import dts from "unplugin-dts/vite";
import {
	copyFile,
	cp,
	mkdir,
	readdir,
	readFile,
	rm,
	writeFile,
} from "node:fs/promises";
import { dirname, join, resolve } from "node:path";
import { fileURLToPath } from "node:url";
import { defineConfig, build as viteBuild } from "vite";
import noBundlePlugin from "vite-plugin-no-bundle";

const __dirname = dirname(fileURLToPath(import.meta.url));

const outputPathPrefix =
	process.env.BUILD_ENV !== "production" ? "dist-temp" : "dist";
const browserOutPath = `${outputPathPrefix}-browser`;
const browserOutDir = resolve(__dirname, browserOutPath);
const demoOutDir = resolve(__dirname, `${outputPathPrefix}-demo`);

const entry = "src/index.ts";

const globalConfig = {
	libraryName: "twtxt-lib",
	basePath: resolve(__dirname),
	outDir: resolve(__dirname, outputPathPrefix),
	builds: [
		{
			entry,
			outDir: browserOutDir,
			outfile: "twtxt-lib.js",
			target: "browser",
		},
		{
			entry,
			outDir: browserOutDir,
			outfile: "twtxt-lib.min.js",
			target: "browser",
		},
		{
			entry,
			outDir: resolve(__dirname, `${outputPathPrefix}-node`),
			target: "node",
		},
	],
	licenseBegin: "", // assigned in init()
	licenseEnd: "", // assigned in init()
	licensePath: resolve(__dirname, ".license-fragments"),

	/** @type Record<string, any>|null */
	pkg: null, // assigned in init()

	async init() {
		this.pkg = JSON.parse(
			await readFile(resolve(this.basePath, "package.json")),
		);

		this.licenseBegin = await readFile(
			resolve(this.licensePath, "license-begin.txt"),
		);
		this.licenseEnd = await readFile(
			resolve(this.licensePath, "license-end.txt"),
		);

		this.builds = this.builds.map((config) => {
			config.entry = resolve(globalConfig.basePath, config.entry);
			config.minify = config?.outfile?.includes(".min.") ?? false;
			config.standalone = config?.target?.includes("browser") ?? false;
			config.format = "es";

			return config;
		});
	},
};

const purgeOutDirs = async (config) => {
	await rm(config.outDir, { recursive: true, force: true });
};

const buildWithVite = async (config) => {
	const plugins = [
		dts({ exclude: ["./vitest.setup.ts", "**/__tests__/*.*"] }),
	];
	if (config.target !== "browser") plugins.push(noBundlePlugin());

	await viteBuild(
		defineConfig({
			define: {
				"globalThis.__BUILD_VERSION__": JSON.stringify(
					globalConfig.pkg.version,
				),
			},
			build: {
				lib: {
					entry: config.entry,
					name: globalConfig.libraryName,
					formats: [config.format],
					fileName: () => config?.outfile ?? "[name].js",
				},
				emptyOutDir: false,
				outDir: config.outDir,
				minify: config.minify || false,
				sourcemap: true,
				rollupOptions: {
					external: [],
					preserveEntrySignatures: "strict",
					shimMissingExports: true,
					treeshake: false,
				},
				target: config.target === "browser" ? "es6" : "node22",
			},
			plugins,
			publicDir: false,
			resolve: {
				extensions: [".ts", ".js"],
				alias: {
					"@": `${globalConfig.basePath}/src`,
				},
			},
		}),
	);
};

const wrapWithLicense = async (config) => {
	const fileText = await readFile(
		resolve(config.outDir, config.outfile ?? "index.js"),
	);

	await writeFile(
		resolve(config.outDir, config.outfile ?? "index.js"),
		[globalConfig.licenseBegin, fileText, globalConfig.licenseEnd].join(""),
		{ encoding: "utf8", flag: "w" },
	);
};

const copyDir = async (source, destination) => {
	const entries = await readdir(source, { withFileTypes: true });
	await mkdir(destination, { recursive: true });

	return Promise.all(
		entries.map(async (entry) => {
			const sourcePath = resolve(source, entry.name);
			const destinationPath = resolve(destination, entry.name);

			return entry.isDirectory()
				? copyDir(sourcePath, destinationPath)
				: copyFile(sourcePath, destinationPath);
		}),
	);
};

const createDemoSite = async () => {
	await rm(demoOutDir, { recursive: true, force: true });

	await copyDir(resolve(__dirname, "public"), demoOutDir);

	await copyFile(
		resolve(__dirname, "index.html"),
		resolve(demoOutDir, "index.html"),
	);

	await copyDir(browserOutDir, resolve(demoOutDir, browserOutPath));
};

async function main() {
	await globalConfig.init();
	await rm(globalConfig.outDir, { recursive: true, force: true });
	await Promise.all([
		...globalConfig.builds.map((config) => purgeOutDirs(config)),
	]);
	await Promise.all([
		...globalConfig.builds.map((config) => buildWithVite(config)),
	]);
	await Promise.all([
		...globalConfig.builds.map((config) => wrapWithLicense(config)),
	]);
	await createDemoSite();
	console.log("All library file builds complete.");
}

main();