require "rubygems"

module Hbc
  class DSL
    class DependsOn
      VALID_KEYS = Set.new [
                             :formula,
                             :cask,
                             :macos,
                             :arch,
                             :x11,
                             :java,
                           ].freeze

      VALID_ARCHES = {
                       intel:    { type: :intel, bits: [32, 64] },
                       ppc:      { type: :ppc,   bits: [32, 64] },
                       # specific
                       i386:     { type: :intel, bits: 32 },
                       x86_64:   { type: :intel, bits: 64 },
                       ppc_7400: { type: :ppc,   bits: 32 },
                       ppc_64:   { type: :ppc,   bits: 64 },
                     }.freeze

      # Intentionally undocumented: catch variant spellings.
      ARCH_SYNONYMS = {
                        x86_32:   :i386,
                        x8632:    :i386,
                        x8664:    :x86_64,
                        intel_32: :i386,
                        intel32:  :i386,
                        intel_64: :x86_64,
                        intel64:  :x86_64,
                        amd_64:   :x86_64,
                        amd64:    :x86_64,
                        ppc7400:  :ppc_7400,
                        ppc_32:   :ppc_7400,
                        ppc32:    :ppc_7400,
                        ppc64:    :ppc_64,
                      }.freeze

      attr_accessor :java
      attr_accessor :pairs
      attr_reader :arch, :cask, :formula, :macos, :x11

      def initialize
        @pairs ||= {}
      end

      def load(pairs = {})
        pairs.each do |key, value|
          raise "invalid depends_on key: '#{key.inspect}'" unless VALID_KEYS.include?(key)
          writer_method = "#{key}=".to_sym
          @pairs[key] = send(writer_method, value)
        end
      end

      def self.coerce_os_release(arg)
        @macos_symbols ||= MacOS::Version::SYMBOLS
        @inverted_macos_symbols ||= @macos_symbols.invert

        begin
          if arg.is_a?(Symbol)
            Gem::Version.new(@macos_symbols.fetch(arg))
          elsif arg =~ %r{^\s*:?([a-z]\S+)\s*$}i
            Gem::Version.new(@macos_symbols.fetch(Regexp.last_match[1].downcase.to_sym))
          elsif @inverted_macos_symbols.key?(arg)
            Gem::Version.new(arg)
          else
            raise
          end
        rescue StandardError
          raise "invalid 'depends_on macos' value: #{arg.inspect}"
        end
      end

      def formula=(*arg)
        @formula ||= []
        @formula.concat(Array(*arg))
      end

      def cask=(*arg)
        @cask ||= []
        @cask.concat(Array(*arg))
      end

      def macos=(*arg)
        @macos ||= []
        macos = if arg.count == 1 && arg.first =~ %r{^\s*(<|>|[=<>]=)\s*(\S+)\s*$}
                  raise "'depends_on macos' comparison expressions cannot be combined" unless @macos.empty?
                  operator = Regexp.last_match[1].to_sym
                  release = self.class.coerce_os_release(Regexp.last_match[2])
                  [[operator, release]]
                else
                  raise "'depends_on macos' comparison expressions cannot be combined" if @macos.first.is_a?(Symbol)
                  Array(*arg).map { |elt|
                    self.class.coerce_os_release(elt)
                  }.sort
                end
        @macos.concat(macos)
      end

      def arch=(*arg)
        @arch ||= []
        arches = Array(*arg).map { |elt|
          elt = elt.to_s.downcase.sub(%r{^:}, "").tr("-", "_").to_sym
          ARCH_SYNONYMS.key?(elt) ? ARCH_SYNONYMS[elt] : elt
        }
        invalid_arches = arches - VALID_ARCHES.keys
        raise "invalid 'depends_on arch' values: #{invalid_arches.inspect}" unless invalid_arches.empty?
        @arch.concat(arches.map { |arch| VALID_ARCHES[arch] })
      end

      def x11=(arg)
        raise "invalid 'depends_on x11' value: #{arg.inspect}" unless [true, false].include?(arg)
        @x11 = arg
      end

      def to_yaml
        @pairs.to_yaml
      end

      def to_s
        @pairs.inspect
      end
    end
  end
end