import { existsSync, readdirSync, statSync } from "node:fs";
import { resolve } from "node:path";
import { fileURLToPath, URL } from "node:url";
import type { Plugin } from "vite";
import { defineConfig } from "vitest/config";

const repoRoot = fileURLToPath(new URL("../..", import.meta.url)).replace(/\/+$/, "");

function repoPath(p: string): string {
  const abs = resolve(repoRoot, p.replace(/^\/+/, ""));
  if (abs !== repoRoot && !abs.startsWith(`${repoRoot}/`)) {
    throw new Error(`path outside repo root: ${p}`);
  }
  return abs;
}

function nengineFsPlugin(): Plugin {
  return {
    name: "nengine-fs",
    configureServer(server) {
      server.middlewares.use((req, res, next) => {
        if (req.url === "/" || req.url?.startsWith("/?")) {
          req.url = "/apps/dev/index.html";
          next();
          return;
        }
        const url = new URL(req.url ?? "/", "http://localhost");
        const target = url.searchParams.get("p");
        if (!target) {
          next();
          return;
        }
        let abs: string;
        try {
          abs = repoPath(target);
        } catch {
          res.statusCode = 404;
          res.end("bad path");
          return;
        }
        if (url.pathname === "/__nengine_fs/readdir") {
          if (!existsSync(abs)) {
            res.statusCode = 404;
            res.end("ENOENT");
            return;
          }
          const entries = readdirSync(abs, { withFileTypes: true });
          const body =
            url.searchParams.get("detailed") === "1"
              ? JSON.stringify(entries.map((e) => ({ name: e.name, isDirectory: e.isDirectory() })))
              : JSON.stringify(entries.map((e) => e.name));
          res.setHeader("content-type", "application/json; charset=utf-8");
          res.end(body);
          return;
        }
        if (url.pathname === "/__nengine_fs/stat") {
          if (!existsSync(abs)) {
            res.statusCode = 404;
            res.end("ENOENT");
            return;
          }
          res.setHeader("content-type", "application/json; charset=utf-8");
          res.end(JSON.stringify({ isDirectory: statSync(abs).isDirectory() }));
          return;
        }
        if (url.pathname === "/__nengine_fs/exists") {
          res.setHeader("content-type", "text/plain; charset=utf-8");
          res.end(existsSync(abs) ? "1" : "0");
          return;
        }
        next();
      });
    },
  };
}

export default defineConfig({
  root: repoRoot,
  plugins: [nengineFsPlugin()],
  resolve: {
    alias: {
      "@nengine/core": fileURLToPath(new URL("../../packages/core/src/index.ts", import.meta.url)),
      "@nengine/render": fileURLToPath(new URL("../../packages/render/src/index.ts", import.meta.url)),
      "node:fs/promises": fileURLToPath(new URL("./src/shim/fs-promises.ts", import.meta.url)),
      "node:fs": fileURLToPath(new URL("./src/shim/fs.ts", import.meta.url)),
      "node:path": fileURLToPath(new URL("./src/shim/path.ts", import.meta.url)),
      "node:url": fileURLToPath(new URL("./src/shim/url.ts", import.meta.url)),
    },
  },
  build: {
    outDir: "apps/dev/dist",
    emptyOutDir: true,
    rollupOptions: {
      input: fileURLToPath(new URL("./index.html", import.meta.url)),
    },
  },
  test: {
    include: ["apps/dev/src/**/*.test.ts"],
    environment: "node",
  },
});