const root = element;
const host = root.spansynthHost;
const find = (role) => root.querySelector(`[data-role="${role}"]`);
const canvas = find("roll"), scroll = root.querySelector(".roll-scroll"), ctx = canvas.getContext("2d");
const track = find("track"), instrument = find("instrument"), detail = find("detail"), trackMenu = find("track-options");
const row = 13, keys = 54, header = 52;
const clone = (value) => JSON.parse(JSON.stringify(value));
const clamp = (value, low, high) => Math.max(low, Math.min(high, value));
const noteName = (pitch) => ["C", "C♯", "D", "D♯", "E", "F", "F♯", "G", "G♯", "A", "A♯", "B"][pitch % 12] + (Math.floor(pitch / 12) - 1);
const trackPalette = ["#79a8e8", "#e68c93", "#69c3a6", "#b091dc", "#e5b05f", "#68bed5", "#d68ec1", "#a9ba66",
                      "#df9a70", "#7b9ab7", "#9894e2", "#d9c669", "#66a58e", "#b57f9b", "#aba5be", "#afa293"];
let palette = {}, data = {notes: [], instruments: [], duration: 20.48, waveform: []}, trackColors = new Map();
let selected = new Set(), program = 0, extraTracks = [], undo = [], redo = [], drag = null, tool = "select";
let lastSent = null, width = 900, timeline = 846, cursorTime = 0, timeRange = null;
let playing = null, audioContext = null, previewStarted = 0, previewOffset = 0, playbackEnd = 0, playbackFrame = null;
let viewFrame = null, auditionPitch = null, previewing = false, soundRequest = 0, voiceNumber = 0;
let soundLibrary = null, gmNames = null;
let midiAccess = null, midiInput = null, midiConnecting = false, recording = null;
const midiNotes = new Map(), midiSustain = new Set();
let recordingButtons = [];
const soundfonts = new Map(), loadingSounds = new Map(), voiceStops = new Set();
const gmBase = host?.gmBase || "https://gleitz.github.io/midi-js-soundfonts/FluidR3_GM/";
const drumUrl = host?.drumUrl || "https://cdn.jsdelivr.net/gh/henrikvilhelmberglund/midi-js-compat-soundfonts@gh-pages/GM-soundfonts/FluidR3_GM/drumkits/Standard-mp3.js";
const name = (p) => data.instruments.find(i => i.members.includes(p))?.name || `Program ${p}`;
const trackColor = (p) => trackColors.get(p) || trackPalette[0];
const snap = (time) => {const unit = Number(find("snap").value); return unit ? Math.round(time / unit) * unit : time;};
const addingTrack = () => !find("add-panel").hidden;
const chosen = () => data.notes.filter(n => n.program === program && selected.has(n.id));
const snapshot = () => ({notes: clone(data.notes), program, extraTracks: [...extraTracks], colors: [...trackColors]});
function remember(before) {undo.push(before); if (undo.length > 50) undo.shift(); redo = [];}
function syncValue() {
  if (!data.clip || recording) return;
  data.view = {program, colors: [...trackColors], extraTracks: [...extraTracks], zoom: Number(find("zoom").value),
               snap: Number(find("snap").value), scrollTop: scroll.scrollTop, scrollLeft: scroll.scrollLeft};
  const value = JSON.stringify(data);
  if (value !== lastSent) {lastSent = value; props.value = value;}
}
function publish() {refresh(); draw(); syncValue();}
function change(fn) {if (!data.clip || addingTrack() || recording) return; finishDrag(); stop(); const before=snapshot(); if(fn()!==false)remember(before); publish();}
function options(select, entries, value) {
  select.replaceChildren(...entries.map(([v, label]) => {const item = document.createElement("option"); item.value = v; item.textContent = label; return item;}));
  select.value = String(value);
}
function selectionRange() {
  if (timeRange) return timeRange;
  const notes = chosen();
  return notes.length ? [Math.min(...notes.map(n => n.start)), Math.max(...notes.map(n => n.start+n.duration))] : null;
}
function refresh() {
  const programs = [...new Set([...data.notes.map(n => n.program), ...extraTracks, program])].sort((a,b) => a-b);
  for (const p of trackColors.keys()) if (!programs.includes(p)) trackColors.delete(p);
  for (const p of programs) if (!trackColors.has(p)) {
    const used = new Set(trackColors.values());
    trackColors.set(p, trackPalette.find(color => !used.has(color)) || trackPalette[programs.indexOf(p) % trackPalette.length]);
  }
  find("track-name").textContent = `${name(program)} · ${data.notes.filter(n => n.program === program).length}`;
  track.style.setProperty("--track-color", trackColor(program));
  trackMenu.replaceChildren(...programs.map(p => {
    const item = document.createElement("button");
    item.type = "button"; item.tabIndex = -1; item.dataset.program = p;
    item.setAttribute("role", "option"); item.setAttribute("aria-selected", String(p === program));
    item.style.setProperty("--track-color", trackColor(p));
    const swatch = document.createElement("span"); swatch.className = "track-swatch"; swatch.setAttribute("aria-hidden", "true");
    const label = document.createElement("span"); label.textContent = `${name(p)} · ${data.notes.filter(n => n.program === p).length}`;
    item.append(swatch, label); return item;
  }));
  const choices = data.instruments.map(i => [i.program, i.name]);
  const entry = data.instruments.find(i => i.members.includes(program));
  if (!entry) choices.push([program, `Imported program ${program} · choose an instrument`]);
  options(instrument, choices, entry ? entry.program : program);
  find("count").textContent = `${data.notes.length} notes · ${data.duration.toFixed(2)} s`;
  const locked = addingTrack() || !!recording;
  root.dataset.adding = String(addingTrack());
  root.dataset.recording = String(!!recording);
  scroll.setAttribute("aria-disabled", String(locked));
  find("edit-lock").hidden = !addingTrack();
  for (const control of [track, instrument, find("velocity"), ...root.querySelectorAll("[data-tool], [data-action=add-track]")]) control.disabled = locked;
