module MacOS extend self

  MDITEM_BUNDLE_ID_KEY = "kMDItemCFBundleIdentifier"
  XCODE_4_BUNDLE_ID = "com.apple.dt.Xcode"
  XCODE_3_BUNDLE_ID = "com.apple.Xcode"
  CLT_STANDALONE_PKG_ID = "com.apple.pkg.DeveloperToolsCLILeo"
  CLT_FROM_XCODE_PKG_ID = "com.apple.pkg.DeveloperToolsCLI"
  APPLE_X11_BUNDLE_ID = "org.x.X11"
  XQUARTZ_BUNDLE_ID = "org.macosforge.xquartz.X11"

  def version
    MACOS_VERSION
  end

  def cat
    if mountain_lion?
      :mountainlion
    elsif lion?
      :lion
    elsif snow_leopard?
      :snowleopard
    elsif leopard?
      :leopard
    else
      nil
    end
  end

  def clt_installed?
    # If the command line tools are installed, most unix standard
    # tools, libs and headers are in /usr.
    # Returns true, also for older Xcode/OSX versions that had everything in /usr
    # Beginning with Xcode 4.3, the dev tools are no longer installed
    # in /usr and SDKs no longer in /Developer by default.
    # But Apple provides an optional "Command Line Tools for Xcode" package.
    not clt_version.empty? or dev_tools_path == Pathname.new("/usr/bin")
  end

  def clt_version
    # Version string (a pretty damn long one) of the CLT package.
    # Note, that different ways to install the CLTs lead to different
    # version numbers.
    @clt_version ||= begin
      standalone = pkgutil_info(CLT_STANDALONE_PKG_ID)
      from_xcode = pkgutil_info(CLT_FROM_XCODE_PKG_ID)

      if not standalone.empty?
        standalone =~ /version: (.*)$/
        $1
      elsif not from_xcode.empty?
        from_xcode =~ /version: (.*)$/
        $1
      else
        # We return "" instead of nil because we want clt_installed? to be true on older Macs.
        # So clt_version.empty? does not mean there are no unix tools in /usr, it just means
        # that the "Command Line Tools for Xcode" package is not installed
        "" # No CLT or recipe available to pkgutil.
      end
    end
  end

  # Locate the "current Xcode folder" via xcode-select. See:
  # man xcode-select
  def xcode_folder
    @xcode_folder ||= `xcode-select -print-path 2>/dev/null`.strip
  end

  # Xcode 4.3 tools hang if "/" is set
  def xctools_fucked?
    xcode_folder == "/"
  end

  def locate tool
    # Don't call tools (cc, make, strip, etc.) directly!
    # Give the name of the binary you look for as a string to this method
    # in order to get the full path back as a Pathname.
    tool = tool.to_s

    @locate_cache ||= {}
    return @locate_cache[tool] if @locate_cache.has_key? tool

    if File.executable? "/usr/bin/#{tool}"
      path = Pathname.new "/usr/bin/#{tool}"
    else
      # Xcrun was provided first with Xcode 4.3 and allows us to proxy
      # tool usage thus avoiding various bugs.
      p = `/usr/bin/xcrun -find #{tool} 2>/dev/null`.chomp unless MacOS.xctools_fucked?
      if !p.nil? and !p.empty? and File.executable? p
        path = Pathname.new p
      else
        # This is for the use-case where xcode-select is not set up correctly
        # with Xcode 4.3+. The tools in Xcode 4.3+ are split over two locations,
        # usually xcrun would figure that out for us, but it won't work if
        # xcode-select is not configured properly.
        p = "#{MacOS.dev_tools_path}/#{tool}"
        if File.executable? p
          path = Pathname.new p
        else
          # Otherwise lets look in the second location.
          p = "#{MacOS.xctoolchain_path}/usr/bin/#{tool}"
          if File.executable? p
            path = Pathname.new p
          else
            # We digged so deep but all is lost now.
            path = nil
          end
        end
      end
    end
    @locate_cache[tool] = path
    return path
  end

