// Ported from filius-ipad (GPLv2/GPLv3):
//   State/TopologyNetworkRuntimeEngine.swift (TopologyNetworkRuntimeSpeed)
// Java counterpart: filius.hardware.Verbindung (MIN_VERZOEGERUNG_IN_MILLIS,
//   verzoegerungsFaktor) and GUIMainMenu.updateLatency.

export const MINIMUM_SPEED_PERCENT = 1;
export const MAXIMUM_SPEED_PERCENT = 100;
export const DEFAULT_SPEED_PERCENT = 90;
export const JAVA_MINIMUM_LINK_DELAY_MILLISECONDS = 5;
/** Java's Verbindung.MAX_HOPS: the round trip time is this many cables. */
export const JAVA_MAXIMUM_HOPS = 50;

export class RuntimeSpeed {
  readonly percent: number;

  constructor(percent: number = DEFAULT_SPEED_PERCENT) {
    this.percent = Math.min(MAXIMUM_SPEED_PERCENT, Math.max(MINIMUM_SPEED_PERCENT, Math.trunc(percent)));
  }

  /** Java's delay factor: 1 at full speed, 100 at the slowest. */
  get javaDelayFactor(): number {
    return MAXIMUM_SPEED_PERCENT - this.percent + 1;
  }

  /** How long a frame travels over one cable. */
  get linkTransmissionDelayMilliseconds(): number {
    return JAVA_MINIMUM_LINK_DELAY_MILLISECONDS * this.javaDelayFactor;
  }

  /**
   * Java's Verbindung.holeRTT: how long an answer may take, 50 cables (2750 ms
   * at the default 90 %). Java's RTT factor (a start option, 1 to 5) is 1.
   */
  get roundTripTimeMilliseconds(): number {
    return JAVA_MAXIMUM_HOPS * this.linkTransmissionDelayMilliseconds;
  }

  /** A base delay scaled like a cable, or undefined past the safe integer range. */
  scaledLinkDelay(baseMilliseconds: number): number | undefined {
    const delay = baseMilliseconds * this.javaDelayFactor;
    return Number.isSafeInteger(delay) ? delay : undefined;
  }
}