cmake_minimum_required(VERSION 3.30)

# --- C++26 modules + `import std;` (clang + libc++) -------------------------
# CMake gates `import std` behind an experimental value documented in
# Help/dev/experimental.rst for the CMake version in use.
set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD "d0edc3af-4c50-42ea-a356-e2862fe7a444")

# Path to the standard-library module description. A cross toolchain overrides
# this before the compiler is probed; this default targets the Linux LLVM
# package.
if(NOT CMAKE_CXX_STDLIB_MODULES_JSON)
    set(CMAKE_CXX_STDLIB_MODULES_JSON "/usr/lib/llvm-21/lib/libc++.modules.json")
endif()

# libc++ must be selected before the compiler is probed: CMake builds its
# internal standard-library module target during `project()`, and that target
# only sees `CMAKE_CXX_FLAGS` (not later `add_compile_options`). The standard
# and extension settings must also be in place before `project()` so the
# internal `std.pcm` is built with the same configuration as our modules.
set(CMAKE_CXX_FLAGS_INIT "-stdlib=libc++")
set(CMAKE_EXE_LINKER_FLAGS_INIT "-stdlib=libc++")
set(CMAKE_SHARED_LINKER_FLAGS_INIT "-stdlib=libc++")
set(CMAKE_CXX_STANDARD 26)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)
set(CMAKE_CXX_SCAN_FOR_MODULES ON)

project(OpenRA3 VERSION 0.3.0 LANGUAGES C CXX)

if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
    set(CMAKE_BUILD_TYPE Release CACHE STRING "Build type" FORCE)
endif()

set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")

option(OPENRA3_WERROR "Treat warnings as errors" OFF)

# Windows: statically link the C++ runtime (libc++, libunwind) so the .exe only
# needs SDL3.dll next to it at runtime.
if(WIN32)
    add_link_options(-static)
endif()

function(openra3_target_defaults target)
    target_compile_options(${target} PRIVATE -Wall -Wextra)
    set_property(TARGET ${target} PROPERTY CXX_MODULE_STD ON)
    if(OPENRA3_WERROR)
        target_compile_options(${target} PRIVATE -Werror)
    endif()
endfunction()

# --- SDL3: pkg-config on Linux, or an explicit MinGW root for Windows --------
add_library(openra3_sdl3 INTERFACE)
set(OPENRA3_HAS_SDL3 OFF)
if(OPENRA3_SDL3_ROOT)
    target_include_directories(openra3_sdl3 INTERFACE "${OPENRA3_SDL3_ROOT}/x86_64-w64-mingw32/include")
    target_link_libraries(openra3_sdl3 INTERFACE "${OPENRA3_SDL3_ROOT}/x86_64-w64-mingw32/lib/libSDL3.dll.a")
    set(OPENRA3_HAS_SDL3 ON)
else()
    find_package(PkgConfig QUIET)
    if(PkgConfig_FOUND)
        pkg_check_modules(SDL3 QUIET IMPORTED_TARGET sdl3)
    endif()
    if(SDL3_FOUND)
        target_link_libraries(openra3_sdl3 INTERFACE PkgConfig::SDL3)
        set(OPENRA3_HAS_SDL3 ON)
    endif()
endif()
if(OPENRA3_HAS_SDL3)
    message(STATUS "OpenRA3: SDL3 found - windowed viewer enabled")
else()
    message(STATUS "OpenRA3: SDL3 not found - offscreen BMP output only")
endif()

# --- Vulkan: vendored volk + headers, so no Vulkan SDK is needed ---------------
# The loader is resolved at runtime (volk dlopen/LoadLibrary), which lets the
# same source build the Vulkan backend on Linux and on the MinGW Windows target.
option(OPENRA3_VULKAN "Build the Vulkan viewer" ON)
set(OPENRA3_HAS_VULKAN OFF)
if(OPENRA3_VULKAN AND OPENRA3_HAS_SDL3)
    set(OPENRA3_HAS_VULKAN ON)
endif()
if(OPENRA3_HAS_VULKAN)
    message(STATUS "OpenRA3: Vulkan viewer enabled (vendored volk)")
else()
    message(STATUS "OpenRA3: Vulkan viewer disabled - offscreen image only")
endif()

add_library(ra3_volk STATIC third_party/volk/volk.c)
target_include_directories(ra3_volk PUBLIC third_party/volk third_party/vulkan/include)
target_compile_definitions(ra3_volk PUBLIC VK_NO_PROTOTYPES)

