import './style.css';
import { defaults, experiments, format, type Experiment, type Parameters } from './experiments';
import { createLab } from './scene/lab';
import { answerUrl, getTestLesson, testLessons } from './test4';
import { renderEquation, renderNotation, renderProse } from './math';

const app = document.querySelector<HTMLDivElement>('#app')!;
app.innerHTML = `
  <header class="app-header">
    <a class="brand" href="#test-work" aria-label="Field Lab home">E<span>/</span>LAB</a>
    <div class="header-title"><h1>Electrotechnique & Electrophysics</h1><p>Explore the invisible. Understand the physical.</p></div>
    <nav class="collections" aria-label="Learning collection"><a href="#test-work" id="test-collection">Test 4 in 3D</a><a href="#field" id="lab-collection">All experiments</a></nav>
  </header>
  <section class="test-overview" id="test-overview"><div><p class="eyebrow">FROM EQUATIONS TO INTUITION</p><h2>Electric energy, made visible.</h2><p>Explore the six questions from Test 4. Change the scene, make a prediction, then follow the derivation.</p></div><div class="test-score"><strong>4A <span>100p</span></strong><strong>4B <span>100p</span></strong><span>6 questions · 3D study guide</span></div></section>
  <nav class="subjects" aria-label="Electrophysics subjects"><div role="tablist" aria-label="Lessons"></div></nav>
  <main id="lesson" role="tabpanel" aria-labelledby="tab-field">
    <aside class="controls-panel">
      <p class="eyebrow" id="lesson-number"></p>
      <h2 id="lesson-title" tabindex="-1"></h2><p class="description" id="description"></p>
      <section id="test-question" class="test-question" aria-label="Original test question"></section>
      <form id="parameters" aria-label="Experiment parameters" onsubmit="return false"></form>
      <div class="panel-actions"><button type="button" id="reset">Reset experiment</button></div>
      <section class="measurements" id="measurements" aria-label="Live measurements" aria-live="polite" aria-atomic="true"></section>
    </aside>
    <div class="workbench">
      <section id="viewport" aria-label="3D workbench">
        <div class="scene-toolbar"><span class="view-tag">3D VIEW</span><div><button type="button" id="camera-reset">Reset camera</button><button type="button" id="pause" aria-pressed="false">Pause animation</button></div></div>
        <div class="legend" id="legend"></div>
        <div class="scene-footer"><p id="scene-note"></p><p class="hint">Drag to orbit · Scroll to zoom · Right-drag to pan · Arrow keys to pan when focused</p></div>
      </section>
      <section id="observation-panel" class="observation" aria-label="Connect the scene to the answer"><span class="eyebrow">NOTICE WHAT CHANGES</span><p id="observation" aria-live="polite"></p></section>
      <section class="learning-panel" aria-label="Learn the physics">
        <div><p class="eyebrow">THE PHYSICS</p><div id="equations" class="equations"></div><p id="explanation"></p><a id="source" target="_blank" rel="noopener noreferrer"></a></div>
        <div class="challenge"><p class="eyebrow">TRY THIS</p><p id="challenge"></p><details><summary>Model & visual scales</summary><p id="limits"></p></details></div>
      </section>
      <section id="test-study" class="test-study" aria-label="Test answers and prediction">
        <div class="solution-heading"><div><p class="eyebrow">BUILD YOUR ANSWER</p><h3>Follow the reasoning</h3></div><a href="${answerUrl}" target="_blank" rel="noopener noreferrer">Original answers ↗</a></div>
        <div id="solution" class="solution"></div>
        <section class="prediction"><p class="eyebrow">PAUSE & PREDICT</p><h3 id="prediction-question"></h3><button type="button" id="reveal-prediction" aria-expanded="false" aria-controls="prediction-answer">Reveal explanation</button><p id="prediction-answer" hidden></p></section>
        <nav class="lesson-pagination" aria-label="Question navigation"><a id="previous-question"></a><span id="question-progress"></span><a id="next-question"></a></nav>
      </section>
    </div>
  </main>`;

const lab = createLab(document.querySelector('#viewport')!);
const allLessons: Experiment[] = [...testLessons, ...experiments];
const settings = new Map(allLessons.map(experiment => [experiment.id, defaults(experiment)]));
const byId = (id: string) => document.getElementById(id)!;
let active: Experiment = testLessons[0];
let collection = '';
const subjects = document.querySelector<HTMLElement>('[role="tablist"]')!;
let paused = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
function updatePause() {
  byId('pause').textContent = paused ? 'Resume animation' : 'Pause animation';
