/*
 * Copyright 2018, 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 Dispatch
import Foundation
import NIO
import NIOSSL
@testable import SwiftGRPCNIO
import SwiftGRPCNIOSampleData
import XCTest

extension Echo_EchoRequest {
  init(text: String) {
    self.text = text
  }
}

extension Echo_EchoResponse {
  init(text: String) {
    self.text = text
  }
}

enum TransportSecurity {
  case none
  case anonymousClient
  case mutualAuthentication
}

extension TransportSecurity {
  var caCert: NIOSSLCertificate {
    let cert = SampleCertificate.ca
    cert.assertNotExpired()
    return cert.certificate
  }

  var clientCert: NIOSSLCertificate {
    let cert = SampleCertificate.client
    cert.assertNotExpired()
    return cert.certificate
  }

  var serverCert: NIOSSLCertificate {
    let cert = SampleCertificate.server
    cert.assertNotExpired()
    return cert.certificate
  }
}

extension TransportSecurity {
  func makeServerTLS() throws -> GRPCServer.TLSMode {
    return try makeServerTLSConfiguration().map { .custom(try NIOSSLContext(configuration: $0)) } ?? .none
  }

  func makeServerTLSConfiguration() throws -> TLSConfiguration? {
    switch self {
    case .none:
      return nil

    case .anonymousClient, .mutualAuthentication:
      return .forServer(certificateChain: [.certificate(self.serverCert)],
                        privateKey: .privateKey(SamplePrivateKey.server), 
                        trustRoots: .certificates ([self.caCert]),
                        applicationProtocols: GRPCApplicationProtocolIdentifier.allCases.map { $0.rawValue })
    }
  }

  func makeClientTLS() throws -> GRPCClientConnection.TLSMode {
    return try makeClientTLSConfiguration().map { .custom(try NIOSSLContext(configuration: $0)) } ?? .none
  }

  func makeClientTLSConfiguration() throws -> TLSConfiguration? {
    switch self {
    case .none:
      return nil

    case .anonymousClient:
      return .forClient(certificateVerification: .noHostnameVerification,
                        trustRoots: .certificates([self.caCert]),
                        applicationProtocols: GRPCApplicationProtocolIdentifier.allCases.map { $0.rawValue })

    case .mutualAuthentication:
      return .forClient(certificateVerification: .noHostnameVerification,
                        trustRoots: .certificates([self.caCert]),
                        certificateChain: [.certificate(self.clientCert)],
                        privateKey: .privateKey(SamplePrivateKey.client),
                        applicationProtocols: GRPCApplicationProtocolIdentifier.allCases.map { $0.rawValue })
    }
  }
}

class NIOEchoTestCaseBase: XCTestCase {
  var defaultTestTimeout: TimeInterval = 1.0

  var serverEventLoopGroup: EventLoopGroup!
  var clientEventLoopGroup: EventLoopGroup!

  var transportSecurity: TransportSecurity { return .none }

  var server: GRPCServer!
  var client: Echo_EchoService_NIOClient!

  func makeServer() throws -> GRPCServer {
    return try GRPCServer.start(
      hostname: "localhost",
      port: 5050,
      eventLoopGroup: self.serverEventLoopGroup,
      serviceProviders: [makeEchoProvider()],
      errorDelegate: makeErrorDelegate(),
      tls: try self.transportSecurity.makeServerTLS()
    ).wait()
  }

  func makeClientConnection() throws -> GRPCClientConnection {
    return try GRPCClientConnection.start(
      host: "localhost",
      port: 5050,
      eventLoopGroup: self.clientEventLoopGroup,
      tls: try self.transportSecurity.makeClientTLS()
    ).wait()
  }

  func makeEchoProvider() -> Echo_EchoProvider_NIO { return EchoProviderNIO() }

  func makeErrorDelegate() -> ServerErrorDelegate? { return nil }

  func makeEchoClient() throws -> Echo_EchoService_NIOClient {
    return Echo_EchoService_NIOClient(connection: try self.makeClientConnection())
  }

  override func setUp() {
    super.setUp()
    self.serverEventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
    self.server = try! self.makeServer()

    self.clientEventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
    self.client = try! self.makeEchoClient()
  }

  override func tearDown() {
    // Some tests close the channel, so would throw here if called twice.
    if self.client.connection.channel.isActive {
      XCTAssertNoThrow(try self.client.connection.close().wait())
    }
    XCTAssertNoThrow(try self.clientEventLoopGroup.syncShutdownGracefully())
    self.client = nil
    self.clientEventLoopGroup = nil

    XCTAssertNoThrow(try self.server.close().wait())
    XCTAssertNoThrow(try self.serverEventLoopGroup.syncShutdownGracefully())
    self.server = nil
    self.serverEventLoopGroup = nil

    super.tearDown()
  }
}

extension NIOEchoTestCaseBase {
  func makeExpectation(description: String, expectedFulfillmentCount: Int = 1, assertForOverFulfill: Bool = true) -> XCTestExpectation {
    let expectation = self.expectation(description: description)
    expectation.expectedFulfillmentCount = expectedFulfillmentCount
    expectation.assertForOverFulfill = assertForOverFulfill
    return expectation
  }

  func makeStatusExpectation(expectedFulfillmentCount: Int = 1) -> XCTestExpectation {
    return makeExpectation(description: "Expecting status received",
                           expectedFulfillmentCount: expectedFulfillmentCount)
  }

  func makeResponseExpectation(expectedFulfillmentCount: Int = 1) -> XCTestExpectation {
    return makeExpectation(description: "Expecting \(expectedFulfillmentCount) response(s)",
      expectedFulfillmentCount: expectedFulfillmentCount)
  }

  func makeRequestExpectation(expectedFulfillmentCount: Int = 1) -> XCTestExpectation {
    return makeExpectation(
      description: "Expecting \(expectedFulfillmentCount) request(s) to have been sent",
      expectedFulfillmentCount: expectedFulfillmentCount)
  }

  func makeInitialMetadataExpectation() -> XCTestExpectation {
    return makeExpectation(description: "Expecting initial metadata")
  }
}