module Jekyll::Algolia::Utils

def self.compact_empty(hash)
  new_hash = {}
  hash.each do |key, value|
    next if value.nil?
    next if value.respond_to?(:empty?) && value.empty?
    new_hash[key] = value
  end
  new_hash
end

def self.find_by_key(items, key, value)
  return nil if items.nil?
  items.find do |item|
    item[key] == value
  end
end

def self.html_to_text(html)
  return nil if html.nil?
  text = Nokogiri::HTML(html).text
  text.tr("\n", ' ').squeeze(' ').strip
end

def self.instance_of?(input, classname)
  return input.instance_of? Object.const_get(classname)
rescue StandardError
  # The class might not even exist
  return false
end

def self.jsonify(item)
  simple_types = [
    NilClass,
    TrueClass, FalseClass,
    Integer, Float,
    String
  ]
  # Integer arrived in Ruby 2.4. Before that it was Fixnum and Bignum
  if Gem::Version.new(RUBY_VERSION) < Gem::Version.new('2.4.0')
    # rubocop:disable Lint/UnifiedInteger
    simple_types += [Fixnum, Bignum]
    # rubocop:enable Lint/UnifiedInteger
  end
  return item if simple_types.member?(item.class)
  # Recursive types
  return item.map { |value| jsonify(value) } if item.is_a?(Array)
  if item.is_a?(Hash)
    return item.map { |key, value| [key, jsonify(value)] }.to_h
  end
  # Can't be stringified, discard it
  return nil unless item.respond_to?(:to_s)
  # Discard also if is a serialized version with unique identifier
  stringified = item.to_s
  return nil if match?(stringified, /#<[^ ].*@[0-9]* .*>/)
  stringified
end

def self.keys_to_symbols(hash)
  Hash[hash.map { |key, value| [key.to_sym, value] }]
end

def self.match?(string, regex)
  # Ruby 2.4 introduces .match?
  return regex.match?(string) if regex.respond_to?(:match?)
  # Older versions of Ruby have to deal with =~ returning nil if no match
  # is found
  !(string =~ regex).nil?
end

def self.monkey_patch(instance, method, block)
  metaclass = class << instance; self; end
  metaclass.send(:define_method, method, block)
end