import { stripHeartbeatToken } from "../heartbeat.js";
import { HEARTBEAT_TOKEN, SILENT_REPLY_TOKEN } from "../tokens.js";
import type { ReplyPayload } from "../types.js";

export type NormalizeReplyOptions = {
  responsePrefix?: string;
  onHeartbeatStrip?: () => void;
  stripHeartbeat?: boolean;
  silentToken?: string;
};

export function normalizeReplyPayload(
  payload: ReplyPayload,
  opts: NormalizeReplyOptions = {},
): ReplyPayload | null {
  const hasMedia = Boolean(
    payload.mediaUrl || (payload.mediaUrls?.length ?? 0) > 0,
  );
  const trimmed = payload.text?.trim() ?? "";
  if (!trimmed && !hasMedia) return null;

  const silentToken = opts.silentToken ?? SILENT_REPLY_TOKEN;
  if (trimmed === silentToken && !hasMedia) return null;

  let text = payload.text ?? undefined;
  if (text && !trimmed) {
    // Keep empty text when media exists so media-only replies still send.
    text = "";
  }

  const shouldStripHeartbeat = opts.stripHeartbeat ?? true;
  if (shouldStripHeartbeat && text?.includes(HEARTBEAT_TOKEN)) {
    const stripped = stripHeartbeatToken(text, { mode: "message" });
    if (stripped.didStrip) opts.onHeartbeatStrip?.();
    if (stripped.shouldSkip && !hasMedia) return null;
    text = stripped.text;
  }

  if (
    opts.responsePrefix &&
    text &&
    text.trim() !== HEARTBEAT_TOKEN &&
    !text.startsWith(opts.responsePrefix)
  ) {
    text = `${opts.responsePrefix} ${text}`;
  }

  return { ...payload, text };
}