import { MONTHS } from '../config.js';

export class Timeline {
  constructor(container) {
    this.container = container;
    this.events = [];
    this.sortedEvents = [];
    this.selectedIndex = -1;
    this.isPlaying = false;
    this.onEventSelect = () => {};
    this.onPlayStateChange = () => {};
  }

  setEvents(events) {
    this.events = events;
    // Sort events by date for playback
    this.sortedEvents = [...events].sort((a, b) => new Date(a.date) - new Date(b.date));
    this.render();
  }

  render() {
    const grouped = this.groupByMonth(this.events);
    const sortedKeys = Object.keys(grouped).sort();

    let currentYear = null;
    let monthsHtml = '';

    for (const monthKey of sortedKeys) {
      const [year] = monthKey.split('-');

      // Add year separator when year changes
      if (year !== currentYear) {
        monthsHtml += `<div class="timeline-year">${year}</div>`;
        currentYear = year;
      }

      monthsHtml += this.renderMonth(monthKey, grouped[monthKey]);
    }

    this.container.innerHTML = `
      <button class="timeline-play-btn" aria-label="Play">
        <svg class="play-icon" width="20" height="20" viewBox="0 0 20 20" fill="currentColor">
          <path d="M6 4l10 6-10 6V4z"/>
        </svg>
        <svg class="pause-icon" width="20" height="20" viewBox="0 0 20 20" fill="currentColor">
          <rect x="5" y="4" width="3" height="12"/>
          <rect x="12" y="4" width="3" height="12"/>
        </svg>
      </button>
      <div class="timeline-months">
        ${monthsHtml}
      </div>
    `;

    this.attachEventListeners();
  }

  groupByMonth(events) {
    return events.reduce((acc, event) => {
      const date = new Date(event.date);
      const key = `${date.getFullYear()}-${String(date.getMonth()).padStart(2, '0')}`;

      if (!acc[key]) {
        acc[key] = [];
      }
      acc[key].push(event);
      return acc;
    }, {});
  }

  renderMonth(monthKey, events) {
    const [year, month] = monthKey.split('-');
    const monthName = MONTHS[parseInt(month)];

    const eventsHtml = events
      .sort((a, b) => new Date(a.date) - new Date(b.date))
      .map(event => this.renderEvent(event))
      .join('');

    return `
      <div class="timeline-month" data-month="${monthKey}">
        <span class="timeline-month-label">${monthName}</span>
        <div class="timeline-events">
          ${eventsHtml}
        </div>
      </div>
    `;
  }

  renderEvent(event) {
    const date = new Date(event.date);
    const day = date.getDate();
    const eventIndex = this.sortedEvents.findIndex(e => e.id === event.id);
    const isSelected = eventIndex === this.selectedIndex;

    return `
      <button
        class="timeline-event ${event.type} ${isSelected ? 'selected' : ''}"
        data-event-id="${event.id}"
        data-event-index="${eventIndex}"
        aria-label="${event.name} - ${day} ${MONTHS[date.getMonth()]}"
      >
        <span class="timeline-event-tooltip">
          <strong>${event.name}</strong><br>
          ${day} ${MONTHS[date.getMonth()]}
        </span>
      </button>
    `;
  }

  attachEventListeners() {
    // Play button
    const playBtn = this.container.querySelector('.timeline-play-btn');
    if (playBtn) {
      playBtn.addEventListener('click', () => this.togglePlay());
    }

    // Event clicks
    this.container.querySelectorAll('.timeline-event').forEach(el => {
      el.addEventListener('click', () => {
        const eventIndex = parseInt(el.dataset.eventIndex, 10);
        this.selectEventByIndex(eventIndex);
      });
    });
  }

  togglePlay() {
    this.isPlaying = !this.isPlaying;
    this.updatePlayButton();
    this.onPlayStateChange(this.isPlaying);
  }

  play() {
    this.isPlaying = true;
    this.updatePlayButton();
  }

  pause() {
    this.isPlaying = false;
    this.updatePlayButton();
  }

  updatePlayButton() {
    const playBtn = this.container.querySelector('.timeline-play-btn');
    if (playBtn) {
      playBtn.classList.toggle('playing', this.isPlaying);
      playBtn.setAttribute('aria-label', this.isPlaying ? 'Pause' : 'Play');
    }
  }

  selectEventByIndex(index) {
    if (index < 0 || index >= this.sortedEvents.length) return;

    this.selectedIndex = index;
    const event = this.sortedEvents[index];

    // Update visual selection
    this.container.querySelectorAll('.timeline-event').forEach(el => {
      const elIndex = parseInt(el.dataset.eventIndex, 10);
      el.classList.toggle('selected', elIndex === index);
    });

    // Scroll event into view
    const eventEl = this.container.querySelector(`[data-event-index="${index}"]`);
    if (eventEl) {
      eventEl.scrollIntoView({ behavior: 'smooth', inline: 'center', block: 'nearest' });
    }

    this.onEventSelect(event, index);
  }

  selectEvent(eventId) {
    const index = this.sortedEvents.findIndex(e => e.id === eventId);
    if (index !== -1) {
      this.selectEventByIndex(index);
    }
  }

  // Advance to next event, returns false if at end
  nextEvent() {
    if (this.selectedIndex < this.sortedEvents.length - 1) {
      this.selectEventByIndex(this.selectedIndex + 1);
      return true;
    }
    return false;
  }

  getCurrentEvent() {
    if (this.selectedIndex >= 0 && this.selectedIndex < this.sortedEvents.length) {
      return this.sortedEvents[this.selectedIndex];
    }
    return null;
  }

  getNextEvent() {
    if (this.selectedIndex >= 0 && this.selectedIndex < this.sortedEvents.length - 1) {
      return this.sortedEvents[this.selectedIndex + 1];
    }
    return null;
  }

  clearSelection() {
    this.selectedIndex = -1;
    this.container.querySelectorAll('.timeline-event').forEach(el => {
      el.classList.remove('selected');
    });
  }

  setOnEventSelect(callback) {
    this.onEventSelect = callback;
  }

  setOnPlayStateChange(callback) {
    this.onPlayStateChange = callback;
  }
}