const {test}=require('node:test');
const assert=require('node:assert/strict');
const vm=require('node:vm');
const fs=require('node:fs');
const Ensemble=require('./ensemble.js');
const Datasets=require('./datasets.js');

test('async training ignores stale results, accepts parameters and preserves hover/removal',async()=>{
  const elements=new Map(),calls=[];
  const fills=[];
  const ctx=new Proxy({}, {get:(target,key)=>key==='fillRect'?()=>fills.push(target.fillStyle):(key in target?target[key]:()=>{})});
  const document={
    getElementById(id){
      if(!elements.has(id)) elements.set(id,{
        width:6,height:6,value:id==='method'?'boosting':id==='params'?'{}':id==='seed'?'42':'DecisionTreeClassifier',
        getContext:()=>ctx,addEventListener(){},replaceChildren(...children){this.children=children;},
        setAttribute(key,value){this[key]=value;},removeAttribute(){},style:{},offsetWidth:240,offsetHeight:60,
      });
      return elements.get(id);
    },querySelectorAll:()=>[],createElement:()=>({}),
  };
  let resolveReady;
  class PythonBackend{
    ready=new Promise(resolve=>{resolveReady=resolve;});
    add(request){return new Promise(resolve=>calls.push({request,resolve}));}
  }
  const sandbox=vm.createContext({document,Ensemble,Datasets,PythonBackend,window:{innerWidth:1000,innerHeight:800}});
  vm.runInContext(fs.readFileSync(require.resolve('./app.js'),'utf8'),sandbox);
  const get=id=>document.getElementById(id);
  assert.equal(get('runtime-status')['data-state'],'loading');
  assert.equal(get('runtime-status-text').textContent,'Loading Pythong runtime...');
  get('dataset-type').value='two_moons';get('dataset-type').onchange();
  assert.equal(get('add').disabled,true);
  resolveReady([{name:'DecisionTreeClassifier',weighted:true}]);
  await Promise.resolve();
  assert.equal(get('runtime-status')['data-state'],'ready');
  assert.equal(get('runtime-status-text').textContent,'Python runtime ready');
  assert.equal(get('add').disabled,false);
  assert.equal(get('method-badge').textContent,'AdaBoost');
  get('dataset-type').value='custom';get('dataset-type').onchange();
  vm.runInContext('points=[{x:.2,y:.2,label:-1},{x:.8,y:.8,label:1}]; reset();',sandbox);
  const model={tree:{size:2,grid:[-1,-1,1,1]},predictions:[-1,1],alpha:1,perfect:true};
  let pending=get('add').onclick();
  assert.equal(get('add').disabled,true);
  assert.equal(calls[0].request.seed,42);
  get('params').value='{"max_depth":2}';get('params').oninput();
  calls[0].resolve(model);await pending;
  assert.equal(get('count').textContent,0);
  for(let i=1;i<=2;i++){
    pending=get('add').onclick();assert.equal(calls[i].request.params.max_depth,2);
    calls[i].resolve(model);await pending;
    assert.equal(get('count').textContent,i);assert.equal(get('add').disabled,false);
  }
  assert.match(get('models').children[0].title,/Training error: 0\.0%/);
  get('models').children[0].onmouseenter();assert.equal(vm.runInContext('hoveredModel',sandbox),0);
  get('models').children[0].onmouseleave();assert.equal(vm.runInContext('hoveredModel',sandbox),null);
  get('remove').onclick();assert.equal(get('count').textContent,1);
  get('boundary').getBoundingClientRect=()=>({left:0,top:0,width:602,height:602});
  get('boundary').onpointermove({clientX:121,clientY:481});
  assert.match(get('point-tooltip').textContent,/Sample weight: 0.5000/);
  get('params').value='[]';await get('add').onclick();
  assert.match(get('status').textContent,/Invalid arguments/);
  // The hovered learner disagrees with the ensemble across the entire plot.
