import {VideoMetrics,receipt} from './metrics.js';
const el=id=>document.getElementById(id);
let generation=0, current=null, last=null;
const stopTracks=stream=>stream?.getTracks().forEach(track=>track.stop());
function release(run) {
    if(run.released)return;
    run.released=true;
    clearTimeout(run.timer); clearTimeout(run.setupTimer);
    if(run.callback)el('preview').cancelVideoFrameCallback(run.callback);
    run.node?.port.postMessage('stop'); run.node?.disconnect(); run.source?.disconnect();
    stopTracks(run.stream);
    // Do not wait on a browser AudioContext close before fencing a stopped run.
    run.context?.close().catch(()=>{});
}
function stop(reason='operator') {
    generation++;
    const run=current; current=null;
    if(run) {
        release(run);
        last=receipt(run.video,run.audio,run.settings,performance.now()-run.started,reason);
        el('metrics').textContent=JSON.stringify(last,null,2);
        el('export').disabled=false;
    }
    el('preview').srcObject=null;
    el('start').disabled=!el('audio-device').value || !el('video-device').value;
    el('stop').disabled=true; el('devices').disabled=false;
    el('status').textContent=`Stopped · ${reason}`;
}
el('devices').onclick=async()=>{
    stop('selecting devices');
    const ticket=++generation;
    el('devices').disabled=true; el('start').disabled=true; el('stop').disabled=false;
    el('status').textContent='Requesting device permission…';
    const timer=setTimeout(()=>{if(generation===ticket)stop('permission timeout');},20000);
    try {
        const stream=await navigator.mediaDevices.getUserMedia({audio:true,video:true});
        stopTracks(stream);
        if(generation!==ticket)return;
        const devices=await navigator.mediaDevices.enumerateDevices();
        if(generation!==ticket)return;
        for(const [id,kind] of [['video-device','videoinput'],['audio-device','audioinput']]) {
            const select=el(id), saved=select.value;
            select.replaceChildren(new Option('Select Lesavka device',''));
            for(const d of devices.filter(d=>d.kind===kind)) select.add(new Option(d.label||'Unnamed device',d.deviceId));
            select.value=saved;
        }
        el('status').textContent='Select both Lesavka devices, then Start.';
        el('devices').disabled=false; el('stop').disabled=true;
    } catch { if(generation===ticket)stop('device permission unavailable'); }
    finally {clearTimeout(timer);}
};
for(const id of ['audio-device','video-device']) el(id).onchange=()=>{
    if(current)stop('device selection changed');
    el('start').disabled=!el('audio-device').value||!el('video-device').value;
};
el('start').onclick=async()=>{
    if(current || !el('audio-device').value || !el('video-device').value)return;
    if(!el('preview').requestVideoFrameCallback || !window.AudioWorkletNode) {
        el('status').textContent='This browser lacks the required observation APIs.';return;
    }
    const ticket=++generation;
    const run={started:performance.now(),video:new VideoMetrics(),audio:null,settings:{}};
    current=run; last=null;
    el('start').disabled=true; el('devices').disabled=true; el('stop').disabled=false; el('export').disabled=true;
    el('status').textContent='Starting…';
    run.setupTimer=setTimeout(()=>{if(current===run)stop('setup timeout');},20000);
    try {
        const stream=await navigator.mediaDevices.getUserMedia({
            video:{deviceId:{exact:el('video-device').value}},
            audio:{deviceId:{exact:el('audio-device').value},echoCancellation:false,noiseSuppression:false,autoGainControl:false},
        });
        if(generation!==ticket){stopTracks(stream);return;}
        run.stream=stream;
        for(const track of stream.getTracks())track.onended=()=>{if(current===run)stop('device ended');};
        const vs=stream.getVideoTracks()[0].getSettings(),as=stream.getAudioTracks()[0].getSettings();
        run.settings={video:{width:vs.width,height:vs.height,frameRate:vs.frameRate},
            audio:{sampleRate:as.sampleRate,channelCount:as.channelCount,echoCancellation:as.echoCancellation,
                noiseSuppression:as.noiseSuppression,autoGainControl:as.autoGainControl}};
        run.context=new AudioContext();
        await run.context.audioWorklet.addModule('activity-worklet.js');
        if(generation!==ticket)return;
        run.node=new AudioWorkletNode(run.context,'av-activity');
        run.node.onprocessorerror=()=>{if(current===run)stop('audio observer error');};
        run.node.port.onmessage=({data})=>{
            if(current!==run)return;
            run.audio=data; run.node.port.postMessage('ack');
            el('metrics').textContent=JSON.stringify(receipt(run.video,run.audio,run.settings,performance.now()-run.started,'observing'),null,2);
        };
        run.source=run.context.createMediaStreamSource(new MediaStream(stream.getAudioTracks()));
        run.source.connect(run.node);run.node.connect(run.context.destination);
        await run.context.resume();
        if(generation!==ticket)return;
        el('preview').srcObject=stream;
        await el('preview').play();
        if(generation!==ticket)return;
        clearTimeout(run.setupTimer);
        run.started=performance.now();
        function frame(now,metadata) {
            if(current!==run)return;
            run.video.observe(metadata.expectedDisplayTime,metadata.presentedFrames);
            run.callback=el('preview').requestVideoFrameCallback(frame);
        }
        run.callback=el('preview').requestVideoFrameCallback(frame);
        run.timer=setTimeout(()=>{if(current===run)stop('120 seconds complete');},120000);
        el('status').textContent='Observing both devices · no recording';
    } catch { if(current===run)stop('capture/setup failed'); }
    finally { if(current!==run)release(run); }
};
el('stop').onclick=()=>stop();
el('export').onclick=()=>{
    if(!last)return;
    const url=URL.createObjectURL(new Blob([JSON.stringify(last,null,2)],{type:'application/json'}));
    const link=document.createElement('a');link.href=url;link.download='lesavka-av-observer.json';link.click();
    setTimeout(()=>URL.revokeObjectURL(url),1000);
};
window.addEventListener('pagehide',()=>stop('page closed'));
document.addEventListener('visibilitychange',()=>{if(document.hidden&&current)stop('page hidden; timing invalid');});