  for (const control of [find("snap"), find("audio-source"), find("listen"), ...root.querySelectorAll('[data-action=play], [data-action=preview], [data-action=restart]')]) control.disabled = !!recording;
  midiControls();
  for (const action of ["undo", "redo"]) root.querySelector(`[data-action="${action}"]`).disabled = locked || !(action === "undo" ? undo : redo).length;
  const notes = chosen();
  root.querySelector('[data-action="delete"]').disabled = locked || !notes.length;
  if (notes.length) find("velocity").value = notes[0].velocity;
  const range = selectionRange();
  find("listen-range").textContent = range ? `${range[0].toFixed(2)}–${range[1].toFixed(2)} s` : `Cursor · ${cursorTime.toFixed(2)} s`;
  if (!data.clip) detail.textContent = "Load a clip to begin.";
  else if (recording) detail.textContent = `Recording into ${name(recording.program)}. Press Stop to finish.`;
  else if (locked) detail.textContent = "Choose Add instrument or Cancel to continue editing.";
  else if (notes.length === 1) {const n = notes[0]; detail.textContent = `${name(n.program)} · ${noteName(n.pitch)} · ${n.start.toFixed(2)}–${(n.start+n.duration).toFixed(2)} s · velocity ${n.velocity}`;}
  else if (notes.length) detail.textContent = `${notes.length} notes selected · drag to move together, ↑ ↓ to transpose, Del to remove.`;
  else detail.textContent = `${name(program)} · ${tool === "pencil" ? "Click or drag to draw a note." : tool === "erase" ? "Click or drag over notes to erase." : "Only this track is editable. Drag empty space to select its notes."}`;
}
function region() {return host ? host.region() : ["edit-start", "edit-end"].map(id => Number(document.querySelector(`#${id} input`)?.value || 0));}
function draw(playhead = cursorTime) {
  if (!scroll.clientWidth) return;
  const scale = window.devicePixelRatio || 1;
  const soundingPitches=new Set([...midiNotes.values()].map(n=>n.pitch));
  width = Math.max(620, scroll.clientWidth) * Number(find("zoom").value); timeline = width-keys;
  const height = header+row*128;
  if (canvas.width !== Math.round(width*scale) || canvas.height !== Math.round(height*scale)) {
    canvas.width = Math.round(width*scale); canvas.height = Math.round(height*scale);
    canvas.style.width = width+"px"; canvas.style.height = height+"px";
  }
  ctx.setTransform(scale,0,0,scale,0,0); ctx.clearRect(0,0,width,height); ctx.font = "10px system-ui";
  for (let pitch=127; pitch>=0; pitch--) {
    const y = header+(127-pitch)*row, black = [1,3,6,8,10].includes(pitch%12);
    ctx.fillStyle = black ? palette["grid-black"] : palette["grid-white"]; ctx.fillRect(keys,y,timeline,row);
    ctx.fillStyle = pitch===auditionPitch || soundingPitches.has(pitch) ? trackColor(program) : black ? palette["piano-black"] : palette["piano-white"]; ctx.fillRect(0,y,keys,row);
    ctx.strokeStyle = pitch%12 === 0 ? palette["octave-line"] : palette["grid-line"]; ctx.beginPath(); ctx.moveTo(0,y+row); ctx.lineTo(width,y+row); ctx.stroke();
    if (pitch%12 === 0) {ctx.fillStyle = palette.muted; ctx.fillText(noteName(pitch),10,y+10);}
  }
  const [start,end] = region(), range = selectionRange();
  if (end>start) {ctx.fillStyle = palette.region; ctx.fillRect(keys+start/data.duration*timeline,header,(end-start)/data.duration*timeline,row*128);}
  const tick = timeline/data.duration<60 ? 2 : 1;
  for (let t=0; t<=data.duration; t+=tick) {const x=keys+t/data.duration*timeline; ctx.strokeStyle=palette["grid-line"]; ctx.beginPath(); ctx.moveTo(x,header); ctx.lineTo(x,height); ctx.stroke();}
  [...data.notes].sort((a,b) => Number(a.program===program)-Number(b.program===program)).forEach(n => {
    const x=keys+n.start/data.duration*timeline, y=header+(127-n.pitch)*row+1, w=Math.max(3,n.duration/data.duration*timeline);
    ctx.globalAlpha = n.program===program || selected.has(n.id) ? 1 : .35;
    ctx.fillStyle=trackColor(n.program); ctx.fillRect(x,y,w,row-2);
    ctx.strokeStyle=selected.has(n.id) ? palette["note-outline"] : "#7f91b077"; ctx.lineWidth=selected.has(n.id) ? 2 : 1; ctx.strokeRect(x,y,w,row-2);
    if ((n.program===program || selected.has(n.id)) && w>25) {ctx.fillStyle="#283747"; ctx.fillText(noteName(n.pitch),x+4,y+9);}
  });
  ctx.globalAlpha=1; ctx.lineWidth=1;
  if (drag?.mode === "box") {
    ctx.fillStyle="#79a8e82b"; ctx.strokeStyle="#79a8e8";
    const x=Math.min(drag.pointer.x,drag.current.x), y=Math.min(drag.pointer.y,drag.current.y);
    const w=Math.abs(drag.current.x-drag.pointer.x), h=Math.abs(drag.current.y-drag.pointer.y);
    ctx.fillRect(x,y,w,h); ctx.strokeRect(x,y,w,h);
  }
  const top=scroll.scrollTop;
  ctx.fillStyle=palette.soft; ctx.fillRect(0,top,width,header);
  const wave=data.waveform || []; ctx.strokeStyle=palette.wave; ctx.beginPath();
  wave.forEach((pair,i) => {const x=keys+i/wave.length*timeline; ctx.moveTo(x,top+28+pair[0]*19); ctx.lineTo(x,top+28+pair[1]*19);}); ctx.stroke();
  if (end>start) {ctx.fillStyle=palette["region-head"]; ctx.fillRect(keys+start/data.duration*timeline,top,(end-start)/data.duration*timeline,header);}
  if (range) {ctx.fillStyle="#79a8e830"; ctx.fillRect(keys+range[0]/data.duration*timeline,top,(range[1]-range[0])/data.duration*timeline,header); ctx.strokeStyle="#79a8e8"; ctx.strokeRect(keys+range[0]/data.duration*timeline,top+1,(range[1]-range[0])/data.duration*timeline,header-2);}
  for (let t=0;t<=data.duration;t+=tick) {ctx.fillStyle=palette.muted; ctx.fillText(`${t}s`,keys+t/data.duration*timeline+4,top+13);}
  const x=keys+playhead/data.duration*timeline; ctx.strokeStyle=palette.playhead; ctx.beginPath(); ctx.moveTo(x,0); ctx.lineTo(x,height); ctx.stroke();
}
function updatePalette() {
  const style=getComputedStyle(root);
  for (const key of ["text","muted","soft","grid-white","grid-black","piano-white","piano-black","grid-line","octave-line","wave","region","region-head","note-outline","playhead"]) palette[key]=style.getPropertyValue(`--ss-${key}`).trim();
