import { z } from "zod";

const nonEmptyString = z.string().trim().min(1);
const urlString = z.url();

export type Environment = Record<string, string | undefined>;

export function requiredEnvironmentValue(
  name: string,
  environment: Environment = process.env,
) {
  const parsed = nonEmptyString.safeParse(environment[name]);
  if (!parsed.success) {
    throw new Error(`Missing required environment variable: ${name}`);
  }
  return parsed.data;
}

export function optionalEnvironmentValue(
  name: string,
  environment: Environment = process.env,
) {
  const parsed = nonEmptyString.safeParse(environment[name]);
  return parsed.success ? parsed.data : null;
}

export function requiredEnvironmentUrl(
  name: string,
  environment: Environment = process.env,
) {
  const value = requiredEnvironmentValue(name, environment);
  const parsed = urlString.safeParse(value);
  if (!parsed.success) {
    throw new Error(`Environment variable ${name} must be an absolute URL`);
  }
  return parsed.data.replace(/\/$/, "");
}

export function readFeatureEnvironment<Names extends readonly string[]>(
  feature: string,
  names: Names,
  environment: Environment = process.env,
): { [Name in Names[number]]: string } {
  try {
    return Object.fromEntries(
      names.map((name) => [name, requiredEnvironmentValue(name, environment)]),
    ) as { [Name in Names[number]]: string };
  } catch (error) {
    const message = error instanceof Error ? error.message : "Invalid configuration";
    throw new Error(`${feature} is not configured: ${message}`, { cause: error });
  }
}