#!/bin/bash

# Usage: git_revision.sh <output_dir>
# Generates git-revision.h in the specified output directory.

OUTPUT_DIR="${1:-.}"

echo "-- Generating header for git hash"
GIT_HEADER="${OUTPUT_DIR}/git-revision.h"
[ -d "${OUTPUT_DIR}" ] || mkdir -p "${OUTPUT_DIR}"

GIT_BRANCH=`git rev-parse --abbrev-ref HEAD`

GIT_VERSION=`git log -n 1 --pretty=format:"%ad - %h"`
if [ -f "$GIT_HEADER" ] && [ "$(grep -cs "$GIT_VERSION" "$GIT_HEADER")" = 1 ]
then
   echo "-- No need to generate new $GIT_HEADER - git hash is unchanged"
   exit 0;
fi

echo "-- git branch is  : " $GIT_BRANCH
echo "-- git version is : " $GIT_VERSION

echo "#ifndef GIT_VERSION_H" > $GIT_HEADER
echo "#define GIT_VERSION_H" >> $GIT_HEADER
echo "" >> $GIT_HEADER
echo "#define GIT_BRANCH \"$GIT_BRANCH\"" >> $GIT_HEADER
echo "#define GIT_CURRENT_SHA1 \"$GIT_VERSION\"" >> $GIT_HEADER
echo "" >> $GIT_HEADER
echo "#endif //GIT_VERSION_H" >> $GIT_HEADER

echo "-- file is generated into" $GIT_HEADER