class AhoCorasick

# File lib/aho_corasick.rb, line 2
def initialize(*args)
  terms = terms_for(args)
  @root = TreeNode.new
  unsafe_insert(terms)
  create_suffix_links
end

# File lib/aho_corasick.rb, line 19
def insert(*args)
  terms = terms_for(args)
  unsafe_insert(terms)
  create_suffix_links
end

# File lib/aho_corasick.rb, line 9
def match(string)
  matches = []
  node = string.each_char.inject(@root) do |node, char|
    matches += node.matches if node
    (node && node.find(char.to_sym)) || @root.find(char.to_sym)
  end
  matches += node.matches if node
  return matches
end

# File lib/aho_corasick.rb, line 41
def create_suffix_links
  queue = @root.children.to_a.dup
  while !queue.empty?
    char, node = queue.shift
    node.suffix = node.parent == @root ? @root : (node.parent.suffix && node.parent.suffix.children[char.to_sym])
    node.children.to_a.each do |entry|
      queue.push(entry)
    end
  end
end

# File lib/aho_corasick.rb, line 27
def terms_for(args)
  if args.length == 1 && args[0].is_a?(Array)
    args[0]
  else
    args
  end
end

# File lib/aho_corasick.rb, line 35
def unsafe_insert(terms)
  terms.each do |t|
    t.each_char.inject(@root) {|node, char| node.child_for(char.to_sym) }.add_match(t)
  end
end