path: root/client/js/radio_emulator.js

// Radio Emulator
// Kaotisk Hund 2024
//
// A simple co-mechanism to pretend playing a live radio as it would happen for
// a radio station that mostly plays prerecoded shows.
//
// Client side implementation
// Let's remind here the structures we are waiting for:
// 1. Hash
// 2. 0
// 3. audio/ogg file
// 4. application/json file
//
// 1. Hash
// Can be an SHA512sum or SHA256sum, we don't do checks, we only ask the hash
// accompanied by what do we think it is.
//
// 2. 0
// When nothing exists on the radio station we are visiting.
//
// 3. audio/ogg file
// An audio file to play.
//
// 4. application/json file
// Could be one of the following:
//   - list
//   - show_info
//
var debugMode = true;
const apiURL = "http://z.kaotisk-hund.com:8010/";
const version = "v0";
const listRequest = `${apiURL}${version}/list`
const jsonRequest = `${apiURL}${version}/application/json/`
const audioRequest = `${apiURL}${version}/audio/ogg/`



function debugLog(message)
{
    if ( debugMode ) console.log(message);
}

var audioElement = document.querySelector('audio');
// var sourceElement = document.querySelector('source');
var currentTimeP = document.querySelector('.current-time');
var listStartedP = document.querySelector('.started-on');
var currentShowHash = document.querySelector('.current-show-hash');
var listHash = document.querySelector('.list-hash');
var artistP = document.querySelector('.artist');
var titleP = document.querySelector('.title');
var radioPlayerDiv = document.querySelector('.radio-player');
var youAreHere = document.querySelector('.you-are-here');
var ProgressBar = document.querySelector('progress');
var startsOnP = document.querySelector('.starts-on');
var showDurationP = document.querySelector('.show-duration');
var relativeTime = document.querySelector('.relative-time');
var listeningAt = document.querySelector('.listening-at');

const documentTitle = "Radio Station Emulator";
const separator = " :: ";

function setTitleSyncing(){
    document.title = "🔃Syncing" + separator + documentTitle;
}

function setTitleMessage(message){
    document.title = message + separator + documentTitle;
}

var seconds_here = 0;
function increaseSeconds()
{
    seconds_here = seconds_here+1;
    youAreHere.innerText = seconds_here;
    var progressbarValue = isNaN(parseInt(currentTimeP.innerText)) ? 0 : parseInt(currentTimeP.innerText) + parseInt(seconds_here);
    debugLog(`${typeof(progressbarValue)} progressbarValue = ${progressbarValue}`)
    ProgressBar.value = progressbarValue;
    relativeTime.innerText = parseInt(currentTimeP.innerText) + seconds_here;
    listeningAt.innerText = Math.floor(audioElement.currentTime);
    return seconds_here;
}
function getSecondsHere()
{
    return seconds_here;
}

setInterval(increaseSeconds, 1000);


function FetchJSON( url, callback, params )
{
    setTitleSyncing();
    const request = new XMLHttpRequest();
    request.addEventListener("load", ()=>{
        var json = JSON.parse(request.response);
        if(request.status !== 404){
            callback(json, params);
        } else {
            debugLog(`ERROR ${request.status} while loading ${url}`);
        }
    });
    request.addEventListener("error", ()=>{
        debugLog("An error occured. While loading: "+url+" for "+callback+".");
    });
    request.addEventListener("abort", ()=>{
        debugLog("Request aborted: "+url+" for "+callback+".");
    });
    request.open("GET", url);
    request.send();
}

function FetchAudio(url)
{
    const request = new XMLHttpRequest();
    request.responseType = 'blob';
    request.addEventListener("load", ()=>{
        if(request.status === 200){
            debugLog("Got it... trying!")
            audioElement.src = URL.createObjectURL(request.response);
            audioElement.play();
            debugLog("Tried... did it work?");
        } else {
            debugLog(`ERROR ${request.status} while loading ${url}`);
        }
    });
    request.addEventListener("error", ()=>{
        debugLog("An error occured. While loading: "+url+" for "+callback+".");
    });
    request.addEventListener("abort", ()=>{
        debugLog("Request aborted: "+url+" for "+callback+".");
    });
    request.open("GET", url);
    request.send();
}

