import fs from "node:fs";
import { IncomingMessage, ServerResponse } from "node:http";
import https from "node:https";
import path from "node:path";
import { Connect, Plugin, ViteDevServer } from "vite";
import { defineConfig, MarkdownOptions } from "vitepress";

const host = process.env.TAURI_DEV_HOST;

// https://vitepress.dev/reference/site-config
export default defineConfig({
  title: "ko-grammar",
  description: "Korean grammar edited",
  lang: "ko-KR",
  themeConfig: {
    socialLinks: [
      { icon: "github", link: "https://git.polv.cc/polv/ko-grammar" },
    ],
    outline: {
      level: "deep",
    },
  },
  markdown: {
    config(md) {
      const mdInline: MarkdownOptions["config"] = (md) => {
        const className = "md";

        md.core.ruler.after("inline", "inline_class_md", (state: any) => {
          const tokens = state.tokens;
          const tagPattern = new RegExp(
            `class=(?:\"|')([^\"']*\\b${escapeReg(className)}\\b[^\"']*)(?:\"|')`,
            "i",
          );

          for (let i = 0; i < tokens.length; i++) {
            const t = tokens[i];
            if (!/^(html_inline|html_block)$/.test(t.type)) continue;
            const html = t.content;
            // match tags with class including the target class, capture inner content (non-greedy)
            const pattern = new RegExp(
              `<([a-zA-Z0-9-]+)(\\b[^>]*)?>([\\s\\S]*?)<\\/\\1>`,
              "gi",
            );
            let lastIndex = 0;
            let out = "";
            let m;
            while ((m = pattern.exec(html)) !== null) {
              const [full, tagName, attrs = "", inner] = m;
              const idx = m.index;
              if (idx > lastIndex) out += html.slice(lastIndex, idx);
              if (tagPattern.test(attrs)) {
                // render inner as inline markdown
                out += `<${tagName}${attrs}>${md.renderInline(inner)}</${tagName}>`;
              } else {
                out += full;
              }
              lastIndex = idx + full.length;
            }
            if (lastIndex === 0) continue;
            if (lastIndex < html.length) out += html.slice(lastIndex);
            t.content = out;
          }
        });

        function escapeReg(s: string) {
          return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
        }
      };
      md.use(mdInline);
    },
  },
  vite: {
    plugins: [audioProxyPlugin() as any],
    envDir: process.cwd(),
    ssr: {
      noExternal: [],
      external: ["pdfjs-dist"], // don't bundle it for SSR — leave it browser-only
    },
    clearScreen: false,
    server: {
      /**
       * Allow Windows Firewall via Admin PowerShell with
       *
       * ```
       * New-NetFirewallRule -DisplayName "Vitepress Server" -Direction Inbound -Protocol TCP -LocalPort 5173 -Action Allow
       * ```
       */
      port: 5173,
      strictPort: true,
      host: host || false,
      watch: {
        // tell vite to ignore watching `src-tauri`
        ignored: ["**/src-tauri/**"],
      },
      hmr: host
        ? {
            protocol: "ws",
            host,
            port: 5174,
          }
        : undefined,
    },
    // Env variables starting with the item of `envPrefix` will be exposed in tauri's source code through `import.meta.env`.
    envPrefix: ["VITE_", "TAURI_ENV_*"],
    build: {
      // Tauri uses Chromium on Windows and WebKit on macOS and Linux
      target:
        process.env.TAURI_ENV_PLATFORM == "windows" ? "chrome105" : "safari13",
      // don't minify for debug builds
      minify: !process.env.TAURI_ENV_DEBUG ? "esbuild" : false,
      // produce sourcemaps for debug builds
      sourcemap: !!process.env.TAURI_ENV_DEBUG,
    },
  },
});

function audioProxyPlugin(): Plugin {
  return {
    name: "audio-proxy",
    configureServer(server: ViteDevServer) {
      // Vite dev server middlewares are connect-style: (req, res, next)
      server.middlewares.use((req, res, next) => {
        const reqUrl = req.url;
        if (!reqUrl || !reqUrl.startsWith("/uploads/")) return next();
        if (!reqUrl.endsWith(".mp3")) return next();

        proxyAudio(req, res, next);
      });
    },
  };
}

function proxyAudio(
  req: Connect.IncomingMessage,
  res: ServerResponse<IncomingMessage>,
  next: Connect.NextFunction,
) {
  const url = new URL(
    `https://www.howtostudykorean.com/wp-content/uploads${req.url}`,
  );

  // Forward common headers (important for Range streaming)
  const headers = {
    ...req.headers,
    host: url.host,
    range: req.headers["range"],
  };

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

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

  fs.mkdirSync(path.join(saveroot, ...segs), { recursive: true });
  const fileStream = fs.createWriteStream(savetemp);

  const upstreamReq = https.request(
    {
      protocol: url.protocol,
      hostname: url.hostname,
      port: url.port || undefined,
      path: url.pathname + url.search,
      method: req.method,
      headers,
    },
    (upstreamRes) => {
      // Pass status (200 or 206 for Range)
      res.writeHead(upstreamRes.statusCode || 200, upstreamRes.headers);

      // Stream through
      upstreamRes.pipe(res);
      upstreamRes.pipe(fileStream);
    },
  );

  fileStream.on("finish", () => {
    fs.renameSync(savetemp, saveto);
    console.log("saved to", saveto);
  });

  fileStream.on("error", (err) => {
    console.error("write failed:", err);
  });

  upstreamReq.on("error", (err) => {
    res.statusCode = 502;
    res.end(`Bad Gateway: ${err.message}`);
  });

  req.pipe(upstreamReq);
}