/**
 * ErrorDisplay - Renders error/warning/info/success messages in #errorContainer.
 * Supports auto-hide after CONFIG.UI.ERROR_DISPLAY_DURATION and a close button.
 * Requirements: 11.1, 11.2, 11.3, 11.4, 11.5
 */

const ErrorDisplay = (function () {
  // ─── Private State ────────────────────────────────────────────────────────

  /** @type {HTMLElement|null} */
  let _container = null;

  /** @type {number|null} Auto-hide timer id */
  let _autoHideTimer = null;

  // ─── Private Helpers ──────────────────────────────────────────────────────

  /**
   * Lazily resolve the #errorContainer element.
   * @returns {HTMLElement|null}
   */
  function _getContainer() {
    if (!_container) {
      _container = document.getElementById('errorContainer');
    }
    return _container;
  }

  /**
   * Map a message type to Bootstrap alert class and icon.
   * @param {'error'|'warning'|'info'|'success'} type
   * @returns {{ alertClass: string, iconClass: string }}
   */
  function _getTypeStyles(type) {
    switch (type) {
      case 'warning':
        return { alertClass: 'alert-warning', iconClass: 'fas fa-exclamation-triangle' };
      case 'info':
        return { alertClass: 'alert-info', iconClass: 'fas fa-info-circle' };
      case 'success':
        return { alertClass: 'alert-success', iconClass: 'fas fa-check-circle' };
      case 'error':
      default:
        return { alertClass: 'alert-danger', iconClass: 'fas fa-times-circle' };
    }
  }

  /**
   * Cancel any pending auto-hide timer.
   */
  function _clearTimer() {
    if (_autoHideTimer !== null) {
      clearTimeout(_autoHideTimer);
      _autoHideTimer = null;
    }
  }

  // ─── Public API ───────────────────────────────────────────────────────────

  return {
    /**
     * Display a message in #errorContainer.
     *
     * @param {string} message - The message text to display
     * @param {'error'|'warning'|'info'|'success'} [type='error'] - Message type
     * @param {boolean} [autoHide=true] - Whether to auto-hide after the configured duration
     */
    show(message, type = 'error', autoHide = true) {
      const container = _getContainer();
      if (!container) {
        console.warn('[ErrorDisplay] #errorContainer not found in DOM.');
        return;
      }

      // Cancel any existing auto-hide
      _clearTimer();

      const { alertClass, iconClass } = _getTypeStyles(type);

      // Build the alert element
      const alert = document.createElement('div');
      alert.className = `alert ${alertClass} alert-dismissible fade show d-flex align-items-start`;
      alert.setAttribute('role', 'alert');
      alert.setAttribute('aria-live', 'assertive');
      alert.setAttribute('aria-atomic', 'true');

      // Icon
      const icon = document.createElement('i');
      icon.className = `${iconClass} me-2 mt-1 flex-shrink-0`;
      icon.setAttribute('aria-hidden', 'true');

      // Message text
      const text = document.createElement('span');
      text.className = 'flex-grow-1';
      text.textContent = message;

      // Close button
      const closeBtn = document.createElement('button');
      closeBtn.type = 'button';
      closeBtn.className = 'btn-close ms-2 flex-shrink-0';
      closeBtn.setAttribute('aria-label', 'Close');
      closeBtn.addEventListener('click', () => {
        _clearTimer();
        ErrorDisplay.hide();
      });

      alert.appendChild(icon);
      alert.appendChild(text);
      alert.appendChild(closeBtn);

      // Replace any existing content
      container.innerHTML = '';
      container.appendChild(alert);

      // Auto-hide after configured duration
      if (autoHide) {
        const duration =
          typeof CONFIG !== 'undefined' && CONFIG.UI && CONFIG.UI.ERROR_DISPLAY_DURATION
            ? CONFIG.UI.ERROR_DISPLAY_DURATION
            : 5000;

        _autoHideTimer = setTimeout(() => {
          ErrorDisplay.hide();
        }, duration);
      }
    },

    /**
     * Hide and clear the current error message.
     */
    hide() {
      _clearTimer();
      const container = _getContainer();
      if (!container) return;

      const alert = container.querySelector('.alert');
      if (alert) {
        // Fade out by removing the 'show' class, then remove element
        alert.classList.remove('show');
        setTimeout(() => {
          if (container.contains(alert)) {
            container.removeChild(alert);
          }
        }, 150); // matches Bootstrap fade transition
      }
    },

    /**
     * Convenience wrappers for each message type.
     */
    showError(message, autoHide = true) {
      this.show(message, 'error', autoHide);
    },

    showWarning(message, autoHide = true) {
      this.show(message, 'warning', autoHide);
    },

    showInfo(message, autoHide = true) {
      this.show(message, 'info', autoHide);
    },

    showSuccess(message, autoHide = true) {
      this.show(message, 'success', autoHide);
    },
  };
})();

// Subscribe to StateManager error changes so the display stays in sync
if (typeof StateManager !== 'undefined') {
  StateManager.subscribe('error', function (errorState) {
    if (errorState && errorState.message) {
      ErrorDisplay.show(errorState.message, errorState.type || 'error');
    } else {
      ErrorDisplay.hide();
    }
  });
}

// Export for global access in vanilla JS context
window.ErrorDisplay = ErrorDisplay;