  def dev_tools_path
    @dev_tools_path ||= if File.exist? "/usr/bin/cc" and File.exist? "/usr/bin/make"
      # probably a safe enough assumption (the unix way)
      Pathname.new "/usr/bin"
    elsif not xctools_fucked? and system "/usr/bin/xcrun -find make 1>/dev/null 2>&1"
      # Wherever "make" is there are the dev tools.
      Pathname.new(`/usr/bin/xcrun -find make`.chomp).dirname
    elsif File.exist? "#{xcode_prefix}/usr/bin/make"
      # cc stopped existing with Xcode 4.3, there are c89 and c99 options though
      Pathname.new "#{xcode_prefix}/usr/bin"
    else
      # Since we are pretty unrelenting in finding Xcode no matter where
      # it hides, we can now throw in the towel.
      opoo "You really should consult the `brew doctor`!"
      ""
    end
  end

  def xctoolchain_path
    # As of Xcode 4.3, some tools are located in the "xctoolchain" directory
    @xctoolchain_path ||= begin
      path = Pathname.new("#{MacOS.xcode_prefix}/Toolchains/XcodeDefault.xctoolchain")
      # If only the CLT are installed, all tools will be under dev_tools_path,
      # this path won't exist, and xctoolchain_path will be nil.
      path if path.exist?
    end
  end

  def sdk_path(v=MacOS.version)
    @sdk_path ||= begin
      path = if !MacOS.xctools_fucked? and File.executable? "#{xcode_folder}/usr/bin/make"
        `#{locate('xcodebuild')} -version -sdk macosx#{v} Path 2>/dev/null`.strip
      elsif File.directory? '/Developer/SDKs/MacOS#{v}.sdk'
        # the old default (or wild wild west style)
        "/Developer/SDKs/MacOS#{v}.sdk"
      elsif File.directory? "#{xcode_prefix}/Platforms/MacOSX.platform/Developer/SDKs/MacOSX#{v}.sdk"
        # xcode_prefix is pretty smart, so lets look inside to find the sdk
        "#{xcode_prefix}/Platforms/MacOSX.platform/Developer/SDKs/MacOSX#{v}.sdk"
      end

      Pathname.new(path) unless path.nil? or path.empty? or not File.directory? path
    end
  end

  def default_cc
    cc = locate 'cc'
    Pathname.new(cc).realpath.basename.to_s rescue nil
  end

  def default_compiler
    case default_cc
      when /^gcc/ then :gcc
      when /^llvm/ then :llvm
      when "clang" then :clang
      else
        # guess :(
        if xcode_version >= "4.3"
          :clang
        elsif xcode_version >= "4.2"
          :llvm
        else
          :gcc
        end
    end
  end

  def xcode_prefix
    @xcode_prefix ||= begin
      path = Pathname.new xcode_folder
      if $?.success? and path.absolute? and File.executable? "#{path}/usr/bin/make"
        path
      elsif File.executable? '/Developer/usr/bin/make'
        # we do this to support cowboys who insist on installing
        # only a subset of Xcode
        Pathname.new '/Developer'
      elsif File.executable? '/Applications/Xcode.app/Contents/Developer/usr/bin/make'
        # fallback for broken Xcode 4.3 installs
        Pathname.new '/Applications/Xcode.app/Contents/Developer'
      else
        # Ask Spotlight where Xcode is. If the user didn't install the
        # helper tools and installed Xcode in a non-conventional place, this
        # is our only option. See: http://superuser.com/questions/390757
        path = app_with_bundle_id(XCODE_4_BUNDLE_ID) || app_with_bundle_id(XCODE_3_BUNDLE_ID)

        unless path.nil?
          path += "Contents/Developer"
          path if File.executable? "#{path}/usr/bin/make"
        end
      end
    end
  end

  def xcode_installed?
    # Telling us whether the Xcode.app is installed or not.
    @xcode_installed ||= File.directory?('/Applications/Xcode.app') ||
      File.directory?('/Developer/Applications/Xcode.app') ||
      app_with_bundle_id(XCODE_4_BUNDLE_ID) ||
      app_with_bundle_id(XCODE_3_BUNDLE_ID) ||
      false
  end

  def xcode_version
    # may return a version string
    # that is guessed based on the compiler, so do not
    # use it in order to check if Xcode is installed.
    @xcode_version ||= begin
      return "0" unless MACOS

