// 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 = false;

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');

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;
    ProgressBar.value = parseInt(currentTimeP.innerText) + seconds_here;
    relativeTime.innerText = parseInt(currentTimeP.innerText) + seconds_here;
    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 {
            if ( debugMode ) console.log(`ERROR ${request.status} while loading ${url}`);
        }
    });
    request.addEventListener("error", ()=>{
        if ( debugMode ) console.log("An error occured. While loading: "+url+" for "+callback+".");
    });
    request.addEventListener("abort", ()=>{
        if ( debugMode ) console.log("Request aborted: "+url+" for "+callback+".");
    });
    request.open("GET", url);
    request.send();
}

function genericCallback(json, params)
{
    if ( debugMode ) console.log('genericCallback');
    if ( debugMode ) console.log(json);
    if ( debugMode ) console.log(params);
}

var calledLoadShowCallback = 0;

function stopHereAndReflect()
{
    return 0;
}

function loadShowCallback(json, params)
{
    const [ list, now_on_sequence, element, hash_of_list ] = params;
    if ( debugMode ) console.log('loadShowCallback');
    if ( debugMode ) console.log(json);
    if ( debugMode ) console.log(element);
    if ( debugMode ) console.log(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);
    sourceElement.type = json.mimetype;
    audioElement.load();
    if ( debugMode ) console.log('plays here: '+(now_on_sequence - element.starts_on)/1000);
    audioElement.addEventListener('canplaythrough', function(){
        if ( debugMode ) console.log('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();
        }
    });
    audioElement.addEventListener('ended', function(){
        location.reload();
    });
    var synced_at = sync_radio();
    if ( debugMode ) console.log("Synced initially at : "+synced_at);
    if ( synced_at === 0 )
    {
        if ( synced_at > audioElement.currentTime )
        {
            if ( debugMode ) console.log('Good sync!');
        }
        else
        {
            setTimeout(sync_radio, 10000);
        }
    }
}

function sync_radio()
{
    var value = currentTimeP.innerText;
    if ( value !== "" )
    {
        var new_now = parseFloat(value) + getSecondsHere();
        if ( debugMode ) console.log("Trying to sync @ "+ value + " + " +getSecondsHere() + " = " + new_now);
        audioElement.currentTime = new_now;
        return new_now;
    }
    return 0;
}

function listCallback(json, params)
{
    if ( debugMode ) console.log('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;
    if ( debugMode ) console.log(`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;
            if ( debugMode ) console.log(now_on_sequence);
            previous = element;
            if ( debugMode ) console.log(element);
            FetchJSON("http://z.kaotisk-hund.com:8010/v0/application/json/" + element.hash, loadShowCallback, [json, now_on_sequence, element, hash_of_list]);
        }
    });
}

function hashCallback(json, params)
{
    var [ now ] = params;
    if ( debugMode ) console.log('hashCallback');
    FetchJSON('http://z.kaotisk-hund.com:8010/v0/application/json/' + json.latest_list, listCallback, [now, json.latest_list]);
}

FetchJSON('http://z.kaotisk-hund.com:8010/v0/list', hashCallback, [ new Date().getTime() ]);