#!/bin/sh
#
# fbi-announce — announce Git commits to the FBI mail-to-IRC gateway
#
# Copyright (c) 2006 Fernando J. Pereda <ferdy@gentoo.org>
# Copyright (c) 2008 Joerg Jaspert <joerg@debian.org>
# Copyright © 2009–2010 martin f. krafft <madduck@debian.org>
#
# Distributed under the terms of the GNU General Public License v2
#
# This script is based on Git ciabot.pl by Petr Baudis.
#
#
#
# The script is meant to be configured using git-config with the following keys:
#   hooks.fbi-project         the project name known to FBI
#   hooks.fbi-component       an optional component name
#   hooks.fbi-url-template    the template to the gitweb URL (containing @@sha1@@)
#   hooks.fbi-emailsender     the sender address to use in the email
#   hooks.fbi-emailcc         carbon-copy recipients (comma-separated) if the message
#   hooks.fbi-refwidth        the width of references to show (default 7)
#   hooks.fbi-noisy           include the entire log message in the announcement
#   hooks.fbi-msg-template    the template for the message to be sent (default:
#                               {@@component@@/}@@project@@[@@ref@@]: @@author@@: \
#                               @@logmessage@@ [@@url@@])
#
# The hook is meant ot be run from the Git post-receive hook.
#
set -eu

# we need to ensure we know $GIT_DIR for the git-config calls
GIT_DIR=$(git rev-parse --git-dir 2>/dev/null)
if [ -z "$GIT_DIR" ]; then
  echo >&2 "E: post-receive: GIT_DIR not set"
  exit 1
fi
export GIT_DIR

project=$(git config hooks.fbi-project 2>/dev/null) || {
  echo >&2 "E: FBI project not set (hooks.fbi-project)"
  exit 1
}
component=$(git config hooks.fbi-component 2>/dev/null ||:)
url=$(git config hooks.fbi-url-template 2>/dev/null ||:)
noisy=$(git config hooks.fbi-noisy 2>/dev/null || echo false)
from=$(git config hooks.fbi-emailsender 2>/dev/null ||:)
to="commit@commit.ganneff.de" #TODO: possibly factor out to config
cc=$(git config hooks.fbi-emailcc 2>/dev/null ||:)

# mail submission client to use
if [ -n "${FBI_ANNOUNCE_TO_STDOUT:-}" ]; then
  sendmail="cat"
  echo >&2 'I: outputting to stdout since $FBI_ANNOUNCE_TO_STDOUT is set.'
else
  sendmail="/usr/sbin/sendmail -t"
fi

if [ $# -eq 0 ] ; then
  # figure out refs from HEAD since they aren't passed
  refname=$(git symbolic-ref HEAD 2>/dev/null)
  merged=$(git rev-parse HEAD)
else
  refname=$1
  merged=$(git rev-parse $2)
fi
refname=${refname##refs/heads/}
refwidth=$(git config hooks.fbi-refwidth 2>/dev/null || echo 7)
ref=$(git describe ${merged} 2>/dev/null || echo ${merged} | cut -c1-${refwidth})

url=$(echo "$url" | sed -e "s,@@sha1@@,${merged},")

rawcommit=$(git cat-file commit ${merged})
author=$(echo "${rawcommit}" | sed -rne 's,^author (.+) <.*,\1,p')
logmessage=$(echo "${rawcommit}" | sed -e '1,/^$/d')
${noisy} || logmessage=$(echo "${logmessage}" | head -n2)

ts=$(echo "${rawcommit}" | sed -n -e '/^author .*> \([0-9]\+\).*$/s--\1-p')
ts=$(date -d "@${ts}")

msg=$(git config hooks.fbi-msg-template 2>/dev/null ||:)
if [ -z "${msg}" ]; then
  msg="${component:+$component/}${refname}[${ref}]: ${author}: ${logmessage} [${url}]"
else
  msg=$(echo "$msg" | sed -re 's,@@([^@]+)@@,${\1},g')
  eval "msg=\"$msg\""
fi

# trim $msg of empty []'s in case no URL was provided, might be better done in
# the above by making the generation conditional, but this will also do for
# now.
msg="${msg% []}"

${sendmail} <<_eom
${from:+From: ${from}
}To: ${to}
${cc:+Cc: ${cc}
}Subject: Announce ${project}
Message-Id: <fbi-announce.${project}.${ref}@$(hostname --fqdn)>
Content-type: text/plain; charset=utf-8

${msg}
_eom