#!/bin/bash

GITEXEC=`which git`

echo "gubllb --- GUB Local Lilypond Build"

# abort if not exactly 3 arguments are provided
if [ $# -ne 3 ]; then
  echo "ERROR: invalid number of command line arguments!"
  echo "USAGE: gubllb gub_directory lilypond_repository_directory lilypond_branch"
  exit 1
fi

GUBDIR=$1
LILYREPODIR=$2
LILYBRANCH=$3

echo "Trying to build branch '$LILYBRANCH' of local lilypond repository '$LILYREPODIR' with gub '$GUBDIR'"

# abort if a git-daemon is active
ps ax | grep git-daemon | grep -v grep | grep git-daemon
if [ $? -eq 0 ]; then
  echo "ERROR: A git-daemon is already running on this system!"
  exit 1
fi

# abort if GUBDIR parameter is invalid
if [ ! -f "$GUBDIR/bin/gub" ]; then
  echo "ERROR: gub_directory parameter '$GUBDIR' invalid!"
  exit 1
fi

# abort if LILYREPODIR parameter is invalid
if [ ! -f "$LILYREPODIR/lily/lilypond-version.cc" ]; then
  echo "ERROR: lilypond_repository_directory '$LILYREPODIR' invalid!"
  exit 1
fi

# abort if there is no  branch LILYBRANCH in  LILYREPODIR
cd $LILYREPODIR
TESTOUT=`git branch --list $LILYBRANCH | grep -o $LILYBRANCH`
if [ "$TESTOUT" != "$LILYBRANCH" ]; then
  echo "ERROR: lilypond branch '$LILYBRANCH'does not exist in '$LILYREPODIR' !"
  exit 1
fi

# create a temporary git server directory in GUBDIR, abort if this fails
TMPSRVDIR=$(mktemp -d -t -p $GUBDIR/ gubllb-XXXXXXXXXX)
if [ ! -d "$TMPSRVDIR" ]; then
  echo ERROR: We failed to created the directory $TMPSRVDIR!
  exit 1
else
  echo Temporary git daemon directory is $TMPSRVDIR
fi

# create the lilypong.git link in TMPSRVDIR
ln -s $LILYREPODIR $TMPSRVDIR/lilypond.git

# start git-daemon in the background
$GITEXEC daemon --log-destination=none --export-all --reuseaddr --base-path=$TMPSRVDIR/ $TMPSRVDIR &> /dev/null &
GITPID=$!
echo Started git daemon with PID $GITPID

# wait until git-daemon starts to provide its service ... abort if this does not occur within a reasonable time
i=0
while [ $i -le 10 ]
do
  ((i++))
  echo Waiting for git daemon ...
  TESTOUT=`git ls-remote git://localhost/lilypond.git $LILYBRANCH 2>&1 | grep -o refs/heads/$LILYBRANCH`
  if [ "$TESTOUT" == "refs/heads/$LILYBRANCH" ]; then
    break;
  fi
  if [ $i -eq 10 ]; then
    echo ERROR: Git daemon timed out or $LILYBRANCH does not exist!
    kill -n 9 -- $(ps -o pid= --ppid $GITPID)
    rm -rf $TMPSRVDIR
    exit 1
  fi
  sleep 1
done

# everything seems to be ok, build LILYBRANCH
cd  $GUBDIR
make LILYPOND_REPO_URL=git://localhost/lilypond.git LILYPOND_BRANCH=$LILYBRANCH lilypond


# kill our git daemon and remove our temporary git server directory
kill -n 9 -- $(ps -o pid= --ppid $GITPID)
rm -rf $TMPSRVDIR