class LCS::ContextChange

# File lib/diff/lcs/change.rb, line 132
def self.from_a(arr)
  Diff::LCS::Change.from_a(arr)
end

# File lib/diff/lcs/change.rb, line 114
def initialize(*args)
  @action, @old_position, @old_element, @new_position, @new_element = *args

  fail "Invalid Change Action '#{@action}'" unless Diff::LCS::Change.valid_action?(@action)
  fail "Invalid (Old) Position Type" unless @old_position.nil? || @old_position.is_a?(IntClass)
  fail "Invalid (New) Position Type" unless @new_position.nil? || @new_position.is_a?(IntClass)
end

# File lib/diff/lcs/change.rb, line 138
def self.simplify(event)
  ea = event.to_a

  case ea[0]
  when "-"
    ea[2][1] = nil
  when "<"
    ea[0] = "-"
    ea[2][1] = nil
  when "+"
    ea[1][1] = nil
  when ">"
    ea[0] = "+"
    ea[1][1] = nil
  end

  Diff::LCS::ContextChange.from_a(ea)
end

# File lib/diff/lcs/change.rb, line 166
def <=>(other)
  r = @action <=> other.action
  r = @old_position <=> other.old_position if r.zero?
  r = @new_position <=> other.new_position if r.zero?
  r = @old_element <=> other.old_element if r.zero?
  r = @new_element <=> other.new_element if r.zero?
  r
end

# File lib/diff/lcs/change.rb, line 157
def ==(other)
  (self.class == other.class) and
    (@action == other.action) and
    (@old_position == other.old_position) and
    (@new_position == other.new_position) and
    (@old_element == other.old_element) and
    (@new_element == other.new_element)
end

# File lib/diff/lcs/change.rb, line 122
def to_a
  [
    @action,
    [@old_position, @old_element],
    [@new_position, @new_element]
  ]
end