import { mkdir, writeFile } from "node:fs/promises";
import { basename, extname, join, resolve } from "node:path";
import type { Integration, IntegrationContext } from "../contracts/index.ts";
import { cssToStcss, reactToSpug } from "../core/backport.ts";

export interface ShadcnIntegrationOptions {
	/** Registry component names, for example `button`, `card`, or `dialog`. */
	components: string[];
	/** Registry origin or `{name}` URL template. Defaults to ShadCN's New York registry. */
	registry?: string;
	/** Destination relative to the Muddle project root. */
	dir?: string;
	/** Injectable for offline registries and tests. */
	fetch?: (input: string) => Promise<Response>;
}

interface RegistryItem {
	files?: { path: string; content: string; type?: string }[];
	registryDependencies?: string[];
}

/**
 * Pulls declaratively selected ShadCN React components and backports them
 * into SPUG and STCSS during application setup.
 */
export function shadcnIntegration(options: ShadcnIntegrationOptions): Integration {
	return {
		name: "shadcn",
		async setup(context: IntegrationContext) {
			const fetcher = options.fetch ?? globalThis.fetch;
			const destination = resolve(context.config.root, options.dir ?? "modules/app/views/components");
			const styles = resolve(context.config.root, "styles/shadcn");
			const seen = new Set<string>();
			const pull = async (name: string): Promise<void> => {
				if (seen.has(name)) return;
				seen.add(name);
				const base = options.registry ?? "https://ui.shadcn.com/r/styles/new-york/{name}.json";
				const url = base.includes("{name}")
					? base.replace("{name}", encodeURIComponent(name))
					: `${base.replace(/\/$/, "")}/${encodeURIComponent(name)}.json`;
				const response = await fetcher(url);
				if (!response.ok) throw new Error(`shadcn registry request failed for ${name} with ${response.status}`);
				const item = await response.json() as RegistryItem;
				for (const dependency of item.registryDependencies ?? []) await pull(dependency.replace(/^@[^/]+\//, ""));
				for (const file of item.files ?? []) {
					const extension = extname(file.path).toLowerCase();
					const stem = basename(file.path).replace(/\.(tsx|jsx|css)$/i, "");
					if (extension === ".tsx" || extension === ".jsx") {
						await mkdir(destination, { recursive: true });
						await writeFile(join(destination, `${stem}.spug`), reactToSpug(file.content, file.path));
					} else if (extension === ".css") {
						await mkdir(styles, { recursive: true });
						await writeFile(join(styles, `${stem}.stcss`), cssToStcss(file.content, file.path));
					}
				}
			};
			for (const component of options.components) await pull(component);
		},
	};
}