import { OUTPUT_DEFAULTS } from "./types.js";
import { redactSecrets } from "./redaction.js";

export interface TruncateResult { truncated: boolean; text: string }

export function truncateOutput(text: string, maxBytes: number = OUTPUT_DEFAULTS.maxBytes, maxLines: number = OUTPUT_DEFAULTS.maxLines): TruncateResult {
  const lines = text.split(/\r?\n/);
  let bounded = lines.length > maxLines ? `${lines.slice(0, maxLines).join("\n")}\n[TRUNCATED:lines ${lines.length - maxLines}]` : text;
  const bytes = Buffer.byteLength(bounded, "utf8");
  if (bytes <= maxBytes) return { truncated: bounded !== text, text: bounded };
  let end = Math.max(0, maxBytes - 64);
  while (Buffer.byteLength(bounded.slice(0, end), "utf8") > maxBytes - 64 && end > 0) end -= 32;
  bounded = `${bounded.slice(0, end)}\n[TRUNCATED:bytes ${bytes - end}]`;
  return { truncated: true, text: bounded };
}

export function safeToolText(text: string, maxBytes = OUTPUT_DEFAULTS.maxBytes): { text: string; truncated: boolean; redacted: boolean } {
  const redacted = redactSecrets(text);
  const truncated = truncateOutput(redacted.text, maxBytes);
  return { text: truncated.text, truncated: truncated.truncated, redacted: redacted.redacted };
}