import { GitClient } from "./git-client.ts";

/** 单条历史主题的最大保留 Unicode 字符数。 */
const MAX_SUBJECT_CHARS = 200;

/* oxlint-disable no-control-regex -- 该正则用于清除控制字符、行分隔符与双向文本控制符 */
const UNSAFE_SUBJECT_CHARACTERS =
  /[\u0000-\u001F\u007F-\u009F\u2028\u2029\u202A-\u202E\u2066-\u2069]/gu;
/* oxlint-enable no-control-regex */

/** 清理并按 Unicode 字符截断一条提交主题。 */
function sanitizeSubject(subject: string): string {
  const cleaned = subject.replace(UNSAFE_SUBJECT_CHARACTERS, " ").trim();
  const characters = Array.from(cleaned);
  if (characters.length <= MAX_SUBJECT_CHARS) {
    return cleaned;
  }
  return `${characters.slice(0, MAX_SUBJECT_CHARS - 1).join("")}…`;
}

/**
 * 单次读取最近提交主题；历史不可用时静默降级，明确的外部取消仍向上传播。
 */
export async function collectRecentCommitSubjects(
  git: GitClient,
  cwd: string,
  count: number,
  signal?: AbortSignal,
): Promise<string[]> {
  if (count <= 0) {
    return [];
  }

  try {
    const result = await git.run(
      ["log", "--no-show-signature", "--format=%s", "-n", String(count)],
      {
        cwd,
        signal,
        acceptedExitCodes: [0, 128],
      },
    );
    if (result.code !== 0) {
      return [];
    }

    return result.stdout
      .split("\n")
      .map(sanitizeSubject)
      .filter((subject) => subject.length > 0)
      .slice(0, count);
  } catch (error) {
    if (signal?.aborted) {
      throw error;
    }
    return [];
  }
}