#
# BaseEmitter
#

require 'yaml/constants'
require 'yaml/encoding'
require 'yaml/error'

module YAML

    module BaseEmitter

        def options( opt = nil )
            if opt
                @options[opt] || YAML::DEFAULTS[opt]
            else
                @options
            end
        end

        def options=( opt )
            @options = opt
        end

        #
        # Emit binary data
        #
        def binary_base64( value )
            self << "!binary "
            self.node_text( [value].pack("m"), '|' )
        end

		#
		# Emit plain, normal flowing text
		#
		def node_text( value, block = '>' )
            @seq_map = false
			valx = value.dup
			if options(:UseBlock)
				block = '|'
			elsif not options(:UseFold) and valx =~ /\n[ \t]/ and not valx =~ /#{YAML::ESCAPE_CHAR}/
				block = '|'
			end 
			str = block.dup
			if valx =~ /\n\Z\n/
				str << "+"
			elsif valx =~ /\Z\n/
			else
				str << "-"
			end
			if valx =~ /#{YAML::ESCAPE_CHAR}/
				valx = YAML::escape( valx )
			end
			if valx =~ /\A[ \t#]/
				str << options(:Indent).to_s
			end
			if block == '>'
				valx = fold( valx ) 
			end
			self << str + indent_text( valx ) + "\n"
		end

		#
		# Emit a simple, unqouted string
		#
		def simple( value )
            @seq_map = false
            self << value.to_s
		end

		#
		# Emit double-quoted string
		#
		def double( value )
			"\"#{YAML.escape( value )}\"" 
		end

		#
		# Emit single-quoted string
		#
		def single( value )
			"'#{value}'"
		end

		#
		# Write a text block with the current indent
		#
		def indent_text( text )
			return "" if text.to_s.empty?
            spacing = " " * ( level * options(:Indent) )
			return "\n" + text.gsub( /^([^\n])/, "#{spacing}\\1" )
		end

		#
		# Write a current indent
		#
		def indent
            #p [ self.id, @level, :INDENT ]
			return " " * ( level * options(:Indent) )
		end

		#
		# Add indent to the buffer
		#
		def indent!
			self << indent
		end

		#
		# Folding paragraphs within a column
		#
		def fold( value )
			value.gsub!( /\A\n+/, '' )
			folded = $&.to_s
			width = (0..options(:BestWidth))
			while not value.empty?
				last = value.index( /(\n+)/ )
				chop_s = false
				if width.include?( last )
					last += $1.length - 1
				elsif width.include?( value.length )
					last = value.length
				else
					last = value.rindex( /[ \t]/, options(:BestWidth) )
					chop_s = true
				end
				folded += value.slice!( 0, width.include?( last ) ? last + 1 : options(:BestWidth) )
				folded.chop! if chop_s
				folded += "\n" unless value.empty?
			end
			folded
		end

        #
        # Quick mapping
        #
        def map( type, &e )
            val = Mapping.new
            e.call( val )
			self << "#{type} " if type.length.nonzero?

			#
			# Empty hashes
			#
			if val.length.zero?
				self << "{}"
                @seq_map = false
			else
                # FIXME
                # if @buffer.length == 1 and options(:UseHeader) == false and type.length.zero? 
			    #     @headless = 1 
                # end

                defkey = @options.delete( :DefaultKey )
                if defkey
                    seq_map_shortcut
                    self << "= : "
                    defkey.to_yaml( :Emitter => self )
                end

				#
				# Emit the key and value
				#
                val.each { |v|
                    seq_map_shortcut
                    if v[0].is_complex_yaml?
                        self << "? "
                    end
                    v[0].to_yaml( :Emitter => self )
                    if v[0].is_complex_yaml?
                        self << "\n"
                        indent!
                    end
                    self << ": " 
                    v[1].to_yaml( :Emitter => self )
                }
			end
        end

        def seq_map_shortcut
            # FIXME: seq_map needs to work with the new anchoring system
            # if @seq_map
            #     @anchor_extras[@buffer.length - 1] = "\n" + indent
            #     @seq_map = false
            # else
                self << "\n"
                indent! 
            # end
        end

        #
        # Quick sequence
        #
        def seq( type, &e )
            @seq_map = false
            val = Sequence.new
            e.call( val )
			self << "#{type} " if type.length.nonzero?

			#
			# Empty arrays
			#
			if val.length.zero?
				self << "[]"
			else
                # FIXME
                # if @buffer.length == 1 and options(:UseHeader) == false and type.length.zero? 
			    #     @headless = 1 
                # end

				#
				# Emit the key and value
				#
                val.each { |v|
                    self << "\n"
                    indent!
                    self << "- "
                    @seq_map = true if v.class == Hash
                    v.to_yaml( :Emitter => self )
                }
			end
        end

    end

    #
    # Emitter helper classes
    #
    class Mapping < Array
        def add( k, v )
            push [k, v]
        end
    end

    class Sequence < Array
        def add( v )
            push v
        end
    end

end