  draw();
}
function centerTrack() {const pitches=data.notes.filter(n=>n.program===program).map(n=>n.pitch); const pitch=pitches.length ? pitches.reduce((a,b)=>a+b,0)/pitches.length : 60; scroll.scrollTop=Math.max(0,header+(127-pitch)*row-scroll.clientHeight/2);}
function position(event) {const box=canvas.getBoundingClientRect(), x=event.clientX-box.left, y=event.clientY-box.top; return {x,y,time:clamp((x-keys)/timeline*data.duration,0,data.duration),pitch:clamp(127-Math.floor((y-header)/row),0,127)};}
function hit(p) {
  return data.notes.findLast(n=>n.program===program && n.pitch===p.pitch && p.time>=n.start && p.time<=n.start+n.duration);
}
function setTool(next) {tool=next; root.dataset.tool=next; for (const button of root.querySelectorAll("[data-tool]")) button.setAttribute("aria-pressed", String(button.dataset.tool===next)); refresh();}
function createNote(p) {
  const start=clamp(snap(p.time),0,data.duration-.01), id=Math.max(-1,...data.notes.map(n=>n.id))+1;
  const note={id,start,duration:Math.min(.4,data.duration-start),pitch:p.pitch,velocity:Math.round(clamp(Number(find("velocity").value)||90,1,127)),program};
  data.notes.push(note); selected=new Set([id]); timeRange=null;
  return note;
}
function moveNotes(originals, seconds, semitones) {
  const dt=clamp(seconds,-Math.min(...originals.map(n=>n.start)),data.duration-Math.max(...originals.map(n=>n.start+n.duration)));
  const dp=clamp(semitones,-Math.min(...originals.map(n=>n.pitch)),127-Math.max(...originals.map(n=>n.pitch)));
  const currentNotes=new Map(data.notes.map(n=>[n.id,n]));
  let moved=false;
  for (const n of originals) {const current=currentNotes.get(n.id); if(current) {
    moved ||= current.start!==n.start+dt || current.pitch!==n.pitch+dp;
    current.start=n.start+dt; current.pitch=n.pitch+dp;
  }}
  timeRange=null;
  return moved;
}
function previewMovedNote(movement, finish=false) {
  const note=data.notes.find(n=>n.id===movement.id), previous=movement.preview, now=performance.now();
  // Always hear a new pitch; limit repeated attacks while sliding along the timeline.
  if(note && (note.pitch!==previous.pitch || (note.start!==previous.start && (finish || now-previous.at>=100)))) {
    movement.preview={pitch:note.pitch,start:note.start,at:now};
    audition(note.pitch,note.velocity);
  }
}
canvas.addEventListener("pointerdown", event => {
  if (!data.clip || addingTrack() || recording || event.button !== 0) return;
  event.preventDefault(); stop(); scroll.focus({preventScroll:true});
  const p=position(event);
  if(p.x<keys) {
    if(p.y>=scroll.scrollTop+header) {
      canvas.setPointerCapture(event.pointerId); drag={mode:"keys",pitch:p.pitch}; audition(p.pitch);
    }
    return;
  }
  canvas.setPointerCapture(event.pointerId);
  if (p.y<scroll.scrollTop+header) {
    selected.clear(); timeRange=null; cursorTime=p.time;
    drag={mode:"time",pointer:p,moved:false}; refresh(); draw(); return;
  }
  const n=hit(p), before=snapshot();
  if (tool==="erase") {
    drag={mode:"erase",before,moved:!!n}; if(n) data.notes=data.notes.filter(item=>item.id!==n.id); selected.clear(); timeRange=null;
  } else if (tool==="pencil" && !n) {
    const note=createNote(p); audition(note.pitch,note.velocity); drag={mode:"draw",id:note.id,before,pointer:p,moved:true};
  } else if (n) {
    timeRange=null; audition(n.pitch,n.velocity);
    if (event.shiftKey) {selected.has(n.id) ? selected.delete(n.id) : selected.add(n.id);}
    else if (!selected.has(n.id)) selected=new Set([n.id]);
    if (selected.has(n.id)) drag={mode:selected.size===1 && n.duration/data.duration*timeline>14 && Math.abs(p.x-(keys+(n.start+n.duration)/data.duration*timeline))<7 ? "resize" : "move",id:n.id,before,originals:clone(chosen()),pointer:p,moved:false,preview:{pitch:n.pitch,start:n.start,at:performance.now()}};
  } else {
    const base=event.shiftKey ? [...selected] : []; selected=new Set(base); timeRange=null;
    drag={mode:"box",pointer:p,current:p,base,moved:false};
  }
  refresh(); draw();
});
canvas.addEventListener("pointermove", event => {
  if (addingTrack() || recording) {canvas.style.cursor="not-allowed"; return;}
  const p=position(event);
  if (!drag) {const n=hit(p); canvas.style.cursor=tool==="select" ? (n ? "grab" : "crosshair") : ""; return;}
  if(drag.mode==="keys") {if(p.x<keys && p.pitch!==drag.pitch && p.y>=scroll.scrollTop+header) {drag.pitch=p.pitch; audition(p.pitch);} return;}
  if (drag.pointer && Math.abs(p.x-drag.pointer.x)+Math.abs(p.y-drag.pointer.y)<3 && !drag.moved) return;
  if (drag.mode==="erase") {const n=hit(p); if(n) {data.notes=data.notes.filter(item=>item.id!==n.id); drag.moved=true;}}
  else {
    drag.moved=true;
    if (drag.mode==="time") {timeRange=[Math.min(p.time,drag.pointer.time),Math.max(p.time,drag.pointer.time)];}
    if (drag.mode==="box") {
      drag.current=p;
      const low=Math.min(p.pitch,drag.pointer.pitch), high=Math.max(p.pitch,drag.pointer.pitch), first=Math.min(p.time,drag.pointer.time), last=Math.max(p.time,drag.pointer.time);
      selected=new Set([...drag.base,...data.notes.filter(n=>n.program===program && n.pitch>=low && n.pitch<=high && n.start<last && n.start+n.duration>first).map(n=>n.id)]);
    }
    if (drag.mode==="move") {
      moveNotes(drag.originals,snap(p.time-drag.pointer.time),p.pitch-drag.pointer.pitch);
      previewMovedNote(drag);
    }
    if (drag.mode==="draw" || drag.mode==="resize") {const n=data.notes.find(n=>n.id===drag.id); if(n) n.duration=clamp(snap(p.time)-n.start,.01,data.duration-n.start); timeRange=null;}
  }
  refresh(); draw();
});
function finishDrag(event) {
  if (!drag) return;
  const previous=drag; drag=null;
