import { useState, useEffect, useRef } from "react";
import { useLocation, useNavigate } from "react-router-dom";
import { Dropdown } from "../ui/dropdown/Dropdown";
import { DropdownItem } from "../ui/dropdown/DropdownItem";
import { fetchSites, Site, setActiveSite as apiSetActiveSite } from "../../services/api";
import { useToast } from "../ui/toast/ToastContainer";
import { useSiteStore } from "../../store/siteStore";
import { useAuthStore } from "../../store/authStore";
import Button from "../ui/button/Button";

/**
 * SiteSwitcher Component
 * 
 * Shows a dropdown menu with all active sites for the user.
 * Should only be visible on planner and writer pages (and their submodules).
 * 
 * Paths where switcher should be shown:
 * - /planner (dashboard and all subpages)
 * - /writer (dashboard and all subpages)
 * 
 * Paths where switcher should be hidden:
 * - /settings (including /settings/sites)
 * - /dashboard
 * - /analytics
 * - /thinker
 * - /signin, /signup
 */

// Paths where switcher should be shown (planner and writer modules)
const SITE_SWITCHER_SHOWN_PATHS = [
  '/planner',
  '/writer',
];

// Paths where switcher should be hidden (override shown paths)
const SITE_SWITCHER_HIDDEN_PATHS = [
  '/settings',
  '/dashboard',
  '/analytics',
  '/thinker',
];

interface SiteSwitcherProps {
  hiddenPaths?: string[]; // Optional override for hidden paths
}

export default function SiteSwitcher({ hiddenPaths }: SiteSwitcherProps) {
  const location = useLocation();
  const navigate = useNavigate();
  const toast = useToast();
  const { activeSite, setActiveSite, loadActiveSite } = useSiteStore();
  const { user, refreshUser, isAuthenticated } = useAuthStore();
  const [isOpen, setIsOpen] = useState(false);
  const [sites, setSites] = useState<Site[]>([]);
  const [loading, setLoading] = useState(true);
  const buttonRef = useRef<HTMLButtonElement>(null);

  // Determine if switcher should be shown
  const hiddenPathsToUse = hiddenPaths || SITE_SWITCHER_HIDDEN_PATHS;
  const shownPaths = SITE_SWITCHER_SHOWN_PATHS;
  
  let shouldHide = false;
  if (shownPaths.length > 0) {
    // If shown paths are defined, only show on those paths
    shouldHide = !shownPaths.some(path => location.pathname.startsWith(path));
  } else {
    // Otherwise, hide on explicitly hidden paths
    shouldHide = hiddenPathsToUse.some(path => location.pathname.startsWith(path));
  }

  // User refresh removed - data loads on-demand from API calls

  useEffect(() => {
    if (shouldHide) {
      setLoading(false);
      return;
    }

    loadSites();
    // Load active site from store (only once, not on every render)
    if (!activeSite) {
      loadActiveSite();
    }
  }, [shouldHide, location.pathname, user?.account?.id]); // Also reload when user's account changes

  const loadSites = async () => {
    try {
      setLoading(true);
      const response = await fetchSites();
      // Filter to only show active sites in the switcher
      const activeSites = (response.results || []).filter(site => site.is_active);
      setSites(activeSites);
    } catch (error: any) {
      console.error('Failed to load sites:', error);
      toast.error(`Failed to load sites: ${error.message}`);
    } finally {
      setLoading(false);
    }
  };

  const handleSiteSelect = async (siteId: number) => {
    try {
      await apiSetActiveSite(siteId);
      const selectedSite = sites.find(s => s.id === siteId);
      if (selectedSite) {
        // Update the global site store - this will dispatch siteChanged event
        setActiveSite(selectedSite);
        toast.success(`Switched to "${selectedSite.name}"`);
      }
      setIsOpen(false);
    } catch (error: any) {
      toast.error(`Failed to switch site: ${error.message}`);
    }
  };

  function toggleDropdown() {
    setIsOpen(!isOpen);
  }

  // Don't render if should be hidden
  if (shouldHide) {
    return null;
  }

  const noSitesAvailable = !loading && sites.length === 0;

  if (loading && sites.length === 0) {
    return (
      <div className="text-xs font-medium text-gray-500 dark:text-gray-400 px-3 py-2 border border-dashed border-gray-300 rounded-lg">
        Loading sites...
      </div>
    );
  }

  if (noSitesAvailable) {
    return (
      <Button size="sm" variant="outline" onClick={() => navigate('/sites')}>
        Create Site
      </Button>
    );
  }

  return (
    <div className="relative inline-block">
      <button
        ref={buttonRef}
        onClick={toggleDropdown}
        className="flex items-center gap-2 px-3 py-2 text-sm font-medium text-gray-700 bg-white border border-gray-300 rounded-lg hover:bg-gray-50 dark:bg-gray-800 dark:text-gray-300 dark:border-gray-700 dark:hover:bg-gray-700 dropdown-toggle"
        aria-label="Switch site"
      >
        <span className="flex items-center gap-2">
          <svg
            className="w-4 h-4"
            fill="none"
            stroke="currentColor"
            viewBox="0 0 24 24"
          >
            <path
              strokeLinecap="round"
              strokeLinejoin="round"
              strokeWidth={2}
              d="M19 21V5a2 2 0 00-2-2H7a2 2 0 00-2 2v16m14 0h2m-2 0h-5m-9 0H3m2 0h5M9 7h1m-1 4h1m4-4h1m-1 4h1m-5 10v-5a1 1 0 011-1h2a1 1 0 011 1v5m-4 0h4"
            />
          </svg>
          <span className="max-w-[150px] truncate">
            {activeSite?.name || 'Select Site'}
          </span>
        </span>
        <svg
          className={`w-4 h-4 transition-transform ${isOpen ? 'rotate-180' : ''}`}
          fill="none"
          stroke="currentColor"
          viewBox="0 0 24 24"
        >
          <path
            strokeLinecap="round"
            strokeLinejoin="round"
            strokeWidth={2}
            d="M19 9l-7 7-7-7"
          />
        </svg>
      </button>

      <Dropdown
        isOpen={isOpen}
        onClose={() => setIsOpen(false)}
        anchorRef={buttonRef}
        placement="bottom-left"
        className="w-64 p-2"
      >
        {sites.map((site) => (
          <DropdownItem
            key={site.id}
            onItemClick={() => handleSiteSelect(site.id)}
            className={`flex items-center gap-3 px-3 py-2 font-medium rounded-lg text-sm text-left ${
              activeSite?.id === site.id
                ? "bg-blue-50 text-blue-700 dark:bg-blue-500/20 dark:text-blue-300"
                : "text-gray-700 hover:bg-gray-100 hover:text-gray-700 dark:text-gray-400 dark:hover:bg-white/5 dark:hover:text-gray-300"
            }`}
          >
            <span className="flex-1">{site.name}</span>
            {activeSite?.id === site.id && (
              <svg
                className="w-4 h-4 text-blue-600 dark:text-blue-400"
                fill="currentColor"
                viewBox="0 0 20 20"
              >
                <path
                  fillRule="evenodd"
                  d="M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z"
                  clipRule="evenodd"
                />
              </svg>
            )}
          </DropdownItem>
        ))}
      </Dropdown>
    </div>
  );
}

