import { PositionalAudio } from "three";
import { PositionalAudioHelper } from 'three/examples/jsm/helpers/PositionalAudioHelper.js';

import { isDevEnvironment } from "../engine/debug/index.js";
import { Application, ApplicationEvents } from "../engine/engine_application.js";
import { findObjectOfType } from "../engine/engine_components.js";
import { serializable } from "../engine/engine_serialization_decorator.js";
import { DeviceUtilities, getParam } from "../engine/engine_utils.js";
import { AudioListener } from "./AudioListener.js";
import { Behaviour, GameObject } from "./Component.js";


const debug = getParam("debugaudio");

/**
 * Defines how audio volume attenuates over distance from the listener.
 */
export enum AudioRolloffMode {
    /**
     * Logarithmic rolloff provides a natural, real-world attenuation where volume decreases
     * exponentially with distance.
     */
    Logarithmic = 0,

    /**
     * Linear rolloff provides a straightforward volume reduction that decreases at a constant
     * rate with distance.
     */
    Linear = 1,

    /**
     * Custom rolloff allows for defining specialized distance-based attenuation curves.
     * Note: Custom rolloff is not fully implemented in this version.
     */
    Custom = 2,
}


/**
 * Plays audio clips in the scene with support for spatial (3D) positioning.  
 *
 * **Browser autoplay policies:**  
 * Web browsers require user interaction before playing audio. Use  
 * `AudioSource.userInteractionRegistered` to check if playback is allowed,  
 * or `registerWaitForAllowAudio()` to queue playback until interaction occurs.  
 *
 * **Spatial audio:**  
 * Set `spatialBlend` to 1 for full 3D positioning, or 0 for 2D (non-spatial).  
 * Requires an {@link AudioListener} in the scene (typically on the camera).  
 *
 * **Visibility handling:**  
 * Audio automatically pauses when the tab is hidden unless `playInBackground = true`.  
 * On mobile, audio always pauses in background regardless of this setting.  
 *
 * @example Play audio on button click
 * ```ts
 * onClick() {
 *   const audio = this.getComponent(AudioSource);
 *   audio.play();
 * }
 * ```
 *
 * @example Wait for user interaction
 * ```ts
 * AudioSource.registerWaitForAllowAudio(() => {
 *   this.getComponent(AudioSource)?.play();
 * });
 * ```
 *
 * @summary Plays audio clips from files or media streams
 * @category Multimedia
 * @group Components
 * @see {@link AudioListener} for the audio receiver component
 * @see {@link AudioRolloffMode} for distance attenuation options
 * @see {@link Voip} for voice communication
 * @see {@link PlayableDirector} for timeline-based audio  
 * @link https://engine.needle.tools/samples/?overlay=samples&tag=audio
 * @link https://spatial-audio-zubckswmztj.needle.run/
 */
export class AudioSource extends Behaviour {

    /**
     * Checks if the user has interacted with the page to allow audio playback.
     * Audio playback often requires a user gesture first due to browser autoplay policies.
     * This is the same as calling {@link Application.userInteractionRegistered}.
     * 
     * @returns Whether user interaction has been registered to allow audio playback
     */
    public static get userInteractionRegistered(): boolean {
        return Application.userInteractionRegistered;
    }

    /**
     * Registers a callback that will be executed once the user has interacted with the page,
     * allowing audio playback to begin.
     * This is the same as calling {@link Application.registerWaitForInteraction}.
     * 
     * @param cb - The callback function to execute when user interaction is registered
     */
    public static registerWaitForAllowAudio(cb: Function) {
        Application.registerWaitForInteraction(cb);
    }

    /**
     * The audio clip to play. Can be a URL string pointing to an audio file or a {@link MediaStream} object.
     */
    @serializable(URL)
    clip: string | MediaStream = "";

    /**
     * When true, the audio will automatically start playing when the component is enabled.
     * When false, you must call play() manually to start audio playback.
     * @default false
     */
    @serializable()
    playOnAwake: boolean = false;

    /**
     * When true, the audio clip will be loaded during initialization rather than when play() is called.
     * This can reduce playback delay but increases initial loading time.
     * @default true
     */
    @serializable()
    preload: boolean = true;

    /**
     * When true, audio will continue playing when the browser tab loses focus.
     * When false, audio will pause when the tab is minimized or not active.
     * @default true
     */
    @serializable()
    playInBackground: boolean = true;

