import fs from "node:fs";
import type { IncomingMessage, ServerResponse } from "node:http";
import path from "node:path";
import type { Connect, Plugin, ViteDevServer } from "vite";
import sqlite3 from "better-sqlite3";
import { Tokenizer } from "./tokenizer";

export function mp3DownloaderPlugin(): Plugin {
  return {
    name: "mp3-downloader",
    async configureServer(server: ViteDevServer) {
      const db = sqlite3(".sentence-mp3.db");
      db.exec(/* sql */ `
        CREATE TABLE IF NOT EXISTS sentence (
          id        INTEGER NOT NULL PRIMARY KEY,
          ko        TEXT NOT NULL,
          original  TEXT NOT NULL,
          [url]     TEXT NOT NULL
        );

        CREATE UNIQUE INDEX IF NOT EXISTS idx_sentence_u_url ON sentence([url]);

        CREATE VIRTUAL TABLE IF NOT EXISTS sentence_fts USING fts5 (
          ko,
          original  UNINDEXED,
          [url]     UNINDEXED,
          content='sentence',
          content_rowid='id'
        );

        -- Triggers to keep the FTS index up to date.
        CREATE TRIGGER IF NOT EXISTS t1_ai AFTER INSERT ON sentence BEGIN
          INSERT INTO sentence_fts(rowid, ko) VALUES (new.id, new.ko);
        END;
        CREATE TRIGGER IF NOT EXISTS t1_ad AFTER DELETE ON sentence BEGIN
          INSERT INTO sentence_fts(fts_idx, rowid, ko) VALUES('delete', old.id, old.ko);
        END;
        CREATE TRIGGER IF NOT EXISTS t1_au AFTER UPDATE ON sentence BEGIN
          INSERT INTO sentence_fts(fts_idx, rowid, ko) VALUES('delete', old.id, old.ko);
          INSERT INTO sentence_fts(rowid, ko) VALUES (new.id, new.ko);
        END;
      `);

      // Vite dev server middlewares are connect-style: (req, res, next)
      server.middlewares.use(async (req, res, next) => {
        const reqUrl = req.url;
        if (!reqUrl || !reqUrl.startsWith("/uploads/")) return next();

        const url = new URL(reqUrl, "http://localhost");
        if (!url.pathname.endsWith(".mp3")) return next();

        try {
          await mp3Downloader(db, await Tokenizer.init(), url, res, next);
        } catch (e) {
          console.error(e, reqUrl);
          next();
        }
      });
    },
  };
}

async function mp3Downloader(
  db: ReturnType<typeof sqlite3>,
  tokenizer: Tokenizer,
  url: URL,
  res: ServerResponse<IncomingMessage>,
  next: Connect.NextFunction,
) {
  const downloadURL = new URL(
    `https://www.howtostudykorean.com/wp-content${url.pathname}`,
  );

  const text = url.searchParams.get("text");
  if (text) {
    db.prepare(
      "INSERT OR IGNORE INTO sentence ([url], ko, original) VALUES (?, ?, ?)",
    ).run(downloadURL.href, tokenizer.normalize(text), text);
  }

  const segs = url.pathname.slice(1).split("/");
  const filename = segs.pop()!;
  const saveroot = "docs/public";
  const saveto = path.join(saveroot, ...segs, filename);

  if (fs.existsSync(saveto)) {
    return next();
  }

  fs.mkdirSync(path.join(saveroot, ...segs), { recursive: true });

  const r = await fetch(downloadURL, { redirect: "follow" });
  if (!r.ok) {
    console.error(r);
    return next();
  }

  fs.writeFileSync(saveto, Buffer.from(await r.arrayBuffer()));
  // console.log(fs.statSync(saveto));
  console.log("saved to", saveto);

  res.setHeader("Content-Type", "audio/mpeg");
  fs.createReadStream(saveto).pipe(res);
}