#!/usr/bin/env python3
"""
Fetch contributors data from Github using their API, convert it to structured
JSON data for the /about page authors section.
"""

# 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

import requests
import 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')
            if author is None:
                print("Unable to access fields for %s" % (user,))
                continue
            result_user = dict(
                avatar=author.get('avatar_url'),
                name=author.get('login'),
                commits=user.get('total')
            )
            contribs.append(result_user)

        out_contrib_data = split_by(
            sorted(contribs, key=lambda k: k.get('commits'), reverse=True),
            6, 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()