# @lint-ignore-every LICENSELINT
# Copyright (c) Facebook, Inc. and its affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

# =============================================================================
# Copyright (c) 2023-2024, NVIDIA CORPORATION.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
# in compliance with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
# or implied. See the License for the specific language governing permissions and limitations under
# the License.
# =============================================================================

cmake_minimum_required(VERSION 3.24.0 FATAL_ERROR)

set(FAISS_LANGUAGES CXX)

if(FAISS_ENABLE_GPU)
  if (FAISS_ENABLE_ROCM)
    list(APPEND FAISS_LANGUAGES HIP)
    list(PREPEND CMAKE_MODULE_PATH "/opt/rocm/lib/cmake")
    list(PREPEND CMAKE_PREFIX_PATH "/opt/rocm")
  else()
    list(APPEND FAISS_LANGUAGES CUDA)
  endif()
endif()

if(FAISS_ENABLE_METAL)
  list(APPEND FAISS_LANGUAGES OBJCXX)
endif()

# FAISS_ENABLE_METAL may not yet be in the cache on the first cmake run
# (the option() call is after project()). If the user didn't pass
# -DFAISS_ENABLE_METAL=... on the command line we pre-seed the cache
# now so that OBJCXX is added to the project languages.
# Only default to ON on Apple Silicon (arm64); Intel Macs are not
# supported by the Metal backend.
# Prefer CMAKE_SYSTEM_* (target platform, set by toolchain files for
# cross-compiles) and fall back to CMAKE_HOST_* (build machine).
if(NOT DEFINED FAISS_ENABLE_METAL)
  if(DEFINED CMAKE_SYSTEM_NAME)
    set(_faiss_metal_sys "${CMAKE_SYSTEM_NAME}")
    set(_faiss_metal_proc "${CMAKE_SYSTEM_PROCESSOR}")
  else()
    set(_faiss_metal_sys "${CMAKE_HOST_SYSTEM_NAME}")
    set(_faiss_metal_proc "${CMAKE_HOST_SYSTEM_PROCESSOR}")
  endif()
  if(_faiss_metal_sys STREQUAL "Darwin" AND _faiss_metal_proc STREQUAL "arm64")
    set(FAISS_ENABLE_METAL ON CACHE BOOL
      "Enable Metal GPU backend for Apple Silicon.")
    list(APPEND FAISS_LANGUAGES OBJCXX)
  endif()
endif()

if(FAISS_ENABLE_CUVS)
  include(cmake/thirdparty/fetch_rapids.cmake)
  include(rapids-cmake)
  include(rapids-cpm)
  include(rapids-cuda)
  include(rapids-export)
  include(rapids-find)

  rapids_cuda_init_architectures(faiss)
  rapids_cuda_init_architectures(pyfaiss)
  rapids_cuda_init_architectures(faiss_c_library)
endif()

project(faiss
  VERSION 1.15.1
  DESCRIPTION "A library for efficient similarity search and clustering of dense vectors."
  HOMEPAGE_URL "https://github.com/facebookresearch/faiss"
  LANGUAGES ${FAISS_LANGUAGES})
include(GNUInstallDirs)

set(CMAKE_CXX_STANDARD 20)

list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")

# Valid values are "generic", "avx2", "avx512", "avx512_spr", "sve".
option(FAISS_OPT_LEVEL "" "generic")
option(FAISS_ENABLE_GPU "Enable support for GPU indexes." ON)
option(FAISS_GPU_STATIC "Link GPU libraries statically." OFF)
option(FAISS_ENABLE_CUVS "Enable cuVS for GPU indexes." OFF)
option(FAISS_ENABLE_ROCM "Enable ROCm for GPU indexes." OFF)
option(FAISS_ENABLE_MKL "Enable MKL." ON)
option(FAISS_ENABLE_PYTHON "Build Python extension." ON)
option(FAISS_ENABLE_C_API "Build C API." OFF)
option(FAISS_ENABLE_EXTRAS "Build extras like benchmarks and demos" ON)
option(FAISS_USE_LTO "Enable Link-Time optimization" OFF)
if(APPLE AND CMAKE_SYSTEM_PROCESSOR STREQUAL "arm64")
  set(_FAISS_METAL_DEFAULT ON)
else()
  set(_FAISS_METAL_DEFAULT OFF)
endif()
option(FAISS_ENABLE_METAL "Enable Metal GPU backend for Apple Silicon."
  ${_FAISS_METAL_DEFAULT})
option(FAISS_ENABLE_SVS "Enable SVS (Intel(R) Scalable Vector Search) integration." OFF)
set(FAISS_SVS_RUNTIME_VERSION "v0" CACHE STRING "Version of the SVS runtime API to use")
set_property(CACHE FAISS_SVS_RUNTIME_VERSION PROPERTY STRINGS "v0")

if(FAISS_ENABLE_GPU)
  if(FAISS_ENABLE_ROCM)
    enable_language(HIP)
    add_definitions(-DUSE_AMD_ROCM)
    find_package(HIP REQUIRED)
    find_package(hipBLAS REQUIRED)
    set(GPU_EXT_PREFIX "hip")
    execute_process(COMMAND ${PROJECT_SOURCE_DIR}/faiss/gpu/hipify.sh)
  else ()
    set(CMAKE_CUDA_HOST_COMPILER ${CMAKE_CXX_COMPILER})
    enable_language(CUDA)
    set(GPU_EXT_PREFIX "cu")
  endif()
endif()

if(FAISS_ENABLE_CUVS AND NOT TARGET cuvs::cuvs)
   find_package(cuvs)
 endif()

if(FAISS_ENABLE_CUVS AND NOT TARGET rmm::rmm)
  find_package(rmm REQUIRED)
endif()

add_subdirectory(faiss)

if(FAISS_ENABLE_GPU)
  add_subdirectory(faiss/gpu)
endif()

if(FAISS_ENABLE_METAL)
  if(NOT APPLE)
    message(FATAL_ERROR "FAISS_ENABLE_METAL requires Apple (macOS) platform.")
  endif()
  add_subdirectory(faiss/gpu_metal)
endif()

if(FAISS_ENABLE_PYTHON)
  add_subdirectory(faiss/python)
endif()

if(FAISS_ENABLE_C_API)
  add_subdirectory(c_api)
endif()

if(FAISS_ENABLE_EXTRAS)
  add_subdirectory(demos)
  add_subdirectory(benchs)
  add_subdirectory(tutorial/cpp)
endif()

# CTest must be included in the top level to enable `make test` target.
include(CTest)
if(BUILD_TESTING)
  add_subdirectory(tests)
  if(NOT WIN32 AND NOT CMAKE_CROSSCOMPILING)
    add_subdirectory(perf_tests)
  endif()
  if(FAISS_ENABLE_GPU)
    if(FAISS_ENABLE_ROCM)
      add_subdirectory(faiss/gpu/test)
    else()
      add_subdirectory(faiss/gpu/test)
    endif()
  endif()
  if(FAISS_ENABLE_METAL)
    add_subdirectory(faiss/gpu_metal/test)
  endif()
endif()