# OrcaSlicer Config Codegen CMake Module
#
# Generates C++ source files from protobuf schema definitions.
# Generated files live in src/slic3r/GUI/generated/ and are gitignored.
# Run 'python tools/run_codegen.py' (requires grpcio-tools or protoc) to regenerate.
#
# Targets:
#   codegen_config  - Custom target to regenerate C++ from .proto files
#   validate_config - Custom target to validate generated vs original
#
# Usage in parent CMakeLists.txt:
#   include(cmake/modules/ConfigCodegen.cmake)

find_program(PROTOC_EXECUTABLE protoc)
find_package(Python3 COMPONENTS Interpreter QUIET)

set(_generated_marker "${CMAKE_SOURCE_DIR}/src/slic3r/GUI/generated/PrintConfigDef_generated.cpp")

# Decide which interpreter can actually run the codegen.
#
# The main CMakeLists forces Python3_EXECUTABLE to the *bundled embed* interpreter (used for
# the in-app Python plugin runtime). That interpreter has neither protoc nor the protobuf /
# pyyaml packages, and for cross-compiled targets it may not even be the host architecture — so
# it cannot run tools/run_codegen.py. In CI the generated sources are produced by a dedicated
# pre-build "Install codegen tools and generate config sources" step; developers run
# tools/run_codegen.py themselves. Only wire up (re)generation when the interpreter really has
# the toolchain, otherwise fall back to the already-generated files.
#
# ORCA_CODEGEN_PYTHON lets a build explicitly point at an interpreter that has the tools
# (independent of the embed interpreter). Falls back to Python3_EXECUTABLE.
if(NOT ORCA_CODEGEN_PYTHON)
    set(ORCA_CODEGEN_PYTHON "${Python3_EXECUTABLE}")
endif()

set(_codegen_usable FALSE)
if(ORCA_CODEGEN_PYTHON)
    # Needs the protobuf python runtime (config_metadata_pb2) plus a protoc (standalone or
    # grpc_tools.protoc). Probe the interpreter for both.
    execute_process(
        COMMAND ${ORCA_CODEGEN_PYTHON} -c
            "import shutil, importlib.util, google.protobuf; import sys; sys.exit(0 if (shutil.which('protoc') or importlib.util.find_spec('grpc_tools')) else 1)"
        RESULT_VARIABLE _codegen_probe
        OUTPUT_QUIET ERROR_QUIET
    )
    if(_codegen_probe EQUAL 0)
        set(_codegen_usable TRUE)
    endif()
endif()

# If generated files are missing (fresh clone) and we can run codegen, do it now at configure
# time so a plain cmake configure + build works without a separate pre-build step.
if(NOT EXISTS "${_generated_marker}")
    if(_codegen_usable)
        message(STATUS "Config codegen: generated files missing — running codegen now...")
        execute_process(
            COMMAND ${ORCA_CODEGEN_PYTHON} "${CMAKE_SOURCE_DIR}/tools/run_codegen.py" --no-validate
            WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
            RESULT_VARIABLE _codegen_result
        )
        if(NOT _codegen_result EQUAL 0)
            message(FATAL_ERROR "Config codegen failed. Install grpcio-tools: pip install grpcio-tools")
        endif()
        message(STATUS "Config codegen: generated files created successfully")
    else()
        message(FATAL_ERROR
            "Config codegen: generated files are missing and no usable codegen toolchain was found.\n"
            "Generate them first with an interpreter that has protoc + protobuf, e.g.:\n"
            "  pip install grpcio-tools pyyaml && python tools/run_codegen.py\n"
            "or pass -DORCA_CODEGEN_PYTHON=<python-with-tools>.")
    endif()
endif()

