/*
 * 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
@testable import SwiftGRPC
import XCTest

fileprivate class TimingOutEchoProvider: Echo_EchoProvider {
  func get(request: Echo_EchoRequest, session _: Echo_EchoGetSession) throws -> Echo_EchoResponse {
    Thread.sleep(forTimeInterval: 0.2)
    return Echo_EchoResponse()
  }
  
  func expand(request: Echo_EchoRequest, session: Echo_EchoExpandSession) throws -> ServerStatus? {
    Thread.sleep(forTimeInterval: 0.2)
    return nil
  }
  
  func collect(session: Echo_EchoCollectSession) throws -> Echo_EchoResponse? {
    Thread.sleep(forTimeInterval: 0.2)
    return nil
  }
  
  func update(session: Echo_EchoUpdateSession) throws -> ServerStatus? {
    Thread.sleep(forTimeInterval: 0.2)
    return nil
  }
}

class ServerTimeoutTests: BasicEchoTestCase {
  static var allTests: [(String, (ServerTimeoutTests) -> () throws -> Void)] {
    return [
      ("testTimeoutUnary", testTimeoutUnary),
      ("testTimeoutClientStreaming", testTimeoutClientStreaming),
      ("testTimeoutServerStreaming", testTimeoutServerStreaming),
      ("testTimeoutBidirectionalStreaming", testTimeoutBidirectionalStreaming)
    ]
  }
  
  override func makeProvider() -> Echo_EchoProvider { return TimingOutEchoProvider() }
  
  override var defaultTimeout: TimeInterval { return 0.1 }
}

extension ServerTimeoutTests {
  func testTimeoutUnary() {
    do {
      let result = try client.get(Echo_EchoRequest(text: "foo")).text
      XCTFail("should have thrown, received \(result) instead")
    } catch {
      guard case let .callError(callResult) = error as! RPCError
        else { XCTFail("unexpected error \(error)"); return }
      XCTAssertEqual(.deadlineExceeded, callResult.statusCode)
      XCTAssertEqual("Deadline Exceeded", callResult.statusMessage)
    }
  }
  
  func testTimeoutClientStreaming() {
    let completionHandlerExpectation = expectation(description: "final completion handler called")
    let call = try! client.collect { callResult in
      XCTAssertEqual(.deadlineExceeded, callResult.statusCode)
      completionHandlerExpectation.fulfill()
    }
    
    let sendExpectation = expectation(description: "send completion handler 1 called")
    try! call.send(Echo_EchoRequest(text: "foo")) { [sendExpectation] in
      // The server only times out later in its lifecycle, so we shouldn't get an error when trying to send a message.
      XCTAssertNil($0)
      sendExpectation.fulfill()
    }
    call.waitForSendOperationsToFinish()
    
    do {
      let result = try call.closeAndReceive()
      XCTFail("should have thrown, instead received \(result)")
    } catch let receiveError {
      XCTAssertEqual(.unknown, (receiveError as! RPCError).callResult!.statusCode)
    }
    
    waitForExpectations(timeout: defaultTimeout)
  }
  
  func testTimeoutServerStreaming() {
    let completionHandlerExpectation = expectation(description: "completion handler called")
    let call = try! client.expand(Echo_EchoRequest(text: "foo bar baz")) { callResult in
      XCTAssertEqual(.deadlineExceeded, callResult.statusCode)
      completionHandlerExpectation.fulfill()
    }
    
    // FIXME(danielalm): Why does `call.receive()` essentially return "end of stream" once the call times out,
    // rather than returning an error?
    XCTAssertNil(try! call.receive())
    
    waitForExpectations(timeout: defaultTimeout)
  }
  
  func testTimeoutBidirectionalStreaming() {
    let completionHandlerExpectation = expectation(description: "completion handler called")
    let call = try! client.update { callResult in
      XCTAssertEqual(.deadlineExceeded, callResult.statusCode)
      completionHandlerExpectation.fulfill()
    }
    
    let sendExpectation = expectation(description: "send completion handler 1 called")
    try! call.send(Echo_EchoRequest(text: "foo")) { [sendExpectation] in
      // The server only times out later in its lifecycle, so we shouldn't get an error when trying to send a message.
      XCTAssertNil($0)
      sendExpectation.fulfill()
    }
    call.waitForSendOperationsToFinish()
    
    // FIXME(danielalm): Why does `call.receive()` essentially return "end of stream" once the call times out,
    // rather than returning an error?
    XCTAssertNil(try! call.receive())
    
    waitForExpectations(timeout: defaultTimeout)
  }
}