      # this shortcut makes xcode_version work for people who don't realise you
      # need to install the CLI tools
      xcode43build = "/Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild"
      if File.file? xcode43build
        `#{xcode43build} -version 2>/dev/null` =~ /Xcode (\d(\.\d)*)/
        return $1 if $1
      end

      # Xcode 4.3 xc* tools hang indefinately if xcode-select path is set thus
      raise if xctools_fucked?

      raise unless which "xcodebuild"
      `xcodebuild -version 2>/dev/null` =~ /Xcode (\d(\.\d)*)/
      raise if $1.nil? or not $?.success?
      $1
    rescue
      # For people who's xcode-select is unset, or who have installed
      # xcode-gcc-installer or whatever other combinations we can try and
      # supprt. See https://github.com/mxcl/homebrew/wiki/Xcode
      case llvm_build_version.to_i
      when 1..2063 then "3.1.0"
      when 2064..2065 then "3.1.4"
      when 2366..2325
        # we have no data for this range so we are guessing
        "3.2.0"
      when 2326
        # also applies to "3.2.3"
        "3.2.4"
      when 2327..2333 then "3.2.5"
      when 2335
        # this build number applies to 3.2.6, 4.0 and 4.1
        # https://github.com/mxcl/homebrew/wiki/Xcode
        "4.0"
      else
        case (clang_version.to_f * 10).to_i
        when 0
          "dunno"
        when 1..14
          "3.2.2"
        when 15
          "3.2.4"
        when 16
          "3.2.5"
        when 17..20
          "4.0"
        when 21
          "4.1"
        when 22..30
          "4.2"
        when 31
          "4.3"
        when 40
          "4.4"
        else
          "4.4"
        end
      end
    end
  end

  def gcc_40_build_version
    @gcc_40_build_version ||= if locate("gcc-4.0")
      `#{locate("gcc-4.0")} --version` =~ /build (\d{4,})/
      $1.to_i
    end
  end

  def gcc_42_build_version
    @gcc_42_build_version ||= if locate("gcc-4.2") \
      and not locate("gcc-4.2").realpath.basename.to_s =~ /^llvm/
      `#{locate("gcc-4.2")} --version` =~ /build (\d{4,})/
      $1.to_i
    end
  end

  def llvm_build_version
    # for Xcode 3 on OS X 10.5 this will not exist
    # NOTE may not be true anymore but we can't test
    @llvm_build_version ||= if locate("llvm-gcc")
      `#{locate("llvm-gcc")} --version` =~ /LLVM build (\d{4,})/
      $1.to_i
    end
  end

  def clang_version
    @clang_version ||= if locate("clang")
      `#{locate("clang")} --version` =~ /clang version (\d\.\d)/
      $1
    end
  end

  def clang_build_version
    @clang_build_version ||= if locate("clang")
      `#{locate("clang")} --version` =~ %r[tags/Apple/clang-(\d{2,})]
      $1.to_i
    end
  end

  def xquartz_version
    # This returns the version number of XQuartz, not of the upstream X.org
    # (which is why it is not called x11_version). Note that the X11.app
    # distributed by Apple is also XQuartz, and therefore covered by this method.
    path = app_with_bundle_id(XQUARTZ_BUNDLE_ID) || app_with_bundle_id(APPLE_X11_BUNDLE_ID)
    version = if not path.nil? and path.exist?
      `mdls -raw -name kMDItemVersion #{path}`.strip
    end
  end

  def x11_prefix
    @x11_prefix ||= if Pathname.new('/opt/X11/lib/libpng.dylib').exist?
      Pathname.new('/opt/X11')
    elsif Pathname.new('/usr/X11/lib/libpng.dylib').exist?
      Pathname.new('/usr/X11')
    end
  end

  def x11_installed?
    not x11_prefix.nil?
  end

  def macports_or_fink_installed?
    # See these issues for some history:
    # http://github.com/mxcl/homebrew/issues/#issue/13
    # http://github.com/mxcl/homebrew/issues/#issue/41
    # http://github.com/mxcl/homebrew/issues/#issue/48
    return false unless MACOS

