import { z } from "zod";

/** Server settings from environment variables (see `.env.example`). */
const envSchema = z.object({
  NODE_ENV: z.enum(["development", "test", "production"]).default("development"),
  PORT: z.coerce.number().int().min(0).max(65535).default(3000),
  LOG_LEVEL: z.enum(["fatal", "error", "warn", "info", "debug", "trace", "silent"]).default("info"),
  DATABASE_URL: z.url(),
  TEST_DATABASE_URL: z.url().optional(),
  BETTER_AUTH_SECRET: z.string().min(32),
  BETTER_AUTH_URL: z.url(),
  /** Run background job workers in this process (Step 7.1). */
  WORKERS_ENABLED: z.enum(["true", "false"]).default("true"),
});

export interface ServerConfig {
  env: "development" | "test" | "production";
  port: number;
  logLevel: z.infer<typeof envSchema>["LOG_LEVEL"];
  databaseUrl: string;
  testDatabaseUrl: string | undefined;
  authSecret: string;
  authUrl: string;
  workersEnabled: boolean;
}

/** Validates the environment, throwing one error that lists every problem. */
export function loadConfig(env: Record<string, string | undefined>): ServerConfig {
  const result = envSchema.safeParse(env);
  if (!result.success) {
    const problems = result.error.issues.map((i) => `  ${i.path.join(".")}: ${i.message}`);
    throw new Error(`Invalid server environment:\n${problems.join("\n")}`);
  }
  const e = result.data;
  return {
    env: e.NODE_ENV,
    port: e.PORT,
    logLevel: e.LOG_LEVEL,
    databaseUrl: e.DATABASE_URL,
    testDatabaseUrl: e.TEST_DATABASE_URL,
    authSecret: e.BETTER_AUTH_SECRET,
    authUrl: e.BETTER_AUTH_URL,
    workersEnabled: e.WORKERS_ENABLED === "true",
  };
}