set(CONFIG_PROTO_DIR   "${CMAKE_SOURCE_DIR}/src/PrintConfigs")
set(CONFIG_CODEGEN_DIR "${CMAKE_SOURCE_DIR}/src/slic3r/GUI/generated")
set(CONFIG_LAYOUT_YAML "${CMAKE_SOURCE_DIR}/src/PrintConfigs/layout.yaml")
set(CONFIG_DESC_FILE   "${CMAKE_BINARY_DIR}/config.desc")

set(CODEGEN_TOOL     "${CMAKE_SOURCE_DIR}/tools/config_codegen.py")
set(VALIDATE_TOOL    "${CMAKE_SOURCE_DIR}/tools/validate_codegen.py")
set(RUN_CODEGEN_TOOL "${CMAKE_SOURCE_DIR}/tools/run_codegen.py")

# Generated output files (TabLayout_generated.cpp is also generated from layout.yaml)
set(CONFIG_GENERATED_SOURCES
    "${CONFIG_CODEGEN_DIR}/PrintConfigDef_generated.cpp"
    "${CONFIG_CODEGEN_DIR}/Preset_options_generated.cpp"
    "${CONFIG_CODEGEN_DIR}/Invalidation_generated.cpp"
    "${CONFIG_CODEGEN_DIR}/OptionKeys_generated.cpp"
    "${CONFIG_CODEGEN_DIR}/TabLayout_generated.cpp"
)
set(CONFIG_GENERATED_SOURCES "${CONFIG_GENERATED_SOURCES}" CACHE INTERNAL "Generated config cpp files")

# Collect all .proto source files (flat in src/PrintConfigs/, excluding config_metadata.proto)
file(GLOB CONFIG_PROTO_FILES
    "${CONFIG_PROTO_DIR}/filament.proto"
    "${CONFIG_PROTO_DIR}/print.proto"
    "${CONFIG_PROTO_DIR}/printer.proto"
)
set(CONFIG_PROTO_FILES
    "${CONFIG_PROTO_DIR}/config_metadata.proto"
    ${CONFIG_PROTO_FILES}
)

if(_codegen_usable)
    # Single command: run_codegen.py handles protoc/grpcio-tools detection internally.
    # Proto files → generated .cpp files. Runs automatically when any .proto changes.
    add_custom_command(
        OUTPUT  ${CONFIG_GENERATED_SOURCES}
        COMMAND ${ORCA_CODEGEN_PYTHON} ${RUN_CODEGEN_TOOL} --no-validate
        DEPENDS ${CONFIG_PROTO_FILES} ${CONFIG_LAYOUT_YAML} ${CODEGEN_TOOL}
        WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
        COMMENT "Re-generating config C++ from changed .proto files"
        VERBATIM
    )

    # codegen_config is part of ALL — runs before every build, checks if protos changed.
    add_custom_target(codegen_config ALL
        DEPENDS ${CONFIG_GENERATED_SOURCES}
        COMMENT "Config codegen up to date"
    )

    # Validation target: cmake --build . --target validate_config
    add_custom_target(validate_config
        COMMAND ${ORCA_CODEGEN_PYTHON} ${VALIDATE_TOOL}
        DEPENDS ${CONFIG_GENERATED_SOURCES}
        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
        COMMENT "Validating generated config code against PrintConfig.cpp"
        VERBATIM
    )

    message(STATUS "Config codegen: enabled — proto changes auto-regenerate on next build")
else()
    # No usable codegen toolchain in this interpreter (e.g. the bundled embed Python in CI).
    # The generated files already exist (checked/produced above); use them as-is and provide a
    # no-op codegen_config target so dependents that reference it still resolve.
    add_custom_target(codegen_config ALL
        COMMENT "Config codegen: using pre-generated files (no codegen toolchain in this interpreter)")
    add_custom_target(validate_config
        COMMENT "Config codegen: validation skipped (no codegen toolchain in this interpreter)")
    message(STATUS "Config codegen: no codegen toolchain in '${ORCA_CODEGEN_PYTHON}' — using pre-generated files")
endif()