class DeclarativeMapper

# File lib/declarative_mapper.rb, line 37
def self.argument_values(argument_names, csv_row)
  argument_names.map { |name| csv_row[name] }
end

# File lib/declarative_mapper.rb, line 5
def self.convert(mapper_methods, mapping_hash, csv_row)
  deep_transform_values_with_path(mapping_hash) do |csv_field_name, path|
    field_name = path.last

    if needs_method?(csv_field_name)
      parsed_signature =
        parse_signature(csv_field_name, field_name)

      args = argument_values(parsed_signature[:arguments], csv_row)
      method_name = parsed_signature[:method_name]

      unless shared_method?(csv_field_name)
        method_name = path[0..-2].push(method_name).join('_')
      end

      mapper_methods.send(method_name, *args)
    else
      csv_row[csv_field_name]
    end
  end
end

# File lib/declarative_mapper.rb, line 83
def self.deep_inject(object, acc, &block)
  case object
  when Hash
    object.inject(acc) { |a, (k, v)| deep_inject(v, a, &block) }
  when Array
    object.inject(acc) { |a, e| deep_inject(e, a, &block) }
  else
    yield(object, acc)
  end
end

# File lib/declarative_mapper.rb, line 72
def self.deep_transform_values_with_path(object, path=[], &block)
  case object
  when Hash
    object.map { |k, v| [k, deep_transform_values_with_path(v, path + [k], &block)] }.to_h
  when Array
    object.map { |e| deep_transform_values_with_path(e, path, &block) }
  else
    yield(object, path)
  end
end

# File lib/declarative_mapper.rb, line 57
def self.needs_method?(signature)
  !!(signature =~ /\(.*\)/)
end

# File lib/declarative_mapper.rb, line 41
def self.parse_signature(signature, field_name=nil)
  match = signature.match(/^(.*)\((.*)\)/)

  method_name = match[1]
  method_name = field_name if method_name.empty?

  {
    arguments: match[2].gsub(/,\s+/, ',').split(','),
    method_name: method_name
  }
end

# File lib/declarative_mapper.rb, line 27
def self.required_csv_fields(mapping_hash)
  deep_inject(mapping_hash, []) do |value, sum|
    if needs_method?(value)
      sum += (parse_signature(value)[:arguments])
    else
      sum.push(value)
    end
  end.uniq.compact
end

# File lib/declarative_mapper.rb, line 53
def self.shared_method?(signature)
  !!(signature =~ /^.+\(.*\)/)
end