module Metanorma::Utils

def set_nested_value(hash, keys, new_val)
  key = keys[0]
  if keys.length == 1
    hash[key] = hash[key].is_a?(Array) ?  (hash[key] << new_val) :
      hash[key].nil? ?  new_val : [hash[key], new_val]
  else
    if hash[key].is_a?(Array)
      hash[key][-1] = {} if !hash[key].empty? && hash[key][-1].nil?
      hash[key] << {} if hash[key].empty? || !hash[key][-1].is_a?(Hash)
      set_nested_value(hash[key][-1], keys[1..-1], new_val)
    elsif hash[key].nil? || hash[key].empty?
      hash[key] = {}
      set_nested_value(hash[key], keys[1..-1], new_val)
    elsif hash[key].is_a?(Hash) && !hash[key][keys[1]]
      set_nested_value(hash[key], keys[1..-1], new_val)
    elsif !hash[key][keys[1]]
      hash[key] = [hash[key], {}]
      set_nested_value(hash[key][-1], keys[1..-1], new_val)
    else
      set_nested_value(hash[key], keys[1..-1], new_val)
    end
  end
  hash
end