/**
 * 将 public/banner.mp4（或 banner.source.mp4）压成首屏 Hero 尺寸。
 * 用法：pnpm run optimize:banner
 * 可选：把未压缩母带重命名为 banner.source.mp4，脚本会优先读取它并写回 banner.mp4。
 */
import { execFileSync } from "node:child_process";
import fs from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";
import ffmpegPath from "ffmpeg-static";

const root = path.join(path.dirname(fileURLToPath(import.meta.url)), "..");
const publicDir = path.join(root, "public");
const sourceCandidates = [
  path.join(publicDir, "banner.source.mp4"),
  path.join(publicDir, "banner.mp4"),
];
const input = sourceCandidates.find((p) => fs.existsSync(p));

if (!input || !ffmpegPath) {
  console.error("缺少 banner.mp4 / banner.source.mp4 或 ffmpeg 二进制。");
  process.exit(1);
}

const outMp4 = path.join(publicDir, "banner.mp4");
const outWebm = path.join(publicDir, "banner.webm");
const tmpMp4 = path.join(publicDir, "banner.opt.mp4");

const scale = "scale=1920:-2";
const common = ["-y", "-i", input, "-an", "-vf", scale, "-pix_fmt", "yuv420p"];

console.log(`输入: ${input}`);

execFileSync(
  ffmpegPath,
  [
    ...common,
    "-c:v",
    "libx264",
    "-preset",
    "slow",
    "-crf",
    "28",
    "-movflags",
    "+faststart",
    tmpMp4,
  ],
  { stdio: "inherit" },
);

execFileSync(
  ffmpegPath,
  [
    ...common,
    "-c:v",
    "libvpx-vp9",
    "-crf",
    "35",
    "-b:v",
    "0",
    "-row-mt",
    "1",
    outWebm,
  ],
  { stdio: "inherit" },
);

fs.copyFileSync(tmpMp4, outMp4);
fs.unlinkSync(tmpMp4);

for (const f of [outMp4, outWebm]) {
  const kb = (fs.statSync(f).size / 1024).toFixed(1);
  console.log(`${path.basename(f)}: ${kb} KiB`);
}