    /**
     * Indicates whether the audio is currently playing.
     * 
     * @returns True if the audio is playing, false otherwise
     */
    get isPlaying(): boolean {
        // For the media-element path (string clips and MediaStreams) three.js does NOT maintain
        // sound.isPlaying (hasPlaybackControl is false once a media/stream source is set), so the
        // <audio> element is the source of truth.
        if (this._audioElement) return !this._audioElement.paused && !this._audioElement.ended;
        return this.sound?.isPlaying ?? false;
    }

    /**
     * The total duration of the currently loaded audio clip in seconds.
     * 
     * @returns Duration in seconds or undefined if no clip is loaded
     * @remarks For MediaStream clips, duration is not directly available and will return undefined. If the audio clip has not started loading or is still loading, duration may also be undefined until the audio buffer is ready.
     */
    get duration() {
        // Media-element path is the primary source of truth for string clips.
        // (NaN/Infinity for MediaStream or before metadata is loaded → treated as "unknown".)
        const elDuration = this._usesMediaElementSource ? this._audioElement?.duration : undefined;
        if (elDuration && isFinite(elDuration)) {
            return elDuration;
        }
        else if (this.sound?.buffer?.duration) {
            return this.sound.buffer.duration;
        }
        else if (this._loadedClip instanceof MediaStream) {
            // MediaStream duration is not directly available; return undefined or estimate if possible
            return undefined;
        }
        return undefined;
    }

    /**
     * The current playback position as a normalized value between 0 and 1.
     * Can be set to seek to a specific position in the audio.
     */
    get time01() {
        const duration = this.duration;
        if (duration) {
            return this.time / duration;
        }
        return 0;
    }
    set time01(val: number) {
        const duration = this.duration;
        if (duration) {
            this.time = val * duration;
        }
    }

    /**
     * The current playback position in seconds.
     * Can be set to seek to a specific time in the audio.
     */
    get time(): number {
        // Media-element path: the element's currentTime is authoritative.
        if (this._usesMediaElementSource && this._audioElement) return this._audioElement.currentTime;
        return this.sound?.source ? (this.sound.source?.context.currentTime - this._lastContextTime + this.sound.offset) : 0;
    }
    set time(val: number) {
        // Media-element path: seek directly on the element (sound.offset is not used for media nodes).
        if (this._usesMediaElementSource && this._audioElement) {
            this._audioElement.currentTime = val;
            return;
        }
        if (this.sound) {
            if (val === this.sound.offset) return;
            const wasPlaying = this.isPlaying;
            this.stop();
            this.sound.offset = val;
            if (wasPlaying)
                this.play();
        }
    }

    /**
     * When true, the audio will repeat after reaching the end.
     * When false, audio will play once and stop.
     * @default false
     */
    @serializable()
    get loop(): boolean {
        // Media-element path: the element holds the authoritative loop flag (sound.getLoop()
        // warns and returns false once hasPlaybackControl is false).
        if (this._usesMediaElementSource && this._audioElement) {
            this._loop = this._audioElement.loop;
            return this._loop;
        }
        if (this.sound) this._loop = this.sound.getLoop();
        return this._loop;
    }
    set loop(val: boolean) {
        this._loop = val;
        if (this._usesMediaElementSource && this._audioElement) this._audioElement.loop = val;
        else if (this.sound) this.sound.setLoop(val);
    }

    /**
     * Controls how the audio is positioned in space.
     * Values range from 0 (2D, non-positional) to 1 (fully 3D positioned).
     * Internally uses a dual-path audio graph to crossfade between a spatialized (PannerNode)
     * and a non-spatialized (direct) signal path.
     */
    @serializable()
    get spatialBlend(): number {
        return this._spatialBlend;
    }
    set spatialBlend(val: number) {
        if (val === this._spatialBlend) return;
        this._spatialBlend = val;
        this._needUpdateSpatialDistanceSettings = true;
    }

    /**
     * The minimum distance from the audio source at which the volume starts to attenuate.
     * Within this radius, the audio plays at full volume regardless of distance.
     */
    @serializable()
    get minDistance(): number {
        return this._minDistance;
    }
    set minDistance(val: number) {
        if (this._minDistance === val) return;
        this._minDistance = val;
        this._needUpdateSpatialDistanceSettings = true;
    }

