#!/usr/bin/sh

print_usage_and_exit() {
	echo "Usage: $0 [-d <date>] [-p <path>]"
	echo ""
	echo "Searches for DM files never edited since a threshold date."
	echo ""
	echo "Arguments:"
	echo "  -d, --date <date>  Threshold date to use, defaults to 2013-01-01."
	echo "  -p, --path <path>  Path inside the git repository to search in."
	echo "  -h, --help         Show this help message."

	exit 0
}

# Parse arguments
THRESHOLD_DATE="2013-01-01"
FOLDER_TO_SEARCH="$PWD"

while [[ $# > 0 ]]; do
	arg="$1"
	case $arg in
		-d|--date)
		THRESHOLD_DATE="$2"
		shift
		;;

		-p|--path)
		FOLDER_TO_SEARCH="$2"
		shift
		;;

		-h|--help)
		print_usage_and_exit
		;;

		*) # default
		echo "Unknown argument found: $arg"
		print_usage_and_exit
		;;
	esac
	shift
done

# Check whether $FOLDER_TO_SEARCH is a git repository and get the root directory
FOLDER_TO_SEARCH=$(git -C "$FOLDER_TO_SEARCH" rev-parse --show-toplevel)
[[ $? -ne 0 ]] && exit 0 # return code is non-zero on failure

# Do stuff
TMP_GITLOG=$(mktemp)
TMP_FIND=$(mktemp)

git -C "$FOLDER_TO_SEARCH" log --name-only --after="$THRESHOLD_DATE" --pretty='tformat:' | grep -E '\.dm$' | sort | uniq > "$TMP_GITLOG"
( cd "$FOLDER_TO_SEARCH" && find . -iname '*.dm' -type f ) | sed 's/^\.\///' | sort > "$TMP_FIND"

# Supress files only in $TMP_GITLOG (i.e. files that no longer exist) and in both $TMP_GITLOG
# and $TMP_FIND (i.e. changed after $THRESHOLD_DATE)
comm -1 -3 "$TMP_GITLOG" "$TMP_FIND"