#!/usr/bin/env bash

SKIP_FILES="(Marshal.c|Marshal_fp.h)"


NO_MELD_FLAG=$((1<<0))

help()
{
	cat <<_EOF_
Usage: TCG_TPM_HOME=... $1 [options] TPM2-directory

The following options are available:

--no-meld,--diff-only   : Only display diffs between files; the first two lines
                          are related to the license and are ignore for the diff.
--help                  : Display this help screen and exit.

The environmet variable TCG_TPM_HOME must be set and point to
the TCG TPM2 git checkout.

Example:

TCG_TPM_HOME=\$HOME/TPM $1 --diff-only src/tpm2

_EOF_
}

main()
{
	local opts f fname upstream flags

	flags=0

	prgname="$0"
	if ! opts=$(getopt -l "help,no-meld,diff-only" -n "$prgname" -- "$prgname" "$@"); then
		echo "Error: Failed to parse options." >&2
		return 1
	fi
	eval set -- "${opts}"

	while :; do
		case "$1" in
			--no-meld|--diff-only)
				flags=$((flags | NO_MELD_FLAG))
				shift
				;;
			--)
				shift
				break
				;;
			--help)
				help "$prgname"
				return 0
				;;
			*)
				echo "Internal error: Unregonized option '$1'" >&2
				shift
				return
				;;
		esac
	done

	if [ ! -r "$1" ]; then
		echo "Cannot find file '$1' in libtpms repo."
		exit 1
	fi

	if [ ! -d "$1" ]; then
		echo "'$1' is not a directory."
		exit 1
	fi

	if [ ! -d "${TCG_TPM_HOME}" ]; then
		echo "TCG_TPM_HOME must point to a directory."
		exit 1
	fi

	for f in \
		$(find "$1" -type f -name '*.[ch]') \
		$(find "$1" -type f -name '*.inl'); do
		fname=$(basename "$f")

		if [[ "${fname}" =~ ^${SKIP_FILES}$ ]]; then
			echo "skipping ${fname}"
			continue
		fi

		fn=${f:${#1}}
		upstream="${TCG_TPM_HOME}/${fn}"
		#echo "$upstream"

		if [ -n "${upstream}" ]; then
			# find first empty line presumably after license
			line=$(grep -m 1 -E "^$" -n "${f}" | cut -d":" -f1)
			if [ -z "$line" ]; then
				if [ $((flags & NO_MELD_FLAG)) -eq 0 ]; then
					meld "${upstrean}" "${f}"
				else
					echo "Something is wrong with file $f"
				fi
			fi
			line=$((line+1))
			if [ $((flags & NO_MELD_FLAG)) -ne 0 ]; then
				echo "============================================================================"
				if [ ! -f "${upstream}" ]; then
					echo "${f}: file does not exist upstream"
				else
					echo "${f}"
					diff --ignore-trailing-space <(sed -n "${line},\$p" < "${f}") "${upstream}"
				fi
			fi
			if ! diff --ignore-trailing-space <(sed -n "${line},\$p" < "${f}") "${upstream}" &>/dev/null; then
				if [ $((flags & NO_MELD_FLAG)) -eq 0 ]; then
					meld "${upstream}" "$f"
				fi
			else
				echo "${f}: nothing to do"
			fi
		else
			echo "Could not find file ${fname} in TCG TPM repo"
		fi
	done
}

main "$@"
exit $?