import { useState, useEffect, useCallback } from 'react';
import { useMyWorkspaces, useWorkspaceContext, type WorkspaceContext } from '@/api/hooks/workspaces';
import { useAuthStore } from '@/store/authStore';

const STORAGE_KEY = 'leocrm-active-workspace';

/**
 * Manages the active workspace for the current browser tab.
 *
 * Uses sessionStorage (per-tab, not shared across tabs) to store the active workspace ID.
 * Sends X-Workspace-ID header on workspace-aware requests.
 *
 * Workspaces are UI/navigation context only — they never affect permissions.
 */
export function useWorkspace() {
  const [activeWorkspaceId, setActiveWorkspaceId] = useState<string | null>(() => {
    return sessionStorage.getItem(STORAGE_KEY);
  });

  const { data: myWorkspaces } = useMyWorkspaces();
  const { data: context } = useWorkspaceContext(activeWorkspaceId);

  // Auto-select default workspace if none selected
  useEffect(() => {
    if (!activeWorkspaceId && myWorkspaces?.items?.length) {
      const defaultWs = myWorkspaces.items.find(w => w.is_user_default) || myWorkspaces.items[0];
      if (defaultWs) {
        setActiveWorkspaceId(defaultWs.id);
        sessionStorage.setItem(STORAGE_KEY, defaultWs.id);
      }
    }
  }, [activeWorkspaceId, myWorkspaces]);

  // Switch workspace (per-tab)
  const switchWorkspace = useCallback((workspaceId: string | null) => {
    if (workspaceId) {
      sessionStorage.setItem(STORAGE_KEY, workspaceId);
    } else {
      sessionStorage.removeItem(STORAGE_KEY);
    }
    setActiveWorkspaceId(workspaceId);
  }, []);

  // Get visible module keys from workspace context
  const visibleModuleKeys: Set<string> = new Set(
    context?.modules?.map(m => m.module_key) || []
  );

  // Check if a module is visible in the current workspace
  const isModuleVisible = useCallback((moduleKey: string): boolean => {
    // System admins see all modules regardless of workspace
    const user = useAuthStore.getState().user;
    if (user?.is_system_admin) return true;
    // While permissions are loading (is_system_admin undefined), show everything
    if (user && user.is_system_admin === undefined) return true;
    // If no workspace context, show all (backward compatible)
    if (!context?.workspace_id || !context?.modules?.length) return true;
    return visibleModuleKeys.has(moduleKey);
  }, [context, visibleModuleKeys]);

  return {
    activeWorkspaceId,
    activeWorkspace: context,
    myWorkspaces: myWorkspaces?.items || [],
    switchWorkspace,
    isModuleVisible,
    visibleModuleKeys,
    hasWorkspaces: (myWorkspaces?.items?.length || 0) > 0,
  };
}