    /**
     * The maximum distance from the audio source beyond which the volume no longer decreases.
     * This defines the outer limit of the attenuation curve.
     */
    @serializable()
    get maxDistance(): number {
        return this._maxDistance;
    }
    set maxDistance(val: number) {
        if (this._maxDistance === val) return;
        this._maxDistance = val;
        this._needUpdateSpatialDistanceSettings = true;
    }

    private _spatialBlend: number = 0;
    private _minDistance: number = 1;
    private _maxDistance: number = 100;

    /**
     * Controls the overall volume/loudness of the audio.
     * Values range from 0 (silent) to 1 (full volume).
     * @default 1
     */
    @serializable()
    get volume(): number { return this._volume; }
    set volume(val: number) {
        this._volume = val;
        if (this.sound && !this.context.application.muted) {
            if (debug) console.log(this.name, "audio set volume", val);
            this.sound.setVolume(val);
        }
    }
    private _volume: number = 1;

    /**
     * Controls the playback rate (speed) of the audio.
     * Values greater than 1 increase speed, values less than 1 decrease it.
     * This affects both speed and pitch of the audio.
     * @default 1
     */
    @serializable()
    set pitch(val: number) {
        // Media-element path: playbackRate on the element (sound.setPlaybackRate warns and is a
        // no-op once hasPlaybackControl is false).
        if (this._usesMediaElementSource && this._audioElement) this._audioElement.playbackRate = val;
        else if (this.sound) this.sound.setPlaybackRate(val);
    }
    get pitch(): number {
        if (this._usesMediaElementSource && this._audioElement) return this._audioElement.playbackRate;
        return this.sound ? this.sound.getPlaybackRate() : 1;
    }

    /**
     * Determines how audio volume decreases with distance from the listener.
     * @default AudioRolloffMode.Logarithmic
     * @see {@link AudioRolloffMode}
     */
    @serializable()
    rollOffMode: AudioRolloffMode = 0;


    private _loop: boolean = false;
    private sound: PositionalAudio | null = null;
    private helper: PositionalAudioHelper | null = null;
    private wasPlaying = false;
    private shouldPlay: boolean = false;
    // set this from audio context time, used to set clip offset when setting "time" property
    // there is maybe a better way to set a audio clip current time?!
    private _loadedClip: string | MediaStream | null = null;
    private _audioElement: HTMLAudioElement | null = null;
    /**
     * True when {@link _audioElement} is a file-URL element routed through
     * `sound.setMediaElementSource()` (the iOS-survivable string-clip path). For this path ALL
     * playback control (play/pause/stop/loop/pitch/time/isPlaying) goes through the element,
     * because three.js sets `hasPlaybackControl = false` once a media source is attached.
     * It is `false` for the distinct MediaStream path (which uses an element with `srcObject`
     * plus `setMediaStreamSource()` and is controlled differently).
     */
    private _usesMediaElementSource: boolean = false;

    // Spatial blend dual-path audio nodes
    private _entryNode: GainNode | null = null;
    private _spatialGain: GainNode | null = null;
    private _bypassGain: GainNode | null = null;

    /**
     * Returns the underlying {@link PositionalAudio} object, creating it if necessary.
     * The audio source needs a user interaction to be initialized due to browser autoplay policies.
     *
     * @returns The three.js PositionalAudio object or null if unavailable
     */
    public get Sound(): PositionalAudio | null {
        if (!this.sound && AudioSource.userInteractionRegistered) {
            // Get or create an audiolistener in the scene
            let listener = this.gameObject.getComponent(AudioListener) // AudioListener on AudioSource?
                ?? this.context.mainCamera.getComponent(AudioListener) // AudioListener on current main camera?
                ?? findObjectOfType(AudioListener, this.context, false); // Active AudioListener in scene?

            if (!listener && this.context.mainCamera) listener = this.context.mainCamera.addComponent(AudioListener);

            if (listener?.listener) {
                this.sound = new PositionalAudio(listener.listener);
                this.gameObject?.add(this.sound);
            }
            else if (debug) console.warn("No audio listener found in scene - can not play audio");
        }
        return this.sound;
    }

    /**
     * Indicates whether the audio source is queued to play when possible.
     * This may be true before user interaction has been registered.
     * 
     * @returns Whether the audio source intends to play
     */
    public get ShouldPlay(): boolean { return this.shouldPlay; }

    /**
     * Returns the Web Audio API context associated with this audio source.
     * 
     * @returns The {@link AudioContext} or null if not available
     */
    public get audioContext() {
        return this.sound?.context;
    }

