if(NOT EXISTS ${GIT_EXECUTABLE})
	unset(GIT_EXECUTABLE CACHE)
endif()

find_package(Git)
if(Git_FOUND)
	set(GIT_EXECUTABLE ${GIT_EXECUTABLE} CACHE INTERNAL "" FORCE)
else()
	message(FATAL_ERROR "Failed to find git.")
endif()

function(CloneExternalLib name url branch shallow_exclude)
	set(external_folder "${CMAKE_CURRENT_SOURCE_DIR}")
	set(external_lib_folder "${external_folder}/${name}")

	if(EXISTS ${external_lib_folder})
		message(STATUS "Removing ${external_lib_folder}...")
		file(REMOVE_RECURSE ${external_lib_folder})
	endif()

	message(STATUS "Cloning ${name}...")
	set(branch_param "")
	set(branch_name_param "")
	if(NOT ("x${branch}" STREQUAL "x"))
		set(branch_param "-b")
		set(branch_name_param "${branch}")
	endif()
	set(shallow_exclude_param "")
	if(NOT ("x${shallow_exclude}" STREQUAL "x"))
		set(shallow_exclude_param "--shallow-exclude=${shallow_exclude}")
	endif()
	execute_process(COMMAND "${GIT_EXECUTABLE}" "clone" ${url} ${branch_param} ${branch_name_param} ${shallow_exclude_param} "${name}" "-n" WORKING_DIRECTORY "${external_folder}")
endfunction()

function(CheckoutExternalLib name rev)
	set(external_folder "${CMAKE_CURRENT_SOURCE_DIR}")
	set(external_lib_folder "${external_folder}/${name}")

	execute_process(COMMAND "${GIT_EXECUTABLE}" "checkout" "-q" ${rev} WORKING_DIRECTORY ${external_lib_folder} RESULT_VARIABLE checkout_err)
	set(${ARGV2} ${checkout_err} PARENT_SCOPE)
endfunction()

function(UpdateExternalLib name url rev)
	set(external_folder "${CMAKE_CURRENT_SOURCE_DIR}")
	set(external_lib_folder "${external_folder}/${name}")

	if(EXISTS "${external_lib_folder}/.git")
		set(need_clone FALSE)

		set(cached_rev_file_name "${CMAKE_CURRENT_BINARY_DIR}/KLAYGE_${name}_REV")
		if(EXISTS "${cached_rev_file_name}")
			file(STRINGS "${cached_rev_file_name}" cached_rev)
		else()
			set(cached_rev "")
		endif()
		IF("${cached_rev}" STREQUAL "${rev}")
			set(need_checkout FALSE)
		else()
			message(STATUS "Updating ${name} to revision ${rev}...")
			execute_process(COMMAND "${GIT_EXECUTABLE}" "fetch" "origin" WORKING_DIRECTORY ${external_lib_folder})
			execute_process(COMMAND "${GIT_EXECUTABLE}" "rev-parse" "HEAD" WORKING_DIRECTORY ${external_lib_folder} OUTPUT_VARIABLE head_rev)
			string(STRIP ${head_rev} head_rev)
			if (${head_rev} STREQUAL ${rev})
				set(need_checkout FALSE)
			else()
				set(need_checkout TRUE)
			endif()
			file(WRITE "${cached_rev_file_name}" ${rev})
		endif()
	else()
		set(need_clone TRUE)
	endif()

	if(need_clone)
		CloneExternalLib(${name} ${url} "${ARGV3}" "${ARGV4}")
		set(need_checkout TRUE)
	endif()

	if(need_checkout)
		message(STATUS "Checking out to revision ${rev}...")
		CheckoutExternalLib(${name} ${rev} checkout_err)
		if(checkout_err)
			message(STATUS "COULD NOT checkout revision ${rev}, reclone the repository.")
			CloneExternalLib(${name} ${url} "${ARGV3}" "${ARGV4}")

			message(STATUS "Checking out to revision ${rev}...")
			CheckoutExternalLib(${name} ${rev})
		endif()
	endif()

	set(${ARGV5} ${need_checkout} PARENT_SCOPE)
endfunction()

function(ApplyPatch name patch)
	set(external_folder "${CMAKE_CURRENT_SOURCE_DIR}")
	set(external_lib_folder "${external_folder}/${name}")

	execute_process(COMMAND "${GIT_EXECUTABLE}" "apply" "--check" "--ignore-space-change" "${patch}" WORKING_DIRECTORY ${external_lib_folder} RESULT_VARIABLE checkout_err)
	if(NOT checkout_err)
		message(STATUS "Applying ${patch}...")
		execute_process(COMMAND "${GIT_EXECUTABLE}" "am" "--ignore-space-change" "${patch}" WORKING_DIRECTORY ${external_lib_folder})
	endif()
endfunction()

FOREACH(flag_var
		CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
	IF(KLAYGE_COMPILER_MSVC OR KLAYGE_COMPILER_CLANGCL)
		STRING(REPLACE "/Wall" "/W0" ${flag_var} "${${flag_var}}")
		STRING(REPLACE "/WX" "/WX-" ${flag_var} "${${flag_var}}")
	ELSE()
		STRING(REPLACE "-Wall" "-w" ${flag_var} "${${flag_var}}")
		STRING(REPLACE "-Werror" "-Wno-error" ${flag_var} "${${flag_var}}")
	ENDIF()
ENDFOREACH()

add_subdirectory(zlib)
add_subdirectory(Python)

add_subdirectory(7z)
add_subdirectory(boost)
add_subdirectory(fmt)
add_subdirectory(NanoRtti)
add_subdirectory(ogg)
add_subdirectory(rapidjson)
add_subdirectory(rapidxml)
add_subdirectory(scope-lite)
add_subdirectory(vorbis)
if(KLAYGE_IS_DEV_PLATFORM)
	add_subdirectory(assimp)
	add_subdirectory(cxxopts)
	add_subdirectory(d3dcompiler)
	add_subdirectory(FreeImage)
	add_subdirectory(freetype)
	add_subdirectory(googletest)
	add_subdirectory(nanosvg)
endif()
if(KLAYGE_PLATFORM_ANDROID)
	add_subdirectory(android_native_app_glue)
endif()
if(KLAYGE_PLATFORM_WINDOWS)
	add_subdirectory(dxsdk)
	add_subdirectory(DirectX-Headers)
endif()
if(NOT KLAYGE_PLATFORM_WINDOWS_STORE)
	add_subdirectory(openal-soft)
endif()
if(KLAYGE_COMPILER_MSVC AND (CMAKE_GENERATOR MATCHES "^Visual Studio") AND KLAYGE_PLATFORM_WINDOWS_DESKTOP AND (KLAYGE_ARCH_NAME STREQUAL "x64"))
	add_subdirectory(wpftoolkit)
endif()