# TODO: Document this and how it interacts with AddDatafile.

set(ADD_DOWNLOADABLE_RESOURCE_SCRIPT ${CMAKE_CURRENT_LIST_DIR}/download_resource.cmake.in)
function(add_downloadable_resource)
	set(RESOURCE_TARGET ${ARGV0})
	cmake_parse_arguments(
		PARSE_ARGV 1
		RESOURCE
		""
		"ARCHIVE;DIRECTORY;BASE_URL;SHA1"
		""
		)
	if(NOT DEFINED RESOURCE_ARCHIVE)
		set(RESOURCE_ARCHIVE ${RESOURCE_TARGET}.tar.xz)
	endif()
	if(NOT DEFINED RESOURCE_BASE_URL)
		set(RESOURCE_BASE_URL https://ftp.ignore.pl/starshatter/resources/latest)
	endif()
	if(NOT DEFINED RESOURCE_DIRECTORY)
		set(RESOURCE_DIRECTORY ${RESOURCE_TARGET}.d)
	endif()
	cmake_path(ABSOLUTE_PATH RESOURCE_ARCHIVE NORMALIZE BASE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
	cmake_path(ABSOLUTE_PATH RESOURCE_DIRECTORY NORMALIZE BASE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
	cmake_path(GET RESOURCE_ARCHIVE FILENAME RESOURCE_ARCHIVE_BASENAME)
	string(REGEX REPLACE "/$" "" RESOURCE_BASE_URL "${RESOURCE_BASE_URL}")
	set(DOWNLOAD_SCRIPT ${CMAKE_CURRENT_BINARY_DIR}/download_${RESOURCE_TARGET}.cmake)
	configure_file(${ADD_DOWNLOADABLE_RESOURCE_SCRIPT} ${DOWNLOAD_SCRIPT} @ONLY)
	add_custom_target(
		download_${RESOURCE_TARGET}
		COMMENT "Downloading ${RESOURCE_TARGET}"
		COMMAND ${CMAKE_COMMAND} -P ${DOWNLOAD_SCRIPT}
		)
	add_custom_target(
		clean_downloaded_${RESOURCE_TARGET}
		COMMENT "Removing downloaded ${RESOURCE_TARGET}"
		COMMAND ${CMAKE_COMMAND} -E rm -f ${RESOURCE_ARCHIVE}
		COMMAND ${CMAKE_COMMAND} -E remove_directory ${RESOURCE_DIRECTORY}
		)
	add_custom_command(
		OUTPUT ${RESOURCE_DIRECTORY}
		DEPENDS download_${RESOURCE_TARGET}
		COMMENT "Unpacking ${RESOURCE_TARGET}"
		COMMAND ${CMAKE_COMMAND} -E make_directory ${RESOURCE_DIRECTORY}
		COMMAND
			${CMAKE_COMMAND} -E chdir ${RESOURCE_DIRECTORY}
			${CMAKE_COMMAND} -E tar xf ${RESOURCE_ARCHIVE}
		)
	add_custom_target(${RESOURCE_TARGET} DEPENDS ${RESOURCE_DIRECTORY})
endfunction()