  if(event?.type==="pointerup" && previous.mode==="move" && previous.moved)previewMovedNote(previous,true);
  if (previous.moved && previous.before && JSON.stringify(previous.before.notes)!==JSON.stringify(data.notes))remember(previous.before);
  publish();
}
for (const event of ["pointerup","pointercancel","lostpointercapture"]) canvas.addEventListener(event,finishDrag);
canvas.addEventListener("dblclick", event=>{const p=position(event); if(data.clip && !addingTrack() && tool==="select" && p.x>=keys && p.y>=scroll.scrollTop+header && !hit(p)) change(()=>{const note=createNote(p);audition(note.pitch,note.velocity);});});
function closeTrackMenu(focus=false) {trackMenu.hidden=true; track.setAttribute("aria-expanded","false"); if(focus) track.focus({preventScroll:true});}
function openTrackMenu() {if(addingTrack() || recording)return;trackMenu.hidden=false; track.setAttribute("aria-expanded","true"); const item=trackMenu.querySelector('[aria-selected="true"]'); item?.focus({preventScroll:true}); item?.scrollIntoView({block:"nearest"});}
track.addEventListener("click",()=>trackMenu.hidden ? openTrackMenu() : closeTrackMenu(true));
track.addEventListener("keydown",event=>{if(["ArrowDown","ArrowUp"].includes(event.key)) {event.preventDefault(); openTrackMenu();}});
trackMenu.addEventListener("click",event=>{const item=event.target.closest('[role="option"]'); if(!item || addingTrack())return; finishDrag(); stop(); program=Number(item.dataset.program); selected.clear(); timeRange=null; closeTrackMenu(true); refresh(); centerTrack(); draw(); syncValue(); warmInstrument();});
trackMenu.addEventListener("keydown",event=>{
  if(["Escape","Tab"].includes(event.key)) {closeTrackMenu(true); return;}
  const items=[...trackMenu.querySelectorAll('[role="option"]')], index=items.indexOf(document.activeElement);
  const next={ArrowDown:(index+1)%items.length,ArrowUp:(index+items.length-1)%items.length,Home:0,End:items.length-1}[event.key];
  if(next!==undefined) {event.preventDefault(); items[next]?.focus({preventScroll:true}); items[next]?.scrollIntoView({block:"nearest"});}
});
instrument.addEventListener("change",()=>{const next=Number(instrument.value);change(()=>{stop(); if(!trackColors.has(next))trackColors.set(next,trackColor(program)); data.notes.filter(n=>n.program===program).forEach(n=>n.program=next); extraTracks=extraTracks.filter(p=>p!==program); program=next; extraTracks.push(next);});warmInstrument();});
find("zoom").addEventListener("input",()=>{draw(); syncValue();});
find("snap").addEventListener("change",syncValue);
find("listen").addEventListener("change",()=>{stop(); refresh(); draw();});
find("audio-source").addEventListener("change",stop);
find("velocity").addEventListener("change",()=>{const velocity=Math.round(clamp(Number(find("velocity").value)||90,1,127));if(selected.size)change(()=>{for(const n of chosen())n.velocity=velocity;});});
function travel(backward=true) {if(addingTrack() || recording)return; finishDrag(); const from=backward?undo:redo, to=backward?redo:undo; if(!from.length)return; stop(); to.push(snapshot()); const previous=from.pop(); data.notes=previous.notes; program=previous.program; extraTracks=previous.extraTracks; trackColors=new Map(previous.colors); selected.clear(); timeRange=null; publish();}
function remove() {if(selected.size)change(()=>{data.notes=data.notes.filter(n=>!selected.has(n.id)); selected.clear(); timeRange=null;});}
function soundStatus(message="GM preview") {find("sound-status").textContent=message;}
function previewProgram(p) {return p===100 ? 52 : p===101 ? 53 : p;}
function previewPitch(p,pitch) {return p!==128 || (pitch>=24 && pitch<=84);}
function soundContext() {
  if(!audioContext)audioContext=new AudioContext();
  return audioContext;
}
async function loadInstrument(p) {
  const key=previewProgram(p), context=soundContext();
  if(soundfonts.has(key))return soundfonts.get(key);
  if(loadingSounds.has(key))return loadingSounds.get(key);
  const pending=(async()=>{
    let url=drumUrl;
    if(key!==128) {
      if(!gmNames)gmNames=fetch(gmBase+"names.json",{signal:AbortSignal.timeout(15000)}).then(response=>{
        if(!response.ok)throw Error("GM instrument list unavailable");return response.json();
      }).catch(error=>{gmNames=null;throw error;});
      const names=await gmNames;
      if(!Array.isArray(names) || !/^[a-z0-9_]+$/.test(names[key]||""))throw Error("Unknown GM program");
      url=gmBase+names[key]+"-mp3.js";
    }
    if(!soundLibrary)soundLibrary=import(host?.soundLibrary || "https://cdn.jsdelivr.net/npm/smplr@1.0.0/dist/index.mjs").catch(error=>{soundLibrary=null;throw error;});
    const {Soundfont}=await soundLibrary;
    if(!root.isConnected)throw Error("Editor closed");
    const player=Soundfont(context,{instrumentUrl:url,volume:75,extraGain:3});
    try {
      await player.ready;
      if(!root.isConnected)throw Error("Editor closed");
      soundfonts.set(key,player);return player;
    } catch(error) {player.dispose();throw error;}
  })();
  loadingSounds.set(key,pending);
  try {return await pending;} finally {loadingSounds.delete(key);}
}
function warmInstrument() {
  if(!data.clip || addingTrack())return;
  const p=program, request=soundRequest;
  soundStatus(soundfonts.has(previewProgram(p)) ? "GM preview ready" : "Loading GM sound…");
  loadInstrument(p).then(()=>{if(request===soundRequest && p===program)soundStatus("GM preview ready");})
    .catch(()=>{if(request===soundRequest && p===program)soundStatus("GM sound unavailable. Click a key to retry.");});
}
function startNote(player,p,pitch,velocity,time,duration,onEnded) {
  if(!previewPitch(p,pitch))return;
  let cancel, releaseTimer;
  // smplr cannot interrupt a voice after scheduling its own future release.