    /**
     * Resumes the shared AudioContext if it is currently suspended/interrupted and the
     * page is visible. Uses the same policy as the global resume handler so this never
     * triggers the iOS `InvalidStateError: Failed to start the audio device` (which
     * happens when resuming while the page is hidden). No-op when the context is already
     * running or when resuming is not currently allowed.
     */
    private ensureContextResumed() {
        const ctx = this.audioContext;
        if (!ctx) return;
        const visibility = typeof document !== "undefined" ? document.visibilityState : "visible";
        // Only skip while hidden — resuming a hidden context throws iOS InvalidStateError.
        if (visibility !== "visible") return;
        // Resume even when ctx.state already reports "running". On iOS an auto-resume that
        // happened OUTSIDE a user gesture (e.g. our visibilitychange retry) can leave the
        // context reporting "running" while the audio HARDWARE stays off ("zombie" context).
        // play() is user-initiated, so this resume() runs inside the gesture and re-enables
        // actual output. It is a harmless no-op on an already-healthy context.
        // (The global handler in engine_audio.ts still uses shouldResumeAudioContext, because
        // it fires on timers/events with no gesture and must not spam resume on a running ctx.)
        ctx.resume().catch(e => { if (debug) console.warn("[AudioSource] Failed to resume AudioContext:", e); });
    }

    /** @internal */
    awake() {
        if (debug) console.log("[AudioSource]", this);

        if (this.playOnAwake) this.shouldPlay = true;

        if (this.preload) {
            if (typeof this.clip === "string" && this.clip.length > 0) {
                // Preload = create the <audio> element and wire it into the Web Audio graph, but do
                // NOT play. Wiring needs the PositionalAudio (Sound), which in turn needs an
                // AudioListener that only exists after a user gesture — so defer when not ready.
                if (this.Sound) {
                    this.createAudioFromElement();
                }
                else {
                    AudioSource.registerWaitForAllowAudio(() => {
                        if (this.destroyed || this.enabled === false) return;
                        if (typeof this.clip === "string" && this.clip.length > 0) this.createAudioFromElement();
                    });
                }
            }
        }
    }

    /** @internal */
    onEnable(): void {
        if (this.sound)
            this.gameObject.add(this.sound);

        if (!AudioSource.userInteractionRegistered) {
            AudioSource.registerWaitForAllowAudio(() => {
                if (this.enabled && !this.destroyed && this.shouldPlay)
                    this.onNewClip(this.clip);
            });
        }
        else if (this.playOnAwake && this.context.application.isVisible) {
            this.play();
        }
        globalThis.addEventListener('visibilitychange', this.onVisibilityChanged);
        this.context.application.addEventListener(ApplicationEvents.MuteChanged, this.onApplicationMuteChanged);
    }

    /** @internal */
    onDisable() {
        globalThis.removeEventListener('visibilitychange', this.onVisibilityChanged);
        this.context.application.removeEventListener(ApplicationEvents.MuteChanged, this.onApplicationMuteChanged);
        this.pause();
    }

    private onVisibilityChanged = () => {
        switch (document.visibilityState) {
            case "hidden":
                if (this.playInBackground === false || DeviceUtilities.isMobileDevice()) {
                    const wasPlaying = this.isPlaying;
                    if (wasPlaying) {
                        this.pause();
                    }
                    // pause() clears wasPlaying so a *user-initiated* pause is not auto-resumed on
                    // the next foreground. This pause is automatic (page hidden / device locked), so
                    // re-assert the resume intent AFTER pause() — otherwise we never resume on unlock.
                    this.wasPlaying = wasPlaying;
                }
                break;
            case "visible":
                if (debug) console.log("visible", this.enabled, this.playOnAwake, !this.isPlaying, AudioSource.userInteractionRegistered, this.wasPlaying);
                // Resume anything that was actively playing when the page was hidden — not
                // just playOnAwake sources. `wasPlaying` is the correct signal: it is only
                // set when this source was playing at hide time, so script-started clips
                // resume too (previously they stayed silent until a manual play()).
                if (this.enabled && !this.isPlaying && AudioSource.userInteractionRegistered && this.wasPlaying) {
                    this.play();
                }
                break;
        }
    }

    private onApplicationMuteChanged = () => {
        if (this.context.application.muted)
            this.sound?.setVolume(0);
        else
            this.sound?.setVolume(this.volume);
    }

