/**
 * EpisodeManager - Manages episode number editing and highlighting
 */
class EpisodeManager {
  constructor() {
    this.isUpdatingEpisodeNumbers = false;
  }

  /**
   * Update episode numbers in the file list
   * @param {HTMLElement} fileListEl - File list element
   */
  updateEpisodeNumbers(fileListEl) {
    if (this.isUpdatingEpisodeNumbers) {
      console.log('[updateEpisodeNumbers] Already updating, skipping re-entrant call');
      return;
    }

    this.isUpdatingEpisodeNumbers = true;

    try {
      const fileItems = fileListEl.querySelectorAll('.file-item:not(.folder-item)');
      let episodeNum = 1;

      fileItems.forEach((item, index) => {
        const episodeEl = item.querySelector('.episode-number');
        if (episodeEl) {
          const storedStart = episodeEl.dataset.episodeStart;
          const storedEnd = episodeEl.dataset.episodeEnd;

          const start = storedStart ? parseInt(storedStart) : episodeNum;
          const end = storedEnd ? parseInt(storedEnd) : start;

          const rangeText = start === end ? `${start}` : `${start}-${end}`;
          episodeEl.textContent = rangeText;
          episodeEl.dataset.episode = episodeNum;
          episodeNum = end + 1;
        }
      });
    } finally {
      this.isUpdatingEpisodeNumbers = false;
    }
  }

  /**
   * Make episode range editable
   * @param {HTMLElement} element - Episode number element
   */
  makeEpisodeRangeEditable(element) {
    if (element.contentEditable === 'true') return;

    const originalText = element.textContent;
    const originalStart = element.dataset.episodeStart;
    const originalEnd = element.dataset.episodeEnd;

    element.contentEditable = 'true';
    element.focus();
    element.classList.add('editing');

    const range = document.createRange();
    range.selectNodeContents(element);
    const selection = window.getSelection();
    selection.removeAllRanges();
    selection.addRange(range);

    const saveEdit = () => {
      const newText = element.textContent.trim();

      if (newText !== originalText) {
        let start, end;

        if (newText.includes('-')) {
          const parts = newText.split('-').map(p => parseInt(p.trim()));
          start = parts[0];
          end = parts[1] || start;
        } else {
          const num = parseInt(newText);
          start = num;
          end = num;
        }

        if (!isNaN(start) && !isNaN(end)) {
          element.dataset.episodeStart = start;
          element.dataset.episodeEnd = end;
          console.log(`Episode range updated: ${start}-${end}`);
          this.updateEpisodeNumbers(element.closest('#file-list'));
        } else {
          element.textContent = originalText;
          element.dataset.episodeStart = originalStart;
          element.dataset.episodeEnd = originalEnd;
        }
      }

      element.contentEditable = 'false';
      element.classList.remove('editing');
    };

    element.addEventListener('keydown', function(e) {
      if (e.key === 'Enter') {
        e.preventDefault();
        saveEdit();
      }
    }, { once: true });

    element.addEventListener('blur', saveEdit, { once: true });
  }

  /**
   * Handle episode arrow click
   * @param {HTMLElement} element - Arrow element
   * @param {string} direction - Direction (left or right)
   * @param {HTMLElement} fileListEl - File list element
   */
  handleEpisodeArrowClick(element, direction, fileListEl) {
    const fileItem = element.closest('.file-item');
    const episodeEl = fileItem.querySelector('.episode-number');

    if (!episodeEl) return;

    // Get current values before updating
    let start = parseInt(episodeEl.dataset.episodeStart) || 1;
    let end = parseInt(episodeEl.dataset.episodeEnd) || start;

    const oldStart = start;
    const oldEnd = end;

    // Update the episode range
    if (direction === 'left') {
      // Decrease range - move start back by 1
      if (start > 1) {
        start--;
      }
    } else {
      // Increase range - move end forward by 1
      end++;
    }

    // Update this episode's data attributes
    episodeEl.dataset.episodeStart = start;
    episodeEl.dataset.episodeEnd = end;

    // Get all media file items (not folders) in order
    const allFileItems = Array.from(fileListEl.querySelectorAll('.file-item:not(.folder-item)'));

    // Find current index by matching file path
    const filePath = fileItem.dataset.filePath;
    let currentIndex = -1;
    for (let i = 0; i < allFileItems.length; i++) {
      if (allFileItems[i].dataset.filePath === filePath) {
        currentIndex = i;
        break;
      }
    }

    if (currentIndex === -1) return;

