module ConfCtl
  class Generation::Unified
    # @return [String]
    attr_reader :host

    # @return [String]
    attr_reader :name

    # @return [Integer, nil]
    attr_reader :id

    # @return [String]
    attr_reader :toplevel

    # @return [Time]
    attr_reader :date

    # @return [Boolean]
    attr_reader :current

    # @return [Generation::Build]
    attr_reader :build_generation

    # @return [Generation::Host]
    attr_reader :host_generation

    # @param host [String]
    # @param build_generation [Generation::Build]
    # @param host_generation [Generation::Host]
    def initialize(host, build_generation: nil, host_generation: nil)
      @host = host
      @build_generation = build_generation
      @host_generation = host_generation
      @id = host_generation && host_generation.id

      if build_generation
        @name = build_generation.name
        @toplevel = build_generation.toplevel
        @date = build_generation.date
        @current ||= build_generation.current
      elsif host_generation
        @name = host_generation.approx_name
        @toplevel = host_generation.toplevel
        @date = host_generation.date
        @current ||= host_generation.current
      else
        raise ArgumentError, 'set build or host'
      end
    end

    # @param gen [Generation::Build]
    def build_generation=(gen)
      @name = gen.name
      @date = gen.date
      @current ||= gen.current
      @build_generation = gen
    end

    # @param gen [Generation::Host]
    def host_generation=(gen)
      @id = gen.id
      @current ||= gen.current
      @host_generation = gen
    end

    # Determines whether `gen` can be wrapped by this object
    # @param gen [Generation::Build, Generation::Host]
    # @return [Boolean]
    def includes?(gen)
      return false if host != gen.host || toplevel != gen.toplevel

      if build_generation && gen.is_a?(Generation::Build)
        build_generation.name == gen.name \
          && build_generation.swpin_paths == gen.swpin_paths
      else
        true
      end
    end

    %i[swpin_names swpin_specs].each do |v|
      define_method(v) do
        build_generation ? build_generation.send(v) : []
      end
    end

    def current_str
      build = build_generation && build_generation.current
      host = host_generation && host_generation.current

      if build && host
        'build+host'
      elsif build
        'build'
      elsif host
        'host'
      end
    end

    def presence_str
      if build_generation && host_generation
        'build+host'
      elsif build_generation
        'build'
      elsif host_generation
        'host'
      else
        raise 'programming error'
      end
    end

    def destroy
      build_generation.destroy if build_generation
      host_generation.destroy if host_generation
      true
    end
  end
end