module Grit

  class Tag < Ref
    extend Lazy

    lazy_reader :message
    lazy_reader :tagger
    lazy_reader :tag_date

    # Writes a new tag object from a hash
    #  +repo+ is a Grit repo
    #  +hash+ is the hash of tag values
    #
    # Returns a hash with +sha+ and +size+ of the created object
    def self.create_tag_object(repo, hash, default_actor = nil)
      tagger = hash[:tagger]
      if !tagger
        tagger = default_actor ? default_actor : Actor.new("none", "none@none")
        tagger_date = Time.now
      else
        tagger_date = tagger[:date] ? Time.parse(tagger[:date]) : Time.now
        tagger = Actor.new(tagger[:name], tagger[:email])
      end
      data = []
      data << "object #{hash[:object]}"
      data << "type #{hash[:type]}"
      data << "tag #{hash[:tag]}"
      data << "tagger #{tagger.output(tagger_date)}"
      data << ""
      data << hash[:message]
      data = data.join("\n")
      sha = repo.git.put_raw_object(data, 'tag')
      { :sha => sha, :size => data.size }
    end

    # Parses the results from `cat-file -p`
    #
    # data - String tag object data.  Example:
    #          object 7bcc0ee821cdd133d8a53e8e7173a334fef448aa
    #          type commit
    #          tag v0.7.0
    #          tagger USER <EMAIL> DATE
    #          
    #          v0.7.0
    #
    # Returns parsed Hash.  Example: 
    #   {:message => "...", :tagger => "bob", :tag_date => ...}
    def self.parse_tag_data(data)
      return unless data =~ /^object/
      parsed = {}
      lines  = data.split("\n")
      parsed[:object] = lines.shift.sub(/^object /, '')
      parsed[:type] = lines.shift.sub(/^type /, '')
      parsed[:tag] = lines.shift.sub(/^tag /, '')
      author_line = lines.shift
      parsed[:tagger], parsed[:tag_date] = Commit.actor(author_line)
      if !parsed[:tagger] || !parsed[:tagger].name
        parsed[:tag_date] ||= Time.utc(1970)
        parsed[:tagger]     = Actor.from_string(author_line.sub(/^tagger /, ''))
      end
      lines.shift # blank line
      parsed[:message] = []
      while lines.first && lines.first !~ /-----BEGIN PGP SIGNATURE-----/
        parsed[:message] << lines.shift
      end
      parsed[:message] = parsed[:message] * "\n"
      parsed[:pgp] = []
      while lines.first
        parsed[:pgp] << lines.shift
      end
      parsed[:pgp] = parsed[:pgp] * "\n"
      parsed
    end

    def lazy_source
      data         = commit.repo.git.cat_ref({:p => true}, name)
      @message     = commit.short_message
      @tagger      = commit.author
      @tag_date    = commit.authored_date
      return self if data.empty?

      if parsed = self.class.parse_tag_data(data)
        @message  = parsed[:message]
        @tagger   = parsed[:tagger]
        @tag_date = parsed[:tag_date]
      end
      self
    end

    def get_commit
      sha = @repo_ref.git.commit_from_sha(@commit_id)
      raise "Unknown object type." if sha == ''
      Commit.create(@repo_ref, :id => sha)
    end
  end

end