function(tf_get_absolute_path path base final_path)
  if (IS_ABSOLUTE ${path})
    set(${final_path} ${path} PARENT_SCOPE)
  else()
    set(${final_path} ${base}/${path} PARENT_SCOPE)
  endif()
endfunction()

function(tf_get_model model final_path)
  string(FIND ${model} "http:" pos_http)
  string(FIND ${model} "https:" pos_https)
  if (${pos_http} EQUAL 0 OR ${pos_https} EQUAL 0)
    message("Downloading model " ${model})
    string(FIND ${model} "/" fname_start REVERSE)
    math(EXPR fname_start "${fname_start}+1")
    string(SUBSTRING ${model} ${fname_start}+1 -1 fname)
    message("Model archive: " ${fname})
    file(DOWNLOAD ${model} ${CMAKE_CURRENT_BINARY_DIR}/${fname})
    file(ARCHIVE_EXTRACT INPUT
      ${CMAKE_CURRENT_BINARY_DIR}/${fname}
      DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/${fname}_model)
    set(${final_path} ${CMAKE_CURRENT_BINARY_DIR}/${fname}_model/model PARENT_SCOPE)
  else()
    tf_get_absolute_path(${model} ${CMAKE_CURRENT_BINARY_DIR} model_path)
    set(${final_path} ${model_path} PARENT_SCOPE)
  endif()
endfunction()

# Generate a mock model for tests.
function(generate_mock_model model generate_mock_model_py config)
  tf_get_absolute_path(${model} ${CMAKE_CURRENT_BINARY_DIR} LLVM_ML_MODELS_ABSOLUTE)
  tf_get_absolute_path(${generate_mock_model_py} ${CMAKE_CURRENT_SOURCE_DIR} GENERATE_INLINING_MODEL_ABSOLUTE)
  tf_get_absolute_path(${config} ${CMAKE_CURRENT_SOURCE_DIR} LLVM_ML_MODEL_CONFIG_ABSOLUTE)
  message(WARNING "Autogenerated mock models should not be used in production builds.")
  execute_process(COMMAND python3
    ${GENERATE_INLINING_MODEL_ABSOLUTE}
    ${LLVM_ML_MODEL_CONFIG_ABSOLUTE}
    ${LLVM_ML_MODELS_ABSOLUTE}-autogenerated
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
  )
endfunction()

# Run the tensorflow compiler (saved_model_cli) on the saved model in the
# ${model} directory, looking for the ${tag_set} tag set, and the SignatureDef
# ${signature_def_key}.
# Produce a pair of files called ${fname}.h and  ${fname}.o in the
# ${CMAKE_CURRENT_BINARY_DIR}. The generated header will define a C++ class
# called ${cpp_class} - which may be a namespace-qualified class name.
function(tfcompile model tag_set signature_def_key fname cpp_class)
  set(prefix ${CMAKE_CURRENT_BINARY_DIR}/${fname})
  set(obj_file ${prefix}.o)
  set(hdr_file ${prefix}.h)
  string(TOUPPER ${fname} fname_allcaps)
  set(override_header ${LLVM_OVERRIDE_MODEL_HEADER_${fname_allcaps}})
  set(override_object ${LLVM_OVERRIDE_MODEL_OBJECT_${fname_allcaps}})
  if (EXISTS "${override_header}" AND EXISTS "${override_object}")
    configure_file(${override_header} ${hdr_file} COPYONLY)
    configure_file(${override_object} ${obj_file} COPYONLY)
    message("Using provided header "
      ${hdr_file} " and object "   ${obj_file}
      " files for model " ${model})
  else()
    tf_get_absolute_path(${model} ${CMAKE_CURRENT_BINARY_DIR} LLVM_ML_MODELS_ABSOLUTE)
    message("Using model at " ${LLVM_ML_MODELS_ABSOLUTE})
    add_custom_command(OUTPUT ${obj_file} ${hdr_file}
      COMMAND ${TENSORFLOW_AOT_COMPILER} aot_compile_cpu
            --multithreading false
            --dir ${LLVM_ML_MODELS_ABSOLUTE}
            --tag_set ${tag_set}
            --signature_def_key ${signature_def_key}
            --output_prefix ${prefix}
            --cpp_class ${cpp_class}
            --target_triple ${LLVM_HOST_TRIPLE}
    )
  endif()

  # Aggregate the objects so that results of different tfcompile calls may be
  # grouped into one target.
  set(GENERATED_OBJS ${GENERATED_OBJS} ${obj_file} PARENT_SCOPE)
  set_source_files_properties(${obj_file} PROPERTIES
    GENERATED 1 EXTERNAL_OBJECT 1)

  set(GENERATED_HEADERS ${GENERATED_HEADERS} ${hdr_file} PARENT_SCOPE)
  set_source_files_properties(${hdr_file} PROPERTIES
    GENERATED 1)

endfunction()

function(tf_find_and_compile model default_url default_path generation_config tag_set signature_def_key fname cpp_class)
  if ("${model}" STREQUAL "download")
    # Crash if the user wants to download a model but a URL is set to "TO_BE_UPDATED"
    if ("${LLVM_INLINER_MODEL_CURRENT_URL}" STREQUAL "TO_BE_UPDATED")
        message(FATAL_ERROR "LLVM_INLINER_MODEL_PATH was set to 'download' but there is no model url currently specified in cmake - likely, the model interface recently changed, and so there is not a released model available.")
    endif()

    set(model ${default_url})
  endif()

  if ("${model}" STREQUAL "autogenerate")
    generate_mock_model(${default_path} models/generate_mock_model.py ${generation_config})
    set(model ${default_path}-autogenerated)
  endif()

  tf_get_model(${model} LLVM_ML_MODELS_ABSOLUTE)
  tfcompile(${LLVM_ML_MODELS_ABSOLUTE} ${tag_set} ${signature_def_key} ${fname} ${cpp_class})

  set(GENERATED_OBJS ${GENERATED_OBJS} ${obj_file} PARENT_SCOPE)
  set_source_files_properties(${obj_file} PROPERTIES
    GENERATED 1 EXTERNAL_OBJECT 1)

  set(GENERATED_HEADERS ${GENERATED_HEADERS} ${hdr_file} PARENT_SCOPE)
  set_source_files_properties(${hdr_file} PROPERTIES
    GENERATED 1)

  set(GeneratedMLSources ${GeneratedMLSources} ${GENERATED_HEADERS} PARENT_SCOPE)
  set(MLDeps ${MLDeps} tf_xla_runtime PARENT_SCOPE)
  set(MLLinkDeps ${MLLinkDeps} tf_xla_runtime ${GENERATED_OBJS} PARENT_SCOPE)

endfunction()