context

import { type ChatMessage, type PromptPreprocessorController } from "@lmstudio/sdk";
import { execSync } from "child_process";

// PromptPreprocessorController has no getPluginConfig.
// Clipboard injection uses a fixed 8000-char cap (mirrors config default).
// To disable: remove context.withPromptPreprocessor in index.ts and rebuild.
const MAX_CLIPBOARD_CHARS = 8000;

export async function promptPreprocessor(
  ctl: PromptPreprocessorController,
  userMessage: ChatMessage,
): Promise<string | ChatMessage> {
  // Only inject on first message of a session
  const history = await ctl.pullHistory();
  if (history.length !== 0) return userMessage;
  if (process.platform !== "darwin") return userMessage;

  try {
    let clip = execSync("pbpaste", { timeout: 3000, encoding: "utf-8" }).trim();
    if (!clip) return userMessage;
    if (clip.length > MAX_CLIPBOARD_CHARS) {
      clip = clip.slice(0, MAX_CLIPBOARD_CHARS) + " [truncated]";
    }
    const injection = `[Clipboard contents:\n${clip}\n]`;
    return `${injection}\n\n${userMessage.getText()}`;
  } catch {
    return userMessage;
  }
}