class ErrataSlip

# File lib/errata_slip.rb, line 9
def self.load_file(filename)
  ErrataSlip.new(YAML::load_file(filename))
end

# File lib/errata_slip.rb, line 15
def initialize(errata)
  @errata = errata
end

# File lib/errata_slip.rb, line 20
def correct!(items)
  items.each do |item|
    correct_item!(item)
  end
end

# File lib/errata_slip.rb, line 26
def correct_item!(item)
  @errata.each do |errata|
    hash_key_is_symbol = nil
    item.each_key { |k| hash_key_is_symbol = k.is_a?(Symbol); break }
    next unless item_matches_errata(item, errata, hash_key_is_symbol)
    change_fields = errata.keys.select { |field| field[0] == '~' }
    change_fields.map! { |field| field[1..-1]}
    change_fields.each do |field|
      hash_field = hash_key_is_symbol ? field.to_sym : field
      item[hash_field] = errata["~#{field}"]
    end
  end
  item
end

# File lib/errata_slip.rb, line 41
def item_matches_errata(hash, errata, hash_key_is_symbol = false)
  find_fields = errata.keys.select { |field| field[0] != '~' }
  find_fields.each do |key|
    hash_key = hash_key_is_symbol ? key.to_sym : key
    return false if hash[hash_key] != errata[key]
  end
  true
end