import {test} from 'node:test';import assert from 'node:assert/strict';
import {createFrameQueue,createFrameSource} from '../../src/lib/canvas-bindings/frame-queue.ts';
import {createSessionFrameSource} from '../../src/lib/canvas-bindings/session-frames.ts';
function clock(){let id=0;const callbacks=new Map();return{request(fn){callbacks.set(++id,fn);return id;},cancel(id){callbacks.delete(id);},step(){const batch=[...callbacks.values()];callbacks.clear();for(const fn of batch)fn();},get size(){return callbacks.size;}};}
test('frame dirty Set deduplicates bursts, flushes last invalidation and preserves reentrant work for the next frame',()=>{const c=clock(),batches=[];let q;q=createFrameQueue(c,dirty=>{batches.push([...dirty]);if(dirty.has('a'))q.invalidate(['next']);});q.invalidate(['a','a']);q.invalidate(['b']);assert.equal(c.size,1);q.flush();assert.deepEqual(batches,[['a','b']]);assert.equal(c.size,1);c.step();assert.deepEqual(batches,[['a','b'],['next']]);q.invalidate(['discard']);q.dispose();c.step();q.invalidate(['closed']);assert.equal(batches.length,2);assert.equal(c.size,0);});
test('canceled late callbacks cannot publish a replaced or disposed frame',()=>{const callbacks=[],c={request(fn){callbacks.push(fn);return callbacks.length;},cancel(){}},batches=[];const q=createFrameQueue(c,dirty=>batches.push([...dirty]));q.invalidate(['first']);q.flush();q.invalidate(['second']);callbacks[0]();assert.deepEqual(batches,[['first']]);q.dispose();callbacks[1]();assert.equal(batches.length,1);});
test('session presentation coalesces preview bursts but live reads and final cancel remain immediate; unsubscribe drops pending frame',()=>{const c=clock(),listeners=new Set();let snapshot={views:new Map(),gesture:null,connectionGesture:null};const source={getSnapshot:()=>snapshot,subscribe(fn){listeners.add(fn);return()=>listeners.delete(fn);}},framed=createSessionFrameSource(source,c);let paints=0;const stop=framed.subscribe(()=>paints++);const emit=next=>{snapshot=next;for(const fn of listeners)fn();};for(let i=0;i<20;i++)emit({...snapshot,gesture:{targets:[{id:'a',incarnation:1}],preview:new Map([['a',{x:i}]])}});assert.equal(c.size,1);assert.equal(paints,0);assert.equal(framed.getSnapshot().gesture.preview.get('a').x,19);c.step();assert.equal(paints,1);emit({...snapshot,gesture:null});assert.equal(framed.getSnapshot().gesture,null);c.step();assert.equal(paints,2);emit({...snapshot,views:new Map([['v',{}]])});stop();c.step();assert.equal(paints,2);assert.equal(listeners.size,0);});

test('root presentation batches a burst while commands, history and authoritative reads advance immediately',async()=>{
 const {createDocument,createEditor,createRegistry,builtinComponents}=await import('../../src/lib/canvas-core/index.ts');let id=0;
 const editor=createEditor({document:createDocument('p',[{id:'canvas',parent:null}],[{id:'a',incarnation:1,ownerCanvasId:'canvas',componentId:'text',dataVersion:1,structure:'node',data:{title:'before',text:''},geometry:{x:0,y:0,width:100,height:100,rotation:0}}]),registry:createRegistry(builtinComponents()),createId:()=>`op-${++id}`}),c=clock(),commits=[],source={getSnapshot:editor.getSnapshot,subscribe:notify=>editor.subscribe((commit,next)=>{commits.push(next.rootRevision);notify();})},framed=createFrameSource(source,c),painted=[],stop=framed.subscribe(()=>painted.push(framed.getSnapshot()));
 for(const title of ['first','second','third'])assert.equal(editor.dispatch({type:'element.data',target:{id:'a',incarnation:1},patch:{title}}).status,'applied');
 assert.equal(commits.length,3);assert.equal(painted.length,0);assert.equal(c.size,1);assert.strictEqual(framed.getSnapshot(),editor.getSnapshot());assert.equal(framed.getSnapshot().document.elements.get('a').data.title,'third');assert.equal(editor.getSnapshot().history.undo.length,3);c.step();assert.equal(painted.length,1);assert.strictEqual(painted[0],editor.getSnapshot());stop();editor.dispose();
});
test('frame source subscriptions own their queues and late callbacks cannot notify an unsubscribed view',()=>{
 const callbacks=[],c={request(fn){callbacks.push(fn);return callbacks.length;},cancel(){}},listeners=new Set();let snapshot=0;
 const source={getSnapshot:()=>snapshot,subscribe(fn){listeners.add(fn);return()=>listeners.delete(fn);}},framed=createFrameSource(source,c);let a=0,b=0;const stopA=framed.subscribe(()=>a++);snapshot++;for(const fn of listeners)fn();stopA();const stopB=framed.subscribe(()=>b++);snapshot++;for(const fn of listeners)fn();callbacks[0]();assert.equal(a,0);assert.equal(b,0);callbacks[1]();assert.equal(b,1);assert.equal(framed.getSnapshot(),2);stopB();assert.equal(listeners.size,0);
});
test('eager failed subscriptions cancel presentation work and reentrant changes wait for the next frame',()=>{
 const c=clock(),broken=createFrameSource({getSnapshot:()=>0,subscribe(notify){notify();throw Error('failed subscribe');}},c);assert.throws(()=>broken.subscribe(()=>assert.fail('failed subscription painted')),/failed subscribe/);assert.equal(c.size,0);
 let current=0,listener;const source={getSnapshot:()=>current,subscribe(fn){listener=fn;return()=>{listener=undefined;};}},framed=createFrameSource(source,c),seen=[],stop=framed.subscribe(()=>{seen.push(framed.getSnapshot());if(current===1){current=2;listener();}});current=1;listener();c.step();assert.deepEqual(seen,[1]);assert.equal(c.size,1);c.step();assert.deepEqual(seen,[1,2]);stop();
});

test('an immediate input invalidation publishes the newest Root and consumes any pending background frame',()=>{
 const c=clock();let value=0,listener;const source={getSnapshot:()=>value,subscribe(fn){listener=fn;return()=>{listener=undefined;};}},framed=createFrameSource(source,c),seen=[],stop=framed.subscribe(()=>seen.push(framed.getSnapshot()));value=1;listener();assert.equal(c.size,1);value=2;listener(true);assert.deepEqual(seen,[2]);assert.equal(c.size,0);c.step();assert.deepEqual(seen,[2]);value=3;listener();c.step();assert.deepEqual(seen,[2,3]);stop();
});