/*
  * Copyright 2017, 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 XCTest
 import Foundation
 import Dispatch
 @testable import gRPC

 class gRPCTests: XCTestCase {
  func testConnectivity() {
    runTest(useSSL:false)
  }
  func testConnectivitySecure() {
    runTest(useSSL:true)
  }

  static var allTests : [(String, (gRPCTests) -> () throws -> Void)] {
    return [
      ("testConnectivity", testConnectivity),
      ("testConnectivitySecure", testConnectivitySecure),
    ]
  }
 }

 let address = "localhost:8085"
 let host = "example.com"
 let clientText = "hello, server!"
 let serverText = "hello, client!"
 let initialClientMetadata =
  ["x": "xylophone",
   "y": "yu",
   "z": "zither"]
 let initialServerMetadata =
  ["a": "Apple",
   "b": "Banana",
   "c": "Cherry"]
 let trailingServerMetadata =
  ["0": "zero",
   "1": "one",
   "2": "two"]
 let steps = 10
 let hello = "/hello"
 let statusCode = 0
 let statusMessage = "OK"

 func runTest(useSSL: Bool) {
  gRPC.initialize()

  let serverRunningSemaphore = DispatchSemaphore(value: 0)

  // create the server
  var server : gRPC.Server!
  if useSSL {
    let certificateURL = URL(fileURLWithPath:"Tests/ssl.crt")
    let keyURL = URL(fileURLWithPath:"Tests/ssl.key")
    guard
      let certificate = try? String(contentsOf: certificateURL, encoding: .utf8),
      let key = try? String(contentsOf: keyURL, encoding: .utf8)
      else {
        return
    }
    server = gRPC.Server(address:address,
                         key:key,
                         certs:certificate)
  } else {
    server = gRPC.Server(address:address)
  }

  // start the server
  DispatchQueue.global().async() {
    do {

      try runServer(server:server)
    } catch (let error) {
      XCTFail("server error \(error)")
    }
    serverRunningSemaphore.signal() // when the server exits, the test is finished
  }

  // run the client
  do {
    try runClient(useSSL:useSSL)
  } catch (let error) {
    XCTFail("client error \(error)")
  }

  // stop the server
  server.stop()

  // wait until the server has shut down
  _ = serverRunningSemaphore.wait(timeout: DispatchTime.distantFuture)
 }

 func verify_metadata(_ metadata: Metadata, expected: [String:String]) {
  XCTAssertGreaterThanOrEqual(metadata.count(), expected.count)
  for i in 0..<metadata.count() {
    if expected[metadata.key(i)] != nil {
      XCTAssertEqual(metadata.value(i), expected[metadata.key(i)])
    }
  }
 }

 func runClient(useSSL: Bool) throws {
  let message = clientText.data(using: .utf8)
  var channel : gRPC.Channel!

  if useSSL {
    let certificateURL = URL(fileURLWithPath:"Tests/ssl.crt")
    guard
      let certificates = try? String(contentsOf: certificateURL, encoding: .utf8)
      else {
        return
    }
    let host = "example.com"
    channel = gRPC.Channel(address:address, certificates:certificates, host:host)
  } else {
    channel = gRPC.Channel(address:address, secure:false)
  }

  channel.host = host
  for i in 0..<steps {
    let sem = DispatchSemaphore(value: 0)
    let method = hello
    let call = channel.makeCall(method)
    let metadata = Metadata(initialClientMetadata)
    try call.start(.unary, metadata:metadata, message:message) {
      (response) in
      // verify the basic response from the server
      XCTAssertEqual(response.statusCode, statusCode)
      XCTAssertEqual(response.statusMessage, statusMessage)
      // verify the message from the server
      let resultData = response.resultData
      let messageString = String(data: resultData!, encoding: .utf8)
      XCTAssertEqual(messageString, serverText)
      // verify the initial metadata from the server
      let initialMetadata = response.initialMetadata!
      verify_metadata(initialMetadata, expected: initialServerMetadata)
      // verify the trailing metadata from the server
      let trailingMetadata = response.trailingMetadata!
      verify_metadata(trailingMetadata, expected: trailingServerMetadata)
      // report completion
      sem.signal()
    }
    // wait for the call to complete
    _ = sem.wait(timeout: DispatchTime.distantFuture)
  }
 }

 func runServer(server: gRPC.Server) throws {
  var requestCount = 0
  let sem = DispatchSemaphore(value: 0)
  server.run() {(requestHandler) in
    do {
      requestCount += 1
      XCTAssertEqual(requestHandler.host, host)
      XCTAssertEqual(requestHandler.method, hello)
      let initialMetadata = requestHandler.requestMetadata
      verify_metadata(initialMetadata, expected: initialClientMetadata)
      let initialMetadataToSend = Metadata(initialServerMetadata)
      try requestHandler.receiveMessage(initialMetadata:initialMetadataToSend)
      {(messageData) in
        let messageString = String(data: messageData!, encoding: .utf8)
        XCTAssertEqual(messageString, clientText)
      }
      let replyMessage = serverText
      let trailingMetadataToSend = Metadata(trailingServerMetadata)
      try requestHandler.sendResponse(message:replyMessage.data(using: .utf8)!,
                                      statusCode:statusCode,
                                      statusMessage:statusMessage,
                                      trailingMetadata:trailingMetadataToSend)
    } catch (let error) {
      XCTFail("error \(error)")
    }
  }
  server.onCompletion() {
    // return from runServer()
    sem.signal()
  }
  // wait for the server to exit
  _ = sem.wait(timeout: DispatchTime.distantFuture)
 }