import { defineConfig } from "@rsbuild/core";
import { pluginBabel } from "@rsbuild/plugin-babel";
import { pluginSolid } from "@rsbuild/plugin-solid";
import tailwindcss from "@tailwindcss/postcss";
import { BundleAnalyzerPlugin } from "webpack-bundle-analyzer";
import { statSync } from "node:fs";
import { join, resolve } from "node:path";

// The CLI content server (`npm run dev:cli`, i.e. `tttk serve ./content`) keeps
// port 3000. It serves the content directory at the URL *root*, so content
// assets are requested as root-relative paths (e.g. `/adventures/map.png`),
// not under `/content`.
const CLI_TARGET = "http://localhost:3000";
const CONTENT_DIR = resolve(process.cwd(), "content");

/**
 * True when a request targets a real file inside the content directory.
 *
 * Mirrors the CLI server's static handling: only files are served, so a
 * directory path falls through to the SPA fallback. Requests for content
 * assets must be proxied to the CLI; otherwise they reach
 * `historyApiFallback` and the browser receives `index.html` instead of the
 * asset (which is why images failed to render in dev).
 */
function isContentFile(pathname: string): boolean {
  // The web dev server owns its own bundled assets under /static/.
  if (pathname.startsWith("/static/")) return false;

  let relativePath: string;
  try {
    relativePath = decodeURIComponent(pathname).replace(/^\/+/, "");
  } catch {
    return false;
  }
  if (!relativePath) return false;

  try {
    return statSync(join(CONTENT_DIR, relativePath)).isFile();
  } catch {
    return false;
  }
}

export default defineConfig({
  plugins: [
    pluginBabel({
      include: /\.(?:jsx|tsx)$/,
    }),
    pluginSolid(),
  ],
  tools: {
    postcss: {
      postcssOptions: {
        plugins: [tailwindcss()],
      },
    },
    rspack: {
      resolve: {
        // Allow TypeScript sources to use explicit `.js` specifiers (required
        // by the CLI's NodeNext build) while the bundler resolves them to .ts.
        extensionAlias: {
          ".js": [".ts", ".tsx", ".js"],
        },
      },
      module: {
        rules: [
          {
            // Built-in doc entries are statically imported as strings
            test: /[\\/]doc-entries[\\/].*\.md$/,
            type: "asset/source",
          },
        ],
      },
      plugins: [
        process.env.ANALYZE ? new BundleAnalyzerPlugin() : undefined,
      ].filter(Boolean),
    },
  },
  html: {
    template: "./src/index.html",
  },
  source: {
    entry: {
      index: "./src/main.tsx",
    },
  },
  server: {
    // Dev web server runs on its own port; the CLI content server keeps
    // port 3000 (see the proxy targets below).
    port: 5173,
    proxy: [
      {
        // Content API requests served by the CLI dev server (npm run dev:cli).
        context: [
          "/__CONTENT_INDEX.json",
          "/__COMPLETIONS.json",
          "/__CONTENT_REGISTRY.json",
          "/.ttrpg",
        ],
        target: CLI_TARGET,
      },
      {
        // Content assets (images, css, csv, …) live at the URL root on the CLI
        // server, so forward any request that maps to a real file under
        // content/ instead of letting it hit the SPA fallback.
        context: (pathname: string) => isContentFile(pathname),
        target: CLI_TARGET,
      },
    ],
    historyApiFallback: true,
  },
  output: {
    distPath: {
      root: "dist/web",
    },
  },
});