#=============================================================================
# SPDX-FileCopyrightText: Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
#=============================================================================

include_guard(GLOBAL)

include("${LEGATE_CMAKE_DIR}/Modules/clang_tidy.cmake")

function(_legate_check_nvcc_pedantic_flags FLAGS)
  if(legate_SKIP_NVCC_PEDANTIC_CHECK)
    message(VERBOSE "Skipping nvcc pedantic check (explicitly skipped by user)")
    return()
  endif()
  if(NOT (CMAKE_CUDA_COMPILER_ID MATCHES "NVIDIA"))
    message(
      VERBOSE
      "Skipping nvcc pedantic check (compiler \"${CMAKE_CUDA_COMPILER_ID}\" is not nvcc)"
    )
    return()
  endif()
  # We want to catch either "-pedantic" or "--compiler-option=-pedantic" or
  # --compiler-options='-pedantic' but we do NOT want to catch -Wformat-pedantic!
  string(REGEX MATCH [=[[ |=|='|="]\-W?pedantic]=] match_var "${FLAGS}")
  if(match_var)
    message(
      FATAL_ERROR
      "-pedantic (or -Wpedantic) is not supported by nvcc and will lead to "
      "spurious warnings in generated code. Please remove it from your build flags. If "
      "you would like to override this behavior, reconfigure with "
      "-Dlegate_SKIP_NVCC_PEDANTIC_CHECK=ON."
    )
  endif()
endfunction()

function(legate_generate_fatbin_modules)
  list(APPEND CMAKE_MESSAGE_CONTEXT "generate_fatbin_modules")

  set(options)
  set(one_value_args DEST_DIR GENERATED_SOURCES_VAR)
  set(multi_value_args SOURCES EXTRA_FLAGS)
  cmake_parse_arguments(
    _LEGATE
    "${options}"
    "${one_value_args}"
    "${multi_value_args}"
    ${ARGN}
  )

  if(NOT _LEGATE_DEST_DIR)
    message(FATAL_ERROR "Must pass DEST_DIR")
  endif()

  if(NOT IS_ABSOLUTE "${_LEGATE_DEST_DIR}")
    set(_LEGATE_DEST_DIR "${CMAKE_CURRENT_BINARY_DIR}/${_LEGATE_DEST_DIR}")
  endif()

  set(cuda_flags ${_LEGATE_EXTRA_FLAGS})

  _legate_check_nvcc_pedantic_flags(cuda_flags)

  include("${LEGATE_CMAKE_DIR}/Modules/utilities.cmake")

  set(src_list)
  set(seen_fatbin_vars)
  foreach(src IN LISTS _LEGATE_SOURCES)
    # Skip clang-tidy for fatbin files - they use NVCC-specific flags that clang-tidy
    # cannot parse
    if(legate_FAKE_FATBINS_FOR_TIDY)
      # Generate stub header and skip real fatbin work
      cmake_path(GET src STEM fatbin_var_name)
      set(VAR_NAME "${fatbin_var_name}")
      configure_file(
        "${LEGATE_CMAKE_DIR}/templates/stubfatbin.h.in"
        "${_LEGATE_DEST_DIR}/${fatbin_var_name}.h"
        @ONLY
      )
      continue()
    endif()
    string(MAKE_C_IDENTIFIER "${src}_fatbin" fatbin_target_name)

    add_library("${fatbin_target_name}" OBJECT "${src}")
    target_include_directories(
      "${fatbin_target_name}"
      PRIVATE
        "${CMAKE_CURRENT_SOURCE_DIR}"
        "${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_INSTALL_INCLUDEDIR}/legate"
    )

    target_link_libraries(
      "${fatbin_target_name}"
      PRIVATE
        CCCL::CCCL
        # Technically none of the remaining libraries need to be
        # linked into the fatbins, but since the fatbins include
        # legate headers, and therefore transitively include the
        # headers from these libraries, we have to include
        # them...
        Legion::Legion
        fmt::fmt-header-only
    )
    # Don't use cuda_flags for this since it does not handle generator expressions.
    target_compile_options(
      "${fatbin_target_name}"
      PRIVATE
        $<$<COMPILE_LANG_AND_ID:CUDA,NVIDIA>:
        -Xcudafe=--diag_suppress=boolean_controlling_expr_is_constant
        -Xfatbin=-compress-all
        --expt-extended-lambda
        --expt-relaxed-constexpr
        -Wno-deprecated-gpu-targets
        --fatbin>
    )

    set_target_properties(
      "${fatbin_target_name}"
      PROPERTIES POSITION_INDEPENDENT_CODE ON INTERFACE_POSITION_INDEPENDENT_CODE ON
    )

    if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.27.0")
      set_target_properties("${fatbin_target_name}" PROPERTIES CUDA_FATBIN_COMPILATION ON)
    endif()

    if(cuda_flags)
      legate_add_target_compile_options("${fatbin_target_name}" CUDA PRIVATE cuda_flags)
    endif()

    cmake_path(GET src STEM fatbin_var_name)
    list_add_if_not_present_error(seen_fatbin_vars "${fatbin_var_name}")
    set(fatbin_cc "${_LEGATE_DEST_DIR}/${fatbin_var_name}.cc")
    set(fatbin_h "${_LEGATE_DEST_DIR}/${fatbin_var_name}.h")
    message(STATUS "Created fatbin target for: ${src}")

    add_custom_command(
      OUTPUT "${fatbin_cc}"
      COMMAND
        ${CMAKE_COMMAND} "-DVAR_NAME=${fatbin_var_name}"
        "-DIN_FILE=$<TARGET_OBJECTS:${fatbin_target_name}>" "-DOUT_CC_FILE=${fatbin_cc}"
        "-DOUT_H_FILE=${fatbin_h}" "-DLEGATE_CMAKE_DIR=${LEGATE_CMAKE_DIR}" -P
        "${LEGATE_CMAKE_DIR}/scripts/bin2c.cmake"
      VERBATIM
      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}"
      DEPENDS "${fatbin_target_name}"
      COMMENT
        "Embedding binary objects $<TARGET_OBJECTS:${fatbin_target_name}> -> ${fatbin_cc}"
    )

    list(APPEND src_list "${fatbin_cc}")
  endforeach()
  set(${_LEGATE_GENERATED_SOURCES_VAR} "${src_list}" PARENT_SCOPE)
endfunction()