  // Trigger the release when it is due so Stop can still cut off held notes.
  const stopVoice=player.start({note:pitch,velocity,time,duration:null,ampRelease:.08,stopId:++voiceNumber,
    onEnded:()=>{clearTimeout(releaseTimer);voiceStops.delete(cancel);onEnded?.();}});
  cancel=()=>{clearTimeout(releaseTimer);voiceStops.delete(cancel);stopVoice();};
  voiceStops.add(cancel);
  if(p!==128 && duration!==null)releaseTimer=setTimeout(cancel,Math.max(0,(time+duration-audioContext.currentTime)*1000));
  return cancel;
}
async function audition(pitch, velocity=Number(find("velocity").value)||90) {
  stop();
  const request=soundRequest, p=program, context=soundContext();
  if(!previewPitch(p,pitch)) {soundStatus("GM drums use MIDI keys 24–84.");return;}
  try {
    await context.resume();
    soundStatus(soundfonts.has(previewProgram(p)) ? "GM preview ready" : "Loading GM sound…");
    const player=await loadInstrument(p);
    if(request!==soundRequest || !root.isConnected)return;
    soundStatus("GM preview ready");auditionPitch=pitch;draw();
    startNote(player,p,pitch,velocity,context.currentTime,.45,()=>{
      if(request===soundRequest){auditionPitch=null;draw();}
    });
  } catch {if(request===soundRequest)soundStatus("GM sound unavailable. Click a key to retry.");}
}
function midiStatus(message) {find("midi-status").textContent=message;}
function midiControls() {
  const connected=midiInput?.state==="connected" && midiInput.onmidimessage===midiMessage;
  const connect=root.querySelector('[data-action="connect-midi"]'), record=root.querySelector('[data-action="record"]');
  connect.textContent=midiAccess ? "Disconnect MIDI" : "Connect MIDI";
  connect.disabled=midiConnecting || !!recording;
  find("midi-input").disabled=!midiAccess || !!recording;
  find("record-snap").disabled=!!recording;
  record.disabled=!connected || !data.clip || addingTrack() || !!recording;
  record.setAttribute("aria-pressed",String(!!recording));
  root.querySelector('[data-action="stop-recording"]').disabled=!recording;
}
function releaseMidiNote(key, time=recordingTime()) {
  const held=midiNotes.get(key);if(!held)return;
  midiNotes.delete(key);if(held.program!==128)held.stop?.();
  if(held.note && recording) {
    const end=recording.unit ? Math.round(time/recording.unit)*recording.unit : time;
    held.note.duration=clamp(end-held.note.start,.01,recording.end-held.note.start);
  }
}
function recordingTime(eventTime) {
  if(!recording?.ready)return recording?.start || 0;
  const time=playing ? playing.currentTime : audioContext.currentTime-recording.clock+recording.start;
  const delay=Number.isFinite(eventTime) ? Math.min(0,(eventTime-performance.now())/1000) : 0;
  return clamp(time+delay,recording.start,recording.end);
}
function midiMessage(event) {
  const [status,pitch,velocity]=event.data, kind=status&0xf0, channel=status&0x0f, key=channel*128+pitch;
  const time=recordingTime(event.timeStamp);
  if(kind===0xb0) {
    if(pitch===64 && velocity>=64)midiSustain.add(channel);
    if((pitch===64 && velocity<64) || pitch===121) {
      midiSustain.delete(channel);
      for(const [id,held] of midiNotes)if(held.channel===channel && !held.down)releaseMidiNote(id,time);
    }
    if(pitch===120 || pitch===123) {
      midiSustain.delete(channel);
      for(const [id,held] of midiNotes)if(held.channel===channel)releaseMidiNote(id,time);
    }
    draw();return;
  }
  if(kind===0x80 || (kind===0x90 && velocity===0)) {
    const held=midiNotes.get(key);
    if(held && midiSustain.has(channel) && held.program!==128)held.down=false;
    else releaseMidiNote(key,time);
    refresh();draw();return;
  }
  if(kind!==0x90 || !data.clip || addingTrack() || (recording && !recording.ready))return;
  if(recording && time>=recording.end-.01)return;
  releaseMidiNote(key,time);
  const held={pitch,velocity,channel,program,down:true};midiNotes.set(key,held);
  if(recording) {
    const start=clamp(recording.unit ? Math.round(time/recording.unit)*recording.unit : time,recording.start,recording.end-.01);
    held.note={id:recording.nextId++,start,duration:.01,pitch,velocity,program:recording.program};
    data.notes.push(held.note);recording.ids.push(held.note.id);selected.add(held.note.id);
  }
  const request=soundRequest, context=soundContext();
  context.resume().then(()=>loadInstrument(held.program)).then(player=>{
    if(request!==soundRequest || midiNotes.get(key)!==held || !root.isConnected)return;
    held.stop=startNote(player,held.program,pitch,velocity,context.currentTime,null);
  }).catch(()=>{if(request===soundRequest)soundStatus("GM sound unavailable; MIDI notes are still recorded.");});
  refresh();draw();
}
async function selectMidiInput(id) {
  stop();
  if(midiInput) {midiInput.onmidimessage=null;midiInput.close().catch(()=>{});}
  const input=midiAccess?.inputs.get(id);midiInput=input || null;
  midiControls();
  if(!input)return;
  try {
    await input.open();
    if(midiInput!==input || !root.isConnected){input.close().catch(()=>{});return;}
    input.onmidimessage=midiMessage;
