import { esc } from './utils.js';

export class SearchableSelect {
  constructor(container, { searchPlaceholder = '...' } = {}) {
    this.container = container;
    this.value = '';
    this.label = '';
    this.groups = [];
    this.open = false;
    this.highlightIdx = -1;
    this.placeholder = container.dataset.placeholder || '...';
    this.onSelect = null;

    this.container.innerHTML = `
      <button type="button" class="ss__trigger">
        <span class="ss__value">${esc(this.placeholder)}</span>
        <svg class="ss__arrow" viewBox="0 0 10 6"><path d="M1 1l4 4 4-4" stroke="currentColor" stroke-width="1.3" fill="none" stroke-linecap="round"/></svg>
      </button>
      <div class="ss__dropdown" hidden>
        <input type="text" class="ss__search" placeholder="${esc(searchPlaceholder)}">
        <div class="ss__list"></div>
      </div>`;

    this.trigger  = container.querySelector('.ss__trigger');
    this.valueEl  = container.querySelector('.ss__value');
    this.dropdown = container.querySelector('.ss__dropdown');
    this.search   = container.querySelector('.ss__search');
    this.list     = container.querySelector('.ss__list');

    this.trigger.addEventListener('click', (e) => {
      e.stopPropagation();
      this.toggle();
    });
    this.search.addEventListener('input', () => this.render());
    this.search.addEventListener('keydown', (e) => this.onKeydown(e));
    this.list.addEventListener('click', (e) => {
      const item = e.target.closest('[data-value]');
      if (item) this.select(item.dataset.value, item.dataset.label);
    });
    document.addEventListener('click', (e) => {
      if (this.open && !this.container.contains(e.target)) this.close();
    });
  }

  setGroups(groups) {
    this.groups = groups;
  }

  setValue(val) {
    for (const g of this.groups) {
      for (const item of g.items) {
        if (String(item.id) === String(val)) {
          this.value = String(item.id);
          this.label = item.name;
          this.valueEl.textContent = item.name;
          this.valueEl.classList.add('ss__value--selected');
          return;
        }
      }
    }
    this.value = '';
    this.label = '';
    this.valueEl.textContent = this.placeholder;
    this.valueEl.classList.remove('ss__value--selected');
  }

  getValue() { return this.value; }

  toggle() {
    this.open ? this.close() : this.openDropdown();
  }

  openDropdown() {
    this.open = true;
    this.dropdown.hidden = false;
    this.search.value = '';
    this.highlightIdx = -1;
    this.render();
    this.search.focus();
  }

  close() {
    this.open = false;
    this.dropdown.hidden = true;
  }

  select(val, label) {
    this.value = val;
    this.label = label;
    this.valueEl.textContent = label;
    this.valueEl.classList.add('ss__value--selected');
    this.close();
    if (this.onSelect) this.onSelect(val, label);
  }

  focus() {
    this.openDropdown();
  }

  render() {
    const q = this.search.value.toLowerCase().trim();
    let html = '';
    let idx = 0;
    const visibleItems = [];

    for (const g of this.groups) {
      const filtered = g.items.filter(item =>
        !q || item.name.toLowerCase().includes(q) || g.label.toLowerCase().includes(q)
      );
      if (!filtered.length) continue;

      if (g.label) {
        html += `<div class="ss__group">${esc(g.label)}</div>`;
      }
      for (const item of filtered) {
        const active = String(item.id) === this.value ? ' ss__item--active' : '';
        const hl = idx === this.highlightIdx ? ' ss__item--highlight' : '';
        html += `<div class="ss__item${active}${hl}" data-value="${item.id}" data-label="${esc(item.name)}" data-idx="${idx}">${esc(item.name)}</div>`;
        visibleItems.push(item);
        idx++;
      }
    }

    this.list.innerHTML = html || `<div class="ss__empty">–</div>`;
    this.visibleCount = visibleItems.length;
  }

  onKeydown(e) {
    if (e.key === 'ArrowDown') {
      e.preventDefault();
      this.highlightIdx = Math.min(this.highlightIdx + 1, this.visibleCount - 1);
      this.render();
      this.scrollToHighlight();
    } else if (e.key === 'ArrowUp') {
      e.preventDefault();
      this.highlightIdx = Math.max(this.highlightIdx - 1, 0);
      this.render();
      this.scrollToHighlight();
    } else if (e.key === 'Enter') {
      e.preventDefault();
      const el = this.list.querySelector(`[data-idx="${this.highlightIdx}"]`);
      if (el) this.select(el.dataset.value, el.dataset.label);
    } else if (e.key === 'Escape') {
      this.close();
    }
  }

  scrollToHighlight() {
    const el = this.list.querySelector('.ss__item--highlight');
    if (el) el.scrollIntoView({ block: 'nearest' });
  }
}