module OS
  module Mac
    X11 = XQuartz = Module.new

    module XQuartz
      extend self

      FORGE_BUNDLE_ID = "org.macosforge.xquartz.X11"
      APPLE_BUNDLE_ID = "org.x.X11"
      FORGE_PKG_ID = "org.macosforge.xquartz.pkg"

      PKGINFO_VERSION_MAP = {
        "2.6.34" => "2.6.3",
        "2.7.4"  => "2.7.0",
        "2.7.14" => "2.7.1",
        "2.7.28" => "2.7.2",
        "2.7.32" => "2.7.3",
        "2.7.43" => "2.7.4",
        "2.7.50" => "2.7.5_rc1",
        "2.7.51" => "2.7.5_rc2",
        "2.7.52" => "2.7.5_rc3",
      }.freeze

      # This returns the version number of XQuartz, not of the upstream X.org.
      # The X11.app distributed by Apple is also XQuartz, and therefore covered
      # by this method.
      def version
        @version ||= detect_version
      end

      def detect_version
        if (path = bundle_path) && path.exist? && (version = version_from_mdls(path))
          version
        elsif prefix.to_s == "/usr/X11"
          guess_system_version
        else
          version_from_pkgutil
        end
      end

      def latest_version
        "2.7.4"
      end

      def bundle_path
        MacOS.app_with_bundle_id(FORGE_BUNDLE_ID) || MacOS.app_with_bundle_id(APPLE_BUNDLE_ID)
      end

      def version_from_mdls(path)
        version = `mdls -raw -nullMarker "" -name kMDItemVersion "#{path}" 2>/dev/null`.strip
        version unless version.empty?
      end

      # The XQuartz that Apple shipped in OS X through 10.7 does not have a
      # pkg-util entry, so if Spotlight indexing is disabled we must make an
      # educated guess as to what version is installed.
      def guess_system_version
        case MacOS.version
        when '10.5' then '2.1.6'
        when '10.6' then '2.3.6'
        when '10.7' then '2.6.3'
        else 'dunno'
        end
      end

      # Upstream XQuartz *does* have a pkg-info entry, so if we can't get it
      # from mdls, we can try pkgutil. This is very slow.
      def version_from_pkgutil
        str = MacOS.pkgutil_info(FORGE_PKG_ID)[/version: (\d\.\d\.\d+)$/, 1]
        PKGINFO_VERSION_MAP.fetch(str, str)
      end

      def provided_by_apple?
        [FORGE_BUNDLE_ID, APPLE_BUNDLE_ID].find do |id|
          MacOS.app_with_bundle_id(id)
        end == APPLE_BUNDLE_ID
      end

      # This should really be private, but for compatibility reasons it must
      # remain public. New code should use MacOS::X11.{bin,lib,include}
      # instead, as that accounts for Xcode-only systems.
      def prefix
        @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 installed?
        !version.nil? && !prefix.nil?
      end

      # If XQuartz and/or the CLT are installed, headers will be found under
      # /opt/X11/include or /usr/X11/include. For Xcode-only systems, they are
      # found in the SDK, so we use sdk_path for both the headers and libraries.
      # Confusingly, executables (e.g. config scripts) are only found under
      # /opt/X11/bin or /usr/X11/bin in all cases.
      def effective_prefix
        if provided_by_apple? && Xcode.without_clt?
          Pathname.new("#{OS::Mac.sdk_path}/usr/X11")
        else
          prefix
        end
      end

      def bin
        prefix/"bin"
      end

      def include
        effective_prefix/"include"
      end

      def lib
        effective_prefix/"lib"
      end

      def share
        prefix/"share"
      end
    end
  end
end