#Copyright 2019 gRPC authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Generate draft and release notes in Markdown from Github PRs.

You'll need a github API token to avoid being rate-limited. See
https://help.github.com/articles/creating-a-personal-access-token-for-the-command-line/

This script collects PRs using "git log X..Y" from local repo where X and Y are
tags or release branch names of previous and current releases respectively.
Typically, notes are generated before the release branch is labelled so Y is
almost always the name of the release branch. X is the previous release branch
if this is not a patch release. Otherwise, it is the previous release tag.
For example, for release v1.17.0, X will be origin/v1.16.x and for release v1.17.3,
X will be v1.17.2. In both cases Y will be origin/v1.17.x.

"""

from collections import defaultdict
import base64
import json

content_header = """Draft Release Notes For {version}
--
Final release notes will be generated from the PR titles that have *"release notes:yes"* label. If you have any additional notes please add them below. These will be appended to auto generated release notes. Previous releases notes are [here](https://github.com/grpc/grpc/releases).

**Also, look at the PRs listed below against your name.** Please apply the missing labels and make necessary corrections (like fixing the title) to the PR in Github. Final release notes will be generated just before the release on {date}.

Add additional notes not in PRs
--

Core
-


C++
-


C#
-


Objective-C
-


PHP
-


Python
-


Ruby
-


"""

rl_header = """This is the {version} release ([{name}](https://github.com/grpc/grpc/blob/master/doc/g_stands_for.md)) of gRPC Core.

Please see the notes for the previous releases here: https://github.com/grpc/grpc/releases. Please consult https://grpc.io/ for all information regarding this product.

This release contains refinements, improvements, and bug fixes, with highlights listed below.


"""

HTML_URL = "https://github.com/grpc/grpc/pull/"
API_URL = 'https://api.github.com/repos/grpc/grpc/pulls/'


def get_commit_log(prevRelLabel, relBranch):
    """Return the output of 'git log --pretty=online --merges prevRelLabel..relBranch' """

    import subprocess
    print("Running git log --pretty=oneline --merges " + prevRelLabel + ".." +
          relBranch)
    return subprocess.check_output([
        "git", "log", "--pretty=oneline", "--merges",
        "%s..%s" % (prevRelLabel, relBranch)
    ])


def get_pr_data(pr_num):
    """Get the PR data from github. Return 'error' on exception"""

    try:
        from urllib2 import Request, urlopen, HTTPError
    except ImportError:
        import urllib
        from urllib.request import Request, urlopen, HTTPError
    url = API_URL + pr_num
    req = Request(url)
    req.add_header('Authorization', 'token %s' % TOKEN)
    try:
        f = urlopen(req)
        response = json.loads(f.read().decode('utf-8'))
        #print(response)
    except HTTPError as e:
        response = json.loads(e.fp.read().decode('utf-8'))
        if 'message' in response:
            print(response['message'])
        response = "error"
    return response


def get_pr_titles(gitLogs):
    import re
    error_count = 0
    match = b"Merge pull request #(\d+)"
    prlist = re.findall(match, gitLogs, re.MULTILINE)
    print("\nPRs matching 'Merge pull request #<num>':")
    print(prlist)
    print("\n")
    langs_pr = defaultdict(list)
    for pr_num in prlist:
        pr_num = str(pr_num)
        print("---------- getting data for PR " + pr_num)
        pr = get_pr_data(pr_num)
        if pr == "error":
            print("\n***ERROR*** Error in getting data for PR " + pr_num + "\n")
            error_count += 1
            continue
        rl_no_found = False
        rl_yes_found = False
        lang_found = False
        for label in pr['labels']:
            if label['name'] == 'release notes: yes':
                rl_yes_found = True
            elif label['name'] == 'release notes: no':
                rl_no_found = True
            elif label['name'].startswith('lang/'):
                lang_found = True
                lang = label['name'].split('/')[1].lower()
                #lang = lang[0].upper() + lang[1:]
        body = pr["title"]
        if not body.endswith("."):
            body = body + "."
        if not pr["merged_by"]:
            print("\n***ERROR***: No merge_by found for PR " + pr_num + "\n")
            error_count += 1
            continue

        prline = "-  " + body + " ([#" + pr_num + "](" + HTML_URL + pr_num + "))"
        detail = "- " + pr["merged_by"]["login"] + "@ " + prline
        prline = prline.encode('ascii', 'ignore')
        detail = detail.encode('ascii', 'ignore')
        print(detail)
        #if no RL label
        if not rl_no_found and not rl_yes_found:
            print("Release notes label missing for " + pr_num)
            langs_pr["nolabel"].append(detail)
        elif rl_yes_found and not lang_found:
            print("Lang label missing for " + pr_num)
            langs_pr["nolang"].append(detail)
        elif rl_no_found:
            print("'Release notes:no' found for " + pr_num)
            langs_pr["notinrel"].append(detail)
        elif rl_yes_found:
            print("'Release notes:yes' found for " + pr_num + " with lang " +
                  lang)
            langs_pr["inrel"].append(detail)
            langs_pr[lang].append(prline)

