module YSI
  class Engine
    attr_reader :assertions
    attr_accessor :version, :tag_date
    attr_accessor :out
    attr_accessor :dry_run

    def self.class_for_assertion_name(name)
      class_name = name.split("_").map { |n| n.capitalize }.join
      begin
        Object.const_get("YSI::" + class_name)
      rescue NameError
        raise YSI::Error.new("Error: Unknown assertion '#{name}'")
      end
    end

    def initialize
      @assertions = []
      @out = STDOUT
    end

    def read(filename)
      config = YAML.load_file(filename)

      assertions = config["assertions"]
      if assertions
        assertions.each do |assertion|
          if assertion == "version_number"
            out.puts "Warning: use `version` instead of `version_number`."
            out.puts
            assertion = "version"
          end

          @assertions << YSI::Engine.class_for_assertion_name(assertion).new(self)
        end
      end
    end

    def project_name
      File.basename(Dir.pwd)
    end

    def run
      failed_assertions = []
      errored_assertions = []

      @assertions.each do |assertion|
        out.print "Checking #{assertion.display_name}: "
        success = assertion.check
        if success
          out.puts success
        else
          if assertion.error
            out.puts "error"
            out.puts "  " + assertion.error
            errored_assertions.push(assertion)
          else
            out.puts "fail"
            failed_assertions.push(assertion)
          end
        end
      end

      out.puts

      if !errored_assertions.empty?
        out.puts "Couldn't ship #{project_name}. Help me."
        return 1
      else
        if failed_assertions.empty?
          if tag_date
            out.puts "#{project_name} #{version} already shipped on #{tag_date}"
          else
            out.puts "#{project_name} #{version} already shipped"
          end
          return 0
        else
          failed_assertions.each do |assertion|
            if dry_run
              out.print "Dry run: "
            end
            out.print "Asserting #{assertion.display_name}: "
            success = assertion.assert(dry_run: dry_run)
            if !success
              out.puts
              out.puts "Ran into an error. Stopping shipping."
              return 1
            end
            out.puts success
          end

          out.puts
          if dry_run
            out.puts "Did a dry run of shipping #{project_name} #{version}." +
              " Nothing was changed."
          else
            out.puts "Shipped #{project_name} #{version}. Hooray!"
          end
          return 0
        end
      end
    end
  end
end