require "fileutils"

class Options
  def initialize(cmake="cmake")
    @cmake = cmake
    @options = {}

    configure
    write_cache_file
  end

  def to_a
    [
      "-D", "BUILD_SHARED_LIBS=OFF",
      "-D", "WHISPER_BUILD_TESTS=OFF",
      "-D", "CMAKE_ARCHIVE_OUTPUT_DIRECTORY=#{__dir__}",
      "-D", "CMAKE_POSITION_INDEPENDENT_CODE=ON",
      "-C", cache_path
    ]
  end

  def to_s
    command_line(*to_a)
  end

  def graphviz_cmake_args
    []
  end

  private

  def cmake_options
    @cmake_options ||= cmake_options_output.lines.drop_while {|line| line.chomp != "-- Cache values"}.drop(1)
                       .filter_map {|line|
                         option, value = line.chomp.split("=", 2)
                         name, type = option.split(":", 2)
                         [
                           name,
                           [
                             type,
                             type == "BOOL" ? value == "ON" : value
                           ]
                         ]
                       }.to_h
  end

  def cmake_options_output
    Dir.chdir(__dir__) do
      IO.popen([@cmake, "-S", "sources", "-B", "build", "-L"]) {|io| io.read}
    end
  end

  def configure
    cmake_options.each_pair do |name, (type, default_value)|
      option = option_name(name)
      value = type == "BOOL" ? enable_config(option) : arg_config("--#{option}")
      @options[name] = [type, value]
    end

    configure_accelerate
    configure_metal
    configure_coreml
  end

  # See ggml/src/ggml-cpu/CMakeLists.txt
  def configure_accelerate
    if RUBY_PLATFORM.match?(/darwin/) && enabled?("GGML_ACCELERATE")
      $LDFLAGS << " -framework Accelerate"
    end
  end

  # See ggml/src/ggml-metal/CMakeLists.txt
  def configure_metal
    $LDFLAGS << " -framework Foundation -framework Metal -framework MetalKit" if enabled?("GGML_METAL")
  end

  # See src/CmakeLists.txt
  def configure_coreml
    if enabled?("WHISPER_COREML")
      $LDFLAGS << " -framework Foundation -framework CoreML"
      $defs << "-DRUBY_WHISPER_USE_COREML"
    end
  end

  def option_name(name)
    name.downcase.gsub("_", "-")
  end

  def enabled?(option)
    op = @options[option]
    return false unless op
    return false unless op[0] == "BOOL"
    if op[1].nil?
      cmake_options[option][1]
    else
      op[1]
    end
  end

  def cache_path
    File.join(__dir__, "sources", "Options.cmake")
  end

  def write_cache_file
    FileUtils.mkpath File.dirname(cache_path)
    File.open cache_path, "w" do |file|
      @options.reject {|name, (type, value)| value.nil?}.each do |name, (type, value)|
        line = 'set(%<name>s %<value>s CACHE %<type>s "" FORCE)' %{
          name:,
          type:,
          value: value == true ? "ON" : value == false ? "OFF" : escape_cmake(value)
        }
        file.puts line
      end
    end
  end

  def escape_cmake(str)
    str.gsub(/[\\"]/, '\\\\\&')
  end

  def command_line(*args)
    args.collect {|arg| %|"#{arg.to_s.gsub(/[\\"]/, '\\\\\&')}"|}.join(" ")
  end
end
