#! /bin/sh
set -euf

config_file="$GL_ADMIN_BASE/conf/irc-announce.conf"
if test -f "$config_file"; then
  . "$config_file"
fi

# XXX when changing IRC_CHANNEL or IRC_SERVER/_PORT, don't forget to update
#     any relevant gitolite LOCAL_CODE!
# CAVEAT we hope that IRC_NICK is unique
IRC_NICK="${IRC_NICK-gl$GL_TID}"
IRC_CHANNEL="${IRC_CHANNEL-#retiolum}"
IRC_SERVER="${IRC_SERVER-ire.retiolum}"
IRC_PORT="${IRC_PORT-6667}"

# for privmsg_cat below
export IRC_CHANNEL

# collect users that are mentioned in the gitolite configuration
interested_users="$(perl -e '
  do "gl-conf";
  print join(" ", keys%{ $one_repo{$ENV{"GL_REPO"}} });
')"

# CAVEAT beware of real TABs in grep pattern!
# CAVEAT there will never be more than 42 relevant log entries!
log="$(tail -n 42 "$GL_LOGFILE" | grep "^[^	]*	$GL_TID	")"
update_log="$(echo "$log" | grep "^[^	]*	$GL_TID	update")"

# (debug output)
env | sed 's/^/env: /'
echo "$log" | sed 's/^/log: /'

# see http://gitolite.com/gitolite/dev-notes.html#lff
reponame=$(echo "$update_log" | cut -f 4)
username=$(echo "$update_log" | cut -f 5)
ref_name=$(echo "$update_log" | cut -f 7 | sed 's|^refs/heads/||')
old_sha=$(echo "$update_log" | cut -f 8)
new_sha=$(echo "$update_log" | cut -f 9)

# check if new branch is created
if test $old_sha = 0000000000000000000000000000000000000000; then
  # TODO what should we really show?
  old_sha=$new_sha^
fi

#
git_log="$(git log $old_sha..$new_sha --pretty=oneline --abbrev-commit)"
commit_count=$(echo "$git_log" | wc -l)

# echo2 and cat2 are used output to both, stdout and stderr
# This is used to see what we send to the irc server. (debug output)
echo2() { echo "$*"; echo "$*" >&2; }
cat2() { tee /dev/stderr; }

# privmsg_cat transforms stdin to a privmsg
privmsg_cat() { awk '{ print "PRIVMSG "ENVIRON["IRC_CHANNEL"]" :"$0 }'; }

# ircin is used to feed the output of netcat back to the "irc client"
# so we can implement expect-like behavior with sed^_^
# XXX mkselfdestructingtmpfifo would be nice instead of this cruft
tmpdir="$(mktemp -d irc-announce_XXXXXXXX)"
cd "$tmpdir"
mkfifo ircin
trap "
  rm ircin
  cd '$OLDPWD'
  rmdir '$tmpdir'
  trap - EXIT INT QUIT
" EXIT INT QUIT

#
#
#
{
  echo2 "USER $LOGNAME 0 * :$LOGNAME@$(hostname)"
  echo2 "NICK $IRC_NICK"

  # wait for MODE message
  sed -n '/^:[^ ]* MODE /q'

  echo2 "JOIN $IRC_CHANNEL"

  echo "$interested_users" \
    | tr ' ' '\n' \
    | grep -v "^$GL_USER" \
    | sed 's/$/: poke/' \
    | privmsg_cat \
    | cat2

  printf '[13%s] %s pushed %s new commit%s to 6%s %s\n' \
      "$reponame" \
      "$username" \
      "$commit_count" \
      "$(test $commit_count = 1 || echo s)" \
      "$(hostname)" \
      "$ref_name" \
    | privmsg_cat \
    | cat2

  echo "$git_log" \
    | sed 's/^/14/;s/ / /' \
    | privmsg_cat \
    | cat2

  echo2 "PART $IRC_CHANNEL"

  # wait for PART confirmation
  sed -n '/:'"$IRC_NICK"'![^ ]* PART /q'

  echo2 'QUIT :Gone to have lunch'
} < ircin \
  | nc "$IRC_SERVER" "$IRC_PORT" | tee -a ircin