/*

 * Copyright 2019, gRPC Authors All rights reserved.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

import Foundation

import Logging

import NIOCore

/// A channel handler which allows caught errors to be passed to a `ClientErrorDelegate`. This

/// handler is intended to be used in the client channel pipeline after the HTTP/2 stream

/// multiplexer to handle errors which occur on the underlying connection.

internal final class DelegatingErrorHandler: ChannelInboundHandler {

  typealias InboundIn = Any

  private var logger: Logger

  private let delegate: ClientErrorDelegate?

  internal init(logger: Logger, delegate: ClientErrorDelegate?) {

    self.logger = logger

    self.delegate = delegate

  }

  internal func channelActive(context: ChannelHandlerContext) {

    self.logger.addIPAddressMetadata(local: context.localAddress, remote: context.remoteAddress)

    context.fireChannelActive()

  }

  internal func errorCaught(context: ChannelHandlerContext, error: Error) {

    // We can ignore unclean shutdown since gRPC is self-terminated and therefore not prone to

    // truncation attacks.

    //

    // Without this we would unnecessarily log when we're communicating with peers which don't

    // send `close_notify`.

    if error.isNIOSSLUncleanShutdown {

      return

    }

    if let delegate = self.delegate {

      if let context = error as? GRPCError.WithContext {

        delegate.didCatchError(

          context.error,

          logger: self.logger,

          file: context.file,

          line: context.line

        )

      } else {

        delegate.didCatchErrorWithoutContext(error, logger: self.logger)

      }

    }

    context.close(promise: nil)

  }

}