    midiStatus(`${input.name || "MIDI input"} ready. Play to preview; Record adds notes.`);
  } catch {if(midiInput===input){midiInput=null;midiStatus("Could not open this MIDI input. Reconnect and try again.");}}
  midiControls();
}
function midiInputsChanged() {
  if(!midiAccess)return;
  const inputs=[...midiAccess.inputs.values()].filter(input=>input.state==="connected");
  const lost=midiInput && !inputs.includes(midiInput), current=inputs.includes(midiInput) ? midiInput : inputs[0];
  if(lost) {stop();midiInput.onmidimessage=null;midiInput.close().catch(()=>{});midiInput=null;}
  options(find("midi-input"),inputs.length ? inputs.map(input=>[input.id,input.name || "MIDI input"]) : [["","No input connected"]],current?.id || "");
  if(current && current!==midiInput)selectMidiInput(current.id);
  if(!inputs.length)midiStatus(lost ? "Keyboard disconnected. Recording kept; reconnect to continue." : "No MIDI input found. Connect a keyboard.");
  midiControls();
}
function disconnectMidi() {
  stop();
  if(midiAccess)midiAccess.onstatechange=null;
  if(midiInput){midiInput.onmidimessage=null;midiInput.close().catch(()=>{});}
  midiInput=null;midiAccess=null;
  options(find("midi-input"),[["","No input connected"]],"");
  midiStatus("MIDI disconnected. Your recorded notes are kept.");midiControls();
}
async function connectMidi() {
  if(midiAccess){disconnectMidi();return;}
  if(midiConnecting)return;
  const policy=document.permissionsPolicy || document.featurePolicy;
  if(!window.isSecureContext){midiStatus("MIDI needs HTTPS or localhost. For a remote server, use an SSH tunnel.");return;}
  if(!navigator.requestMIDIAccess){midiStatus("Web MIDI is unavailable in this browser. Try Chrome or Edge.");return;}
  if(policy?.allowsFeature && !policy.allowsFeature("midi")) {
    midiStatus("MIDI is blocked in this embedded page. Open the demo directly.");
    const link=find("midi-standalone");link.href=location.href;link.hidden=false;return;
  }
  midiConnecting=true;midiControls();midiStatus("Allow MIDI access in your browser to connect.");
  try {
    await soundContext().resume();
    const access=await navigator.requestMIDIAccess({sysex:false});
    if(!root.isConnected || events.signal.aborted)return;
    midiAccess=access;access.onstatechange=midiInputsChanged;midiInputsChanged();
  } catch {midiStatus("MIDI access was not granted. Allow it in the browser's site settings, then retry.");}
  finally {midiConnecting=false;midiControls();}
}
function recordingControls(active) {
  host?.recording?.(active);
  if(active) {
    recordingButtons=[...document.querySelectorAll('#apply-edits button, button#apply-edits, #generate-audio button, button#generate-audio')].map(button=>[button,button.disabled]);
    for(const [button] of recordingButtons)button.disabled=true;
  } else {
    for(const [button,disabled] of recordingButtons)button.disabled=disabled;
    recordingButtons=[];
  }
  refresh();
}
async function recordMidi() {
  if(recording || !data.clip || addingTrack() || midiInput?.state!=="connected" || midiInput.onmidimessage!==midiMessage)return;
  finishDrag();stop();closeTrackMenu();
  const [start,end]=timeRange || [cursorTime>=data.duration ? 0 : cursorTime,data.duration];
  if(end-start<.01){midiStatus("Choose a longer range on the waveform.");return;}
  const take={before:snapshot(),start,end,program,unit:find("record-snap").checked ? Number(find("snap").value) : 0,
    ids:[],nextId:Math.max(-1,...data.notes.map(n=>n.id))+1,ready:false};
  recording=take;selected.clear();timeRange=null;cursorTime=start;
  recordingControls(true);midiStatus("Preparing recording…");
  try {
    const context=soundContext();await context.resume();
    // Load the monitor before the take, so first notes are not delayed by a download.
    await loadInstrument(program).catch(()=>soundStatus("GM sound unavailable; recording without monitoring."));
    if(recording!==take || !root.isConnected)return;
    pauseOtherAudio();
    const id=find("audio-source").value==="generated" ? "result-audio" : "source-audio";
    const url=host ? host.audio(id) : document.querySelector(`#${id} a[download]`)?.href;
    if(url) {
      const audio=find("player");if(audio.src!==url)audio.src=url;
      audio.currentTime=start;playing=audio;await audio.play();
      if(recording!==take || !root.isConnected)return;
    } else if(find("audio-source").value==="generated")throw Error("Generate audio first, or choose Original.");
    take.clock=context.currentTime;take.ready=true;
    midiStatus(`Recording into ${name(program)} · press Stop to finish.`);animate();
  } catch(error) {if(recording===take){stop();midiStatus(`Recording could not start. ${error.message || "Try again."}`);}}
}
function finishRecording() {
  if(!recording)return;
  const take=recording, time=recordingTime();
  for(const key of [...midiNotes.keys()])releaseMidiNote(key,time);
  recording=null;cursorTime=time;
  if(take.ids.length) {
    // MIDI note-offs cannot identify overlapping voices at the same pitch/channel.
