function(get_version_from_file VERSION_MAJOR VERSION_MINOR VERSION_PATCH)
	file(STRINGS "Version.txt" VERSION_STR)
	foreach(STR ${VERSION_STR})
		if(${STR} MATCHES "OR_TOOLS_MAJOR=(.*)")
			set(${VERSION_MAJOR} ${CMAKE_MATCH_1} PARENT_SCOPE)
		endif()
		if(${STR} MATCHES "OR_TOOLS_MINOR=(.*)")
			set(${VERSION_MINOR} ${CMAKE_MATCH_1} PARENT_SCOPE)
		endif()
	endforeach()
	set(${VERSION_PATCH} 999 PARENT_SCOPE)
endfunction()

function(get_version_from_git VERSION_MAJOR VERSION_MINOR VERSION_PATCH)
	find_package(Git QUIET)
	if(NOT GIT_FOUND)
		message(STATUS "Did not find git package, get version from file...")
		get_version_from_file(MAJOR MINOR PATCH)
	else()
		execute_process(COMMAND
			${GIT_EXECUTABLE}
			"describe" "--tags"
			RESULT_VARIABLE _OUTPUT_VAR
			OUTPUT_VARIABLE FULL
			ERROR_QUIET)
		if(NOT _OUTPUT_VAR)
			execute_process(COMMAND
				${GIT_EXECUTABLE}
				"rev-list" "HEAD" "--count"
				RESULT_VARIABLE _OUTPUT_VAR
				OUTPUT_VARIABLE PATCH
				ERROR_QUIET)
			STRING(STRIP PATCH ${PATCH})
			STRING(REGEX REPLACE "\n$" "" PATCH ${PATCH})
			STRING(REGEX REPLACE " " "" PATCH ${PATCH})
			STRING(REGEX REPLACE "^v([0-9]+)\\..*" "\\1" MAJOR "${FULL}")
			STRING(REGEX REPLACE "^v[0-9]+\\.([0-9]+).*" "\\1" MINOR "${FULL}")
		else()
			message(STATUS "Did not find any tag")
			get_version_from_file(MAJOR MINOR PATCH)
		endif()
	endif()
	set(${VERSION_MAJOR} ${MAJOR} PARENT_SCOPE)
	set(${VERSION_MINOR} ${MINOR} PARENT_SCOPE)
	set(${VERSION_PATCH} ${PATCH} PARENT_SCOPE)
endfunction()

function(set_version VERSION)
	get_filename_component(GIT_DIR ".git" ABSOLUTE)
	if(EXISTS ${GIT_DIR})
		get_version_from_git(MAJOR MINOR PATCH)
	else()
		get_version_from_file(MAJOR MINOR PATCH)
	endif()
	set(${VERSION} "${MAJOR}.${MINOR}.${PATCH}" PARENT_SCOPE)
endfunction()

function(check_target my_target)
	if(NOT TARGET ${my_target})
		message(FATAL_ERROR " Or-Tools: compiling Or-Tools requires a ${my_target}
		CMake target in your project, see CMake/README.md for more details")
	endif(NOT TARGET ${my_target})
endfunction()