    /**
     * Sets up playback of a string (file URL) clip through an `HTMLAudioElement` routed into the
     * Web Audio graph via `sound.setMediaElementSource()`.
     *
     * Why a media element instead of a decoded `AudioBuffer`: on iOS Safari an
     * `AudioBufferSourceNode` has its output torn down after a device lock / audio-session
     * interruption and cannot be reliably revived. A `MediaElementAudioSourceNode` survives the
     * lock because the playing `<audio>` element keeps iOS's media session alive, so the shared
     * AudioContext is never torn down and resumes cleanly. This is the same approach three.js's own
     * `webaudio_orientation` example uses.
     *
     * This does NOT start playback — it only creates/wires the element so a later `.play()` (driven
     * by a user gesture) is cheap.
     */
    private createAudioFromElement() {
        if (this.destroyed) {
            if (debug) console.warn("AudioSource destroyed, not creating audio", this.name);
            return;
        }
        const sound = this.Sound;
        if (!sound) {
            if (debug) console.warn("Failed getting sound?", this.name);
            return;
        }

        // If the element is already wired for the CURRENT clip, there is nothing to (re)create —
        // re-running setMediaElementSource on the same element throws InvalidStateError
        // ("already connected to a MediaElementSourceNode"), so bail out early.
        if (this._audioElement && this._usesMediaElementSource && this._loadedClip === this.clip) {
            // keep volume/mute in sync, then we're done
            if (this.context.application.muted) sound.setVolume(0);
            else sound.setVolume(this.volume);
            return;
        }

        // (re)create the element when the clip changed since the element was wired.
        if (this._audioElement && this._loadedClip !== this.clip) {
            this._audioElement.pause();
            this._audioElement = null;
            this._usesMediaElementSource = false;
        }
        const created = !this._audioElement;
        if (created) {
            const el = new Audio();
            el.crossOrigin = "anonymous";
            el.preload = "auto";
            el.src = this.clip as string;
            this._audioElement = el;
        }
        this._audioElement!.loop = this._loop;

        // IMPORTANT: build the spatial-blend graph FIRST so getOutput() returns the entry node,
        // THEN route the media element source into it. setMediaElementSource() immediately calls
        // sound.connect() (source → getOutput()), so the entry node and the getOutput override
        // must already exist. Order matters.
        this.setupSpatialBlendNodes();
        // Only connect once per element — createMediaElementSource() throws if the same
        // HTMLMediaElement is passed to it twice.
        if (!this._usesMediaElementSource) {
            sound.setMediaElementSource(this._audioElement!);
            this._usesMediaElementSource = true;
        }
        this._loadedClip = this.clip;

        if (this.context.application.muted) sound.setVolume(0);
        else sound.setVolume(this.volume);
        this.applySpatialDistanceSettings();

        // Playback is started explicitly by onNewClip()/play()/onEnable — do NOT auto-play here.
        // Registering __onAllowAudioCallback would (once the user has interacted) fire immediately
        // and call play() a SECOND time, restarting the element → audible "clipping repeat".
    }

    /**
     * Sets up the {@link PositionalAudio} graph for a MediaStream clip (used for the MediaStream
     * path only — string clips go through {@link createAudioFromElement}). The actual stream node
     * is attached in {@link play} via `setMediaStreamSource`.
     */
    private createAudio = () => {
        if (this.destroyed) {
            if (debug) console.warn("AudioSource destroyed, not creating audio", this.name);
            return;
        }

        const sound = this.Sound;
        if (!sound) {
            if (debug) console.warn("Failed getting sound?", this.name);
            return;
        }

        this._loadedClip = this.clip;
        if (this.context.application.muted) sound.setVolume(0);
        else sound.setVolume(this.volume);
        this.setupSpatialBlendNodes();
        this.applySpatialDistanceSettings();

        // make sure we only play the sound if the user has interacted with the page
        AudioSource.registerWaitForAllowAudio(this.__onAllowAudioCallback);
    }
    private __onAllowAudioCallback = () => {
        if (this.shouldPlay)
            this.play();
    }

    /**
     * Sets up the dual-path audio graph for spatial blend crossfading.
     * Creates two parallel signal paths from source to output:
     * - 3D path: entry → panner → spatialGain → gain (spatialized)
     * - 2D path: entry → bypassGain → gain (non-spatialized)
     */
    private setupSpatialBlendNodes() {
        const sound = this.sound;
        if (!sound || this._entryNode) return;

        const ctx = sound.context;
        this._entryNode = ctx.createGain();
        this._spatialGain = ctx.createGain();
        this._bypassGain = ctx.createGain();

