import { mkdirSync } from "node:fs";
import { resolve } from "node:path";

function env(name: string, fallback?: string): string {
  const v = process.env[name];
  if (v === undefined || v === "") {
    if (fallback !== undefined) return fallback;
    throw new Error(`missing environment variable ${name}`);
  }
  return v;
}

export type Role = "all" | "api" | "worker";

export const config = {
  appEnv: env("APP_ENV", "development"),
  isProd: env("APP_ENV", "development") === "production",
  siteUrl: env("MA_SITE_URL", "http://localhost:8390"),
  apiHost: env("MA_API_HOST", "127.0.0.1"),
  apiPort: Number(env("MA_API_PORT", "8391")),
  role: env("MA_ROLE", "all") as Role,
  databaseUrl: env("DATABASE_URL", "postgres://localhost:5432/market_atlas"),
  dataDir: resolve(env("MA_DATA_DIR", "./data")),
  adminToken: env("MA_ADMIN_TOKEN", ""),
  /** When set, the API process is the public edge: /v1/* served locally, everything else proxied to the Next.js web app. */
  webUpstream: env("MA_WEB_UPSTREAM", ""),
  logJson: env("MA_LOG_JSON", "0") === "1",
  contactEmail: env("MA_CONTACT_EMAIL", "contact@market-atlas.co"),
  userAgent: `MarketAtlas/0.1 (+https://www.market-atlas.co; ${env("MA_CONTACT_EMAIL", "contact@market-atlas.co")})`,
  disabledConnectors: new Set(
    env("MA_DISABLED_CONNECTORS", "")
      .split(",")
      .map((s) => s.trim())
      .filter(Boolean),
  ),
  rawSampleRate: Number(env("MA_RAW_SAMPLE_RATE", "0.02")),
  observationRetentionDays: Number(env("MA_OBSERVATION_RETENTION_DAYS", "45")),
  /** Observation writer batching. */
  writerFlushMs: 1000,
  writerMaxBatch: 2000, // 17 columns × 2000 rows stays under Postgres' 65,535 bind-parameter limit
  /** Consensus: observations older than this (ms) are excluded for REALTIME sources. */
  consensusFreshWindowMs: 15_000,
  /**
   * Persistence sampling for REALTIME streaming ticks: at most one stored observation per
   * (source, instrument, field) per interval. Consensus/events still see every tick in memory.
   * 0 disables sampling (store everything).
   */
  tickPersistIntervalMs: Number(env("MA_TICK_PERSIST_INTERVAL_MS", "2000")),
  version: "0.1.0",
};

export function ensureDataDirs(): void {
  for (const d of ["raw", "archive", "backups", "logs", "cache"]) mkdirSync(resolve(config.dataDir, d), { recursive: true });
}

export const runsWorker = () => config.role === "all" || config.role === "worker";
export const runsApi = () => config.role === "all" || config.role === "api";