import { mkdir, readdir, rm, writeFile } from "node:fs/promises";
import { dirname, relative, sep } from "node:path";
import { fileURLToPath } from "node:url";
import { $ } from "bun";

const rootDir = fileURLToPath(new URL("../", import.meta.url));
const buildDir = fileURLToPath(new URL("../.build/", import.meta.url));
const webDistDir = fileURLToPath(new URL("../dist/web/", import.meta.url));
const executablePath = fileURLToPath(new URL("../dist/gateway-checker", import.meta.url));
const generatedAssetsPath = fileURLToPath(new URL("../.build/static-assets.ts", import.meta.url));
const generatedEntryPath = fileURLToPath(new URL("../.build/server-entry.ts", import.meta.url));

await rm(buildDir, { recursive: true, force: true });
await rm(executablePath, { force: true });
await mkdir(buildDir, { recursive: true });

await $`bunx --bun vite build`;

const files = await listFiles(webDistDir);
const indexPath = files.find((file) => normalize(relative(webDistDir, file)) === "index.html");

if (!indexPath) {
  throw new Error("Vite build 未生成 dist/web/index.html");
}

const assetFiles = files.filter((file) => file !== indexPath);
await writeGeneratedAssets(indexPath, assetFiles);
await writeGeneratedEntry();

const target = process.env.BUN_TARGET ?? process.env.BUILD_TARGET;
const result = await Bun.build({
  entrypoints: [generatedEntryPath],
  compile: target
    ? {
        target: target as Bun.Build.CompileTarget,
        outfile: executablePath,
        autoloadDotenv: true,
        autoloadBunfig: true,
      }
    : {
        outfile: executablePath,
        autoloadDotenv: true,
        autoloadBunfig: true,
      },
  minify: true,
  sourcemap: "linked",
});

if (!result.success) {
  await rm(executablePath, { force: true });
  throw new Error("Bun executable 构建失败");
}

console.log(`Built executable: ${executablePath}`);

async function listFiles(directory: string): Promise<string[]> {
  const entries = await readdir(directory, { withFileTypes: true });
  const files = await Promise.all(
    entries.map(async (entry) => {
      const path = `${directory.replace(/\/$/, "")}/${entry.name}`;

      if (entry.isDirectory()) {
        return listFiles(path);
      }

      return [path];
    }),
  );

  return files.flat();
}

async function writeGeneratedAssets(indexPath: string, assetFiles: string[]) {
  const imports = [
    `import type { StaticAssets } from "../src/server/app";`,
    `import indexPath from "${toImportPath(indexPath)}" with { type: "file" };`,
    ...assetFiles.map(
      (file, index) => `import asset${index}Path from "${toImportPath(file)}" with { type: "file" };`,
    ),
  ];
  const assetEntries = assetFiles.map((file, index) => {
    const urlPath = `/${normalize(relative(webDistDir, file))}`;
    return `    ${JSON.stringify(urlPath)}: Bun.file(asset${index}Path),`;
  });
  const source = `${imports.join("\n")}

export const staticAssets: StaticAssets = {
  indexHtml: Bun.file(indexPath),
  files: {
${assetEntries.join("\n")}
  },
};
`;

  await mkdir(dirname(generatedAssetsPath), { recursive: true });
  await writeFile(generatedAssetsPath, source);
}

async function writeGeneratedEntry() {
  await writeFile(
    generatedEntryPath,
    `import { readRuntimeConfig } from "../src/server/config";
import { startServer } from "../src/server/server";
import { staticAssets } from "./static-assets";

startServer({
  config: readRuntimeConfig(),
  mode: "production",
  staticAssets,
});
`,
  );
}

function toImportPath(path: string): string {
  const rel = normalize(relative(buildDir, path));
  return rel.startsWith(".") ? rel : `./${rel}`;
}

function normalize(path: string): string {
  return path.split(sep).join("/");
}