require "macho"
require "os/mac/architecture_list"

module MachOShim
  # @private
  def macho
    @macho ||= begin
      MachO.open(to_s)
    end
  end

  # @private
  def mach_data
    @mach_data ||= begin
      machos = []
      mach_data = []

      if MachO::Utils.fat_magic?(macho.magic)
        machos = macho.machos
      else
        machos << macho
      end

      machos.each do |m|
        arch = case m.cputype
        when :x86_64, :i386, :ppc64 then m.cputype
        when :ppc then :ppc7400
        else :dunno
        end

        type = case m.filetype
        when :dylib, :bundle then m.filetype
        when :execute then :executable
        else :dunno
        end

        mach_data << { arch: arch, type: type }
      end

      mach_data
    rescue MachO::NotAMachOError
      # Silently ignore errors that indicate the file is not a Mach-O binary ...
      []
    rescue
      # ... but complain about other (parse) errors for further investigation.
      onoe "Failed to read Mach-O binary: #{self}"
      raise if ARGV.homebrew_developer?

      []
    end
  end

  def dynamically_linked_libraries(except: :none)
    lcs = macho.dylib_load_commands.reject { |lc| lc.type == except }

    lcs.map(&:name).map(&:to_s).uniq
  end

  def dylib_id
    macho.dylib_id
  end

  def archs
    mach_data.map { |m| m.fetch :arch }.extend(ArchitectureListExtension)
  end

  def arch
    case archs.length
    when 0 then :dunno
    when 1 then archs.first
    else :universal
    end
  end

  def universal?
    arch == :universal
  end

  def i386?
    arch == :i386
  end

  def x86_64?
    arch == :x86_64
  end

  def ppc7400?
    arch == :ppc7400
  end

  def ppc64?
    arch == :ppc64
  end

  # @private
  def dylib?
    mach_data.any? { |m| m.fetch(:type) == :dylib }
  end

  # @private
  def mach_o_executable?
    mach_data.any? { |m| m.fetch(:type) == :executable }
  end

  alias binary_executable? mach_o_executable?

  # @private
  def mach_o_bundle?
    mach_data.any? { |m| m.fetch(:type) == :bundle }
  end
end
