import { createHash } from "crypto";

export type SignOptions = {
  apiAppId: string;
  apiSecret: string;
  timestamp?: string;
};

export type SignedRequest = {
  bodyString: string;
  headers: Record<string, string>;
};

export function stringifyBody(payload: unknown): string {
  return JSON.stringify(payload);
}

export function dreameSign(bodyString: string, timestamp: string, apiSecret: string): string {
  return createHash("md5").update(Buffer.from(bodyString + timestamp + apiSecret, "utf8")).digest("hex");
}

export function buildSignedRequest(payload: unknown, options: SignOptions): SignedRequest {
  const bodyString = stringifyBody(payload);
  const timestamp = options.timestamp ?? Date.now().toString();

  return {
    bodyString,
    headers: {
      "content-type": "application/json",
      "dreame-api-app-id": options.apiAppId,
      "dreame-api-timestamp": timestamp,
      "dreame-api-sign": dreameSign(bodyString, timestamp, options.apiSecret),
    },
  };
}