/**
 * UI Store Module
 *
 * Zustand store for managing UI state and operations.
 * Handles:
 * - Global loading state
 * - Global error messages
 * - Left panel width with localStorage persistence
 *
 * @module stores/uiStore
 */

import { create } from 'zustand';
import type { UIStoreState } from '../types/store';
import { getItem, setItem } from '../utils/storage';

/**
 * LocalStorage key for persisting left panel width
 */
const LEFT_PANEL_WIDTH_KEY = 'ax-leftPanelWidth';

/**
 * Default left panel width percentage
 */
const DEFAULT_LEFT_PANEL_WIDTH = 40;

/**
 * Load left panel width from localStorage
 *
 * @returns Persisted width or default value
 */
const loadLeftPanelWidth = (): number => {
  const saved = getItem<number>(LEFT_PANEL_WIDTH_KEY);
  return saved ?? DEFAULT_LEFT_PANEL_WIDTH;
};

/**
 * UI store
 *
 * Manages global UI state including loading indicators, error messages,
 * panel width preferences, and document preview state.
 *
 * The left panel width is automatically persisted to localStorage
 * when updated via setLeftPanelWidth action.
 *
 * @example
 * ```typescript
 * // Set global loading state
 * useUIStore.getState().setLoading(true);
 *
 * // Set global error message
 * useUIStore.getState().setError('Failed to load document');
 *
 * // Clear error
 * useUIStore.getState().setError(null);
 *
 * // Update left panel width (persists to localStorage)
 * useUIStore.getState().setLeftPanelWidth(35);
 *
 * // Open document preview
 * useUIStore.getState().openDocumentPreview('doc-abc123');
 *
 * // Close document preview and return to chat
 * useUIStore.getState().closeDocumentPreview();
 * ```
 */
export const useUIStore = create<UIStoreState>((set) => ({
  // ============ State ============
  loading: false,
  error: null,
  leftPanelWidth: loadLeftPanelWidth(),
  // Note: previewMode is deprecated. Right panel now shows EditorPanel by default.
  // Kept for backward compatibility.
  previewMode: false,
  previewDocumentId: null,
  previewDocumentName: null,

  // ============ Actions ============

  /**
   * Set global loading state
   *
   * Controls the global loading indicator.
   * Used for app-wide loading states like initial app load.
   *
   * @param loading - True to show loading, false to hide
   */
  setLoading: (loading: boolean) => {
    set({ loading });
  },

  /**
   * Set global error message
   *
   * Sets a global error message to display to the user.
   * Pass null to clear the error.
   *
   * @param error - Error message string or null to clear
   */
  setError: (error: string | null) => {
    set({ error });
  },

  /**
   * Set left panel width and persist to localStorage
   *
   * Updates the left panel width and saves it to localStorage
   * for persistence across sessions.
   *
   * @param width - Width percentage (0-100)
   */
  setLeftPanelWidth: (width: number) => {
    // Update store state
    set({ leftPanelWidth: width });

    // Persist to localStorage
    setItem(LEFT_PANEL_WIDTH_KEY, width);
  },

  /**
   * Open document preview mode
   *
   * Opens the document in the right panel EditorPanel for preview and editing.
   * Used when user clicks on an export record link in the chat.
   *
   * @param documentId - ID of the document to preview
   * @param documentName - Optional name of the document to display in the editor toolbar
   */
  openDocumentPreview: (documentId: string, documentName?: string) => {
    set({
      previewDocumentId: documentId,
      previewDocumentName: documentName || null,
    });
  },

  /**
   * Close document preview mode
   *
   * Closes the document in the right panel EditorPanel.
   */
  closeDocumentPreview: () => {
    set({
      previewDocumentId: null,
      previewDocumentName: null,
    });
  },
}));

export default useUIStore;