class Grape::Middleware::Error

def call!(env)
  @env = env
  error_response(catch(:error) { return @app.call(@env) })
rescue Exception => e # rubocop:disable Lint/RescueException
  run_rescue_handler(find_handler(e.class), e, @env[Grape::Env::API_ENDPOINT])
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(exception)
  error_response(message: exception.message, backtrace: exception.backtrace, original_exception: exception)
end

def error!(message, status = options[:default_status], headers = {}, backtrace = [], original_exception = nil)
  env[Grape::Env::API_ENDPOINT].status(status) # not error! inside route
  rack_response(
    status, headers.reverse_merge(Rack::CONTENT_TYPE => content_type),
    format_message(message, backtrace, original_exception)
  )
end

def error?(response)
  return false unless response.is_a?(Hash)
  response.key?(:message) && response.key?(:status) && response.key?(:headers)
end

def error_response(error = {})
  status = error[:status] || options[:default_status]
  env[Grape::Env::API_ENDPOINT].status(status) # error! may not have been called
  message = error[:message] || options[:default_message]
  headers = { Rack::CONTENT_TYPE => content_type }.tap do |h|
    h.merge!(error[:headers]) if error[:headers].is_a?(Hash)
  end
  backtrace = error[:backtrace] || error[:original_exception]&.backtrace || []
  original_exception = error.is_a?(Exception) ? error : error[:original_exception] || nil
  rack_response(status, headers, format_message(message, backtrace, original_exception))
end

def find_handler(klass)
  rescue_handler_for_base_only_class(klass) ||
    rescue_handler_for_class_or_its_ancestor(klass) ||
    rescue_handler_for_grape_exception(klass) ||
    rescue_handler_for_any_class(klass) ||
    raise
end

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

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

def rack_response(status, headers, message)
  message = Rack::Utils.escape_html(message) if headers[Rack::CONTENT_TYPE] == TEXT_HTML
  Rack::Response.new(Array.wrap(message), Rack::Utils.status_code(status), Grape::Util::Header.new.merge(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] || method(: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 || method(: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 || method(:default_rescue_handler)
end

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

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