#!/usr/bin/env python
#
# Licensed to the Apache Software Foundation (ASF) under one
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# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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.

import argparse
import collections
import compile_flags
import json
import logging
import multiprocessing
from multiprocessing.pool import ThreadPool
import os
import re
import subprocess
import sys
import unittest
import tempfile

from kudu_util import init_logging

ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))

CLANG_TIDY_DIFF = os.path.join(
    ROOT, "thirdparty/installed/uninstrumented/share/clang/clang-tidy-diff.py")
CLANG_TIDY = os.path.join(
    ROOT, "thirdparty/clang-toolchain/bin/clang-tidy")

GERRIT_USER = 'tidybot'
GERRIT_PASSWORD = os.getenv('TIDYBOT_PASSWORD')

GERRIT_URL = "https://gerrit.cloudera.org"

DISABLED_TIDY_CHECKS=[
    # Although useful in production code, we use magic numbers liberally in
    # tests, and many would be net less clear as named constants.
    'readability-magic-numbers',

    # IWYU has specific rules for ordering '-inl.h' include files, i.e.
    # 'header.h' and its 'header-inl.h' counterpart. It seems in some cases
    # including 'header-inl.h' before 'header.h' might even lead to compilation
    # failures. So, IWYU intentionally re-orders them even if 'header-inl.h'
    # comes before 'header.h' lexicographically in default C locale:
    #   https://github.com/apache/kudu/blob/ \
    #     89ce529e945731c48445db4a6f8af11f9f905aab/build-support/iwyu/ \
    #     fix_includes.py#L1786-L1787
    #
    # That ordering contradicts with what clang-tidy recommends when using the
    # 'llvm-include-order' check. To avoid confusion, let's disable the
    # 'llvm-include-order'.
    #
    # TODO(aserbin): clarify whether it's possible to customize clang-tidy
    #                behavior w.r.t. the sorting of such header files using
    #                the format style options described at
    #                https://clang.llvm.org/docs/ClangFormatStyleOptions.html
    'llvm-include-order',
]

def run_tidy(sha="HEAD", is_rev_range=False):
    diff_cmdline = ["git", "diff" if is_rev_range else "show", sha]

    # Figure out which paths changed in the given diff.
    changed_paths = subprocess.check_output(diff_cmdline + ["--name-only", "--pretty=format:"]).splitlines()
    changed_paths = [p for p in changed_paths if p]

    # Produce a separate diff for each file and run clang-tidy-diff on it
    # in parallel.
    def tidy_on_path(path):
        patch_file = tempfile.NamedTemporaryFile()
        cmd = diff_cmdline + [
            "--src-prefix=%s/" % ROOT,
            "--dst-prefix=%s/" % ROOT,
            "--",
            path]
        subprocess.check_call(cmd, stdout=patch_file, cwd=ROOT)
        checks_arg_value = ",".join([ "-" + c for c in DISABLED_TIDY_CHECKS ])
        cmdline = [CLANG_TIDY_DIFF,
                   "-clang-tidy-binary", CLANG_TIDY,
                   "-p0",
                   "-checks=" + checks_arg_value,
                   "--",
                   "-DCLANG_TIDY"] + compile_flags.get_flags()
        return subprocess.check_output(
            cmdline,
            stdin=file(patch_file.name),
            cwd=ROOT)
    pool = ThreadPool(multiprocessing.cpu_count())
    try:
        return "".join(pool.imap(tidy_on_path, changed_paths))
    except KeyboardInterrupt as ki:
        sys.exit(1)
    finally:
        pool.terminate()
        pool.join()


def split_warnings(clang_output):
    accumulated = ""
    for l in clang_output.splitlines():
        if l == "" or l == "No relevant changes found.":
            continue
        if l.startswith(ROOT) and re.search(r'(warning|error): ', l):
            if accumulated:
                yield accumulated
            accumulated = ""
        accumulated += l + "\n"
    if accumulated:
        yield accumulated


def parse_clang_output(clang_output):
    ret = []
    for w in split_warnings(clang_output):
        m = re.match(r"^(.+?):(\d+):\d+: ((?:warning|error): .+)$", w, re.MULTILINE | re.DOTALL)
        if not m:
            raise Exception("bad warning: " + w)
        path, line, warning = m.groups()
        ret.append(dict(
            path=os.path.relpath(path, ROOT),
            line=int(line),
            warning=warning.strip()))
    return ret

