class GeoRuby::SimpleFeatures::LineString

  def is_closed
        #a bit naive...
      points.first == points.last
  end
  alias :closed? :is_closed

  def change(options)
    self.class.from_points(options[:points] || points, 
                           options[:srid] || srid,
                           options[:with_z] || with_z, 
                           options[:with_m] || with_m)
    # or instead of || requires parenthesis
  end

  def reverse
    change :points => points.reverse
  end

  def project_to(target_srid)
    return self if srid == target_srid
    change :points => points.map { |point| point.project_to(target_srid) }, :srid => target_srid
  end

  def self.merge(lines)
    # FIXME flatten.uniq can break crossing lines
    merged_points = lines.map(&:points).flatten.uniq
    if merged_points.size > 1
      from_points merged_points, srid!(lines), lines.first.with_z, lines.first.with_m
    end
  end
  
  def to_rgeo
    rgeo_factory.line_string(points.collect(&:to_rgeo))
   end

  def side_count
    size - 1
  end

  def ==(other)
    other.respond_to?(:points) and points == other.points
  end

  def close!
    points << points.first unless closed?
    self
  end

  def to_ring
    GeoRuby::SimpleFeatures::LinearRing.from_points points, srid, with_z, with_m
  end

  def to_kml
    GeoRuby::SimpleFeatures::Geometry.to_kml self
  end

end