    return langs_pr, error_count


def write_draft(langs_pr, file, version, date):
    file.write(content_header.format(version=version, date=date))
    file.write("PRs with missing release notes label - please fix in Github\n")
    file.write("---\n")
    file.write("\n")
    if langs_pr["nolabel"]:
        langs_pr["nolabel"].sort()
        file.write("\n".join(langs_pr["nolabel"]))
    else:
        file.write("- None")
    file.write("\n")
    file.write("\n")
    file.write("PRs with missing lang label - please fix in Github\n")
    file.write("---\n")
    file.write("\n")
    if langs_pr["nolang"]:
        langs_pr["nolang"].sort()
        file.write("\n".join(langs_pr["nolang"]))
    else:
        file.write("- None")
    file.write("\n")
    file.write("\n")
    file.write(
        "PRs going into release notes - please check title and fix in Github. Do not edit here.\n"
    )
    file.write("---\n")
    file.write("\n")
    if langs_pr["inrel"]:
        langs_pr["inrel"].sort()
        file.write("\n".join(langs_pr["inrel"]))
    else:
        file.write("- None")
    file.write("\n")
    file.write("\n")
    file.write("PRs not going into release notes\n")
    file.write("---\n")
    file.write("\n")
    if langs_pr["notinrel"]:
        langs_pr["notinrel"].sort()
        file.write("\n".join(langs_pr["notinrel"]))
    else:
        file.write("- None")
    file.write("\n")
    file.write("\n")


def write_rel_notes(langs_pr, file, version, name):
    file.write(rl_header.format(version=version, name=name))
    if langs_pr["core"]:
        file.write("Core\n---\n\n")
        file.write("\n".join(langs_pr["core"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["c++"]:
        file.write("C++\n---\n\n")
        file.write("\n".join(langs_pr["c++"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["c#"]:
        file.write("C#\n---\n\n")
        file.write("\n".join(langs_pr["c#"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["go"]:
        file.write("Go\n---\n\n")
        file.write("\n".join(langs_pr["go"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["Java"]:
        file.write("Java\n---\n\n")
        file.write("\n".join(langs_pr["Java"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["node"]:
        file.write("Node\n---\n\n")
        file.write("\n".join(langs_pr["node"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["objc"]:
        file.write("Objective-C\n---\n\n")
        file.write("\n".join(langs_pr["objc"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["php"]:
        file.write("PHP\n---\n\n")
        file.write("\n".join(langs_pr["php"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["python"]:
        file.write("Python\n---\n\n")
        file.write("\n".join(langs_pr["python"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["ruby"]:
        file.write("Ruby\n---\n\n")
        file.write("\n".join(langs_pr["ruby"]))
        file.write("\n")
        file.write("\n")
    if langs_pr["other"]:
        file.write("Other\n---\n\n")
        file.write("\n".join(langs_pr["other"]))
        file.write("\n")
        file.write("\n")


def build_args_parser():
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument(
        'release_version', type=str, help='New release version e.g. 1.14.0')
    parser.add_argument(
        'release_name', type=str, help='New release name e.g. gladiolus')
    parser.add_argument(
        'release_date', type=str, help='Release date e.g. 7/30/18')
    parser.add_argument(
        'previous_release_label',
        type=str,
        help='Previous release branch/tag e.g. v1.13.x')
    parser.add_argument(
        'release_branch',
        type=str,
        help='Current release branch e.g. origin/v1.14.x')
    parser.add_argument(
        'draft_filename', type=str, help='Name of the draft file e.g. draft.md')
    parser.add_argument(
        'release_notes_filename',
        type=str,
        help='Name of the release notes file e.g. relnotes.md')
    parser.add_argument(
        '--token',
        type=str,
        default='',
        help='GitHub API token to avoid being rate limited')
    return parser


def main():
    import os
    global TOKEN

    parser = build_args_parser()
    args = parser.parse_args()
    version, name, date = args.release_version, args.release_name, args.release_date
    start, end = args.previous_release_label, args.release_branch

    TOKEN = args.token
    if TOKEN == '':
        try:
            TOKEN = os.environ["GITHUB_TOKEN"]
        except:
            pass
    if TOKEN == '':
        print(
            "Error: Github API token required. Either include param --token=<your github token> or set environment variable GITHUB_TOKEN to your github token"
        )
        return

    langs_pr, error_count = get_pr_titles(get_commit_log(start, end))

    draft_file, rel_file = args.draft_filename, args.release_notes_filename
    filename = os.path.abspath(draft_file)
    if os.path.exists(filename):
        file = open(filename, 'r+')
    else:
        file = open(filename, 'w')

    file.seek(0)
    write_draft(langs_pr, file, version, date)
    file.truncate()
    file.close()
    print("\nDraft notes written to " + filename)

    filename = os.path.abspath(rel_file)
    if os.path.exists(filename):
        file = open(filename, 'r+')
    else:
        file = open(filename, 'w')

    file.seek(0)
    write_rel_notes(langs_pr, file, version, name)
    file.truncate()
    file.close()
    print("\nRelease notes written to " + filename)
    if error_count > 0:
        print("\n\n*** Errors were encountered. See log. *********\n")


if __name__ == "__main__":
    main()