# Embed the committed SPIR-V blobs into a generated header at configure time.
# Regenerate with shaders/compile.sh after editing a .vert/.frag.
function(openra3_embed_spirv out_header)
    set(content "// Generated by CMake from shaders/generated/*.spv.\n")
    string(APPEND content "#pragma once\n#include <cstddef>\n#include <cstdint>\n\nnamespace ra3_shaders {\n")
    foreach(spv IN LISTS ARGN)
        if(NOT EXISTS "${spv}")
            message(FATAL_ERROR "Missing precompiled shader ${spv}; run shaders/compile.sh")
        endif()
        get_filename_component(base "${spv}" NAME)
        string(MAKE_C_IDENTIFIER "${base}" ident)
        file(READ "${spv}" hex HEX)
        string(LENGTH "${hex}" hexlen)
        math(EXPR words "${hexlen} / 8")
        string(REGEX REPLACE "(..)(..)(..)(..)" "0x\\4\\3\\2\\1," words_list "${hex}")
        string(APPEND content "inline constexpr std::uint32_t ${ident}[] = {${words_list}};\n")
        string(APPEND content "inline constexpr std::size_t ${ident}_words = ${words};\n\n")
    endforeach()
    string(APPEND content "} // namespace ra3_shaders\n")
    file(WRITE "${out_header}" "${content}")
endfunction()

# --- engine core -------------------------------------------------------------
add_library(ra3_core STATIC)
target_sources(ra3_core PUBLIC FILE_SET CXX_MODULES FILES src/core/ra3.core.cppm)
openra3_target_defaults(ra3_core)

# --- game logic --------------------------------------------------------------
add_library(ra3_logic STATIC)
target_sources(ra3_logic PUBLIC FILE_SET CXX_MODULES FILES src/logic/ra3.logic.cppm)
target_link_libraries(ra3_logic PUBLIC ra3_core)
openra3_target_defaults(ra3_logic)

# --- RA3 gameplay data (real balance) ----------------------------------------
add_library(ra3_data STATIC)
target_sources(ra3_data PUBLIC FILE_SET CXX_MODULES FILES src/data/ra3.data.cppm)
target_link_libraries(ra3_data PUBLIC ra3_core)
openra3_target_defaults(ra3_data)

# --- client ------------------------------------------------------------------
add_library(ra3_client STATIC)
target_sources(ra3_client PUBLIC FILE_SET CXX_MODULES FILES src/client/ra3.client.cppm)
target_link_libraries(ra3_client PUBLIC ra3_core ra3_logic)
openra3_target_defaults(ra3_client)

# --- RA3 game definitions ----------------------------------------------------
add_library(ra3_game STATIC)
target_sources(ra3_game PUBLIC FILE_SET CXX_MODULES FILES src/game/ra3.game.cppm)
target_link_libraries(ra3_game PUBLIC ra3_core ra3_logic)
openra3_target_defaults(ra3_game)

# --- filesystem: BIG4 + RefPack ---------------------------------------------
add_library(ra3_fs STATIC)
target_sources(ra3_fs PUBLIC FILE_SET CXX_MODULES FILES src/fs/ra3.fs.cppm)
target_link_libraries(ra3_fs PUBLIC ra3_core)
openra3_target_defaults(ra3_fs)

# --- map discovery/loading ---------------------------------------------------
add_library(ra3_map STATIC)
target_sources(ra3_map PUBLIC FILE_SET CXX_MODULES FILES src/map/ra3.map.cppm)
target_link_libraries(ra3_map PUBLIC ra3_core ra3_fs)
openra3_target_defaults(ra3_map)

