module MultiRepo::Service
  class RubygemsStub
    attr_reader :repo, :owners, :dry_run

    def initialize(repo, owners: [], dry_run: false, **_)
      @repo    = repo
      @owners  = owners
      @dry_run = dry_run
    end

    def run
      if stub_exists?
        puts "A stub gem for #{repo.inspect} already exists."
        return
      end

      if gem_exists?
        puts "A gem for #{repo.inspect} already exists with the following versions:"
        puts "  #{gem_versions}"
        puts
        loop do
          print "Would you still like to create a stub? (y/N) "
          answer = gets.chomp.downcase[0] || "n"
          break  if answer == "y"
          return if answer == "n"
        end
        puts
      end

      Dir.mktmpdir do |dir|
        package = create_gem(dir)
        push_gem(package)

        owners.each do |o|
          set_gem_owner(o)
        end
      end
    end

    private

    def stub_exists?
      gem_versions.include?("0.0.1")
    end

    def gem_exists?
      gem_string.presence
    end

    # Returns a gem's versions as listed by gem list
    #
    # Example (where @repo is the "foo" gem):
    #   # => ["2.1.0", "2.0.0", "1.1.0", "1.0.0"]
    def gem_versions
      gem_string.split(" ", 2).last.to_s[1..-2].to_s.split(", ")
    end

    # Returns a gem string as listed by gem list
    #
    # Example (where @repo is the "foo" gem):
    #   # => "foo (2.1.0, 2.0.0, 1.1.0, 1.0.0)"
    def gem_string
      @gem_string ||= `gem list #{repo} --exact --remote --all`.chomp.split("\n").last.to_s
    end

    def create_gem(dir)
      path = File.join(dir, "#{repo}.gemspec")
      File.write(path , <<~RUBY)
        Gem::Specification.new do |s|
          s.name        = "#{repo}"
          s.version     = "0.0.1"
          s.licenses    = ["Apache-2.0"]
          s.summary     = "#{repo}"
          s.description = s.summary
          s.authors     = ["ManageIQ Authors"]
          s.homepage    = "https://github.com/ManageIQ/#{repo}"
          s.metadata    = { "source_code_uri" => s.homepage }
        end
      RUBY

      system("gem build #{path}", :chdir => dir)

      File.join(dir, "#{repo}-0.0.1.gem")
    end

    def push_gem(package)
      if dry_run
        raise "#{package} not found" unless File.file?(package)
        puts "** dry-run: gem push #{package}".light_black
      else
        system("gem push #{package}")
      end
    end

    def set_gem_owner(owner)
      if dry_run
        puts "** dry-run: gem owner #{repo} --add #{owner}".light_black
      else
        system("gem owner #{repo} --add #{owner}")
      end
    end
  end
end