import { existsSync, readFileSync } from "node:fs";

// Minimal .env loader, no dependency. Doesn't override a variable already
// set in the real environment, so `FOO=bar npm start` still wins over
// whatever's sitting in .env.
export function loadEnvFile(path = ".env"): void {
  if (!existsSync(path)) {
    return;
  }

  const content = readFileSync(path, "utf8");
  for (const line of content.split("\n")) {
    const trimmed = line.trim();
    if (!trimmed || trimmed.startsWith("#")) {
      continue;
    }

    const eq = trimmed.indexOf("=");
    if (eq === -1) {
      continue;
    }

    const key = trimmed.slice(0, eq).trim();
    let value = trimmed.slice(eq + 1).trim();
    if ((value.startsWith('"') && value.endsWith('"')) || (value.startsWith("'") && value.endsWith("'"))) {
      value = value.slice(1, -1);
    }

    if (!(key in process.env)) {
      process.env[key] = value;
    }
  }
}