        // Disconnect the default panner → gain connection set up by three.js
        try { sound.panner.disconnect(sound.gain); } catch { /* not connected */ }

        // 3D path: entry → panner → spatialGain → gain
        this._entryNode.connect(sound.panner);
        sound.panner.connect(this._spatialGain);
        this._spatialGain.connect(sound.gain);

        // 2D path: entry → bypassGain → gain
        this._entryNode.connect(this._bypassGain);
        this._bypassGain.connect(sound.gain);

        // Override getOutput so three.js connects source → entryNode instead of panner
        sound.getOutput = () => this._entryNode! as unknown as PannerNode;

        // Wrap connect() to undo PositionalAudio's redundant panner → gain reconnection
        const origConnect = sound.connect;
        sound.connect = function () {
            origConnect.call(sound);
            try { sound.panner.disconnect(sound.gain); } catch { /* expected */ }
            return sound;
        };

        // Wrap disconnect() to prevent error when panner → gain doesn't exist
        const origDisconnect = sound.disconnect;
        sound.disconnect = function () {
            try { origDisconnect.call(sound); } catch { /* panner → gain already removed */ }
            return sound;
        };

        this.updateSpatialBlendGains();
    }

    /** Updates the spatial/bypass gain values based on the current spatialBlend. */
    private updateSpatialBlendGains() {
        if (!this._spatialGain || !this._bypassGain || !this.sound) return;
        const t = this.sound.context.currentTime;
        // Use setTargetAtTime for smooth transitions (avoids clicks/pops)
        this._spatialGain.gain.setTargetAtTime(this._spatialBlend, t, 0.01);
        this._bypassGain.gain.setTargetAtTime(1 - this._spatialBlend, t, 0.01);
    }

    private applySpatialDistanceSettings() {
        const sound = this.sound;
        if (!sound) return;
        this._needUpdateSpatialDistanceSettings = false;

        const ref = Math.max(0.0001, this._minDistance);
        const max = Math.max(0.01, this._maxDistance);
        if (debug) console.log(this.name, ref, max, this.spatialBlend);
        sound.setRefDistance(ref);
        sound.setMaxDistance(max);

        // https://developer.mozilla.org/en-US/docs/Web/API/PannerNode/distanceModel
        switch (this.rollOffMode) {
            case AudioRolloffMode.Logarithmic:
                // Unity's logarithmic rolloff matches Web Audio's 'inverse' model:
                // gain = refDistance / (refDistance + rolloffFactor * (distance - refDistance))
                // We compute rolloffFactor so gain reaches ~0.01 (-40dB) at maxDistance,
                // matching Unity's behavior of effective silence at maxDistance.
                sound.setDistanceModel('inverse');
                sound.setRolloffFactor(99 * ref / Math.max(0.001, max - ref));
                break;
            case AudioRolloffMode.Linear:
                // gain = 1 - rolloffFactor * (distance - refDistance) / (maxDistance - refDistance)
                // With rolloffFactor=1 this reaches exactly 0 at maxDistance.
                sound.setDistanceModel('linear');
                sound.setRolloffFactor(1);
                break;
            case AudioRolloffMode.Custom:
                console.warn("Custom rolloff for AudioSource is not supported: " + this.name);
                break;
        }

        this.updateSpatialBlendGains();

        if (this.spatialBlend > 0) {
            if (debug && !this.helper) {
                this.helper = new PositionalAudioHelper(sound, sound.getRefDistance());
                sound.add(this.helper);
            }
        }
        else if (this.helper && this.helper.parent) {
            this.helper.removeFromParent();
        }
    }