    // For right arrow: shift all subsequent episodes forward by 1
    if (direction === 'right') {
      for (let i = currentIndex + 1; i < allFileItems.length; i++) {
        const nextItem = allFileItems[i];
        const nextEpisodeEl = nextItem.querySelector('.episode-number');

        if (nextEpisodeEl) {
          let nextStart = parseInt(nextEpisodeEl.dataset.episodeStart) || 1;
          const nextEnd = parseInt(nextEpisodeEl.dataset.episodeEnd) || nextStart;

          nextEpisodeEl.dataset.episodeStart = nextStart + 1;
          nextEpisodeEl.dataset.episodeEnd = nextEnd + 1;
        }
      }
    } else {
      // For left arrow: all subsequent episodes shift down
      const shiftAmount = oldStart - start;
      for (let i = currentIndex + 1; i < allFileItems.length; i++) {
        const nextItem = allFileItems[i];
        const nextEpisodeEl = nextItem.querySelector('.episode-number');

        if (nextEpisodeEl) {
          let nextStart = parseInt(nextEpisodeEl.dataset.episodeStart) || 1;
          const nextEnd = parseInt(nextEpisodeEl.dataset.episodeEnd) || nextStart;

          nextEpisodeEl.dataset.episodeStart = nextStart - shiftAmount;
          nextEpisodeEl.dataset.episodeEnd = nextEnd - shiftAmount;
        }
      }
    }

    // Force immediate DOM update
    this.updateEpisodeNumbers(fileListEl);
  }

  /**
   * Highlight episodes in the episodes container
   * @param {number} startEpisode - Start episode number
   * @param {number} endEpisode - End episode number
   * @param {HTMLElement} episodesContainer - Episodes container element
   */
  highlightEpisodes(startEpisode, endEpisode, episodesContainer) {
    if (!episodesContainer) return;

    const episodeItems = episodesContainer.querySelectorAll('.episode-item');

    episodeItems.forEach(item => {
      const episodeText = item.textContent.trim();
      const episodeMatch = episodeText.match(/E(\d+)/);

      if (episodeMatch) {
        const episodeNum = parseInt(episodeMatch[1]);

        if (episodeNum >= startEpisode && episodeNum <= endEpisode) {
          item.classList.add('highlighted-episode');
        }
      }
    });
  }

  /**
   * Remove highlights from all episodes
   * @param {HTMLElement} episodesContainer - Episodes container element
   */
  removeEpisodeHighlights(episodesContainer) {
    if (!episodesContainer) return;

    const episodeItems = episodesContainer.querySelectorAll('.episode-item');

    episodeItems.forEach(item => {
      item.classList.remove('highlighted-episode');
    });
  }

  /**
   * Get episode range from element
   * @param {HTMLElement} episodeEl - Episode element
   * @returns {Object} Episode range object
   */
  getEpisodeRange(episodeEl) {
    const episodeStart = parseInt(episodeEl.dataset.episodeStart) || 1;
    const episodeEnd = parseInt(episodeEl.dataset.episodeEnd) || episodeStart;
    return { start: episodeStart, end: episodeEnd };
  }

  /**
   * Calculate total episode count from file items
   * @param {HTMLElement} fileListEl - File list element
   * @returns {number} Total episode count
   */
  calculateTotalEpisodeCount(fileListEl) {
    const mediaFiles = fileListEl.querySelectorAll('.file-item:not(.folder-item)');
    let totalEpisodeCount = 0;

    mediaFiles.forEach(item => {
      const episodeEl = item.querySelector('.episode-number');
      if (episodeEl) {
        const { start, end } = this.getEpisodeRange(episodeEl);
        totalEpisodeCount += (end - start + 1);
      }
    });

    return totalEpisodeCount;
  }

  /**
   * Get last episode end from file items
   * @param {HTMLElement} fileListEl - File list element
   * @returns {number} Last episode end number
   */
  getLastEpisodeEnd(fileListEl) {
    const mediaFiles = fileListEl.querySelectorAll('.file-item:not(.folder-item)');
    let lastEpisodeEnd = 0;

    mediaFiles.forEach((item, index) => {
      const episodeEl = item.querySelector('.episode-number');
      if (episodeEl) {
        const episodeEnd = parseInt(episodeEl.dataset.episodeEnd) || 1;
        if (index === 0 || episodeEnd > lastEpisodeEnd) {
          lastEpisodeEnd = episodeEnd;
        }
      }
    });

    return lastEpisodeEnd;
  }
}

module.exports = EpisodeManager;