/**
 * Git diff preview helper — shells out to `git diff` over the workspace
 * roots and returns the combined output text. Mirrors
 * `apps/interfaces/tui/src/action/git.rs`.
 */
import { execSync } from "node:child_process";

/** Run `git diff` across the given workspace roots and return the output. */
export function gitDiffOutput(workspaceRoots: string[]): string {
  for (const root of workspaceRoots) {
    try {
      const out = execSync("git diff --stat && git diff", {
        cwd: root,
        encoding: "utf8",
        maxBuffer: 4 * 1024 * 1024,
        stdio: ["ignore", "pipe", "ignore"],
      });
      if (out.trim().length > 0) {
        return out;
      }
    } catch {
      // Not a git repo or git not available — continue to the next root.
    }
  }
  return "No diff available (not a git repository).";
}