import { execSync } from "node:child_process";
import { readFile } from "node:fs/promises";

import { reactRouter } from "@react-router/dev/vite";
import tailwindcss from "@tailwindcss/vite";
import { defineConfig } from "vite";
import { parse } from "yaml";

import { headplaneDevServer } from "./runtime/vite-plugin";

const PROD_ENTRY = "./app/server/main.ts";
const DEV_ENTRY = "./app/server/app.ts";

const PREFIX = process.env.__INTERNAL_PREFIX || "/admin";
if (PREFIX.endsWith("/")) {
  throw new Error("Prefix must not end with a slash");
}

// Derive version: HEADPLANE_VERSION env > git describe > package.json
const isNext = process.env.IMAGE_TAG?.includes("next");
let VERSION: string;
if (process.env.HEADPLANE_VERSION) {
  VERSION = process.env.HEADPLANE_VERSION;
} else {
  try {
    const describe = execSync("git describe --tags", { encoding: "utf-8" })
      .trim()
      .replace(/^v/, "");
    const tag = execSync("git describe --tags --abbrev=0", { encoding: "utf-8" })
      .trim()
      .replace(/^v/, "");
    VERSION = describe === tag ? tag : `${tag}-dev+${describe.split("-").pop()}`;
  } catch {
    const pkg = await readFile("package.json", "utf-8");
    VERSION = JSON.parse(pkg).version;
  }
}

if (!VERSION) {
  throw new Error("Unable to determine version");
}

// Load the config without any environment variables (not needed here)
const config = await readFile("config.example.yaml", "utf-8");
const { server } = parse(config);

export default defineConfig(({ command, isSsrBuild }) => ({
  base: command === "build" ? `${PREFIX}/` : undefined,
  plugins: [
    headplaneDevServer({
      entry: DEV_ENTRY,
      basename: PREFIX,
      publicDir: new URL("./public", import.meta.url).pathname,
    }),
    reactRouter(),
    tailwindcss(),
  ],
  server: {
    host: server.host,
    port: server.port,
  },
  resolve: {
    tsconfigPaths: true,
  },
  build: {
    target: "baseline-widely-available",
    sourcemap: true,
    rollupOptions:
      command === "build"
        ? {
            // Override the SSR build entry so React Router emits the
            // production bootstrap (`app/server/main.ts`) as
            // `build/server/index.js`. It transitively imports the
            // SSR entry, which pulls in the React Router server build
            // via the virtual module `virtual:react-router/server-build`.
            input: isSsrBuild ? PROD_ENTRY : undefined,

            // Exclude WASM from the client since it fetches from the server
            external: isSsrBuild ? [] : [/\.wasm(\?url)?$/],
          }
        : undefined,
  },
  ssr: {
    noExternal: command === "build" ? true : undefined,
  },
  define: {
    __VERSION__: JSON.stringify(isNext ? `${VERSION}-next` : VERSION),
    __PREFIX__: JSON.stringify(PREFIX),
  },
}));