import { browser } from '$app/environment';
import type { Infer } from 'superstruct';
import { assert, object, optional, number, string } from 'superstruct';

const Config = object({
  active_project: optional(string())
});

type Config = Infer<typeof Config>;

const CachedConfig = object({
  config: Config,
  expires: number()
});

type CachedConfig = Infer<typeof CachedConfig>;

const CACHE_TTL = 10 * 60 * 60 * 1000;

async function get_config(): Promise<Config> {
  // Cache, might be outdated but saves on call to server
  if (browser) {
    try {
      // TODO: Use async localStorage
      const stored = localStorage.getItem('config');
      if (stored !== null) {
        const cached: CachedConfig = JSON.parse(stored);
        assert(cached, CachedConfig);
        if (cached.expires < Date.now()) {
          // TODO: Should we update expires here?
          // If page is in use we probably don't need to sync for a while.
          return cached.config;
        }
      }
    } catch {
      // ignore errors
    }
  }

  // Default config
  // eslint-disable-next-line prefer-const
  let config: Config = { active_project: undefined };

  // TODO: Fetch config

  if (browser) {
    const cached: CachedConfig = { config: config, expires: Date.now() + CACHE_TTL };
    // TODO: Use async localStorage
    localStorage.setItem('config', JSON.stringify(cached));
  }
  return config;
}

export { type Config, get_config };