//
  //  Timeline.swift
  //
  //  Copyright (c) 2014-2016 Alamofire Software Foundation (http://alamofire.org/)
  //
  //  Permission is hereby granted, free of charge, to any person obtaining a copy
  //  of this software and associated documentation files (the "Software"), to deal
  //  in the Software without restriction, including without limitation the rights
  //  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  //  copies of the Software, and to permit persons to whom the Software is
  //  furnished to do so, subject to the following conditions:
  //
  //  The above copyright notice and this permission notice shall be included in
  //  all copies or substantial portions of the Software.
  //
  //  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  //  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  //  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  //  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  //  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  //  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  //  THE SOFTWARE.
  //
  
  import Foundation
  
  /// Responsible for computing the timing metrics for the complete lifecycle of a `Request`.
  public struct Timeline {
      /// The time the request was initialized.
      public let requestStartTime: CFAbsoluteTime
  
      /// The time the first bytes were received from or sent to the server.
      public let initialResponseTime: CFAbsoluteTime
  
      /// The time when the request was completed.
      public let requestCompletedTime: CFAbsoluteTime
  
      /// The time when the response serialization was completed.
      public let serializationCompletedTime: CFAbsoluteTime
  
      /// The time interval in seconds from the time the request started to the initial response from the server.
      public let latency: TimeInterval
  
      /// The time interval in seconds from the time the request started to the time the request completed.
      public let requestDuration: TimeInterval
  
      /// The time interval in seconds from the time the request completed to the time response serialization completed.
      public let serializationDuration: TimeInterval
  
      /// The time interval in seconds from the time the request started to the time response serialization completed.
      public let totalDuration: TimeInterval
  
      /// Creates a new `Timeline` instance with the specified request times.
      ///
      /// - parameter requestStartTime:           The time the request was initialized. Defaults to `0.0`.
      /// - parameter initialResponseTime:        The time the first bytes were received from or sent to the server.
      ///                                         Defaults to `0.0`.
      /// - parameter requestCompletedTime:       The time when the request was completed. Defaults to `0.0`.
      /// - parameter serializationCompletedTime: The time when the response serialization was completed. Defaults
      ///                                         to `0.0`.
      ///
      /// - returns: The new `Timeline` instance.
      public init(
          requestStartTime: CFAbsoluteTime = 0.0,
          initialResponseTime: CFAbsoluteTime = 0.0,
          requestCompletedTime: CFAbsoluteTime = 0.0,
          serializationCompletedTime: CFAbsoluteTime = 0.0)
      {
          self.requestStartTime = requestStartTime
          self.initialResponseTime = initialResponseTime
          self.requestCompletedTime = requestCompletedTime
          self.serializationCompletedTime = serializationCompletedTime
  
          self.latency = initialResponseTime - requestStartTime
          self.requestDuration = requestCompletedTime - requestStartTime
          self.serializationDuration = serializationCompletedTime - requestCompletedTime
          self.totalDuration = serializationCompletedTime - requestStartTime
      }
  }
  
  // MARK: - CustomStringConvertible
  
  extension Timeline: CustomStringConvertible {
      /// The textual representation used when written to an output stream, which includes the latency, the request
      /// duration and the total duration.
      public var description: String {
          let latency = String(format: "%.3f", self.latency)
          let requestDuration = String(format: "%.3f", self.requestDuration)
          let serializationDuration = String(format: "%.3f", self.serializationDuration)
          let totalDuration = String(format: "%.3f", self.totalDuration)
  
          // NOTE: Had to move to string concatenation due to memory leak filed as rdar://26761490. Once memory leak is
          // fixed, we should move back to string interpolation by reverting commit 7d4a43b1.
          let timings = [
              "\"Latency\": " + latency + " secs",
              "\"Request Duration\": " + requestDuration + " secs",
              "\"Serialization Duration\": " + serializationDuration + " secs",
              "\"Total Duration\": " + totalDuration + " secs"
          ]
  
          return "Timeline: { " + timings.joined(separator: ", ") + " }"
      }
  }
  
  // MARK: - CustomDebugStringConvertible
  
  extension Timeline: CustomDebugStringConvertible {
      /// The textual representation used when written to an output stream, which includes the request start time, the
      /// initial response time, the request completed time, the serialization completed time, the latency, the request
      /// duration and the total duration.
      public var debugDescription: String {
          let requestStartTime = String(format: "%.3f", self.requestStartTime)
          let initialResponseTime = String(format: "%.3f", self.initialResponseTime)
          let requestCompletedTime = String(format: "%.3f", self.requestCompletedTime)
          let serializationCompletedTime = String(format: "%.3f", self.serializationCompletedTime)
          let latency = String(format: "%.3f", self.latency)
          let requestDuration = String(format: "%.3f", self.requestDuration)
          let serializationDuration = String(format: "%.3f", self.serializationDuration)
          let totalDuration = String(format: "%.3f", self.totalDuration)
  
          // NOTE: Had to move to string concatenation due to memory leak filed as rdar://26761490. Once memory leak is
          // fixed, we should move back to string interpolation by reverting commit 7d4a43b1.
          let timings = [
              "\"Request Start Time\": " + requestStartTime,
              "\"Initial Response Time\": " + initialResponseTime,
              "\"Request Completed Time\": " + requestCompletedTime,
              "\"Serialization Completed Time\": " + serializationCompletedTime,
              "\"Latency\": " + latency + " secs",
              "\"Request Duration\": " + requestDuration + " secs",
              "\"Serialization Duration\": " + serializationDuration + " secs",
              "\"Total Duration\": " + totalDuration + " secs"
          ]
  
          return "Timeline: { " + timings.joined(separator: ", ") + " }"
      }
  }