    // Keep the new performance and the non-overlapping portions of earlier notes.
    const ids=new Set(take.ids), added=data.notes.filter(n=>ids.has(n.id));
    let notes=data.notes.filter(n=>!ids.has(n.id));
    for(const fresh of added) {
      const end=fresh.start+fresh.duration;
      notes=notes.flatMap(n=>{
        const oldEnd=n.start+n.duration;
        if(n.program!==fresh.program || n.pitch!==fresh.pitch || n.start>=end || oldEnd<=fresh.start)return [n];
        const parts=[];
        if(fresh.start-n.start>=.01)parts.push({...n,duration:fresh.start-n.start});
        if(oldEnd-end>=.01) {
          const tail={...n,id:take.nextId++,start:end,duration:oldEnd-end};
          delete tail.source_onset;parts.push(tail);
        }
        return parts;
      });
      notes.push(fresh);
    }
    data.notes=notes;selected=new Set(notes.filter(n=>ids.has(n.id)).map(n=>n.id));
    remember(take.before);
  }
  recordingControls(false);publish();
  midiStatus(take.ids.length ? `${take.ids.length} notes recorded. Undo restores the previous score; Apply edits saves it.` : "No notes recorded. Click Record to try again.");
}
find("midi-input").addEventListener("change",()=>selectMidiInput(find("midi-input").value));
function transportState(action) {for(const name of ["play","preview"])root.querySelector(`[data-action="${name}"]`).setAttribute("aria-pressed",String(name===action));}
function stop() {
  finishRecording();
  for(const key of [...midiNotes.keys()])releaseMidiNote(key);
  midiSustain.clear();
  soundRequest++;
  if (playing) cursorTime=clamp(playing.currentTime,0,data.duration);
  if (previewing) cursorTime=clamp(audioContext.currentTime-previewStarted+previewOffset,0,data.duration);
  previewing=false;auditionPitch=null;
  for(const cancel of voiceStops)cancel();voiceStops.clear();
  cancelAnimationFrame(playbackFrame); playbackFrame=null;
  playing?.pause(); playing=null;
  soundStatus();transportState(null); draw();
}
function animate() {
  if(!root.isConnected){stop();return;}
  if(recording?.ready) {
    const time=recordingTime();
    if(time>=recording.end || playing?.ended) {stop();refresh();return;}
    for(const held of midiNotes.values())if(held.note)held.note.duration=Math.max(.01,time-held.note.start);
    find("listen-range").textContent=`Recording · ${time.toFixed(2)} s`;
    draw(time);playbackFrame=requestAnimationFrame(animate);return;
  }
  const time=previewing ? audioContext.currentTime-previewStarted+previewOffset : playing?.currentTime;
  if(time===undefined)return;
  if(time>=playbackEnd || playing?.ended) {
    // Let sampled drum hits and note releases decay after the playback range.
    if(previewing){previewing=false;transportState(null);}else stop();
    playbackFrame=null;cursorTime=playbackEnd;refresh();draw();return;
  }
  find("listen-range").textContent=`Playing · ${Math.max(0,time).toFixed(2)} s`;
  draw(Math.max(0,time)); playbackFrame=requestAnimationFrame(animate);
}
function playbackRange() {
  const range=selectionRange();
  if(range)return range;
  return [cursorTime>=data.duration ? 0 : cursorTime,data.duration];
}
function pauseOtherAudio(except=null) {
  const owner=except?.closest("#upload-audio, #source-audio, #result-audio");
  document.querySelectorAll("audio").forEach(audio=>{if(audio!==except && !owner?.contains(audio))audio.pause();});
  for(const id of ["upload-audio","source-audio","result-audio"]) {
    const player=document.getElementById(id);
    if(player!==owner)player?.querySelector('button[aria-label="Pause"]')?.click();
  }
}
async function play(action) {
  stop(); if(!data.clip)return;
  const [start,end]=playbackRange(); if(end<=start)return;
  playbackEnd=end;
  pauseOtherAudio();
  if(action==="play") {
    const request=soundRequest;
    const id=find("audio-source").value==="generated" ? "result-audio" : "source-audio";
    const url=host ? host.audio(id) : document.querySelector(`#${id} a[download]`)?.href;
    const audio=find("player");
    if(!url) {detail.textContent="Generate audio first, or choose Original.";return;}
    if(audio.src!==url)audio.src=url;
    playing=audio; audio.currentTime=start;
    try {await audio.play(); if(request!==soundRequest || playing!==audio)return; transportState("play"); animate();}
    catch {if(request===soundRequest){stop();detail.textContent="Playback could not start. Try the audio player below.";}}
  } else {
    const request=soundRequest, context=soundContext(), onlyTrack=find("listen").value==="selected";
    const notes=data.notes.filter(n=>(!onlyTrack || n.program===program) && n.start<end && n.start+n.duration>start && previewPitch(n.program,n.pitch));
    if(!notes.length){soundStatus("No notes to preview in this range.");return;}
    await context.resume();
    if(request!==soundRequest || !root.isConnected)return;
    const programs=[...new Set(notes.map(n=>n.program))];
    soundStatus(programs.every(p=>soundfonts.has(previewProgram(p))) ? "GM preview ready" : "Loading GM sounds…");
    let players;
    try {players=new Map(await Promise.all(programs.map(async p=>[p,await loadInstrument(p)])));}
    catch {if(request===soundRequest)soundStatus("GM sound unavailable. Press Preview notes to retry.");return;}
    if(request!==soundRequest || !root.isConnected)return;
    soundStatus("GM preview ready");previewStarted=context.currentTime+.03;previewOffset=start;previewing=true;
    for(const n of notes) {
      const onset=previewStarted+Math.max(0,n.start-start), finish=previewStarted+Math.min(end,n.start+n.duration)-start;
      startNote(players.get(n.program),n.program,n.pitch,n.velocity,onset,Math.max(.01,finish-onset));
    }
    transportState("preview"); animate();
  }
}
root.addEventListener("click",event=>{
  const button=event.target.closest("button"); if(!button)return;
  if(button.disabled)return;
  if(button.dataset.tool) {setTool(button.dataset.tool); canvas.style.cursor=""; return;}
  const action=button.dataset.action;
  if(action==="connect-midi")connectMidi();
  if(action==="record")recordMidi();
  if(action==="undo")travel();
  if(action==="redo")travel(false);
  if(action==="delete")remove();
  if(action==="add-track") {
    stop(); finishDrag(); closeTrackMenu();
    const used=[...data.notes.map(n=>n.program),...extraTracks];
