import { configLoader } from "../../src/shared/config";
import { compilePolicies, normalizeTarget } from "../guardrails/rules";

/**
 * Predicate over result paths for the search tools: true when the path may be
 * shown to the agent. Filters files matched by enabled noAccess policy rules
 * so protected contents (e.g. .env in a workspace root) cannot enter the
 * agent's context through our own tools.
 */
export function createNoAccessFilter(cwd: string): (path: string) => boolean {
  const config = configLoader.getConfig();
  if (!config.enabled || !config.features.policies) return () => true;

  const policies = compilePolicies(config.policies.rules).filter(
    (policy) => policy.protection === "noAccess",
  );
  return (path) => {
    const normalized = normalizeTarget(path, cwd);
    return !policies.some(
      (policy) =>
        policy.patterns.some((pattern) => pattern.test(normalized)) &&
        !policy.allowedPatterns.some((pattern) => pattern.test(normalized)),
    );
  };
}

/**
 * Extract the file path prefix of a ripgrep output line ("path:match"),
 * tolerating Windows drive letters ("C:\repo\file.ts:match").
 */
export function rgLinePath(line: string): string {
  const searchFrom = /^[A-Za-z]:[\\/]/.test(line) ? 2 : 0;
  const idx = line.indexOf(":", searchFrom);
  return idx === -1 ? line : line.slice(0, idx);
}

/**
 * Drop ripgrep output lines whose file is protected by a noAccess policy.
 * Returns the kept text and how many lines were hidden.
 */
export function filterRipgrepOutput(
  output: string,
  allowPath: (path: string) => boolean,
): { text: string; hidden: number } {
  const lines = output.split("\n");
  const kept = lines.filter((line) => !line || allowPath(rgLinePath(line)));
  return { text: kept.join("\n"), hidden: lines.length - kept.length };
}