# --- minimal skirmish simulation --------------------------------------------
add_library(ra3_skirmish STATIC)
target_sources(ra3_skirmish PUBLIC FILE_SET CXX_MODULES FILES src/skirmish/ra3.skirmish.cppm)
target_link_libraries(ra3_skirmish PUBLIC ra3_core ra3_logic ra3_game ra3_data ra3_map)
openra3_target_defaults(ra3_skirmish)

# --- software renderer -------------------------------------------------------
add_library(ra3_render STATIC)
target_sources(ra3_render PUBLIC FILE_SET CXX_MODULES FILES src/render/ra3.render.cppm)
target_link_libraries(ra3_render PUBLIC ra3_core)
openra3_target_defaults(ra3_render)

# --- real map terrain (HeightMapData / BlendTileData) ------------------------
add_library(ra3_terrain STATIC)
target_sources(ra3_terrain PUBLIC FILE_SET CXX_MODULES FILES src/terrain/ra3.terrain.cppm)
target_link_libraries(ra3_terrain PUBLIC ra3_core ra3_fs ra3_render)
openra3_target_defaults(ra3_terrain)

# The presentation facade imports render + terrain (for the terrain capability).
target_link_libraries(ra3_client PUBLIC ra3_render ra3_terrain)

# --- windowed viewer (SDL3 or null) -----------------------------------------
add_library(ra3_ui STATIC)
if(OPENRA3_HAS_SDL3)
    target_sources(ra3_ui PUBLIC FILE_SET CXX_MODULES FILES src/ui/ra3.ui.sdl.cppm)
    target_link_libraries(ra3_ui PUBLIC ra3_core ra3_render ra3_client openra3_sdl3)
else()
    target_sources(ra3_ui PUBLIC FILE_SET CXX_MODULES FILES src/ui/ra3.ui.null.cppm)
    target_link_libraries(ra3_ui PUBLIC ra3_core ra3_render ra3_client)
endif()
openra3_target_defaults(ra3_ui)

# --- Vulkan viewer (SDL3 surface + Vulkan, or null fallback) ------------------
add_library(ra3_vulkan STATIC)
if(OPENRA3_HAS_VULKAN AND OPENRA3_HAS_SDL3)
    openra3_embed_spirv(
        "${CMAKE_CURRENT_BINARY_DIR}/generated/shaders_embedded.hpp"
        "${CMAKE_CURRENT_SOURCE_DIR}/shaders/generated/scene.vert.spv"
        "${CMAKE_CURRENT_SOURCE_DIR}/shaders/generated/scene.frag.spv"
        "${CMAKE_CURRENT_SOURCE_DIR}/shaders/generated/terrain.vert.spv"
        "${CMAKE_CURRENT_SOURCE_DIR}/shaders/generated/terrain.frag.spv"
    )
    # The blobs are read at configure time, so re-run CMake when they change.
    set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS
        "${CMAKE_CURRENT_SOURCE_DIR}/shaders/generated/scene.vert.spv"
        "${CMAKE_CURRENT_SOURCE_DIR}/shaders/generated/scene.frag.spv"
        "${CMAKE_CURRENT_SOURCE_DIR}/shaders/generated/terrain.vert.spv"
        "${CMAKE_CURRENT_SOURCE_DIR}/shaders/generated/terrain.frag.spv")
    target_sources(ra3_vulkan PUBLIC FILE_SET CXX_MODULES FILES src/vulkan/ra3.vulkan.sdl.cppm)
    target_include_directories(ra3_vulkan PRIVATE "${CMAKE_CURRENT_BINARY_DIR}/generated")
    target_link_libraries(ra3_vulkan PUBLIC ra3_core ra3_render ra3_terrain ra3_client openra3_sdl3 ra3_volk)
else()
    target_sources(ra3_vulkan PUBLIC FILE_SET CXX_MODULES FILES src/vulkan/ra3.vulkan.null.cppm)
    target_link_libraries(ra3_vulkan PUBLIC ra3_core ra3_render ra3_client)
endif()
openra3_target_defaults(ra3_vulkan)