    private async onNewClip(clip?: string | MediaStream) {
        if (clip) this.clip = clip;
        if (typeof clip === "string") {
            if (debug)
                console.log(clip);
            if (clip.endsWith(".mp3") || clip.endsWith(".wav") || clip.endsWith(".ogg") || clip.endsWith(".opus") || clip.endsWith(".flac") || clip.endsWith(".aac") || clip.endsWith(".webm")) {
                this.shouldPlay = true;
                // Route the file URL through an <audio> element (survives iOS lock — see
                // createAudioFromElement). This creates/wires the element without playing.
                this.createAudioFromElement();
                // Start playback through the element (NOT this.sound — hasPlaybackControl is false
                // for a media-element source). __onAllowAudioCallback would also play once
                // interaction is registered; this covers the already-interacted case directly.
                if (this.shouldPlay && AudioSource.userInteractionRegistered) {
                    this.ensureContextResumed();
                    this._hasEnded = false;
                    this._audioElement?.play().catch(e => {
                        if (debug) console.warn(`[AudioSource] Failed to play audio clip "${clip}":`, e);
                    });
                    this.fadeEntryGain(1); // fade in (no-op on first play; undoes a prior pause() fade)
                }
            }
            else console.warn("Unsupported audio clip type", clip)
        }
        else {
            this.shouldPlay = true;
            this.createAudio();
        }
    }

    /**
     * Plays the audio clip or media stream.
     * If no argument is provided, plays the currently assigned clip.
     * 
     * @param clip - Optional audio clip or {@link MediaStream} to play
     * @returns A promise that resolves when playback starts successfully, or rejects on error
     */
    async play(clip: string | MediaStream | undefined = undefined): Promise<boolean> {
        // use audio source's clip when no clip is passed in
        if (!clip && this.clip)
            clip = this.clip;

        // We only support strings and media stream
        // TODO: maybe we should return here if an invalid value is passed in
        if (clip !== undefined && typeof clip !== "string" && !(clip instanceof MediaStream)) {
            // e.g. when a AudioSource.Play is called from SpatialTrigger onEnter this event is called with the TriggerReceiver... to still make this work we *re-use* our already assigned clip. Because otherwise calling `play` would not play the clip...
            clip = this.clip;
            if (isDevEnvironment()) console.warn("[AudioSource] Called play on AudioSource with unknown argument type:", clip + "\nUsing the assigned clip instead:", this.clip)
        }

        // Load if the sound hasn't been created yet or if the clip changed since last load
        let needsLoading = !this.sound || (clip && clip !== this._loadedClip);
        // For string clips the <audio> element must additionally be wired (createAudioFromElement);
        // if it isn't yet (e.g. preload was off, or the element was torn down), force a (re)load.
        if (typeof clip === "string" && (!this._audioElement || !this._usesMediaElementSource)) needsLoading = true;
        if (clip instanceof MediaStream || typeof clip === "string")
            this.clip = clip;

        if (needsLoading) {
            this.shouldPlay = true;
            return this.onNewClip(clip).then(() => true).catch(() => false);
        }

        this.shouldPlay = true;
        this._hasEnded = false;

        if (debug) console.log("[AudioSource] play", this.sound?.getVolume(), this.sound);
        // If a different clip was passed in, needsLoading above would be true and onNewClip handles it.
        // This guard prevents double-playing the same already-playing sound.
        if (this.sound && !this.isPlaying) {
            // On iOS the shared context can be suspended/interrupted (device locked, app
            // backgrounded, audio session interrupted by a call) — starting playback on it produces
            // no sound until it is resumed. Resume it here (we are inside a user gesture) so playback
            // does not silently depend on the global resume handler running first. See engine_audio.ts.
            this.ensureContextResumed();
            const muted = this.context.application.muted;
            if (muted) this.sound.setVolume(0);
            this.gameObject?.add(this.sound);

            if (this.clip instanceof MediaStream) {

                // Distinct from the file-URL media-element path: a MediaStream uses
                // setMediaStreamSource + an element holding srcObject (the element is only needed
                // so the stream actually plays — playback is not controlled through it here).
                this._usesMediaElementSource = false;
                this.sound.setMediaStreamSource(this.clip);

                if (!this._audioElement) {
                    this._audioElement = document.createElement('audio');
                    this._audioElement.style.display = "none";
                }
                if (!this._audioElement.parentNode)
                    this.context.domElement.shadowRoot?.append(this._audioElement);
                this._audioElement.srcObject = this.clip;
                this._audioElement.autoplay = false;
                return true;

