import { defineConfig } from "vite-plus";
import react from "@vitejs/plugin-react";
import { stat } from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";

const rootDir = path.dirname(fileURLToPath(import.meta.url));
const imageRootDir = path.resolve(rootDir, "img");
const imageFallbackBase = "https://ski.aarongutierrez.com";

const fileExists = async (filename: string): Promise<boolean> => {
  try {
    await stat(filename);
    return true;
  } catch {
    return false;
  }
};

const imageFallbackMiddleware = async (
  req: { method?: string; url?: string },
  res: { statusCode: number; setHeader: (name: string, value: string) => void; end: () => void },
  next: () => void,
): Promise<void> => {
  if ((req.method !== "GET" && req.method !== "HEAD") || !req.url) {
    next();
    return;
  }

  const requestUrl = new URL(req.url, "http://localhost");
  const pathname = decodeURIComponent(requestUrl.pathname);
  if (!pathname.startsWith("/img/")) {
    next();
    return;
  }

  const relativePath = pathname.slice(1);
  const localFile = path.resolve(rootDir, relativePath);
  const relativeToImageRoot = path.relative(imageRootDir, localFile);
  const isWithinImageRoot =
    relativeToImageRoot !== "" &&
    relativeToImageRoot !== ".." &&
    !relativeToImageRoot.startsWith(`..${path.sep}`) &&
    !path.isAbsolute(relativeToImageRoot);

  if (!isWithinImageRoot || (await fileExists(localFile))) {
    next();
    return;
  }

  const fallbackUrl = new URL(pathname, imageFallbackBase);
  fallbackUrl.search = requestUrl.search;

  res.statusCode = 302;
  res.setHeader("Location", fallbackUrl.toString());
  res.end();
};

export default defineConfig({
  staged: {
    "*": "vp check --fix",
  },
  fmt: {},
  plugins: [
    react({
      babel: {
        // React Compiler must run first in the Babel pipeline.
        plugins: ["babel-plugin-react-compiler"],
      },
    }),
    {
      // Rolldown-vite's JSON HMR logs an update but doesn't reload the browser.
      // Force a full reload when data.json changes.
      name: "reload-data-json",
      handleHotUpdate({ file, server }) {
        if (file.endsWith("/data.json")) {
          server.ws.send({ type: "full-reload" });
          return [];
        }
      },
    },
    {
      name: "image-fallback-to-production",
      configureServer(server) {
        server.middlewares.use(imageFallbackMiddleware);
      },
      configurePreviewServer(server) {
        server.middlewares.use(imageFallbackMiddleware);
      },
    },
  ],
  resolve: {
    alias: {
      "@": path.resolve(rootDir, "src"),
    },
  },
});