    const available=data.instruments.filter(i=>!i.members.some(p=>used.includes(p)));
    options(find("new-instrument"),available.map(i=>[i.program,i.name]),available[0]?.program);
    find("add-panel").hidden=false; refresh(); canvas.style.cursor="not-allowed"; find("new-instrument").focus();
    root.querySelector('[data-action="confirm-track"]').disabled=!available.length || !data.clip;
  }
  if(action==="cancel-track") {find("add-panel").hidden=true; canvas.style.cursor=""; refresh(); draw();}
  if(action==="confirm-track" && find("new-instrument").value!=="") {
    find("add-panel").hidden=true;
    change(()=>{program=Number(find("new-instrument").value); extraTracks.push(program); selected.clear(); timeRange=null; setTool("pencil"); canvas.style.cursor=""; centerTrack();});warmInstrument();
  }
  if(action==="stop" || action==="stop-recording") {stop();refresh();}
  if(action==="restart") {stop();cursorTime=0;timeRange=null;selected.clear();for(const id of ["source-audio","result-audio"]){const a=document.querySelector(`#${id} audio`);if(a)a.currentTime=0;}refresh();draw();}
  if(action==="play" || action==="preview")play(action).catch(()=>{stop();detail.textContent="Playback could not start. Please try again.";});
});
scroll.addEventListener("keydown",event=>{
  if(recording) {if([" ","Escape"].includes(event.key)){event.preventDefault();stop();refresh();}return;}
  if(addingTrack()) {if(event.key!=="Tab")event.preventDefault(); return;}
  const key=event.key.toLowerCase(), modifier=event.metaKey||event.ctrlKey;
  if(modifier && key==="z") {event.preventDefault();event.shiftKey?travel(false):travel();return;}
  if(modifier && key==="a") {event.preventDefault();selected=new Set(data.notes.filter(n=>n.program===program).map(n=>n.id));timeRange=null;refresh();draw();return;}
  if(event.key==="Escape") {selected.clear();timeRange=null;refresh();draw();}
  if(["Delete","Backspace"].includes(event.key)) {event.preventDefault();remove();}
  if(["v","d","e"].includes(key) && !modifier) {setTool({v:"select",d:"pencil",e:"erase"}[key]);canvas.style.cursor="";}
  if(event.key===" ") {event.preventDefault();playing||previewing?stop():play("play");}
  if(["ArrowUp","ArrowDown","ArrowLeft","ArrowRight"].includes(event.key) && selected.size) {
    event.preventDefault(); const unit=Number(find("snap").value)||.04;
    change(()=>{
      const moved=moveNotes(clone(chosen()),event.key==="ArrowLeft"?-unit:event.key==="ArrowRight"?unit:0,event.key==="ArrowUp"?(event.shiftKey?12:1):event.key==="ArrowDown"?-(event.shiftKey?12:1):0);
      const id=[...selected].at(-1), note=data.notes.find(n=>n.id===id);
      if(moved && note)audition(note.pitch,note.velocity);
      return moved;
    });
  }
});
const events=new AbortController();
window.addEventListener("spansynth-stop",()=>{stop();refresh();},{signal:events.signal});
window.addEventListener("pagehide",disconnectMidi,{signal:events.signal});
document.addEventListener("visibilitychange",()=>{if(document.hidden){stop();refresh();}},{signal:events.signal});
document.addEventListener("pointerdown",event=>{if(!track.parentElement.contains(event.target))closeTrackMenu();},{signal:events.signal});
document.addEventListener("input",event=>{if(event.target.closest?.("#edit-start, #edit-end"))draw();},{signal:events.signal});
document.addEventListener("click",event=>{
  const button=event.target.closest("#upload-audio button, #source-audio button, #result-audio button");
  const label=button?.getAttribute("aria-label");
  if(label==="Play" || label==="Go to start") {stop();if(label==="Play")pauseOtherAudio(button);else{cursorTime=0;timeRange=null;selected.clear();}refresh();draw();}
},{capture:true,signal:events.signal});
document.addEventListener("play",event=>{if(event.target.tagName==="AUDIO" && !event.target.paused){if(event.target!==playing)stop();pauseOtherAudio(event.target);}},{capture:true,signal:events.signal});
document.addEventListener("pause",event=>{if(event.target===playing && event.target.paused){stop();refresh();}},{capture:true,signal:events.signal});
window.addEventListener("spansynth-generated",()=>{stop();find("audio-source").value=(host ? host.audio("result-audio") : document.querySelector("#result-audio a[download]"))?"generated":"original";refresh();draw();},{signal:events.signal});
window.addEventListener("spansynth-region",()=>requestAnimationFrame(()=>draw()),{signal:events.signal});
const observer=new ResizeObserver(()=>draw());observer.observe(scroll);
const themeObserver=new MutationObserver(updatePalette);
for(let node=root;node;node=node.parentElement)themeObserver.observe(node,{attributes:true,attributeFilter:["class"]});
scroll.addEventListener("scroll",()=>{draw();cancelAnimationFrame(viewFrame);viewFrame=requestAnimationFrame(syncValue);});
const lifetime=new MutationObserver(()=>{if(!root.isConnected){disconnectMidi();events.abort();observer.disconnect();themeObserver.disconnect();lifetime.disconnect();cancelAnimationFrame(viewFrame);for(const player of soundfonts.values())player.dispose();soundfonts.clear();if(audioContext)audioContext.close().catch(()=>{});}});
lifetime.observe(root.parentElement,{childList:true});
function receive() {
  if(props.value===lastSent)return;
  try {
    const next=JSON.parse(props.value||"{}");
    if(!next.clip){refresh();draw();centerTrack();return;}
    stop();closeTrackMenu();find("add-panel").hidden=true;drag=null;timeRange=null;
    if(next.clip!==data.clip){trackColors.clear();cursorTime=0;timeRange=null;}
    data=next;data.notes=data.notes.map((n,i)=>({...n,id:i}));
    const view=data.view||{};if(view.colors)trackColors=new Map(view.colors);
    program=view.program??data.notes[0]?.program??0;extraTracks=view.extraTracks||[];
    find("zoom").value=view.zoom??1;find("snap").value=view.snap??.04;
    selected=new Set(Array.isArray(view.selected) ? view.selected.filter(id=>data.notes.some(n=>n.id===id && n.program===program)) : []);
    undo=[];redo=[];setTool("select");refresh();draw();centerTrack();
    if(view.scrollTop!==undefined)scroll.scrollTop=view.scrollTop;scroll.scrollLeft=view.scrollLeft??0;
    syncValue();warmInstrument();
  } catch {detail.textContent="Unable to read MIDI. Please load the clip again.";}
}
watch("value",receive);updatePalette();setTool("select");receive();