class AttributedString

# File lib/attributed_string.rb, line 8
def initialize(string, attributes = [])
  @string     = string
  @attributes = attributes
end

# File lib/attributed_string.rb, line 13
def <<(attributed_string)
  @string << attributed_string.string
  @attributes += attributed_string.attributes
end

# File lib/attributed_string.rb, line 28
def fix
  # Group into identical data structures
  grouped_attributes = @attributes.group_by { |a| a.data }.values

  # Sort each group into order
  grouped_attributes.each do |group|
    group.sort_by! { |a| a.range.begin }
  end

  # Merge attributes in identical groups together
  merged_attributes = grouped_attributes.map do |group|
    group.inject([]) do |attrs, a|
      if !attrs.empty? && attributes_overlap?(attrs.last, a)
        attrs[0...-1] + [merge_attributes(attrs.last, a)]
      else
        attrs + [a]
      end
    end
  end

  @attributes = merged_attributes.flatten
end

# File lib/attributed_string.rb, line 24
def length
  @string.length
end

# File lib/attributed_string.rb, line 18
def prepend(attributed_string)
  @string.prepend(attributed_string.string)
  move_attributes(attributed_string.length)
  @attributes += attributed_string.attributes
end

# File lib/attributed_string.rb, line 59
def attributes_overlap?(a, b)
  a.data == b.data && (a.range.include?(b.range.begin) || b.range.include?(a.range.begin))
end

# File lib/attributed_string.rb, line 63
def merge_attributes(a, b)
  range = [a.range.begin, b.range.begin].min..[a.range.end, b.range.end].max
  AttributedString::Attribute.new(range, a.data)
end

# File lib/attributed_string.rb, line 53
def move_attributes(offset)
  @attributes.each do |attribute|
    attribute.move(offset)
  end
end