    %w[port fink].each do |ponk|
      path = which(ponk)
      return ponk unless path.nil?
    end

    # we do the above check because macports can be relocated and fink may be
    # able to be relocated in the future. This following check is because if
    # fink and macports are not in the PATH but are still installed it can
    # *still* break the build -- because some build scripts hardcode these paths:
    %w[/sw/bin/fink /opt/local/bin/port].each do |ponk|
      return ponk if File.exist? ponk
    end

    # finally, sometimes people make their MacPorts or Fink read-only so they
    # can quickly test Homebrew out, but still in theory obey the README's
    # advise to rename the root directory. This doesn't work, many build scripts
    # error out when they try to read from these now unreadable directories.
    %w[/sw /opt/local].each do |path|
      path = Pathname.new(path)
      return path if path.exist? and not path.readable?
    end

    false
  end

  def leopard?
    10.5 == MACOS_VERSION
  end

  def snow_leopard?
    10.6 <= MACOS_VERSION # Actually Snow Leopard or newer
  end

  def lion?
    10.7 <= MACOS_VERSION # Actually Lion or newer
  end

  def mountain_lion?
    10.8 <= MACOS_VERSION # Actually Mountain Lion or newer
  end

  def prefer_64_bit?
    Hardware.is_64_bit? and not leopard?
  end

  StandardCompilers = {
    "3.1.4" => {:gcc_40_build_version=>5493, :gcc_42_build_version=>5577},
    "3.2.6" => {:gcc_40_build_version=>5494, :gcc_42_build_version=>5666, :llvm_build_version=>2335, :clang_version=>"1.7", :clang_build_version=>77},
    "4.0" => {:gcc_40_build_version=>5494, :gcc_42_build_version=>5666, :llvm_build_version=>2335, :clang_version=>"2.0", :clang_build_version=>137},
    "4.0.1" => {:gcc_40_build_version=>5494, :gcc_42_build_version=>5666, :llvm_build_version=>2335, :clang_version=>"2.0", :clang_build_version=>137},
    "4.0.2" => {:gcc_40_build_version=>5494, :gcc_42_build_version=>5666, :llvm_build_version=>2335, :clang_version=>"2.0", :clang_build_version=>137},
    "4.2" => {:llvm_build_version=>2336, :clang_version=>"3.0", :clang_build_version=>211},
    "4.3" => {:llvm_build_version=>2336, :clang_version=>"3.1", :clang_build_version=>318},
    "4.3.1" => {:llvm_build_version=>2336, :clang_version=>"3.1", :clang_build_version=>318},
    "4.3.2" => {:llvm_build_version=>2336, :clang_version=>"3.1", :clang_build_version=>318},
    "4.3.3" => {:llvm_build_version=>2336, :clang_version=>"3.1", :clang_build_version=>318},
    "4.4" => {:llvm_build_version=>2336, :clang_version=>"4.0", :clang_build_version=>421}
  }

  def compilers_standard?
    xcode = MacOS.xcode_version
    # Assume compilers are okay if Xcode version not in hash
    return true unless StandardCompilers.keys.include? xcode

    StandardCompilers[xcode].all? {|k,v| MacOS.send(k) == v}
  end

  def app_with_bundle_id id
    mdfind(MDITEM_BUNDLE_ID_KEY, id)
  end

  private

  def mdfind attribute, id
    path = `mdfind "#{attribute} == '#{id}'"`.strip
    Pathname.new(path) unless path.empty?
  end

  def pkgutil_info id
    `pkgutil --pkg-info #{id} 2>/dev/null`.strip
  end
end