/*
 * 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 GRPC
import Logging
import XCTest

/// This should be used instead of `XCTestCase`.
class GRPCTestCase: XCTestCase {
  /// Unless `GRPC_ALWAYS_LOG` is set, logs will only be printed if a test case fails.
  private static let alwaysLog = Bool(
    fromTruthLike: ProcessInfo.processInfo.environment["GRPC_ALWAYS_LOG"],
    defaultingTo: false
  )

  private static let runTimeSensitiveTests = Bool(
    fromTruthLike: ProcessInfo.processInfo.environment["ENABLE_TIMING_TESTS"],
    defaultingTo: true
  )

  override func setUp() {
    super.setUp()
    self.logFactory = CapturingLogHandlerFactory()
  }

  override func tearDown() {
    let logs = self.capturedLogs()

    // The default source emitted by swift-log is the directory containing the '#file' in which the
    // log was emitted. It's meant to represent the system which emitted the log, typically the
    // module name. In most cases it's right but in a few places, i.e. where the source lives in
    // child directories below 'GRPC', it isn't. We'll use this as a sanity check.
    //
    // See also: https://github.com/apple/swift-log/issues/145
    for log in logs {
      XCTAssertEqual(log.source, "GRPC", "Incorrect log source in \(log.file) on line \(log.line)")
    }

    if GRPCTestCase.alwaysLog || (self.testRun.map { $0.totalFailureCount > 0 } ?? false) {
      self.printCapturedLogs(logs)
    }

    super.tearDown()
  }

  func runTimeSensitiveTests() -> Bool {
    let shouldRun = GRPCTestCase.runTimeSensitiveTests
    if !shouldRun {
      print("Skipping '\(self.name)' as ENABLE_TIMING_TESTS=false")
    }
    return shouldRun
  }

  private(set) var logFactory: CapturingLogHandlerFactory!

  /// A general-use logger.
  var logger: Logger {
    return Logger(label: "grpc", factory: self.logFactory.make)
  }

  /// A logger for clients to use.
  var clientLogger: Logger {
    // Label is ignored; we already have a handler.
    return Logger(label: "client", factory: self.logFactory.make)
  }

  /// A logger for servers to use.
  var serverLogger: Logger {
    // Label is ignored; we already have a handler.
    return Logger(label: "server", factory: self.logFactory.make)
  }

  /// The default client call options using `self.clientLogger`.
  var callOptionsWithLogger: CallOptions {
    return CallOptions(logger: self.clientLogger)
  }

  /// Returns all captured logs sorted by date.
  private func capturedLogs() -> [CapturedLog] {
    assert(self.logFactory != nil, "Missing call to super.setUp()")

    var logs = self.logFactory.clearCapturedLogs()
    logs.sort(by: { $0.date < $1.date })

    return logs
  }

  /// Prints all captured logs.
  private func printCapturedLogs(_ logs: [CapturedLog]) {
    let formatter = DateFormatter()
    // We don't care about the date.
    formatter.dateFormat = "HH:mm:ss.SSS"

    print("Test Case '\(self.name)' logs started")

    // The logs are already sorted by date.
    for log in logs {
      let date = formatter.string(from: log.date)
      let level = log.level.short

      // Format the metadata.
      let formattedMetadata = log.metadata
        .sorted(by: { $0.key < $1.key })
        .map { key, value in "\(key)=\(value)" }
        .joined(separator: " ")

      print("\(date) \(log.label) \(level):", log.message, formattedMetadata)
    }

    print("Test Case '\(self.name)' logs finished")
  }
}

extension Bool {
  fileprivate init(fromTruthLike value: String?, defaultingTo defaultValue: Bool) {
    switch value?.lowercased() {
    case "0", "false", "no":
      self = false
    case "1", "true", "yes":
      self = true
    default:
      self = defaultValue
    }
  }
}

extension Logger.Level {
  fileprivate var short: String {
    switch self {
    case .info:
      return "I"
    case .debug:
      return "D"
    case .warning:
      return "W"
    case .error:
      return "E"
    case .critical:
      return "C"
    case .trace:
      return "T"
    case .notice:
      return "N"
    }
  }
}