// 把预生成的解说语音（e2e/voice/clips.json）按字幕出现的真实时间点（narration.json）合成到视频。
// 因为 run.mjs 已让每步停留足够长，时间点本身不重叠，故直接按时间点放置即可保持声画同步。
import { execSync } from "child_process";
import fs from "fs";
import path from "path";
import { clean } from "./narration.mjs";

const DIR = path.resolve("e2e/videos");
const VIDEO_IN = path.join(DIR, "wenwumap-e2e.mp4");
const VIDEO_OUT = path.join(DIR, "wenwumap-e2e-voiced.mp4");

const sh = (cmd) => execSync(cmd, { stdio: ["ignore", "pipe", "pipe"] }).toString();
const durationOf = (f) =>
  parseFloat(sh(`ffprobe -v error -show_entries format=duration -of csv=p=0 "${f}"`).trim());

if (!fs.existsSync(VIDEO_IN)) {
  console.error("缺少视频：先 node e2e/run.mjs 并转码生成 wenwumap-e2e.mp4");
  process.exit(1);
}
const { narration } = JSON.parse(fs.readFileSync(path.join(DIR, "narration.json"), "utf-8"));
const clipsMap = JSON.parse(fs.readFileSync(path.resolve("e2e/voice/clips.json"), "utf-8"));

// 按字幕时间点匹配预生成语音
const clips = [];
for (const n of narration) {
  const key = clean(n.text);
  const c = clipsMap[key];
  if (!c) {
    console.warn(`× 缺少语音：${key.slice(0, 24)}…`);
    continue;
  }
  clips.push({ file: path.resolve(c.file), start: n.t, dur: c.dur });
  console.log(`✓ [${(n.t / 1000).toFixed(1)}s ${c.dur.toFixed(1)}s] ${key.slice(0, 26)}…`);
}
if (clips.length === 0) {
  console.error("无可用解说，请先运行 node e2e/gen-voice.mjs");
  process.exit(1);
}

// 视频不够长则冻结末帧补足
const videoDur = durationOf(VIDEO_IN);
const audioEnd = Math.max(...clips.map((c) => c.start / 1000 + c.dur)) + 0.6;
const pad = audioEnd - videoDur;

const inputs = clips.map((c) => `-i "${c.file}"`).join(" ");
const audioFilters = clips
  .map((c, i) => `[${i + 1}:a]adelay=${Math.round(c.start)}|${Math.round(c.start)}[a${i}]`)
  .join(";");
const mixIn = clips.map((_, i) => `[a${i}]`).join("");
const amix = `${mixIn}amix=inputs=${clips.length}:normalize=0[a]`;

let videoMap = "0:v";
let vcodec = "-c:v copy";
let vfilter = "";
if (pad > 0.3) {
  vfilter = `[0:v]tpad=stop_mode=clone:stop_duration=${pad.toFixed(2)}[v];`;
  videoMap = '"[v]"';
  vcodec = "-c:v libx264 -pix_fmt yuv420p";
}

const cmd =
  `ffmpeg -y -i "${VIDEO_IN}" ${inputs} ` +
  `-filter_complex "${vfilter}${audioFilters};${amix}" ` +
  `-map ${videoMap} -map "[a]" ${vcodec} -c:a aac -b:a 160k "${VIDEO_OUT}"`;

console.log(`视频 ${videoDur.toFixed(1)}s / 解说至 ${audioEnd.toFixed(1)}s${pad > 0.3 ? `（末帧补 ${pad.toFixed(1)}s）` : ""}`);
execSync(cmd, { stdio: "inherit" });
console.log(`完成：${VIDEO_OUT}`);