  byId('pause').setAttribute('aria-pressed', String(paused));
  lab.setPaused(paused);
}
updatePause();

function parameters(): Parameters { return settings.get(active.id)!; }
function update() {
  const p = parameters();
  for (const control of active.controls) {
    if (control.kind !== 'range') continue;
    byId(`output-${control.id}`).textContent = `${format(Number(p[control.id]), 3)}${control.unit ? ` ${control.unit}` : ''}`;
  }
  if (active.id === 'semiconductor') {
    (byId('parameter-concentration') as HTMLInputElement).disabled = p.doping === 'intrinsic';
  }
  if (active.id === 'test-central') (byId('parameter-rb') as HTMLInputElement).disabled = p.destination === 'infinity';
  const testLesson = getTestLesson(active);
  if (testLesson) renderProse(byId('observation'), testLesson.observe(p));
  byId('measurements').innerHTML = active.measure(p).map(m => `<div class="measurement"><span>${m.label}</span><div><strong aria-label="${m.label}">${m.value}</strong><small>${m.unit}</small></div></div>`).join('');
  byId('measurements').querySelectorAll<HTMLElement>('.measurement > span').forEach(label => renderNotation(label, label.textContent!));
  lab.update(active.id, p);
}
function show(experiment: Experiment) {
  active = experiment;
  const testLesson = getTestLesson(experiment);
  const lessons: Experiment[] = testLesson ? testLessons : experiments;
  const index = lessons.indexOf(experiment);
  const nextCollection = testLesson ? 'test' : 'lab';
  if (collection !== nextCollection) {
    collection = nextCollection;
    subjects.innerHTML = lessons.map((e, i) => `<button type="button" role="tab" id="tab-${e.id}" aria-controls="lesson" aria-selected="false" tabindex="-1" data-experiment="${e.id}"><span>${String(i + 1).padStart(2, '0')}</span>${e.shortTitle}${getTestLesson(e) ? `<small>${getTestLesson(e)!.points}p</small>` : ''}</button>`).join('');
  }
  for (const [id, selected] of [['test-collection', Boolean(testLesson)], ['lab-collection', !testLesson]] as const) {
    if (selected) byId(id).setAttribute('aria-current', 'page');
    else byId(id).removeAttribute('aria-current');
  }
  byId('test-overview').hidden = !testLesson;
  byId('test-question').hidden = !testLesson;
  byId('test-study').hidden = !testLesson;
  byId('observation-panel').hidden = !testLesson;
  byId('lesson-number').textContent = testLesson ? `TEST ${testLesson.section} · QUESTION ${index + 1} · ${testLesson.points} POINTS` : `EXPERIMENT ${String(index + 1).padStart(2, '0')} / 08`;
  if (testLesson) {
    byId('test-question').replaceChildren(...testLesson.questions.map((text, i) => {
      const paragraph = document.createElement('p');
      renderProse(paragraph, text);
      if (i === 0) paragraph.className = 'question-lead';
      return paragraph;
    }));
    byId('solution').replaceChildren(...testLesson.answers.map(part => {
      const details = document.createElement('details');
      const summary = document.createElement('summary');
      renderNotation(summary, part.title);
      const steps = document.createElement('ol');
      steps.className = 'derivation';
      for (const step of part.steps) {
        const item = document.createElement('li');
        const why = document.createElement('p'); renderProse(why, step.why); item.append(why);
        if (step.math) { const math = document.createElement('p'); math.className = 'math-step'; renderEquation(math, step.math); item.append(math); }
        steps.append(item);
      }
      details.append(summary, steps);
      return details;
    }));
    renderProse(byId('prediction-question'), testLesson.prediction);
    renderProse(byId('prediction-answer'), testLesson.predictionAnswer);
    byId('prediction-answer').hidden = true;
    byId('reveal-prediction').textContent = 'Reveal explanation';
    byId('reveal-prediction').setAttribute('aria-expanded', 'false');
    const previous = byId('previous-question') as HTMLAnchorElement;
    const next = byId('next-question') as HTMLAnchorElement;
    previous.hidden = index === 0;
    next.hidden = index === testLessons.length - 1;
    previous.textContent = '← Previous question';
    next.textContent = 'Next question →';
    if (index > 0) previous.href = `#${testLessons[index - 1].id}`;
    if (index < testLessons.length - 1) next.href = `#${testLessons[index + 1].id}`;
    byId('question-progress').textContent = `${index + 1} / 6`;
  }
  byId('lesson-title').textContent = experiment.title;
  renderProse(byId('description'), experiment.description);
  renderProse(byId('scene-note'), experiment.sceneNote);
  renderProse(byId('explanation'), experiment.explanation);
