/*
import {Device} from "tc-shared/audio/player";

export function initialize() : boolean;
export function initialized() : boolean;

export function context() : AudioContext;
export function get_master_volume() : number;
export function set_master_volume(volume: number);

export function destination() : AudioNode;

export function on_ready(cb: () => any);

export function available_devices() : Promise<Device[]>;
export function set_device(device_id: string) : Promise<void>;

export function current_device() : Device;

export function initializeFromGesture();
*/

import {Device} from "tc-shared/audio/player";
import {LogCategory} from "tc-shared/log";
import * as log from "tc-shared/log";
import * as loader from "tc-loader";

let _globalContext: AudioContext;
let _global_destination: GainNode;

let _globalContextPromise: Promise<void>;
let _initialized_listener: (() => any)[] = [];
let _master_volume: number = 1;
let _no_device = false;

export function initialize() : boolean {
    context();
    return true;
}

export function initialized() : boolean {
    return !!_globalContext && _globalContext.state === 'running';
}

function fire_initialized() {
    log.info(LogCategory.AUDIO, tr("File initialized for %d listeners"), _initialized_listener.length);
    while(_initialized_listener.length > 0)
        _initialized_listener.pop_front()();
}


export function context() : AudioContext {
    if(_globalContext && _globalContext.state != "suspended") return _globalContext;

    if(!_globalContext)
        _globalContext = new (window.webkitAudioContext || window.AudioContext)();

    _initialized_listener.unshift(() => {
        _global_destination = _globalContext.createGain();
        _global_destination.gain.value = _no_device ? 0 : _master_volume;
        _global_destination.connect(_globalContext.destination);
    });
    if(_globalContext.state == "suspended") {
        if(!_globalContextPromise) {
            (_globalContextPromise = _globalContext.resume()).then(() => {
                fire_initialized();
            }).catch(error => {
                loader.critical_error("Failed to initialize global audio context! (" + error + ")");
            });
        }
        _globalContext.resume(); //We already have our listener
        return _globalContext;
    }

    if(_globalContext.state == "running") {
        fire_initialized();
        return _globalContext;
    }
    return _globalContext;
}

export function get_master_volume() : number {
    return _master_volume;
}
export function set_master_volume(volume: number) {
    _master_volume = volume;
    if(_global_destination)
        _global_destination.gain.value = _no_device ? 0 : _master_volume;
}

export function destination() : AudioNode {
    const ctx = context();
    if(!ctx) throw tr("Audio player isn't initialized yet!");

    return _global_destination;
}

export function on_ready(cb: () => any) {
    if(initialized())
        cb();
    else
        _initialized_listener.push(cb);
}

export const WEB_DEVICE: Device = {
    device_id: "default",
    name: "default playback",
    driver: 'Web Audio'
};

export function available_devices() : Promise<Device[]> {
    return Promise.resolve([WEB_DEVICE])
}

export function set_device(device_id: string) : Promise<void> {
    _no_device = !device_id;
    _global_destination.gain.value = _no_device ? 0 : _master_volume;

    return Promise.resolve();
}

export function current_device() : Device {
    return WEB_DEVICE;
}

export function initializeFromGesture() {
    context();
}