module Calabash
  module Android
    VERSION = "0.9.22"

    # A model of a software release version that can be used to compare two versions.
    #
    # Calabash and RunLoop try very hard to comply with Semantic Versioning rules.
    # However, the semantic versioning spec is incompatible with RubyGem's patterns
    # for pre-release gems.
    #
    # > "But returning to the practical: No release version of SemVer is compatible
    # > with Rubygems." - _David Kellum_
    #
    # Calabash and RunLoop version numbers will be in the form `<major>.<minor>.<patch>[.pre<N>]`.
    #
    # @see http://semver.org/
    # @see http://gravitext.com/2012/07/22/versioning.html
    #
    # TODO Expand to handle versions with more than 1 "." and no "."
    # ^ Needs to handle arbitrary versions from Info.plists.  In particular it
    #   needs to handle a unix timestamp - found the DeviceAgent-Runner.app.
    class Version

      # @!attribute [rw] major
      #   @return [Integer] the major version
      attr_accessor :major

      # @!attribute [rw] minor
      #   @return [Integer] the minor version
      attr_accessor :minor

      # @!attribute [rw] patch
      #   @return [Integer] the patch version
      attr_accessor :patch

      # @!attribute [rw] pre
      #   @return [Boolean] true if this is a pre-release version
      attr_accessor :pre

      # @!attribute [rw] pre_version
      #   @return [Integer] if this is a pre-release version, returns the
      #     pre-release version; otherwise this is nil
      attr_accessor :pre_version

      # Creates a new Version instance with all the attributes set.
      #
      # @example
      #  version = Version.new(0.10.1)
      #  version.major       => 0
      #  version.minor       => 10
      #  version.patch       => 1
      #  version.pre         => false
      #  version.pre_version => nil
      #
      # @example
      #  version = Version.new(1.6.3.pre5)
      #  version.major       => 1
      #  version.minor       => 6
      #  version.patch       => 3
      #  version.pre         => true
      #  version.pre_version => 5
      #
      # @param [String] version the version string to parse.
      # @raise [ArgumentError] if version is not in the form 5, 6.1, 7.1.2, 8.2.3.pre1
      def initialize(version)
        tokens = version.strip.split('.')
        count = tokens.count
        if tokens.empty?
          raise ArgumentError, "expected '#{version}' to be like 5, 6.1, 7.1.2, 8.2.3.pre1"
        end

        if count < 4 and tokens.any? { |elm| elm =~ /\D/ }
          raise ArgumentError, "expected '#{version}' to be like 5, 6.1, 7.1.2, 8.2.3.pre1"
        end

        if count == 4
          @pre = tokens[3]
          pre_tokens = @pre.scan(/\D+|\d+/)
          @pre_version = pre_tokens[1].to_i if pre_tokens.count == 2
        end

        @major, @minor, @patch = version.split('.').map(&:to_i)
      end

      # Returns an string representation of this version.
      # @return [String] a string in the form `<major>.<minor>.<patch>[.pre<N>]`
      def to_s
        str = [major, minor, patch].compact.join('.')
        str = "#{str}.#{pre}" if pre
        str
      end

      def inspect
        "#<Version #{to_s}>"
      end

      # Compare this version to another for _object_ equality.  This allows
      # Version instances to be used as Hash keys.
      # @param [Version] other the version to compare against.
      def eql?(other)
        hash == other.hash
      end

      # The hash method for this instance.
      def hash
        str = [major, minor, patch].map do |str|
          str ? str : "0"
        end.join(".")

        if pre
          str = "#{str}.#{pre}"
        end

        str.hash
      end

      # Compare this version to another for equality.
      # @param [Version] other the version to compare against
      # @return [Boolean] true if this Version is the same as `other`
      def == (other)
        Version.compare(self, other) == 0
      end

      # Compare this version to another for inequality.
      # @param [Version] other the version to compare against
      # @return [Boolean] true if this Version is not the same as `other`
      def != (other)
        Version.compare(self, other) != 0
      end

      # Is this version less-than another version?
      # @param [Version] other the version to compare against
      # @return [Boolean] true if this Version is less-than `other`
      def < (other)
        Version.compare(self, other) < 0
      end

      # Is this version greater-than another version?
      # @param [Version] other the version to compare against
      # @return [Boolean] true if this Version is greater-than `other`
      def > (other)
        Version.compare(self, other) > 0
      end

      # Is this version less-than or equal to another version?
      # @param [Version] other the version to compare against
      # @return [Boolean] true if this Version is less-than or equal `other`
      def <= (other)
        Version.compare(self, other) <= 0
      end

      # Is this version greater-than or equal to another version?
      # @param [Version] other the version to compare against
      # @return [Boolean] true if this Version is greater-than or equal `other`
      def >= (other)
        Version.compare(self, other) >= 0
      end

      # Compare version `a` to version `b`.
      #
      # @example
      #   compare Version.new(0.10.0), Version.new(0.9.0)  =>  1
      #   compare Version.new(0.9.0),  Version.new(0.10.0) => -1
      #   compare Version.new(0.9.0),  Version.new(0.9.0)  =>  0
      #
      # @return [Integer] an integer `(-1, 1)`
      def <=> (other)
        Version.compare(self, other)
      end

      # Compare version `a` to version `b`.
      #
      # @example
      #   compare Version.new(0.10.0), Version.new(0.9.0)  =>  1
      #   compare Version.new(0.9.0),  Version.new(0.10.0) => -1
      #   compare Version.new(0.9.0),  Version.new(0.9.0)  =>  0
      #
      # @return [Integer] an integer `(-1, 1)`
      def self.compare(a, b)

        if a.major != b.major
          return a.major.to_i > b.major.to_i ? 1 : -1
        end

        a_minor = a.minor ? a.minor.to_i : 0
        b_minor = b.minor ? b.minor.to_i : 0
        if a_minor != b_minor
          return a_minor > b_minor.to_i ? 1 : -1
        end

        a_patch = a.patch ? a.patch.to_i : 0
        b_patch = b.patch ? b.patch.to_i : 0
        if a_patch != b_patch
          return a_patch.to_i > b_patch.to_i ? 1 : -1
        end

        return -1 if a.pre && (!a.pre_version) && b.pre_version
        return 1 if a.pre_version && b.pre && (!b.pre_version)

        return -1 if a.pre && (!b.pre)
        return 1 if (!a.pre) && b.pre

        return -1 if a.pre_version && (!b.pre_version)
        return 1 if (!a.pre_version) && b.pre_version

        if a.pre_version != b.pre_version
          return a.pre_version.to_i > b.pre_version.to_i ? 1 : -1
        end
        0
      end
    end
  end
end