  renderProse(byId('challenge'), experiment.challenge);
  renderProse(byId('limits'), experiment.limits);
  byId('equations').replaceChildren(...experiment.equations.map(equation => {
    const div = document.createElement('p');
    renderEquation(div, equation);
    return div;
  }));
  const source = byId('source') as HTMLAnchorElement;
  source.textContent = `${experiment.source.title} ↗`;
  source.href = experiment.source.url;
  byId('legend').innerHTML = experiment.legend.map(([colour, text]) => `<span><i style="background:${colour}"></i>${text}</span>`).join('');
  byId('lesson').setAttribute('aria-labelledby', `tab-${experiment.id}`);
  document.querySelectorAll<HTMLButtonElement>('[role="tab"]').forEach(tab => {
    const selected = tab.dataset.experiment === experiment.id;
    tab.setAttribute('aria-selected', String(selected));
    tab.tabIndex = selected ? 0 : -1;
  });
  const p = parameters();
  byId('parameters').innerHTML = experiment.controls.map(control => {
    const id = `parameter-${control.id}`;
    if (control.kind === 'select') return `<div class="parameter"><label for="${id}">${control.label}</label><select id="${id}" name="${control.id}">${control.options.map(option => `<option value="${option.value}" ${option.value === p[control.id] ? 'selected' : ''}>${option.label}</option>`).join('')}</select></div>`;
    return `<div class="parameter"><div class="parameter-label"><label for="${id}">${control.label}</label><output for="${id}" id="output-${control.id}"></output></div><input id="${id}" name="${control.id}" type="range" min="${control.min}" max="${control.max}" step="${control.step}" value="${p[control.id]}" /></div>`;
  }).join('');
  byId('parameters').querySelectorAll<HTMLLabelElement>('label').forEach(label => {
    const input = document.getElementById(label.htmlFor)!;
    input.setAttribute('aria-label', label.textContent!);
    renderNotation(label, label.textContent!);
  });
  lab.resetCamera(experiment.id);
  update();
}
function fromHash() {
  const id = window.location.hash.slice(1);
  show(allLessons.find(experiment => experiment.id === id) ?? testLessons[0]);
}
let focusNextQuestion = false;
document.querySelector('.lesson-pagination')!.addEventListener('click', event => {
  const link = (event.target as HTMLElement).closest('a');
  if (link && !((event as MouseEvent).ctrlKey || (event as MouseEvent).metaKey || (event as MouseEvent).shiftKey || (event as MouseEvent).altKey)) focusNextQuestion = true;
});
const onHashChange = () => {
  fromHash();
  if (focusNextQuestion) {
    focusNextQuestion = false;
    byId('lesson-title').focus({ preventScroll: true });
    byId('lesson-title').scrollIntoView({ block: 'start' });
  }
};
window.addEventListener('hashchange', onHashChange);
fromHash();
byId('parameters').addEventListener('input', event => {
  const input = event.target as HTMLInputElement | HTMLSelectElement;
  if (!input.name) return;
  parameters()[input.name] = input.type === 'range' ? Number(input.value) : input.value;
  update();
});
byId('reset').addEventListener('click', () => {
  settings.set(active.id, defaults(active));
  show(active);
});
byId('camera-reset').addEventListener('click', () => lab.resetCamera());
byId('pause').addEventListener('click', () => {
  paused = !paused;
  updatePause();
});
byId('reveal-prediction').addEventListener('click', () => {
  const reveal = byId('prediction-answer').hidden;
  byId('prediction-answer').hidden = !reveal;
  byId('reveal-prediction').setAttribute('aria-expanded', String(reveal));
  byId('reveal-prediction').textContent = reveal ? 'Hide explanation' : 'Reveal explanation';
});
subjects.addEventListener('click', event => {
  const tab = (event.target as HTMLElement).closest<HTMLButtonElement>('[data-experiment]');
  if (!tab) return;
  const id = tab.dataset.experiment!;
  if (window.location.hash === `#${id}`) show(allLessons.find(e => e.id === id)!);
  else window.location.hash = id;
});
subjects.addEventListener('keydown', event => {
    const tabs = [...subjects.querySelectorAll<HTMLButtonElement>('[role="tab"]')];
    const index = tabs.indexOf(event.target as HTMLButtonElement);
    if (index < 0) return;
    let next: number;
    if (event.key === 'ArrowRight') next = (index + 1) % tabs.length;
    else if (event.key === 'ArrowLeft') next = (index - 1 + tabs.length) % tabs.length;
    else if (event.key === 'Home') next = 0;
    else if (event.key === 'End') next = tabs.length - 1;
    else return;
    event.preventDefault();
    tabs[next].focus();
    tabs[next].click();
});
if (import.meta.hot) import.meta.hot.dispose(() => {
  window.removeEventListener('hashchange', onHashChange);
  lab.dispose();
});