import express from "express";
import ffmpeg from "fluent-ffmpeg";
import { PassThrough } from "stream";
import NodeCache from "node-cache";

const app = express();
const PORT = process.env.PORT || 3100;

const thumbnailCache = new NodeCache({
  stdTTL: 3600,
  checkperiod: 600,
  useClones: false
});

app.get("/thumbnail", (req, res) => {
  const videoUrl = req.query.url?.trim();

  if (!videoUrl) {
    return res.status(400).json({ error: "Missing 'url' query parameter" });
  }

  const cachedImage = thumbnailCache.get(videoUrl);
  if (cachedImage) {
    res.setHeader("Content-Type", "image/jpeg");
    res.setHeader("Cache-Control", "public, max-age=86400");
    return res.send(cachedImage);
  }

  try {
    const passthrough = new PassThrough();
    let imageBuffer = Buffer.alloc(0);

    passthrough.on("data", (chunk) => {
      imageBuffer = Buffer.concat([imageBuffer, chunk]);
    });

    passthrough.on("end", () => {
      if (imageBuffer.length > 0) {
        thumbnailCache.set(videoUrl, imageBuffer);
      }
    });

    ffmpeg(videoUrl)
      .seekInput(1)
      .frames(1)
      .format("image2")
      .outputOptions("-vcodec", "mjpeg")
      .on("error", (err) => {
        console.error("ffmpeg error:", err.message);
        if (!res.headersSent) {
          res.status(500).json({ error: "Failed to generate thumbnail" });
        }
      })
      .pipe(passthrough, { end: true });

    res.setHeader("Content-Type", "image/jpeg");
    res.setHeader("Cache-Control", "public, max-age=86400");

    passthrough.pipe(res);

  } catch (err) {
    console.error("Error:", err);
    if (!res.headersSent) {
      res.status(500).json({ error: "Failed to process video" });
    }
  }
});

app.get("/health", (_req, res) => {
  res.json({ status: "ok" });
});

app.listen(PORT, () => {
  console.log(`Video thumbnail service running on port ${PORT}`);
});