/*
 * 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 Dispatch
import Foundation
@testable import GRPC
import NIOCore
import XCTest

class GRPCTimeoutTests: GRPCTestCase {
  func testRoundingNegativeTimeout() {
    let timeout = GRPCTimeout(rounding: -10, unit: .seconds)
    XCTAssertEqual(String(describing: timeout), "0S")
    XCTAssertEqual(timeout.nanoseconds, 0)
  }

  func testRoundingNanosecondsTimeout() throws {
    let timeout = GRPCTimeout(rounding: 123_456_789, unit: .nanoseconds)
    XCTAssertEqual(timeout, GRPCTimeout(amount: 123_457, unit: .microseconds))

    // 123_456_789 (nanoseconds) / 1_000
    //   = 123_456.789
    //   = 123_457 (microseconds, rounded up)
    XCTAssertEqual(String(describing: timeout), "123457u")

    // 123_457 (microseconds) * 1_000
    //   = 123_457_000 (nanoseconds)
    XCTAssertEqual(timeout.nanoseconds, 123_457_000)
  }

  func testRoundingMicrosecondsTimeout() throws {
    let timeout = GRPCTimeout(rounding: 123_456_789, unit: .microseconds)
    XCTAssertEqual(timeout, GRPCTimeout(amount: 123_457, unit: .milliseconds))

    // 123_456_789 (microseconds) / 1_000
    //   = 123_456.789
    //   = 123_457 (milliseconds, rounded up)
    XCTAssertEqual(String(describing: timeout), "123457m")

    // 123_457 (milliseconds) * 1_000 * 1_000
    //   = 123_457_000_000 (nanoseconds)
    XCTAssertEqual(timeout.nanoseconds, 123_457_000_000)
  }

  func testRoundingMillisecondsTimeout() throws {
    let timeout = GRPCTimeout(rounding: 123_456_789, unit: .milliseconds)
    XCTAssertEqual(timeout, GRPCTimeout(amount: 123_457, unit: .seconds))

    // 123_456_789 (milliseconds) / 1_000
    //   = 123_456.789
    //   = 123_457 (seconds, rounded up)
    XCTAssertEqual(String(describing: timeout), "123457S")

    // 123_457 (milliseconds) * 1_000 * 1_000 * 1_000
    //   = 123_457_000_000_000 (nanoseconds)
    XCTAssertEqual(timeout.nanoseconds, 123_457_000_000_000)
  }

  func testRoundingSecondsTimeout() throws {
    let timeout = GRPCTimeout(rounding: 123_456_789, unit: .seconds)
    XCTAssertEqual(timeout, GRPCTimeout(amount: 2_057_614, unit: .minutes))

    // 123_456_789 (seconds) / 60
    //   = 2_057_613.15
    //   = 2_057_614 (minutes, rounded up)
    XCTAssertEqual(String(describing: timeout), "2057614M")

    // 2_057_614 (minutes) * 60 * 1_000 * 1_000 * 1_000
    //   = 123_456_840_000_000_000 (nanoseconds)
    XCTAssertEqual(timeout.nanoseconds, 123_456_840_000_000_000)
  }

  func testRoundingMinutesTimeout() throws {
    let timeout = GRPCTimeout(rounding: 123_456_789, unit: .minutes)
    XCTAssertEqual(timeout, GRPCTimeout(amount: 2_057_614, unit: .hours))

    // 123_456_789 (minutes) / 60
    //   = 2_057_613.15
    //   = 2_057_614 (hours, rounded up)
    XCTAssertEqual(String(describing: timeout), "2057614H")

    // 123_457 (minutes) * 60 * 60 * 1_000 * 1_000 * 1_000
    //   = 7_407_410_400_000_000_000 (nanoseconds)
    XCTAssertEqual(timeout.nanoseconds, 7_407_410_400_000_000_000)
  }

  func testRoundingHoursTimeout() throws {
    let timeout = GRPCTimeout(rounding: 123_456_789, unit: .hours)
    XCTAssertEqual(timeout, GRPCTimeout(amount: 99_999_999, unit: .hours))

    // Hours are the largest unit of time we have (as per the gRPC spec) so we can't round to a
    // different unit. In this case we clamp to the largest value.
    XCTAssertEqual(String(describing: timeout), "99999999H")
    // Unfortunately the largest value representable by the specification is too long to represent
    // in nanoseconds within 64 bits, again the value is clamped.
    XCTAssertEqual(timeout.nanoseconds, Int64.max)
  }

  func testTimeoutFromDeadline() throws {
    let deadline = NIODeadline.uptimeNanoseconds(0) + .seconds(42)
    let timeout = GRPCTimeout(deadline: deadline, testingOnlyNow: .uptimeNanoseconds(0))
    XCTAssertEqual(timeout.nanoseconds, 42_000_000_000)

    // Wire encoding may have at most 8 digits, we should automatically coarsen the resolution until
    // we're within that limit.
    XCTAssertEqual(timeout.wireEncoding, "42000000u")
  }

  func testTimeoutFromPastDeadline() throws {
    let deadline = NIODeadline.uptimeNanoseconds(100) + .nanoseconds(50)
    // testingOnlyNow >= deadline: timeout should be zero.
    let timeout = GRPCTimeout(deadline: deadline, testingOnlyNow: .uptimeNanoseconds(200))
    XCTAssertEqual(timeout.nanoseconds, 0)
  }

  func testTimeoutFromDistantFuture() throws {
    XCTAssertEqual(GRPCTimeout(deadline: .distantFuture), .infinite)
  }
}