class Grape::Middleware::Error

def call!(env)
  @env = env
  begin
    error_response(catch(:error) do
      return @app.call(@env)
    end)
  rescue Exception => e # rubocop:disable Lint/RescueException
    handler =
      rescue_handler_for_base_only_class(e.class) ||
      rescue_handler_for_class_or_its_ancestor(e.class) ||
      rescue_handler_for_grape_exception(e.class) ||
      rescue_handler_for_any_class(e.class) ||
      raise
    run_rescue_handler(handler, e)
  end
end

def default_options
  {
    default_status: 500, # default status returned on error
    default_message: '',
    format: :txt,
    helpers: nil,
    formatters: {},
    error_formatters: {},
    rescue_all: false, # true to rescue all exceptions
    rescue_grape_exceptions: false,
    rescue_subclasses: true, # rescue subclasses of exceptions listed
    rescue_options: {
      backtrace: false, # true to display backtrace, true to let Grape handle Grape::Exceptions
      original_exception: false # true to display exception
    },
    rescue_handlers: {}, # rescue handler blocks
    base_only_rescue_handlers: {}, # rescue handler blocks rescuing only the base class
    all_rescue_handler: nil # rescue handler block to rescue from all exceptions
  }
end

def default_rescue_handler(e)
  error_response(message: e.message, backtrace: e.backtrace, original_exception: e)
end

def error!(message, status = options[:default_status], headers = {}, backtrace = [], original_exception = nil)
  headers = headers.reverse_merge(Rack::CONTENT_TYPE => content_type)
  rack_response(format_message(message, backtrace, original_exception), status, headers)
end

def error_response(error = {})
  status = error[:status] || options[:default_status]
  message = error[:message] || options[:default_message]
  headers = { Rack::CONTENT_TYPE => content_type }
  headers.merge!(error[:headers]) if error[:headers].is_a?(Hash)
  backtrace = error[:backtrace] || error[:original_exception]&.backtrace || []
  original_exception = error.is_a?(Exception) ? error : error[:original_exception] || nil
  rack_response(format_message(message, backtrace, original_exception), status, headers)
end

def format_message(message, backtrace, original_exception = nil)
  format = env[Grape::Env::API_FORMAT] || options[:format]
  formatter = Grape::ErrorFormatter.formatter_for(format, **options)
  throw :error,
        status: 406,
        message: "The requested format '#{format}' is not supported.",
        backtrace: backtrace,
        original_exception: original_exception unless formatter
  formatter.call(message, backtrace, options, env, original_exception)
end

def initialize(app, *options)
  super
  self.class.send(:include, @options[:helpers]) if @options[:helpers]
end

def rack_response(message, status = options[:default_status], headers = { Rack::CONTENT_TYPE => content_type })
  message = ERB::Util.html_escape(message) if headers[Rack::CONTENT_TYPE] == TEXT_HTML
  Rack::Response.new([message], Rack::Utils.status_code(status), headers)
end

def rescue_handler_for_any_class(klass)
  return unless klass <= StandardError
  return unless options[:rescue_all] || options[:rescue_grape_exceptions]
  options[:all_rescue_handler] || :default_rescue_handler
end

def rescue_handler_for_base_only_class(klass)
  error, handler = options[:base_only_rescue_handlers].find { |err, _handler| klass == err }
  return unless error
  handler || :default_rescue_handler
end

def rescue_handler_for_class_or_its_ancestor(klass)
  error, handler = options[:rescue_handlers].find { |err, _handler| klass <= err }
  return unless error
  handler || :default_rescue_handler
end

def rescue_handler_for_grape_exception(klass)
  return unless klass <= Grape::Exceptions::Base
  return :error_response if klass == Grape::Exceptions::InvalidVersionHeader
  return unless options[:rescue_grape_exceptions] || !options[:rescue_all]
  options[:grape_exceptions_rescue_handler] || :error_response
end

def run_rescue_handler(handler, error)
  if handler.instance_of?(Symbol)
    raise NoMethodError, "undefined method '#{handler}'" unless respond_to?(handler)
    handler = public_method(handler)
  end
  response = handler.arity.zero? ? instance_exec(&handler) : instance_exec(error, &handler)
  if response.is_a?(Rack::Response)
    response
  else
    run_rescue_handler(:default_rescue_handler, Grape::Exceptions::InvalidResponse.new)
  end
end