#!/usr/bin/env python

#

# Copyright 2014 Matt Mackall <mpm@selenic.com>

#

# A tool/hook to run basic sanity checks on commits/patches for

# submission to Mercurial. Install by adding the following to your

# .hg/hgrc:

#

# [hooks]

# pretxncommit = contrib/check-commit

#

# The hook can be temporarily bypassed with:

#

# $ BYPASS= hg commit

#

# See also: https://mercurial-scm.org/wiki/ContributingChanges

from __future__ import absolute_import, print_function

import os

import re

import sys

commitheader = r"^(?:# [^\n]*\n)*"

afterheader = commitheader + r"(?!#)"

beforepatch = afterheader + r"(?!\n(?!@@))"

errors = [

    (beforepatch + r".*[(]bc[)]", "(BC) needs to be uppercase"),

    (beforepatch + r".*[(]issue \d\d\d",

     "no space allowed between issue and number"),

    (beforepatch + r".*[(]bug(\d|\s)", "use (issueDDDD) instead of bug"),

    (commitheader + r"# User [^@\n]+\n", "username is not an email address"),

    (commitheader + r"(?!merge with )[^#]\S+[^:] ",

     "summary line doesn't start with 'topic: '"),

    (afterheader + r"[A-Z][a-z]\S+", "don't capitalize summary lines"),

    (afterheader + r"[^\n]*: *[A-Z][a-z]\S+", "don't capitalize summary lines"),

    (afterheader + r"\S*[^A-Za-z0-9-_]\S*: ",

     "summary keyword should be most user-relevant one-word command or topic"),

    (afterheader + r".*\.\s*\n", "don't add trailing period on summary line"),

    (afterheader + r".{79,}", "summary line too long (limit is 78)"),

    (r"\n\+\n( |\+)\n", "adds double empty line"),

    (r"\n \n\+\n", "adds double empty line"),

    # Forbid "_" in function name.

    #

    # We skip the check for cffi related functions. They use names mapping the

    # name of the C function. C function names may contain "_".

    (r"\n\+[ \t]+def (?!cffi)[a-z]+_[a-z]",

     "adds a function with foo_bar naming"),

]

word = re.compile('\S')

def nonempty(first, second):

    if word.search(first):

        return first

    return second

def checkcommit(commit, node=None):

    exitcode = 0

    printed = node is None

    hits = []

    signtag = (afterheader +

          r'Added (tag [^ ]+|signature) for changeset [a-f0-9]{12}')

    if re.search(signtag, commit):

        return 0

    for exp, msg in errors:

        for m in re.finditer(exp, commit):

            end = m.end()

            trailing = re.search(r'(\\n)+$', exp)

            if trailing:

                end -= len(trailing.group()) / 2

            hits.append((end, exp, msg))

    if hits:

        hits.sort()

        pos = 0

        last = ''

        for n, l in enumerate(commit.splitlines(True)):

            pos += len(l)

            while len(hits):

                end, exp, msg = hits[0]

                if pos < end:

                    break

                if not printed:

                    printed = True

                    print("node: %s" % node)

                print("%d: %s" % (n, msg))

                print(" %s" % nonempty(l, last)[:-1])

                if "BYPASS" not in os.environ:

                    exitcode = 1

                del hits[0]

            last = nonempty(l, last)

    return exitcode

def readcommit(node):

    return os.popen("hg export %s" % node).read()

if __name__ == "__main__":

    exitcode = 0

    node = os.environ.get("HG_NODE")

    if node:

        commit = readcommit(node)

        exitcode = checkcommit(commit)

    elif sys.argv[1:]:

        for node in sys.argv[1:]:

            exitcode |= checkcommit(readcommit(node), node)

    else:

        commit = sys.stdin.read()

        exitcode = checkcommit(commit)

    sys.exit(exitcode)