export interface Config {
  databaseUrl: string;
  dataDir: string;
  secret: string;
  publicUrl: string | undefined;
  port: number;
  pluginDirs: string[];
}

export const MISSING_SECRET = "Set STTRACKER_SECRET to a long random string. It encrypts source credentials.";

/** Read the server config from the environment. Throws when `STTRACKER_SECRET` is missing. */
export function loadConfig(env: Record<string, string | undefined> = process.env): Config {
  const secret = env.STTRACKER_SECRET;
  if (!secret) throw new Error(MISSING_SECRET);
  const dataDir = env.DATA_DIR || "./data";
  const port = Number(env.PORT || 3000);
  if (!Number.isInteger(port) || port < 0 || port > 65535) throw new Error(`PORT must be a port number, got "${env.PORT}"`);
  return {
    databaseUrl: env.DATABASE_URL || `sqlite://${dataDir}/sttracker.db`,
    dataDir,
    secret,
    publicUrl: env.PUBLIC_URL || undefined,
    port,
    pluginDirs: (env.PLUGIN_DIRS || `plugins,${dataDir}/plugins`)
      .split(",")
      .map((d) => d.trim())
      .filter((d) => d !== ""),
  };
}