sexy/lib/buttplug/player.ts

import { getDevice } from "./client";
import { buildOutputCommand, findFeature, type ButtplugRuntime } from "./commands";
import type { ActuatorInfo, CommandEvent } from "./types";

export interface SessionEventRow {
  tsMs: number;
  commandType: CommandEvent["commandType"];
  featureIndex: number;
  value: number;
  durationMs: number | null;
  sessionDeviceId: number;
}

export interface PlayerOptions {
  events: SessionEventRow[];
  /** The source session's actual duration (sessions.duration_ms from the DB) - this is
   *  the source of truth for playback length, NOT the last event's timestamp: a session can run
   *  for a while after its last command (e.g. the user stopped the toy but let the session
   *  continue), so deriving duration from events would end playback early and misreport it as
   *  "finished". */
  durationMs: number;
  /** Source session's session_device_id -> currently-connected device index, from the remap step. */
  sessionDeviceIdToDeviceIndex: Map<number, number>;
  actuatorsByDeviceIndex: Map<number, ActuatorInfo[]>;
  runtime: ButtplugRuntime;
  speed?: number;
  onProgress?: (elapsedMs: number, durationMs: number) => void;
  onComplete?: () => void;
  onError?: (message: string) => void;
}

/**
 * Replays a session's events against the currently-connected devices,
 * using performance.now()-relative scheduling (not wall-clock Date.now())
 * so long sessions don't accumulate drift from setTimeout jitter.
 */
export class SessionPlayer {
  private readonly durationMs: number;
  private startedAtPerf = 0;
  private pausedAtMs = 0;
  private timers: ReturnType<typeof setTimeout>[] = [];
  private progressTimer: ReturnType<typeof setInterval> | null = null;
  private playing = false;

  constructor(private readonly options: PlayerOptions) {
    this.durationMs = options.durationMs;
  }

  get isPlaying(): boolean {
    return this.playing;
  }

  play(): void {
    if (this.playing) return;
    const speed = this.options.speed ?? 1;
    this.playing = true;
    this.startedAtPerf = performance.now() - this.pausedAtMs / speed;
    this.scheduleFrom(this.pausedAtMs);
  }

  pause(): void {
    if (!this.playing) return;
    const speed = this.options.speed ?? 1;
    this.pausedAtMs = (performance.now() - this.startedAtPerf) * speed;
    this.playing = false;
    this.clearTimers();
  }

  seek(ms: number): void {
    const wasPlaying = this.playing;
    this.clearTimers();
    this.playing = false;
    this.pausedAtMs = Math.max(0, Math.min(ms, this.durationMs));
    if (wasPlaying) this.play();
  }

  stop(): void {
    this.playing = false;
    this.pausedAtMs = 0;
    this.clearTimers();
  }

  private clearTimers(): void {
    this.timers.forEach(clearTimeout);
    this.timers = [];
    if (this.progressTimer) clearInterval(this.progressTimer);
    this.progressTimer = null;
  }

  private scheduleFrom(fromMs: number): void {
    const speed = this.options.speed ?? 1;

    for (const event of this.options.events.filter((e) => e.tsMs >= fromMs)) {
      const delay = (event.tsMs - fromMs) / speed;
      this.timers.push(setTimeout(() => void this.dispatch(event), delay));
    }

    this.timers.push(
      setTimeout(() => {
        this.playing = false;
        this.clearTimers();
        this.options.onComplete?.();
      }, (this.durationMs - fromMs) / speed),
    );

    this.progressTimer = setInterval(() => {
      if (!this.playing) return;
      const elapsed = Math.min((performance.now() - this.startedAtPerf) * speed, this.durationMs);
      this.options.onProgress?.(elapsed, this.durationMs);
    }, 200);
  }

  private async dispatch(event: SessionEventRow): Promise<void> {
    const deviceIndex = this.options.sessionDeviceIdToDeviceIndex.get(event.sessionDeviceId);
    if (deviceIndex === undefined) return;

    try {
      const device = await getDevice(deviceIndex);
      if (!device) return;

      if (event.commandType === "stop") {
        await device.stop();
      } else {
        const actuator = this.options.actuatorsByDeviceIndex
          .get(deviceIndex)
          ?.find((a) => a.featureIndex === event.featureIndex);
        const feature = findFeature(device, event.featureIndex);
        if (!actuator || !feature) return;

        const cmd = buildOutputCommand(this.options.runtime, actuator, event.value, event.durationMs ?? undefined);
        await feature.runOutput(cmd);
      }
    } catch (err) {
      this.options.onError?.(err instanceof Error ? err.message : String(err));
    }
  }
}