import path from "node:path";
import type { ModuleNode, ViteDevServer } from "vite";

async function find_deps(
	vite: import("vite").ViteDevServer,
	node: import("vite").ModuleNode,
	deps: Set<import("vite").ModuleNode>,
) {
	// since `ssrTransformResult.deps` contains URLs instead of `ModuleNode`s, this process is asynchronous.
	// instead of using `await`, we resolve all branches in parallel.
	const branches: Promise<void>[] = [];

	async function add(node: import("vite").ModuleNode) {
		if (!deps.has(node)) {
			deps.add(node);
			await find_deps(vite, node, deps);
		}
	}

	async function add_by_url(url: string) {
		const node = await vite.moduleGraph.getModuleByUrl(url);

		if (node) {
			await add(node);
		}
	}

	if (node.ssrTransformResult) {
		if (node.ssrTransformResult.deps) {
			node.ssrTransformResult.deps.forEach((url) =>
				branches.push(add_by_url(url)),
			);
		}

		// if (node.ssrTransformResult.dynamicDeps) {
		//   node.ssrTransformResult.dynamicDeps.forEach(url => branches.push(add_by_url(url)));
		// }
	} else {
		node.importedModules.forEach((node) => branches.push(add(node)));
	}

	await Promise.all(branches);
}

// Vite doesn't expose this so we just copy the list for now
// https://github.com/vitejs/vite/blob/3edd1af56e980aef56641a5a51cf2932bb580d41/packages/vite/src/node/plugins/css.ts#L96
const style_pattern = /\.(css|less|sass|scss|styl|stylus|pcss|postcss)$/;
const module_style_pattern =
	/\.module\.(css|less|sass|scss|styl|stylus|pcss|postcss)$/;

export async function collectStyles(devServer: ViteDevServer, match: string[]) {
	const styles: { [key: string]: string } = {};
	const deps = new Set<ModuleNode>();
	try {
		for (const file of match) {
			const resolvedId = await devServer.pluginContainer.resolveId(file);

			if (!resolvedId) {
				console.log("not found");
				continue;
			}

			const id = resolvedId.id;

			const normalizedPath = path.resolve(id).replace(/\\/g, "/");
			let node = devServer.moduleGraph.getModuleById(normalizedPath);
			if (!node) {
				const absolutePath = path.resolve(file);
				await devServer.ssrLoadModule(absolutePath);
				node = await devServer.moduleGraph.getModuleByUrl(absolutePath);

				if (!node) {
					console.log("not found");
					return;
				}
			}

			await find_deps(devServer, node, deps);
		}
	} catch (e) {}

	for (const dep of deps) {
		const parsed = new URL(dep.url, "http://localhost/");
		const query = parsed.searchParams;

		if (style_pattern.test(dep.file ?? "")) {
			try {
				const mod = await devServer.ssrLoadModule(dep.url);
				// if (module_style_pattern.test(dep.file)) {
				// 	styles[dep.url] = env.cssModules?.[dep.file];
				// } else {
				styles[dep.url] = mod.default;
				// }
			} catch {
				// this can happen with dynamically imported modules, I think
				// because the Vite module graph doesn't distinguish between
				// static and dynamic imports? TODO investigate, submit fix
			}
		}
	}
	return styles;
}