/** A compact palette picker. Palette references stay references when saved. */
let sequence = 0;
const node = (tag, className, text) => {
  const el = document.createElement(tag);
  el.className = className;
  if (text !== undefined) el.textContent = text;
  return el;
};
const hexPattern = /^#[0-9a-f]{6}([0-9a-f]{2})?$/i;

export function createColorControl({ id, label, value = '', inheritedValue = '', colors, onChange, onComplete = () => {} }) {
  const wrap = node('div', 'color-control');
  const trigger = node('button', 'color-trigger');
  trigger.type = 'button'; trigger.id = id;
  trigger.setAttribute('aria-expanded', 'false');
  trigger.setAttribute('aria-controls', `${id}-choices`);
  const sample = node('span', 'color-sample'); sample.setAttribute('aria-hidden', 'true');
  const ink = node('span', 'color-sample-ink'); sample.append(ink);
  const description = node('span', 'color-description');
  const name = node('span', 'color-name'), detail = node('span', 'color-detail');
  description.append(name, detail);
  const arrow = node('span', 'color-chevron', '⌄'); arrow.setAttribute('aria-hidden', 'true');
  trigger.append(sample, description, arrow);

  const choices = node('div', 'color-choices'); choices.id = `${id}-choices`; choices.hidden = true;
  const heading = node('p', 'color-heading', 'Website-Farben');
  const palette = node('div', 'color-palette');
  palette.setAttribute('role', 'group'); palette.setAttribute('aria-label', `Website-Farben für ${label}`);
  const buttons = [];
  let current = value, editing = false, mergeKey = `color-${++sequence}`;
  const entryFor = raw => colors.find(color => `@${color.key}` === raw);
  const resolve = raw => hexPattern.test(raw) ? raw : entryFor(raw)?.value || '';
  const restoreFocus = () => document.getElementById(id)?.focus();
  const choose = raw => { current = raw; sync(); onChange(raw); restoreFocus(); };
  for (const color of colors) {
    const button = node('button', 'color-option'); button.type = 'button';
    button.dataset.color = `@${color.key}`;
    button.title = `${color.name} · ${color.value}`;
    button.setAttribute('aria-label', button.title);
    const swatch = node('span', 'color-option-swatch'); swatch.style.backgroundColor = color.value;
    swatch.setAttribute('aria-hidden', 'true');
    button.append(swatch, node('span', 'color-option-name', color.name));
    button.addEventListener('click', () => choose(`@${color.key}`));
    buttons.push(button); palette.append(button);
  }
  if (colors.length) choices.append(heading, palette);

  const customLabel = node('label', 'color-heading', 'Eigene Farbe'); customLabel.htmlFor = `${id}-hex`;
  const custom = node('div', 'color-custom');
  const picker = node('input', 'color-native'); picker.type = 'color';
  picker.setAttribute('aria-label', `Eigene Farbe für ${label}`);
  const text = node('input', 'color-text'); text.type = 'text'; text.id = `${id}-hex`;
  text.autocomplete = 'off'; text.spellcheck = false; text.placeholder = '#RRGGBB';
  text.setAttribute('aria-label', `Farbwert für ${label}`);
  const accept = node('button', 'color-accept', '✓'); accept.type = 'button';
  accept.setAttribute('aria-label', `Farbwert für ${label} übernehmen`); accept.title = 'Farbwert übernehmen';
  custom.append(picker, text, accept);
  const error = node('p', 'field-error'); error.id = `${id}-error`; error.hidden = true;
  error.setAttribute('role', 'status'); text.setAttribute('aria-describedby', error.id);
  const clear = node('button', 'color-inherit', 'Geerbten Wert verwenden'); clear.type = 'button';
  clear.addEventListener('click', () => choose(''));
  choices.append(customLabel, custom, error, clear);
  wrap.append(trigger, choices);

  function sync() {
    const shown = current || inheritedValue, entry = entryFor(shown), hex = resolve(shown);
    ink.style.backgroundColor = hex || 'transparent';
    name.textContent = entry?.name || (hex ? 'Eigene Farbe' : current ? 'Unbekannte Palettenfarbe' : 'Übernehmen');
    detail.textContent = [!current ? 'Geerbt' : entry ? 'Palette' : '', hex || (current || 'Kein eigener Farbwert')].filter(Boolean).join(' · ');
    trigger.setAttribute('aria-label', `${label}: ${name.textContent}, ${detail.textContent}. Farbe auswählen`);
    picker.value = hex ? hex.slice(0, 7) : '#ffffff';
    text.value = hex || current || '';
    for (const button of buttons) button.setAttribute('aria-pressed', String(button.dataset.color === shown));
    clear.disabled = current === '';
  }
  const finish = () => {
    if (!editing) return;
    editing = false;
    onComplete();
  };
  trigger.addEventListener('click', () => {
    if (!choices.hidden) {
      choices.hidden = true; trigger.setAttribute('aria-expanded', 'false'); finish(); restoreFocus();
    } else {
      choices.hidden = false; trigger.setAttribute('aria-expanded', 'true');
    }
  });
  // A native picker emits many input events during one gesture. Keep its DOM and one undo entry.
  picker.addEventListener('input', () => {
    current = picker.value + (resolve(current || inheritedValue).slice(7) || '');
    editing = true; sync(); onChange(current, mergeKey);
  });
  picker.addEventListener('change', () => {
    current = picker.value + (resolve(current || inheritedValue).slice(7) || '');
    sync(); onChange(current, editing ? mergeKey : undefined);
    if (editing) finish();
    restoreFocus();
  });
  const applyText = () => {
    let raw = text.value.trim();
    if (/^#[0-9a-f]{3}$/i.test(raw)) raw = '#' + [...raw.slice(1)].map(char => char + char).join('');
    if (raw && !hexPattern.test(raw) && !entryFor(raw)) {
      text.setAttribute('aria-invalid', 'true'); error.hidden = false;
      error.textContent = 'Hexfarbe wie #1a2b3c oder eine vorhandene Palettenfarbe eingeben.';
      text.focus(); return;
    }
    choose(raw);
  };
  text.addEventListener('input', () => { text.removeAttribute('aria-invalid'); error.hidden = true; });
  text.addEventListener('keydown', event => {
    if (event.key === 'Enter') { event.preventDefault(); applyText(); }
  });
  accept.addEventListener('click', applyText);
  wrap.addEventListener('keydown', event => {
    if (event.key !== 'Escape' || choices.hidden) return;
    event.preventDefault(); event.stopPropagation(); choices.hidden = true;
    trigger.setAttribute('aria-expanded', 'false'); finish(); restoreFocus();
  });
  // Commit after leaving the native picker even on browsers that omit its change event.
  wrap.addEventListener('focusout', () => setTimeout(() => {
    if (wrap.isConnected && !wrap.contains(document.activeElement)) finish();
  }, 0));
  sync();
  return wrap;
}