  vm.runInContext('models=[{classes:[-1,1,2],alpha:1,predictions:[2,2],tree:{size:1,grid:[2]}},{classes:[-1,1,2],alpha:2,predictions:[1,1],tree:{size:1,grid:[1]}}]; render();',sandbox);
  assert.equal(fills.at(-1),'#fae8d8');
  assert.match(get('models').children[0].title,/Training error: 100\.0%/);
  assert.match(get('models').children[1].title,/Training error: 50\.0%/);
  fills.length=0;get('models').children[0].onmouseenter();
  assert.ok(fills.length>0);assert.ok(fills.every(color=>color==='#e6f5f0'));
  fills.length=0;get('models').children[0].onmouseleave();
  assert.ok(fills.every(color=>color==='#fae8d8'));
  fills.length=0;get('models').children[0].onfocus();
  assert.ok(fills.every(color=>color==='#e6f5f0'));
  get('models').children[0].onblur();
  // Each model's weighted error uses only the learners preceding it.
  vm.runInContext('models=[{alpha:Math.log(3),predictions:[1,1],tree:{size:1,grid:[1]}},{alpha:2,predictions:[1,1],tree:{size:1,grid:[1]}}]; render();',sandbox);
  assert.equal(get('models').children[0].title,'Training error: 50.0%\nWeighted error: 50.0%\nVote weight: 1.099');
  assert.equal(get('models').children[1].title,'Training error: 50.0%\nWeighted error: 75.0%\nVote weight: 2.000');
  get('method').value='bagging';
  vm.runInContext('render();',sandbox);
  assert.equal(get('models').children[1].title,'Training error: 50.0%\nWeighted error: 50.0%\nVote weight: 2.000');

  // Presets prevent both pointer and keyboard editing and restore custom data.
  const custom=vm.runInContext('JSON.stringify(points)',sandbox);
  get('dataset-type').value='xor';get('dataset-type').onchange();
  assert.equal(get('count').textContent,0);
  assert.equal(get('points').textContent,4);
  assert.equal(get('undo').disabled,true);
  assert.equal(get('clear').disabled,true);
  const xor=vm.runInContext('JSON.stringify(points)',sandbox);
  assert.deepEqual(JSON.parse(xor),Datasets.create('xor'));
  get('boundary').onpointerdown({button:0});
  get('boundary').onkeydown({key:'Enter'});
  get('undo').onclick();get('clear').onclick();
  assert.equal(vm.runInContext('JSON.stringify(points)',sandbox),xor);
  get('dataset-type').value='custom';get('dataset-type').onchange();
  assert.equal(vm.runInContext('JSON.stringify(points)',sandbox),custom);
  assert.equal(get('undo').disabled,false);
  get('boundary').onkeydown({key:'Enter',preventDefault(){}});
  assert.equal(get('points').textContent,3);
  // Switching datasets also invalidates an in-flight training result.
  get('params').value='{}';
  pending=get('add').onclick();
  get('dataset-type').value='circles';get('dataset-type').onchange();
  calls.at(-1).resolve(model);await pending;
  assert.equal(get('count').textContent,0);
  assert.equal(get('points').textContent,120);
  const callCount=calls.length;
  for(const invalid of ['', '-1', '1.5', '4294967296']){
    get('seed').value=invalid;get('seed').oninput();
    await get('add').onclick();
    assert.match(get('status').textContent,/Invalid random seed/);
    assert.equal(calls.length,callCount);
  }
  get('seed').value='0';get('seed').oninput();
  pending=get('add').onclick();
  assert.equal(calls.at(-1).request.seed,0);
  get('seed').value='17';get('seed').oninput();
  calls.at(-1).resolve(model);await pending;
  assert.equal(get('count').textContent,0);
  pending=get('add').onclick();
  assert.equal(calls.at(-1).request.seed,17);
  calls.at(-1).resolve(model);await pending;
  assert.equal(get('count').textContent,1);
  get('seed').value='42';get('seed').oninput();
  assert.equal(get('count').textContent,0);
});