import path from "node:path";
import { readFile, writeFile, mkdir, rename, rm } from "node:fs/promises";
import { createHash, randomUUID } from "node:crypto";
import { execFile } from "node:child_process";
import { promisify } from "node:util";
import { captionFont } from "./fonts";
const pending = new Map<string, Promise<string>>();
const sha = (data: Uint8Array) => createHash("sha256").update(data).digest("hex");
export function captionFontFile(id: string): Promise<string> {
  const font = captionFont(id);
  if (!font) return Promise.reject(Error("未知字幕字体"));
  if (!font.url)
    return Promise.resolve(
      path.join(
        process.env.SMART_EDIT_FONTS_DIR || path.resolve("public/fonts/smart-edit"),
        font.file,
      ),
    );
  if (pending.has(id)) return pending.get(id)!;
  const work = (async () => {
    const root = path.resolve(
      process.env.SMART_EDIT_FONT_CACHE_DIR || ".cache/smart-edit-fonts",
    );
    await mkdir(root, { recursive: true });
    const output = path.join(root, font.file);
    try {
      const data = await readFile(output);
      if (font.preparedSha256 && sha(data) === font.preparedSha256) return output;
    } catch {}
    if (pending.size > 4) throw Error("字体正在加载，请稍后重试");
    const source = new URL(font.url!);
    if (
      source.protocol !== "https:" ||
      !["fonts.gstatic.com", "fonts.gstatic.cn", "libtv-res.liblib.art"].includes(
        source.hostname,
      )
    )
      throw Error("字体来源无效");
    const response = await fetch(source, {
      signal: AbortSignal.timeout(60000),
      redirect: "error",
      cache: "no-store",
    });
    if (!response.ok || Number(response.headers.get("content-length")) > 40 * 1024 * 1024)
      throw Error("字体下载失败");
    const reader = response.body!.getReader(),
      chunks: Uint8Array[] = [];
    let bytes = 0;
    try {
      while (true) {
        const { done, value } = await reader.read();
        if (done) break;
        bytes += value.length;
        if (bytes > 40 * 1024 * 1024) throw Error("字体文件过大");
        chunks.push(value);
      }
    } finally {
      await reader.cancel();
    }
    const data = Buffer.concat(chunks);
    if (!font.sha256 || sha(data) !== font.sha256)
      throw Error("字体资源校验失败，请更新字体目录");
    const temp = path.join(root, randomUUID()),
      prepared = temp + ".ttf";
    try {
      await writeFile(temp, data);
      await promisify(execFile)(
        process.env.SMART_EDIT_FONT_PYTHON || process.env.SMART_EDIT_PYTHON || "python3",
        [
          process.env.SMART_EDIT_FONT_SCRIPT || path.resolve("services/smart-edit/font.py"),
          temp,
          prepared,
          font.family,
        ],
        { timeout: 120000, maxBuffer: 512 * 1024 },
      );
      if (sha(await readFile(prepared)) !== font.preparedSha256)
        throw Error("字体处理版本不一致，请安装指定字体依赖");
      await rename(prepared, output);
      return output;
    } finally {
      await rm(temp, { force: true });
      await rm(prepared, { force: true });
    }
  })().finally(() => pending.delete(id));
  pending.set(id, work);
  return work;
}