require 'eymiha/math3'
require 'envelope'

# Envelope3 is the minimum 3D envelope that will completely contain a set of
# 3D points. 3D cartersian points or other 3D envelopes may be added to an
# instance, and it can return the number or points considered so far, the
# x, y and z envelopes, and the high and low Point3 boundaries.
class Envelope3 < BaseEnvelope

  include ThreeDimensions
  
  # 3D cartesian x coordinate envelope reader.
  attr_reader :x
  # 3D cartesian y coordinate envelope reader.
  attr_reader :y
  # 3D cartesian z coordinate envelope reader.
  attr_reader :z
  
  # Creates and returns an instance. If arguments are given, they are passed to
  # the set method to initialize the new instance.
  def initialize(x=nil,y=0,z=0)
    super()
    @x = Envelope.new
    @y = Envelope.new
    @z = Envelope.new
    add(x,y,z) unless x == nil
  end
  
  # Returns a string representation of the instance.
  def to_s
    values = (count > 0)? "\n  high  #{high}\n  low   #{low}" : ""
    "Envelope3: count #{count}#{values}"
  end
  
  # Adds a value to the instance. When
  # * x is an Envelope3, it is coalesced into the instance.
  # * x responds like a Point3, its coordinates are added.
  # * x us Numeric, the arguments are added.
  # * otherwise, an EnvelopeException is raised.
  # The modified instance is returned.
  def add(x=0,y=0,z=0)
    if x.kind_of? Envelope3
      count = x.count
      if count > 0
        add x.high
        add x.low
        @count += (count-2)
      end
      self
    elsif x.point3_like?
      add x.x, x.y, x.z
    elsif x.kind_of? Numeric
      @x.add x
      @y.add y
      @z.add z
      @count += 1
      self
    else
      raise_no_compare x
    end
  end
  
  # Returns a Point3 whose coordinates are the high values of the x, y, and z
  # envelopes.
  # * if there are no boundaries, an EnvelopeException is raised.
  def high
    raise_no_envelope if @count == 0
    (@high ||= Point3.new).set @x.high, @y.high, @z.high
  end
  
  # Returns a Point3 whose coordinates are the low values of the x, y, and z
  # envelopes.
  # * if there are no boundaries, an EnvelopeException is raised.
  def low
    raise_no_envelope if @count == 0
    (@low ||= Point3.new).set @x.low, @y.low, @z.low
  end

  # Returns true if the instance completely contains the arguments:
  # * x is an Envelope3, its high and low are contained.
  # * x responds like a Point3, its coordinates are contained.
  # * x is Numeric, the arguments are contained.
  # * otherwise, false is returned.
  def contains?(x=0,y=0,z=0)
    if x.kind_of? Envelope3
      (contains? x.high) && (contains? x.low)
    elsif x.point3_like?
      contains?(x.x,x.y,x.z)
    elsif x.kind_of? Numeric
      (@x.contains? x) && (@y.contains? y) && (@z.contains? z)
    else
      raise_no_compare x
    end
  end

end