import "server-only";
import { createHash, randomBytes } from "node:crypto";

export const CART_CAPABILITY_COOKIE = "salix_cart_v1";
export const CART_CAPABILITY_MAX_AGE_SECONDS = 60 * 60 * 24 * 30;

const capabilityPattern = /^[A-Za-z0-9_-]{43}$/u;

export function createCartCapability(): string {
  return randomBytes(32).toString("base64url");
}

export function parseCartCapability(value: string | undefined): string | null {
  return value !== undefined && capabilityPattern.test(value) ? value : null;
}

export function hashCartCapability(capability: string): string {
  const parsed = parseCartCapability(capability);
  if (parsed === null) throw new TypeError("Invalid cart capability.");
  return createHash("sha256").update(parsed, "utf8").digest("hex");
}

export function hashCommerceRequest(value: unknown): string {
  return createHash("sha256")
    .update(JSON.stringify(canonicalize(value)), "utf8")
    .digest("hex");
}

function canonicalize(value: unknown): unknown {
  if (Array.isArray(value)) return value.map(canonicalize);
  if (value !== null && typeof value === "object") {
    return Object.fromEntries(
      Object.entries(value)
        .sort(([left], [right]) => left.localeCompare(right))
        .map(([key, child]) => [key, canonicalize(child)]),
    );
  }
  if (
    value === null ||
    typeof value === "boolean" ||
    typeof value === "number" ||
    typeof value === "string"
  ) {
    return value;
  }
  throw new TypeError("Commerce request contains a non-JSON value.");
}