import { adminPath } from '../../constants';
import type { NavKey } from '../components/BottomNav';

const STORAGE_KEY = 'admin-mobile-tab-history-v2';
const EXPIRY_MS = 1000 * 60 * 60 * 2; // 2 hours

type TabHistory = {
  paths: Partial<Record<NavKey, string>>;
  updatedAt: number;
};

function readHistory(): TabHistory {
  if (typeof window === 'undefined') {
    return { paths: {}, updatedAt: 0 };
  }

  try {
    const raw = window.localStorage.getItem(STORAGE_KEY);
    if (!raw) {
      return { paths: {}, updatedAt: 0 };
    }
    const parsed = JSON.parse(raw) as TabHistory;
    
    // Check for expiry
    if (Date.now() - parsed.updatedAt > EXPIRY_MS) {
      window.localStorage.removeItem(STORAGE_KEY);
      return { paths: {}, updatedAt: 0 };
    }

    return parsed ?? { paths: {}, updatedAt: 0 };
  } catch {
    return { paths: {}, updatedAt: 0 };
  }
}

function writeHistory(history: TabHistory): void {
  if (typeof window === 'undefined') {
    return;
  }

  try {
    window.localStorage.setItem(STORAGE_KEY, JSON.stringify(history));
  } catch {
    // Ignore storage errors.
  }
}

export function setTabHistory(key: NavKey, path: string): void {
  const history = readHistory();
  history.paths[key] = path;
  history.updatedAt = Date.now();
  writeHistory(history);
}

export function getTabHistory(): Partial<Record<NavKey, string>> {
  return readHistory().paths;
}

export function resolveDefaultTarget(key: NavKey, slug?: string | null): string {
  if (key === 'tasks') {
    return slug ? adminPath(`/mobile/events/${slug}/tasks`) : adminPath('/mobile/tasks');
  }
  if (key === 'uploads') {
    return slug ? adminPath(`/mobile/events/${slug}/photos`) : adminPath('/mobile/uploads');
  }
  if (key === 'profile') {
    return adminPath('/mobile/profile');
  }
  return adminPath('/mobile/dashboard');
}

function resolveEventScopedTarget(path: string, slug: string | null | undefined, key: NavKey): string {
  if (!slug) {
    return path;
  }

  if (key !== 'tasks' && key !== 'uploads') {
    return path;
  }

  const match = path.match(/\/event-admin\/mobile\/events\/([^/]+)\/(tasks|photos)(?:\/.*)?$/);
  if (!match) {
    return resolveDefaultTarget(key, slug);
  }

  const storedSlug = match[1];
  if (storedSlug === slug) {
    return path;
  }

  return resolveDefaultTarget(key, slug);
}

export function resolveTabTarget(key: NavKey, slug?: string | null): string {
  const history = readHistory();
  const stored = history.paths[key];
  const fallback = resolveDefaultTarget(key, slug);

  if (!stored) {
    return fallback;
  }

  return resolveEventScopedTarget(stored, slug, key);
}