#!/usr/bin/env python
"""
Fetch contributors data from Github using their API, convert it to structured
JSON data for the /authors page.
"""

from __future__ import absolute_import, print_function

# check for the venv
from lib import sanity_check
sanity_check.check_venv(__file__)

from typing import Any, Dict, List, Optional, Union, Text

import os
import sys
import argparse
from datetime import date
import subprocess

from six.moves import range
import requests
import simplejson as json

sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..'))
os.environ['DJANGO_SETTINGS_MODULE'] = 'zproject.settings'
from django.conf import settings
from zerver.lib.utils import split_by

FIXTURE_FILE = os.path.join(os.path.dirname(__file__), '../zerver/fixtures/authors.json')
GITHUB_LINK = 'https://api.github.com/repos/zulip/zulip/stats/contributors'

parser = argparse.ArgumentParser()
parser.add_argument('--max-retries', type=int, default=3,
                    help='Number of times to retry fetching data from Github')
# In Travis CI and development environment, we use test fixture to avoid
# fetching from Github constantly.
parser.add_argument('--use-fixture', action='store_true', default=False,
                    help='Use fixture data instead of fetching from Github')
parser.add_argument('--not-required', action='store_true', default=False,
                    help='Consider failures to reach GitHub nonfatal')
args = parser.parse_args()

def fetch_data(retries, link):
    # type: (int, str) -> Optional[List[Dict[str, Any]]]
    for _ in range(retries):
        try:
            r = requests.get(link)  # type: requests.Response
            if r.status_code == 200:
                return r.json()
            else:
                print('Github API return non 200 status.')
        except requests.exceptions.RequestException as e:
            print(e)

    return None

def write_to_disk(json_data, out_file):
    # type: (Dict[str, Any], str) -> None
    with open(out_file, 'w') as f:
        try:
            f.write("{}\n".format(json.dumps(json_data)))
        except IOError as e:
            print(e)
            sys.exit(1)

def run_production():
    # type: () -> None
    """
    Fetch data from Github and stored it in
    `static/generated/github-contributors.json`
    """
    json_data = fetch_data(args.max_retries, GITHUB_LINK)  # type: Optional[List[Dict[str, Any]]]
    if json_data:
        # Successfully fetch data from Github
        contribs = []
        for user in json_data:
            author = user.get('author')
            try:
                result_user = dict(
                    avatar=author.get('avatar_url'),
                    name=author.get('login'),
                    commits=user.get('total')
                )
                contribs.append(result_user)
            except AttributeError:
                print("Unable to access fields for %s" % (user,))

        out_contrib_data = split_by(
            sorted(contribs, key=lambda k: k.get('commits'), reverse=True),
            4, None
        )  # type: List[List[Optional[Dict[str, Union[Text, int]]]]]

        out_data = dict(
            data=out_contrib_data,
            date=str(date.today())
        )  # type: Dict[str, Any]

        write_to_disk(out_data, settings.CONTRIBUTORS_DATA)

    elif not args.not_required:
        print('Fail to fetch data from Github.')
        sys.exit(1)

def copy_fixture():
    # type: () -> None
    """
    Copy test fixture file from zerver/fixtures. This is used to avoid
    constantly fetching data from Github during testing.
    """
    subprocess.check_call(['cp', FIXTURE_FILE, settings.CONTRIBUTORS_DATA])

if args.use_fixture:
    copy_fixture()
else:
    run_production()