import { parsePatchFiles } from "@pierre/diffs";

export interface TurnDiffFileSummary {
  readonly path: string;
  readonly additions: number;
  readonly deletions: number;
}

export function parseTurnDiffFilesFromUnifiedDiff(
  diff: string,
): ReadonlyArray<TurnDiffFileSummary> {
  const normalized = diff.replace(/\r\n/g, "\n").trim();
  if (normalized.length === 0) {
    return [];
  }

  const parsedPatches = parsePatchFiles(normalized);
  const files = parsedPatches.flatMap((patch) =>
    patch.files.map((file) => ({
      path: file.name,
      additions: file.hunks.reduce((total, hunk) => total + hunk.additionLines, 0),
      deletions: file.hunks.reduce((total, hunk) => total + hunk.deletionLines, 0),
    })),
  );

  return files.toSorted((left, right) => left.path.localeCompare(right.path));
}