            }
            else {
                // File-URL media-element path: playback control is on the element, not this.sound
                // (hasPlaybackControl is false once setMediaElementSource was called). Volume/mute
                // is still applied via sound.setVolume() above (the gain node still works).
                // Resume the element from its (frozen) position, then fade the entry gain back in so
                // the resume is click-free. No seek, no graph reconnect — both caused the stutter.
                this._audioElement?.play().catch(e => {
                    if (debug) console.warn("[AudioSource] Failed to play audio element:", e);
                });
                this.fadeEntryGain(1);
                return true;
            }
        }

        return false;
    }

    /**
     * Smoothly ramp the spatial-graph entry-gain node to `target` (1 = audible, 0 = silent) over a
     * few ms. A short *fade* — not a hard 0/1 gain change and not a connect/disconnect — is what
     * avoids the click on pause/resume (an instant change or a graph (dis)connect steps the waveform
     * → audible click). On iOS the MediaElementAudioSourceNode keeps feeding the graph after
     * element.pause() following an interruption, so fading this gain to 0 is what actually silences a
     * "paused" media clip; element.pause() only freezes its playback position.
     */
    private fadeEntryGain(target: number, seconds = 0.02) {
        if (!this._entryNode || !this.sound) return;
        const ctx = this.sound.context;
        const g = this._entryNode.gain;
        g.cancelScheduledValues(ctx.currentTime);
        g.setValueAtTime(g.value, ctx.currentTime);
        g.linearRampToValueAtTime(target, ctx.currentTime + seconds);
    }

    /**
     * Pauses audio playback while maintaining the current position.
     * Use play() to resume from the paused position.
     */
    pause() {
        if (debug) console.log("[AudioSource] pause", this);
        this._hasEnded = true;
        this.shouldPlay = false;
        // A user-initiated pause must not be revived by the visibility handler on the next
        // foreground (it replays sources whose `wasPlaying` is set).
        this.wasPlaying = false;
        if (this._usesMediaElementSource) {
            // File-URL media-element path. On iOS the MediaElementAudioSourceNode keeps emitting into
            // the Web Audio graph after element.pause() once the audio session has been interrupted
            // (lock/unlock) — pausing the element does NOT silence it (confirmed on-device). So we
            // fade the entry gain to 0 (click-free silence — the fade is what actually silences it),
            // then freeze the element's position. play() fades it back in.
            this.fadeEntryGain(0);
            this._audioElement?.pause();
            return;
        }
        if (this.sound && this.sound.isPlaying && this.sound.source) {
            this._lastContextTime = this.sound?.context.currentTime;
            this.sound.pause();
        }
        // MediaStream / legacy path: drop the stream element as before.
        this._audioElement?.remove();
    }

    /**
     * Stops audio playback completely and resets the playback position to the beginning.
     * Unlike pause(), calling play() after stop() will start from the beginning.
     */
    stop() {
        if (debug) console.log("[AudioSource] stop", this);
        this._hasEnded = true;
        this.shouldPlay = false;
        this.wasPlaying = false;
        if (this._usesMediaElementSource) {
            // True stop: detach the source from the graph (see pause() — element.pause() alone does
            // not silence it on iOS after an interruption), pause, and rewind to the start.
            this.fadeEntryGain(0);
            this._audioElement?.pause();
            if (this._audioElement) this._audioElement.currentTime = 0;
            return;
        }
        if (this.sound && this.sound.source) {
            this._lastContextTime = this.sound?.context.currentTime;
            if (debug)
                console.log("[AudioSource] lastContextTime", this._lastContextTime);
            this.sound.stop();
        }
        // MediaStream / legacy path: drop the stream element as before.
        this._audioElement?.remove();
    }

    private _lastContextTime: number = 0;

    private _hasEnded: boolean = true;
    private _needUpdateSpatialDistanceSettings: boolean = false;

    /** @internal */
    update() {
        if (this.helper) {
            if (this.isPlaying)
                this.helper.update();
            this.helper.visible = this.isPlaying;
        }

        if (this._needUpdateSpatialDistanceSettings) {
            this.applySpatialDistanceSettings();
        }

        // Use the element-aware `isPlaying` getter, NOT `sound.isPlaying`: for a media-element
        // source three.js leaves `sound.isPlaying` permanently false (hasPlaybackControl=false),
        // which would otherwise fire "ended" every frame during playback.
        if (this.sound && !this.isPlaying && this.shouldPlay && !this._hasEnded) {
            this._hasEnded = true;
            if (debug) console.log("[AudioSource] Audio clip ended", this.clip);
            this.dispatchEvent(new CustomEvent("ended", { detail: this }));
        }

        // this.gameObject.position.x = Math.sin(time.time) * 2;
        // this.gameObject.position.z = Math.cos(time.time * .5) * 2;
    }
}