import type { ProviderLimitsCacheEntry } from "@/lib/db/providerLimits";
import { sanitizeGrokBillingStatus } from "@/shared/utils/grokBilling";

const GROK_CLI_PROVIDER = "grok-cli";

type JsonRecord = Record<string, unknown>;

function isRecord(value: unknown): value is JsonRecord {
  return Boolean(value && typeof value === "object" && !Array.isArray(value));
}

function hasUsableCachedData(cache: ProviderLimitsCacheEntry | null | undefined): boolean {
  return Boolean(cache?.billing || (cache?.quotas && Object.keys(cache.quotas).length > 0));
}

export function toProviderLimitsCacheEntry(
  usage: JsonRecord,
  source: string,
  fetchedAt = new Date().toISOString()
): ProviderLimitsCacheEntry {
  const bankedResetCredits = Number(usage.bankedResetCredits);
  return {
    quotas: isRecord(usage.quotas) ? usage.quotas : null,
    plan: usage.plan ?? null,
    message: typeof usage.message === "string" ? usage.message : null,
    fetchedAt,
    source,
    bankedResetCredits: Number.isFinite(bankedResetCredits) ? bankedResetCredits : undefined,
    billing: sanitizeGrokBillingStatus(usage.billing),
  };
}

export function mergeProviderLimitsCacheEntry(
  provider: string,
  next: ProviderLimitsCacheEntry,
  previous: ProviderLimitsCacheEntry | null | undefined
): ProviderLimitsCacheEntry {
  if (!previous) return next;

  if (!next.quotas && next.message && hasUsableCachedData(previous)) {
    return previous;
  }

  if (provider !== GROK_CLI_PROVIDER) return next;

  const nextBilling = next.billing;
  const previousAutoTopUp = previous.billing?.autoTopUp;
  if (!nextBilling || nextBilling.autoTopUp.available || !previousAutoTopUp) return next;

  return {
    ...next,
    billing: {
      ...nextBilling,
      autoTopUp: previousAutoTopUp,
    },
  };
}