': 'today'}],
            'metrics': [{'expression': 'ga:sessions'}, {'expression': 'ga:pageViews'}],
            'dimensions': [
                    {'name': 'ga:date'},
                    {'name': 'ga:pagePath'},
                    {'name': 'ga:channelGrouping'},
                    {'name': 'ga:medium'},
                    {'name': 'ga:source'},
                    {'name': 'ga:referralPath'},
                    {'name': 'ga:fullReferrer'}
                ]
            }
        ]
      }
  ).execute()

def parse_data(response):
  reports = response['reports'][0]
  columnHeader = reports['columnHeader']['dimensions']
  metricHeader = reports['columnHeader']['metricHeader']['metricHeaderEntries']

  columns = columnHeader
  for metric in metricHeader:
    columns.append(metric['name'])

  data = json_normalize(reports['data']['rows'])
  data_dimensions = pd.DataFrame(data['dimensions'].tolist())
  data_metrics = pd.DataFrame(data['metrics'].tolist())
  data_metrics = data_metrics.applymap(lambda x: x['values'])
  data_metrics = pd.DataFrame(data_metrics[0].tolist())
  result = pd.concat([data_dimensions, data_metrics], axis=1, ignore_index=True)

  return result


def main():
  analytics = initialize_analyticsreporting()
  response = get_report(analytics)
  parse_data(response).to_csv('file.csv', encoding = 'utf-8')

if __name__ == '__main__':
  main()


"""
expected result
Referral Path   Full Referrer   Source      Medium      Page    Date            Channel Grouping    Sessions    Pageviews
(not set)       (direct)        (direct)    (none)      /       Sep 29, 2019    Direct              0           5
(not set)       (direct)        (direct)    (none)      /       Sep 30, 2019    Direct              6           8

current result [I want headers to change like expected]
    0           1   2               3       4       5           6       7   8
0   20190928    /   Organic Search  organic google  (not set)   google  4   6
"""