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Running on Zero
Running on Zero
| /* Read-only public reference library. No cookies or browser-persistent storage. */ | |
| (function(root,factory){ | |
| if(typeof module==='object'&&module.exports)module.exports=factory(); | |
| else root.TrackLibrary=factory(); | |
| })(typeof window==='undefined'?this:window,function(){ | |
| function create({fetch,digest,upload}){ | |
| let entries=[],selected='',cached=null; | |
| return { | |
| async load(){ | |
| const response=await fetch('/api/tracks',{cache:'no-store',credentials:'same-origin'}); | |
| if(!response.ok)throw Error('Built-in track catalog unavailable'); | |
| const catalog=await response.json(); | |
| if(!Array.isArray(catalog.tracks)||catalog.tracks.length>128)throw Error('Invalid track catalog'); | |
| const ids=new Set(); | |
| for(const entry of catalog.tracks){ | |
| if(!/^[a-z0-9-]{1,80}$/.test(entry.id)||ids.has(entry.id)|| | |
| typeof entry.display_name!=='string'||!entry.display_name.length||entry.display_name.length>100|| | |
| !Number.isInteger(entry.bytes)||entry.bytes<1||entry.bytes>1048576|| | |
| !/^[a-f0-9]{64}$/.test(entry.sha256))throw Error('Invalid track catalog'); | |
| ids.add(entry.id); | |
| } | |
| entries=catalog.tracks.map(entry=>({...entry})); | |
| return this.entries(); | |
| }, | |
| entries:()=>entries.map(entry=>({...entry})), | |
| selected:()=>selected, | |
| select(id){ | |
| if(id&&!entries.some(entry=>entry.id===id))throw Error('Unknown built-in track'); | |
| if(id!==selected)cached=null; | |
| selected=id; | |
| }, | |
| info(){const entry=entries.find(entry=>entry.id===selected);return entry?{source:'builtin',...entry}:{source:'upload'};}, | |
| async file(){ | |
| if(!selected)return upload(); | |
| const entry=entries.find(entry=>entry.id===selected); | |
| if(cached?.id===selected)return cached.blob; | |
| const response=await fetch('/api/tracks/'+encodeURIComponent(selected)+'/file', | |
| {cache:'no-store',credentials:'same-origin'}); | |
| if(!response.ok)throw Error('Built-in track unavailable; retry or choose an upload'); | |
| const bytes=await response.arrayBuffer(); | |
| if(bytes.byteLength!==entry.bytes||await digest(bytes)!==entry.sha256) | |
| throw Error('Built-in track validation failed'); | |
| const blob=new Blob([bytes],{type:'application/octet-stream'}); | |
| cached={id:entry.id,blob};return blob; | |
| } | |
| }; | |
| } | |
| function mount({document,fetch,digest}){ | |
| const selects=Array.from(document.querySelectorAll('[data-track-library]')); | |
| const statuses=Array.from(document.querySelectorAll('[data-track-status]')); | |
| const input=document.getElementById('track'); | |
| const picker=create({fetch,digest,upload:()=>input.files[0]}); | |
| let ready=false,busy=false; | |
| function changed(){ | |
| if(typeof document.dispatchEvent==='function'&&document.defaultView?.Event) | |
| document.dispatchEvent(new document.defaultView.Event('track-library-change')); | |
| } | |
| function render(message){ | |
| for(const select of selects){select.value=picker.selected();select.disabled=busy||!ready;} | |
| const info=picker.info(); | |
| for(const status of statuses)status.textContent=message??(info.source==='builtin'? | |
| info.display_name+' selected. It remains selected after a run.': | |
| 'Upload mode selected. Built-in replicas can be selected instead.'); | |
| } | |
| for(const select of selects)select.addEventListener('change',()=>{ | |
| picker.select(select.value);if(select.value)input.value='';render();changed(); | |
| }); | |
| input.addEventListener('change',()=>{picker.select('');render();changed();}); | |
| picker.setBusy=value=>{busy=value;render();}; | |
| picker.load().then(()=>{ | |
| for(const select of selects){ | |
| for(const entry of picker.entries()){ | |
| const option=document.createElement('option');option.value=entry.id; | |
| option.textContent=entry.display_name;select.append(option); | |
| } | |
| } | |
| ready=picker.entries().length>0; | |
| if(ready)picker.select(picker.entries()[0].id); | |
| render(ready?undefined:'No built-in tracks in this installation. Custom uploads still work.'); | |
| changed(); | |
| }).catch(()=>render('Built-in catalog unavailable. Custom uploads still work.')); | |
| return picker; | |
| } | |
| return {create,mount}; | |
| }); | |