// Standard response envelope. Every /relay/* response (success and
// error both) goes through this so Recap clients can keep their
// credit-balance display accurate regardless of what happened.
//
// Shape: { result, credits_remaining, tier, credit_charged }

import { getOrCreateRow, computeRemaining } from "../credits.js";
import { getTierQuotas } from "../config.js";

// Build the envelope around a result object.
export async function envelope({
  result = null,
  installId,
  tier,
  creditCharged = 0,
}) {
  const quota = await getTierQuotas();
  const row = await getOrCreateRow(installId);
  // tier_snapshot on the row was just updated by commitCredit; if no
  // credit was committed (free reuse via job_id) it still reflects
  // the last-known tier for this install, which is fine.
  const balance = computeRemaining(row, quota);
  return {
    result,
    credits_remaining: balance.remaining, // null = unlimited (Max)
    tier,
    credit_charged: creditCharged,
  };
}

// Same shape but for error responses. The error reason goes in `error`
// alongside `result: null`. Clients should still update their balance
// display from `credits_remaining` so failed calls (which were
// refunded) reflect the unchanged balance.
export async function errorEnvelope({
  error,
  installId,
  tier = "core",
  statusHint = 500,
}) {
  let creditsRemaining = null;
  try {
    const quota = await getTierQuotas();
    const row = await getOrCreateRow(installId || "unknown");
    const balance = computeRemaining(row, quota);
    creditsRemaining = balance.remaining;
  } catch {}
  return {
    statusHint,
    body: {
      result: null,
      error: typeof error === "string" ? error : error?.message || "unknown_error",
      credits_remaining: creditsRemaining,
      tier,
      credit_charged: 0,
    },
  };
}