import postgres from "postgres";

// Lazy, env-guarded Postgres client. Works with Vercel Postgres (POSTGRES_URL)
// or any DATABASE_URL. Returns null when no DB is configured so the app still
// builds/runs (with in-memory fallback) before storage is provisioned.
let _sql: ReturnType<typeof postgres> | null = null;

export function dbUrl(): string | undefined {
  return process.env.DATABASE_URL || process.env.POSTGRES_URL || process.env.POSTGRES_PRISMA_URL;
}

export function hasDb(): boolean {
  return Boolean(dbUrl());
}

/**
 * P014 fix: `ssl` used to be hardcoded to `"require"` unconditionally. That
 * is the right default for every REAL deployment target this app has
 * (Vercel Postgres, managed Postgres providers), but it made `compose.dev.yaml`'s
 * local Postgres container -- which speaks plain, non-TLS Postgres -- and
 * ANY other throwaway/local Postgres (e.g. a restore-drill target) silently
 * unreachable via this function, contradicting that file's own doc comment
 * ("local-only Postgres for developers who want real persistence") and its
 * own "UNVERIFIED... not smoke-tested end to end" caveat -- this is
 * precisely why it was never smoke-tested: it could not have worked.
 * `DATABASE_SSL` is opt-in-to-disable ONLY; absence (the default, matching
 * every existing deployment's actual env) keeps the exact prior behavior.
 */
export function sslMode(): "require" | false {
  const raw = process.env.DATABASE_SSL?.trim().toLowerCase();
  if (raw === "false" || raw === "disable" || raw === "off" || raw === "0") return false;
  return "require";
}

export function getSql() {
  const url = dbUrl();
  if (!url) return null;
  if (!_sql) {
    _sql = postgres(url, { prepare: false, idle_timeout: 20, max: 5, ssl: sslMode() });
  }
  return _sql;
}