import { z } from 'zod';

const envSchema = z.object({
  PORT: z.coerce.number().default(8096),
  HOST: z.string().default('0.0.0.0'),
  DATA_DIR: z.string().default('./data'),
  STATIC_DIR: z.string().optional(),
  PUBLIC_URL: z.string().url().default('http://localhost:8096'),
  // Set when this instance is deployed under a path prefix on a shared domain
  // (e.g. "/regress" on podsteadr.atobitcoin.io/regress/) rather than at
  // root. Must match nginx's location block, which must NOT strip the
  // prefix — the NIP-98 `u` tag the frontend signs includes it, so the
  // backend needs to see (and route) the same full path. Leave unset ("") to
  // deploy at root, e.g. its own dedicated host/port.
  ROUTE_PREFIX: z.string().default(''),
  NIP98_MAX_SKEW_SECS: z.coerce.number().default(60),
  SESSION_TTL_DAYS: z.coerce.number().default(30),
  // Base URL for BTC Map's API — global sync pulls every place worldwide via
  // the chronological /v4/places endpoint (paginated, incremental via a
  // stored watermark — see routes/sync.ts), not scoped to any region.
  // Overridable for tests to point at a mock server instead of the real API.
  BTCMAP_API_BASE_URL: z.string().url().default('https://api.btcmap.org'),
  // How close (in meters) a player must be to a place to claim it or link from it.
  CLAIM_RADIUS_METERS: z.coerce.number().default(40),
  // Maximum link length, in kilometers — mirrors Ingress's level-scaled link
  // range (up to ~655km at max level) with a single flat cap instead, since
  // Regress has no resonator-leveling system to scale it off of.
  MAX_LINK_DISTANCE_KM: z.coerce.number().default(500),
  // Claims expire after this many Bitcoin blocks and revert to neutral —
  // mirrors Ingress's real-world portal decay, but block-height-based
  // instead of wall-clock, since that's the native "clock" for this game.
  PORTAL_TIMEOUT_BLOCKS: z.coerce.number().default(2100),
  BLOCK_HEIGHT_API_URL: z.string().url().default('https://mempool.space/api/blocks/tip/height'),
  // How often to sweep for and expire timed-out claims.
  EXPIRY_SWEEP_INTERVAL_MS: z.coerce.number().default(5 * 60 * 1000),
});

export type Config = z.infer<typeof envSchema>;

export function loadConfig(env: NodeJS.ProcessEnv = process.env): Config {
  return envSchema.parse(env);
}