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

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

from typing import Any, Dict, List, Optional, Union, cast
from mypy_extensions import TypedDict

import os
import shutil
import sys
import argparse
from time import sleep
from datetime import date

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/tests/fixtures/authors.json')
duplicate_commits_file = os.path.join(os.path.dirname(__file__),
                                      '../zerver/tests/fixtures/duplicate_commits.json')

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()


ContributorsJSON = TypedDict('ContributorsJSON', {
    'date': str,
    'contrib': List[Dict[str, Union[str, int]]],
})


def fetch_contributors(repo_link: str) -> Optional[List[Dict[str, Dict[str, Any]]]]:
    r = requests.get(repo_link)  # type: requests.Response
    return r.json() if r.status_code == 200 else None

def write_to_disk(json_data: ContributorsJSON, out_file: str) -> None:
    with open(out_file, 'w') as f:
        try:
            f.write("{}\n".format(json.dumps(json_data, indent=2, sort_keys=True)))
        except IOError as e:
            print(e)
            sys.exit(1)


def run_production() -> None:
    """
    Get contributors data from Github and insert them into a temporary
    dictionary. Retry fetching each repository if responded with non HTTP 200
    status.
    """
    repositories = {
        'server': 'https://api.github.com/repos/zulip/zulip/stats/contributors',
        'desktop': 'https://api.github.com/repos/zulip/zulip-electron/stats/contributors',
        'mobile': 'https://api.github.com/repos/zulip/zulip-mobile/stats/contributors',
        'python-zulip-api': 'https://api.github.com/repos/zulip/python-zulip-api/stats/contributors',
        'zulip-js': 'https://api.github.com/repos/zulip/zulip-js/stats/contributors',
        'zulipbot': 'https://api.github.com/repos/zulip/zulipbot/stats/contributors',
        'terminal': 'https://api.github.com/repos/zulip/zulip-terminal/stats/contributors',
    }

    data = dict(date=str(date.today()), contrib=[])  # type: ContributorsJSON
    contribs_list = {}  # type: Dict[str, Dict[str, Union[str, int]]]

    for _ in range(args.max_retries):
        repos_done = []
        for name, link in repositories.items():
            contribs = fetch_contributors(link)
            if contribs:
                repos_done.append(name)
                for contrib in contribs:
                    assert contrib is not None  # TODO: To improve/clarify

                    author = contrib.get('author')
                    if author is None:
                        # This happens for users who've deleted their GitHub account.
                        continue

                    username = author.get('login')
                    assert username is not None  # TODO: To improve/clarify

                    avatar = author.get('avatar_url')
                    assert avatar is not None  # TODO: To improve/clarify
                    total = contrib.get('total')
                    assert total is not None  # TODO: To improve/clarify

                    contrib_data = {
                        'avatar': avatar,
                        name: total,
                    }
                    if username in contribs_list:
                        contribs_list[username].update(contrib_data)
                    else:
                        contribs_list[username] = contrib_data

        # remove duplicate contributions count
        # find commits at the time of split and substract from zulip-server
        with open(duplicate_commits_file, 'r') as f:
            duplicate_commits = json.loads(f.read())
            for committer in duplicate_commits:
                if committer in contribs_list and contribs_list[committer].get('server'):
                    total_commits = cast(int, contribs_list[committer]['server'])
                    duplicate_commits_count = duplicate_commits[committer]
                    original_commits = total_commits - duplicate_commits_count
                    contribs_list[committer]['server'] = original_commits

        for repo in repos_done:
            del repositories[repo]

        if not repositories:
            break

        # Wait before retrying failed requests for Github to aggregate data.
        sleep(2)
    else:
        print("ERROR: Failed fetching contributors data from Github.")
        if not args.not_required:
            sys.exit(1)

    for contributor_name, contributor_data in contribs_list.items():
        contributor_data['name'] = contributor_name
        data['contrib'].append(contributor_data)

    write_to_disk(data, settings.CONTRIBUTORS_DATA)


def copy_fixture() -> None:
    """
    Copy test fixture file from zerver/tests/fixtures. This is used to avoid
    constantly fetching data from Github during testing.
    """
    shutil.copyfile(FIXTURE_FILE, settings.CONTRIBUTORS_DATA)


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