import * as fs from "fs-extra";
import * as path from "path";
import type { RollupOutput } from "rollup";
import type { ResolvedConfig } from "vite";
import { build as viteBuild } from "vite";
import { CLIENT_PATH } from "../constants";

export async function ssrBuild(
  viteConfig: ResolvedConfig,
  ssrConfig: any,
  argv: any
) {
  // ssr build should not use hash router
  // if (viteOptions?.define?.['__HASH_ROUTER__'])
  //   viteOptions!.define!['__HASH_ROUTER__'] = false
  const root = viteConfig.root;
  let outDir = viteConfig.build?.outDir ?? "dist";
  outDir = path.resolve(root, outDir);
  await fs.emptyDir(outDir);

  const ssrOutDir = path.join(outDir, "ssr-tmp");
  const clientOutDir = path.join(outDir, "client-tmp");

  console.log("\n\npreparing vite pages ssr bundle...");
  const ssrOutput = await viteBuild({
    root,
    configFile: viteConfig.configFile,
    build: {
      ssr: true,
      cssCodeSplit: false,
      rollupOptions: {
        input: path.join(CLIENT_PATH, "ssr", "serverRender.js"),
        preserveEntrySignatures: "allow-extension",
        output: {
          format: "cjs",
          exports: "named",
          entryFileNames: "[name].js",
        },
      },
      outDir: ssrOutDir,
      minify: false,
    },
    // @ts-ignore
    ssr: {
      external: ["react", "react-router-dom", "react-dom", "react-dom/server"],
      noExternal: [
        // TODO: remove this
        "vite-pages-theme-basic",
        "vite-plugin-react18-pages",
        "vite-plugin-react18-pages/client",
      ],
    },
  });

  console.log("\n\nrendering html...");

  const { renderToString, ssrData } = require(path.join(
    ssrOutDir,
    "serverRender.js"
  ));

  const pagePaths = Object.keys(ssrData);

  console.log("\n\npreparing vite pages client bundle...");
  const _clientResult = await viteBuild({
    root,
    configFile: viteConfig.configFile,
    build: {
      cssCodeSplit: false,
      rollupOptions: {
        input: path.join(CLIENT_PATH, "ssr", "clientRender.js"),
        preserveEntrySignatures: "allow-extension",
      },
      assetsDir: "assets",
      outDir: clientOutDir,
    },
  });
  let clientResult: RollupOutput;
  if (Array.isArray(_clientResult)) {
    if (_clientResult.length !== 1)
      throw new Error(`expect viteBuild to have only one BuildResult`);
    clientResult = _clientResult[0];
  } else {
    clientResult = _clientResult as RollupOutput;
  }

  const entryChunk = (() => {
    const _entryChunks = clientResult.output.filter((chunkOrAsset) => {
      return chunkOrAsset.type === "chunk" && chunkOrAsset.isEntry;
    });
    if (_entryChunks.length !== 1) {
      throw new Error(`Expect one entryChunk. Got ${_entryChunks.length}.`);
    }
    return _entryChunks[0];
  })();

  const cssChunks = clientResult.output.filter((chunk) => {
    return chunk.type === "asset" && chunk.fileName.endsWith(".css");
  });

  const basePath = viteConfig.base ?? "/";

  const htmlCode = await fs.readFile(path.join(root, "index.html"), "utf-8");
  const RootElementInjectPoint = '<div id="root"></div>';
  if (!htmlCode.includes(RootElementInjectPoint)) {
    throw new Error(
      `Your index.html should contain the RootElementInjectPoint: "${RootElementInjectPoint}" (it must appear exactly as-is)`
    );
  }
  const EntryModuleInjectPoint =
    '<script type="module" src="/@pages-infra/main.js"></script>';
  if (!htmlCode.includes(EntryModuleInjectPoint)) {
    throw new Error(
      `Your index.html should contain EntryModuleInjectPoint: "${EntryModuleInjectPoint}" (it must appear exactly as-is)`
    );
  }
  const CSSInjectPoint = "</head>";
  if (!htmlCode.includes(CSSInjectPoint)) {
    throw new Error(
      `Your index.html should contain CSSInjectPoint: "${CSSInjectPoint}" (it must appear exactly as-is)`
    );
  }

  await Promise.all(
    pagePaths.map(async (pagePath) => {
      // currently not support pages with path params
      // .e.g /users/:userId
      if (pagePath.match(/\/:\w/)) return;
      const html = renderHTML(pagePath);
      // TODO: injectPreload
      // preload data module for this page
      // html = injectPreload(html, "path/to/page/data")
      const writePath = path.join(
        clientOutDir,
        pagePath.replace(/^\//, ""),
        "index.html"
      );
      await fs.ensureDir(path.dirname(writePath));
      await fs.writeFile(writePath, html);
      if (pagePath !== "/") {
        // should write to both /pagePath/index.html and /pagePath.html
        const writePath2 = path.join(
          clientOutDir,
          pagePath.replace(/^\//, "") + ".html"
        );
        await fs.ensureDir(path.dirname(writePath2));
        await fs.writeFile(writePath2, html);
      }
    })
  );

  const html404Path = path.join(clientOutDir, "404.html");
  // pass in a pagePath that won't match any defined page
  // so the render result will be 404 page
  const html404 = renderHTML("/internal-404-page");
  await fs.writeFile(html404Path, html404);
  // move 404 page to `/` if `/` doesn't exists
  if (!pagePaths.includes("/")) {
    await fs.copy(html404Path, path.join(clientOutDir, "index.html"));
  }

  await fs.copy(clientOutDir, outDir);
  await fs.remove(clientOutDir);
  await fs.remove(ssrOutDir);
  console.log("vite pages ssr build finished successfully.");
  return;

  function renderHTML(pagePath: string) {
    const ssrContent = renderToString(pagePath);
    const ssrInfo = {
      routePath: pagePath,
    };
    let html = htmlCode.replace(
      RootElementInjectPoint,
      // let client know the current ssr page
      `<script>window._vitePagesSSR=${JSON.stringify(ssrInfo)};</script>
<div id="root">${ssrContent}</div>`
    );
    const cssInject = cssChunks
      .map((cssChunk) => {
        return `<link rel="stylesheet" href="${basePath}${cssChunk.fileName}" />`;
      })
      .join("\n");
    html = html.replace(
      CSSInjectPoint,
      `${cssInject}
${CSSInjectPoint}`
    );
    html = html.replace(
      EntryModuleInjectPoint,
      `<script type="module" src="${basePath}${entryChunk.fileName}"></script>`
    );
    return html;
  }
}

const injectPreload = (html: string, filePath: string) => {
  const tag = `<link rel="modulepreload" href="${filePath}" />`;
  if (/<\/head>/.test(html)) {
    return html.replace(/<\/head>/, `${tag}\n</head>`);
  } else {
    return tag + "\n" + html;
  }
};