import { readFileSync } from "node:fs";

/**
 * Read a configuration value from the environment, with `<NAME>_FILE`
 * indirection: if `<NAME>_FILE` is set, the value is read from that file
 * (trailing whitespace stripped). This keeps secrets out of process
 * environments and lets systemd credentials / agenix-managed files be used
 * directly.
 */
export function envOrFile(name: string): string | undefined {
  const direct = process.env[name];
  const file = process.env[`${name}_FILE`];
  if (direct && file) {
    throw new Error(`Both ${name} and ${name}_FILE are set; use only one.`);
  }
  if (file) {
    try {
      return readFileSync(file, "utf8").replace(/\s+$/, "");
    } catch (err) {
      const message = err instanceof Error ? err.message : String(err);
      throw new Error(`Could not read ${name}_FILE (${file}): ${message}`);
    }
  }
  return direct || undefined;
}

/** Like envOrFile, but exits with a helpful message when unset. */
export function requireEnvOrFile(name: string, hint: string): string {
  const value = envOrFile(name);
  if (!value) {
    console.error(`[jortt-mcp] Missing required configuration: ${name}\n${hint}`);
    process.exit(1);
  }
  return value;
}

export function envFlag(name: string): boolean {
  const value = process.env[name]?.toLowerCase();
  return value === "1" || value === "true" || value === "yes";
}

/** Parse a comma- or whitespace-separated env list. */
export function envList(name: string): string[] {
  const value = process.env[name];
  if (!value) return [];
  return value
    .split(/[,\s]+/)
    .map((s) => s.trim())
    .filter(Boolean);
}