cmake_minimum_required (VERSION 3.13)

if(CMAKE_HOST_UNIX)
    set(CMAKE_SYSTEM_NAME Windows)
    set(TOOLCHAIN_PREFIX x86_64-w64-mingw32)

    # cross compilers to use for C, C++ and Fortran
    set(CMAKE_C_COMPILER ${TOOLCHAIN_PREFIX}-gcc)
    set(CMAKE_CXX_COMPILER ${TOOLCHAIN_PREFIX}-g++)
    set(CMAKE_Fortran_COMPILER ${TOOLCHAIN_PREFIX}-gfortran)
    set(CMAKE_RC_COMPILER ${TOOLCHAIN_PREFIX}-windres)

    # target environment on the build host system
    set(CMAKE_FIND_ROOT_PATH /usr/${TOOLCHAIN_PREFIX})


    # modify default behavior of FIND_XXX() commands
    set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
    set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
    set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
    set(PKG_CONFIG_EXECUTABLE ${TOOLCHAIN_PREFIX}-pkg-config)

    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_FORTIFY_SOURCE=0")
endif()

project (XEGE)

add_library(xege STATIC)

target_include_directories(xege PUBLIC include)

# 是否使用 libpng 和 zlib 处理 PNG 图片。
# 目前只能为 ON，未来或允许选择使用 WIC。
option(USE_LIBPNG_AND_ZLIB "Use libpng and zlib to process PNG images" ON)

# 是否将 libpng 和 zlib 合并入最终的 EGE 静态库
# 如果为 OFF，将寻找已有的库进行编译
option(MERGE_LIBPNG_AND_ZLIB "Merge libpng and zlib into EGE library" ON)

if (USE_LIBPNG_AND_ZLIB)
    set(EGE_ZLIB_PATH_SUBFIX 3rdparty/zlib)
    set(EGE_ZLIB_SOURCE_DIR ${PROJECT_SOURCE_DIR}/${EGE_ZLIB_PATH_SUBFIX})
    set(EGE_ZLIB_BINARY_DIR ${PROJECT_BINARY_DIR}/${EGE_ZLIB_PATH_SUBFIX})
    set(EGE_LIBPNG_PATH_SUBFIX 3rdparty/libpng)
    set(EGE_LIBPNG_SOURCE_DIR ${PROJECT_SOURCE_DIR}/${EGE_LIBPNG_PATH_SUBFIX})
    set(EGE_LIBPNG_BINARY_DIR ${PROJECT_BINARY_DIR}/${EGE_LIBPNG_PATH_SUBFIX})

    if (MERGE_LIBPNG_AND_ZLIB)
        # 如果子目录下没有源代码，则自动更新 git submodule
        if (
            NOT EXISTS ${EGE_ZLIB_SOURCE_DIR}/CMakeLists.txt OR
            NOT EXISTS ${EGE_LIBPNG_SOURCE_DIR}/CMakeLists.txt
        )
            find_package(Git REQUIRED)
            execute_process(COMMAND ${GIT_EXECUTABLE} submodule update --init --recursive)
        endif ()

        add_subdirectory(${EGE_ZLIB_SOURCE_DIR} EXCLUDE_FROM_ALL)

        set(PNG_BUILD_ZLIB  ON   CACHE INTERNAL "")
        set(PNG_SHARED      OFF  CACHE INTERNAL "")
        set(PNG_STATIC      ON   CACHE INTERNAL "")
        set(PNG_TESTS       OFF  CACHE INTERNAL "")
        set(ZLIB_INCLUDE_DIR ${EGE_ZLIB_BINARY_DIR} ${EGE_ZLIB_SOURCE_DIR})
        add_subdirectory(${EGE_LIBPNG_SOURCE_DIR} EXCLUDE_FROM_ALL)

        # zlib 的 CMake 执行过程会重命名其 zconf.h 文件，这里改回来
        if (EXISTS ${EGE_ZLIB_SOURCE_DIR}/zconf.h.included)
            file(RENAME ${EGE_ZLIB_SOURCE_DIR}/zconf.h.included ${EGE_ZLIB_SOURCE_DIR}/zconf.h)
        endif ()

        if (MSVC)
            target_compile_options(png_static PRIVATE 
                /MP
                /MT
                /Zl)
            target_compile_options(zlibstatic PRIVATE
                /MP
                /MT
                /Zl)
        else ()
            target_compile_options(png_static PRIVATE
                -fPIC -fno-exceptions)
            target_compile_options(zlibstatic PRIVATE
                -fPIC -fno-exceptions)
            target_compile_options(xege PRIVATE
                -fPIC -fno-exceptions)
        endif()

        target_include_directories(xege
            PRIVATE ${EGE_ZLIB_BINARY_DIR}
            PRIVATE ${EGE_ZLIB_SOURCE_DIR}
        )
        target_include_directories(xege
            PRIVATE ${EGE_LIBPNG_BINARY_DIR}
            PRIVATE ${EGE_LIBPNG_SOURCE_DIR}
        )

        target_sources(xege
            PRIVATE $<TARGET_OBJECTS:png_static>
            PRIVATE $<TARGET_OBJECTS:zlibstatic>
        )
        target_include_directories(png_static
            PRIVATE ${EGE_ZLIB_BINARY_DIR}
            PRIVATE ${EGE_ZLIB_SOURCE_DIR}
        )
    else ()
        find_package(ZLIB REQUIRED)
        find_package(PNG REQUIRED)
        target_link_libraries(xege
            PRIVATE ZLIB::ZLIB
            PRIVATE PNG::PNG
        )
    endif ()
else ()
    message(FATAL_ERROR "EGE MUST BE COMPILED WITH LIBPNG AND ZLIB!")
endif ()

# 设置库文件名
set_property(TARGET xege PROPERTY OUTPUT_NAME graphics)

# 打印编译器信息
if (MSVC)
    message(STATUS "MSVC target: MSVC ${MSVC_VERSION}")
    target_compile_options(xege PRIVATE 
        /MP
        /MT
        /Zl)
elseif (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
    message(STATUS "GNU target: GCC ${CMAKE_C_COMPILER_VERSION}")
else ()
    if (CMAKE_CXX_COMPILER_ID)
        message(FATAL_ERROR "Unsupported compiler: ${CMAKE_CXX_COMPILER_ID}")
    else ()
        message(FATAL_ERROR "Unsupported compiler: ${CMAKE_CXX_COMPILER}")
    endif ()
endif ()

# 增加链接 ege 的可执行目标
macro(ege_add_executable name source)
    add_executable(${name} ${source})
    target_link_libraries(${name} xege)
    if (MSVC)
        target_compile_options(${name} PRIVATE
            /utf-8
            /D_USE_MATH_DEFINES
            /D__STDC_LIMIT_MACROS
            /MP
        )
    endif()
    if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
        if(CMAKE_HOST_UNIX)
            target_link_options(${name}
                PRIVATE -D_FORTIFY_SOURCE=0 -mwindows -static)
        else()
            target_link_options(${name} PRIVATE -mwindows)
        endif()
    endif ()
endmacro()

# 编译测试
ege_add_executable(graphicstest test/src/maintest.cpp)

add_subdirectory(src)

add_subdirectory(demo)

if (EXISTS ${PROJECT_SOURCE_DIR}/temp/CMakeLists.txt)
    add_subdirectory(temp)
endif ()