def create_gerrit_json_obj(parsed_warnings):
    comments = collections.defaultdict(lambda: [])
    for warning in parsed_warnings:
        comments[warning['path']].append({
            'line': warning['line'],
            'message': warning['warning']
            })
    return {"comments": comments,
            "notify": "OWNER",
            "omit_duplicate_comments": "true"}


def get_gerrit_revision_url(git_ref):
    sha = subprocess.check_output(["git", "rev-parse", git_ref]).strip()

    commit_msg = subprocess.check_output(
        ["git", "show", sha])
    matches = re.findall(r'^\s+Change-Id: (I.+)$', commit_msg, re.MULTILINE)
    if not matches:
        raise Exception("Could not find gerrit Change-Id for commit %s" % sha)
    if len(matches) != 1:
        raise Exception("Found multiple gerrit Change-Ids for commit %s" % sha)
    change_id = matches[0]
    return "%s/a/changes/%s/revisions/%s" % (GERRIT_URL, change_id, sha)


def post_comments(revision_url_base, gerrit_json_obj):
    import requests
    r = requests.post(revision_url_base + "/review",
                      auth=(GERRIT_USER, GERRIT_PASSWORD),
                      data=json.dumps(gerrit_json_obj),
                      headers={'Content-Type': 'application/json'})
    print "Response:"
    print r.headers
    print r.status_code
    print r.text


class TestClangTidyGerrit(unittest.TestCase):
    TEST_INPUT = \
"""
No relevant changes found.

/home/todd/git/kudu/src/kudu/integration-tests/tablet_history_gc-itest.cc:579:55: warning: some warning [warning-name]
   some example line of code

/home/todd/git/kudu/foo/../src/kudu/blah.cc:123:55: error: some error
   blah blah

No relevant changes found.
"""

    def test_parse_clang_output(self):
        global ROOT
        save_root = ROOT
        try:
            ROOT = "/home/todd/git/kudu"
            parsed = parse_clang_output(self.TEST_INPUT)
        finally:
            ROOT = save_root
        self.assertEqual(2, len(parsed))

        self.assertEqual("src/kudu/integration-tests/tablet_history_gc-itest.cc", parsed[0]['path'])
        self.assertEqual(579, parsed[0]['line'])
        self.assertEqual("warning: some warning [warning-name]\n" +
                         "   some example line of code",
                         parsed[0]['warning'])

        self.assertEqual("src/kudu/blah.cc", parsed[1]['path'])


if __name__ == "__main__":
    # Basic setup and argument parsing.
    init_logging()
    parser = argparse.ArgumentParser(
        description="Run clang-tidy on a patch, optionally posting warnings as comments to gerrit")
    parser.add_argument("-n", "--no-gerrit", action="store_true",
                        help="Whether to run locally i.e. (no interaction with gerrit)")
    parser.add_argument("--rev-range", action="store_true",
                        default=False,
                        help="Whether the revision specifies the 'rev..' range")
    parser.add_argument('rev', help="The git revision (or range of revisions) to process")
    args = parser.parse_args()

    if args.rev_range and not args.no_gerrit:
        print >>sys.stderr, "--rev-range works only with --no-gerrit"
        sys.exit(1)

    # Find the gerrit revision URL, if applicable.
    if not args.no_gerrit:
        revision_url = get_gerrit_revision_url(args.rev)
        print revision_url

    # Run clang-tidy and parse the output.
    clang_output = run_tidy(args.rev, args.rev_range)
    logging.info("Clang output")
    logging.info(clang_output)
    if args.no_gerrit:
        print >>sys.stderr, "Skipping gerrit"
        sys.exit(0)
    logging.info("=" * 80)
    parsed = parse_clang_output(clang_output)
    if not parsed:
        print >>sys.stderr, "No warnings"
        sys.exit(0)
    print "Parsed clang warnings:"
    print json.dumps(parsed, indent=4)

    # Post the output as comments to the gerrit URL.
    gerrit_json_obj = create_gerrit_json_obj(parsed)
    print "Will post to gerrit:"
    print json.dumps(gerrit_json_obj, indent=4)
    post_comments(revision_url, gerrit_json_obj)