function genericCallback(json, params)
{
    debugLog('genericCallback');
    debugLog(json);
    debugLog(params);
}

var calledLoadShowCallback = 0;

function stopHereAndReflect()
{
    return 0;
}

function loadShowCallback(json, params)
{
    const [ list, now_on_sequence, element, hash_of_list ] = params;
    debugLog('loadShowCallback');
    debugLog(json);
    debugLog(element);
    debugLog(params);
    listStartedP.innerText = list.started_on;
    listHash.innerText = hash_of_list;
    currentShowHash.innerText = json.hash;
    artistP.innerText = json.artist;
    titleP.innerText = json.title;
    setTitleMessage ( "▶️ " + json.artist + " - " + json.title );
    showDurationP.innerText = Math.floor(element.duration/1000);
    startsOnP.innerText = element.starts_on;
    ProgressBar.max = Math.floor(element.duration/1000);
    // sourceElement.src = "http://z.kaotisk-hund.com:8010/v0/audio/ogg/" + json.hash + "#t=" + Math.floor((now_on_sequence - element.starts_on)/1000);
    audioElement.load();
    FetchAudio(`${audioRequest}${json.hash}`);
    audioElement.type = json.mimetype;
    // debugLog('plays here: '+(now_on_sequence - element.starts_on)/1000);
    // audioElement.addEventListener('canplaythrough', function(){
    //     debugLog('CAN PLAY THROUGH');
    //     if ( calledLoadShowCallback < 100 )
    //     {
    //         calledLoadShowCallback++;
             currentTimeP.innerText = ((now_on_sequence - element.starts_on)/1000);
    //         audioElement.currentTime = ((now_on_sequence - element.starts_on)/1000);
    //         audioElement.play();
    //     }
    // }, {passive: true});
    // audioElement.addEventListener('ended', function(){
    //     location.reload();
    // });
    // audioElement.addEventListener('complete', ()=>{
    //     debugLog("Download completed!")
    //     var synced_at = sync_radio();
    //     debugLog("Synced initially at : "+synced_at);
    //     if ( synced_at === 0 )
    //     {
    //         if ( synced_at > audioElement.currentTime )
    //         {
    //             debugLog('Good sync!');
    //         }
    //         else
    //         {
                 setTimeout(sync_radio, 10000);
    //         }
    //     }
    // }, {passive: true});
}

function sync_radio()
{
    var value = currentTimeP.innerText;
    if ( value !== "" )
    {
        var new_now = parseFloat(value) + getSecondsHere();
        debugLog("Trying to sync @ "+ value + " + " +getSecondsHere() + " = " + new_now);
        audioElement.currentTime = new_now;
        audioElement.play();
        audioElement.muted = false;
        for ( av = 0.1; av === 1; av = av+0.1 )
            audioElement.volume = 0.1;
        return new_now;
    }
    return 0;
}

function listCallback(json, params)
{
    debugLog('listCallback');
    var [ now, hash_of_list ] = params;
    var delta_time = now - json.started_on;
    var min_times_played = Math.floor( delta_time / json.duration );
    var max_times_to_be_played = delta_time / json.duration;
    var Dt = max_times_to_be_played - min_times_played;
    var now_on_sequence = Dt * json.duration;
    debugLog(`now_on_sequence: ${now_on_sequence}, Dt: ${Dt}`)
    previous = { starts_on: 0 };
    json.list.forEach((element)=>{
        if ( now_on_sequence < element.starts_on && now_on_sequence > previous.starts_on){
        } else {
            now_on_sequence = now_on_sequence - previous.starts_on;
            debugLog(now_on_sequence);
            previous = element;
            debugLog(element);
            FetchJSON(`${jsonRequest}${element.hash}`, loadShowCallback, [json, now_on_sequence, element, hash_of_list]);
        }
    });
}

function hashCallback(json, params)
{
    var [ now ] = params;
    debugLog('hashCallback');
    FetchJSON(`${jsonRequest}${json.latest_list}`, listCallback, [now, json.latest_list]);
}

FetchJSON(`${listRequest}`, hashCallback, [ new Date().getTime() ]);