# --- display backend selection ------------------------------------------------
add_library(ra3_display STATIC)
target_sources(ra3_display PUBLIC FILE_SET CXX_MODULES FILES src/display/ra3.display.cppm)
target_link_libraries(ra3_display PUBLIC ra3_core ra3_render ra3_terrain ra3_client ra3_ui ra3_vulkan)
openra3_target_defaults(ra3_display)

# --- umbrella -----------------------------------------------------------------
add_library(ra3 STATIC)
target_sources(ra3 PUBLIC FILE_SET CXX_MODULES FILES src/ra3.cppm)
target_link_libraries(ra3 PUBLIC ra3_core ra3_logic ra3_client ra3_data ra3_game ra3_fs ra3_map ra3_skirmish ra3_render ra3_terrain ra3_display ra3_ui ra3_vulkan)
openra3_target_defaults(ra3)

# --- executable ---------------------------------------------------------------
add_executable(openra3 apps/openra3/main.cpp)
target_link_libraries(openra3 PRIVATE ra3)
openra3_target_defaults(openra3)

if(WIN32 AND OPENRA3_SDL3_ROOT)
    add_custom_command(TARGET openra3 POST_BUILD
        COMMAND ${CMAKE_COMMAND} -E copy_if_different
            "${OPENRA3_SDL3_ROOT}/x86_64-w64-mingw32/bin/SDL3.dll"
            "$<TARGET_FILE_DIR:openra3>")
endif()

# --- extracted assets ---------------------------------------------------------
# At build time, extract the retail assets into <exe_dir>/assets so the
# executable is self-contained (no --game-dir at run time). This drives the
# ra3tools Python scripts (the game install + Python, no target executable), so
# it also runs for a cross-build when the install is mounted into the container
# and RA3_GAME_DIR points at it. The engine's own map/terrain reader is embedded
# in the exe (run `openra3 extract` on a native host if you prefer).
set(RA3_GAME_DIR "C:/Red Alert 3" CACHE PATH "Red Alert 3 installation used to extract assets")
set(RA3TOOLS_DIR "C:/Users/Ender/CLionProjects/ra3-headless/ra3tools" CACHE PATH "ra3tools scripts (asset extraction)")
find_program(OPENRA3_PYTHON NAMES python3 python)
set(PYTHON_EXECUTABLE "${OPENRA3_PYTHON}" CACHE FILEPATH "Python interpreter used to run ra3tools")
option(OPENRA3_EXTRACT_ALL "Extract every asset (models/textures/audio/movies) via ra3tools" ON)

if(EXISTS "${RA3_GAME_DIR}/Data" AND OPENRA3_PYTHON)
    add_custom_command(
        OUTPUT "${CMAKE_BINARY_DIR}/.assets_stamp"
        COMMAND ${CMAKE_COMMAND}
            "-DGAME_DIR=${RA3_GAME_DIR}"
            "-DOUT=$<TARGET_FILE_DIR:openra3>/assets"
            "-DPYTHON=${PYTHON_EXECUTABLE}"
            "-DRA3TOOLS=${RA3TOOLS_DIR}"
            "-DEXTRACT_ALL=$<IF:$<BOOL:${OPENRA3_EXTRACT_ALL}>,ON,OFF>"
            "-DSTAMP=${CMAKE_BINARY_DIR}/.assets_stamp"
            -P "${CMAKE_CURRENT_SOURCE_DIR}/cmake/extract_assets.cmake"
        DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/cmake/extract_assets.cmake"
        COMMENT "Extracting Red Alert 3 assets to $<TARGET_FILE_DIR:openra3>/assets"
        VERBATIM)
    add_custom_target(openra3_assets ALL DEPENDS "${CMAKE_BINARY_DIR}/.assets_stamp")
else()
    message(STATUS "OpenRA3: asset extraction skipped (RA3_GAME_DIR '${RA3_GAME_DIR}' or Python not found)")
endif()

# --- tests --------------------------------------------------------------------
enable_testing()
add_executable(ra3_tests tests/ra3_tests.cpp)
target_link_libraries(ra3_tests PRIVATE ra3)
openra3_target_defaults(ra3_tests)
add_test(NAME ra3_tests COMMAND ra3_tests)