#!/bin/sh
#
# Usage:
#   gnc-vcs-info -r <srcdir>
#   gnc-vcs-info -d <srcdir>
#   gnc-vcs-info -t <srcdir>
#
# With -r prints the revision number to stdout and exits 0 on success
# With -d prints the commit date to stdout and exits 0 on success
# With -t prints the vcs type that was detected to stdout and exits 0
#         on success.
#
# Exits with errorcode 1 if we're not in a git work tree
#
# Written By:  Derek Atkins <derek@ihtfp.com>
# Updated By:  Geert Janssens <geert@kobaltwit.be>
#
# $Id$

# Default string to return if not invoked properly
usage="Usage: $0 -r <srcdir>
       $0 -d <srcdir>
       $0 -t <srcdir>"

# Print an error message and then exit
my_die()
{
  echo "$1"
  exit 1
}

if [ "$BUILDING_FROM_VCS" = "0" -o \
     "$BUILDING_FROM_VCS" = "no" -o \
     "$BUILDING_FROM_VCS" = "false" ]; then
  # Something outside of the Gnucash build system knows that we
  # are NOT building from a git work tree.
  # We should believe it (needed by packagers that maintain the
  # packaging code in git too)
  echo "Environment variable BUILDING_FROM_VCS=$BUILDING_FROM_VCS" >&2
  exit 1
fi

# Make sure we have a srcdir
[ -n "$1" ] || my_die "$usage"
[ -n "$2" ] || my_die "$usage"
[ -d "$2" ] || my_die "$0: $2: not a directory"


if [ "$1" = "-t" ]
then
  request="type"
elif [ "$1" = "-r" ]
then
  request="revision"
elif [ "$1" = "-d" ]
then
  request="date"
else
  my_die "$usage"
fi

srcdir=$2

# Find the real srcdir.
# This handles the case of a symlink (lndir) tree
# $real_srcdir will hold the actual source dir
if test -h "$srcdir"/CMakeLists.txt
then 
  tmp_srcdir=`readlink "$srcdir"/CMakeLists.txt`
  real_srcdir="$srcdir/`dirname ${tmp_srcdir}`"
else
  real_srcdir="$srcdir"
fi

# Test if this code is in a git worktree
real_gitdir="${real_srcdir}"/.git
if test -d "${real_gitdir}" || test -e "${real_gitdir}"
then
  # If we're only interested in the vcs type, then we're done here
  if [ "$request" = "type" ]
  then
    echo "git"
    exit 0
  fi

  # The windows build uses environment variable $GIT_CMD to invoke git (adding git
  # to the PATH in Windows results in a build failure).
  # So for platform independence, use GIT_CMD for all
  [ -n "$GIT_CMD" ] || GIT_CMD=git
  if [ "$request" = "date" ]
  then
    exec "$GIT_CMD" --git-dir "${real_gitdir}" log -1 --format=%cd --date=short
    exit 0
  fi

  githead=$("$GIT_CMD" --git-dir "${real_gitdir}" describe 2>/dev/null)
  rc=$?
  if [ $rc != 0 ]; then
    # On travis describe seems to fail due to missing tags in the git clone the system takes
    # So specifically to catch those errors, use only the short commit hash as a backup
    githead=$("$GIT_CMD" --git-dir "${real_gitdir}" log -1 --pretty=format:"%h" HEAD 2>/dev/null)
    rc=$?
  fi
  if [ $rc = 0 ]; then
    /bin/echo -n $githead
    # Add a "+" to the hash if there deleted or modified files (not excluded by .gitignore and friends)
    # "Ignores" untracked files
    # [ $("$GIT_CMD" --git-dir "${real_gitdir}" ls-files -dkm 2>/dev/null | wc -l) -gt 0 ] && /bin/echo -n "+"
    # Includes untracked files
    [ $("$GIT_CMD" --git-dir "${real_gitdir}" ls-files -dkmo --exclude-standard 2>/dev/null | wc -l) -gt 0 ] && /bin/echo -n "+"
    echo
    exit 0
  else
    exit 1
  fi
else
  exit 1
fi