import path from "node:path";
import { readFile } from "node:fs/promises";
import { writeFileAtomic } from "../lib/jsonFile-server";
import type { Paths } from "../lib/paths";

export function failedTranscriptionsFile(paths: Paths, slug: string): string {
  return path.join(paths.channelsDir, slug, "failed-transcriptions");
}

export async function loadFailedTranscriptions(
  paths: Paths,
  slug: string,
): Promise<string[]> {
  try {
    const raw = await readFile(failedTranscriptionsFile(paths, slug), "utf8");
    return raw.split("\n").filter(Boolean);
  } catch {
    return [];
  }
}

export async function pruneFailedTranscriptions(
  failureListFile: string,
  idsToRemove: Set<string>,
): Promise<{ remaining: number; pruned: number }> {
  let raw: string;
  try {
    raw = await readFile(failureListFile, "utf8");
  } catch {
    return { remaining: 0, pruned: 0 };
  }
  const original = raw.split("\n").filter(Boolean);
  const filtered = original.filter((id) => !idsToRemove.has(id));
  await writeFileAtomic(
    failureListFile,
    filtered.length ? filtered.join("\n") + "\n" : "",
  );
  return {
    remaining: filtered.length,
    pruned: original.length - filtered.length,
  };
}

export async function clearFailedTranscriptions(
  paths: Paths,
  slug: string,
): Promise<{ cleared: number }> {
  const file = failedTranscriptionsFile(paths, slug);
  let cleared = 0;
  try {
    const raw = await readFile(file, "utf8");
    cleared = raw.split("\n").filter(Boolean).length;
  } catch {
    return { cleared: 0 };
  }
  await writeFileAtomic(file, "");
  return { cleared };
}