import { readdir, readFile } from "node:fs/promises";
import { existsSync } from "node:fs";
import { join, resolve } from "node:path";
import type {
	ContentSchema,
	Integration,
	IntegrationContext,
} from "../contracts/index.ts";
import { compileCss, type CompileOptions } from "./css/index.ts";
import { compileStcssModule } from "./css/modules.ts";
import { markdownLoader } from "./markdown.ts";
import { sassLoader, type SassLoaderOptions } from "./css/sass.ts";

export {
	shadcnIntegration,
	type ShadcnIntegrationOptions,
} from "../integrations/shadcn.ts";

export interface MarkdownIntegrationOptions {
	/** Name of the collection, defaults to `notes`. */
	name?: string;
	/** Directory of the collection, relative to the project root. */
	dir?: string;
	/** Schema of the frontmatter. */
	schema?: ContentSchema;
}

/**
 * Markdown integration.
 *
 * The integration registers the markdown loader and adds the collection of
 * the content directory to the project.
 */
export function markdownIntegration(
	options: MarkdownIntegrationOptions = {},
): Integration {
	const name = options.name ?? "notes";
	const dir = options.dir ?? "content/notes";

	return {
		name: "markdown",
		setup(context: IntegrationContext) {
			context.loader("markdown", markdownLoader());
			const collections = context.config.collections ?? [];
			if (collections.some((collection) => collection.name === name)) return;
			collections.push({
				name,
				dir,
				loader: "markdown",
				schema: options.schema,
			});
			context.config.collections = collections;
		},
	};
}

export interface StcssIntegrationOptions extends CompileOptions {
	/** Directory of the stylesheets, relative to the project root. */
	dir?: string;
	/** Route the compiled css is served at. */
	route?: string;
}

/**
 * Css integration.
 *
 * The integration compiles the structured stylesheets of the project and
 * serves them at a single route, the browser caches the result.
 */
export function stcssIntegration(
	options: StcssIntegrationOptions = {},
): Integration {
	const route = options.route ?? "/_muddle/styles.css";

	return {
		name: "stcss",
		async setup(context: IntegrationContext) {
			context.loader("stcss", {
				name: "stcss",
				extensions: [".stcss"],
				load(file) {
					return { data: {}, content: compileCss(file.source, options) };
				},
			});

			const dir = resolve(context.config.root, options.dir ?? "styles");
			if (!existsSync(dir)) return;

			const files = await stcssFiles(dir);
			const parts: string[] = [];
			for (const file of files.sort()) {
				const path = join(dir, file);
				const source = await readFile(path, "utf8");
				parts.push(
					file.endsWith(".module.stcss")
						? (
								await compileStcssModule(source, {
									...options,
									filename: path,
									root: context.config.root,
								})
							).css
						: compileCss(source, options),
				);
			}
			const css = parts.join("\n");

			context.route(
				"GET",
				route,
				() =>
					new Response(css, {
						headers: {
							"content-type": "text/css; charset=utf-8",
							"cache-control": "public, max-age=3600",
						},
					}),
			);
		},
	};
}

async function stcssFiles(dir: string, prefix = ""): Promise<string[]> {
	const files: string[] = [];
	for (const entry of await readdir(dir, { withFileTypes: true })) {
		const relative = `${prefix}${entry.name}`;
		if (entry.isDirectory())
			files.push(...(await stcssFiles(join(dir, entry.name), `${relative}/`)));
		else if (entry.name.endsWith(".stcss")) files.push(relative);
	}
	return files.sort();
}

/** Registers Sass files as loaders and serves their compiled CSS alongside STCSS. */
export function sassIntegration(options: SassLoaderOptions = {}): Integration {
	const route = "/_muddle/sass.css";
	return {
		name: "sass",
		async setup(context) {
			const loader = sassLoader(options);
			context.loader("sass", loader);
			const dir = resolve(context.config.root, options.dir ?? "styles");
			if (!existsSync(dir)) return;
			const files = await sassFiles(dir);
			context.route("GET", route, async () => {
				const css = await Promise.all(
					files
						.filter((file) => !file.split("/").at(-1)?.startsWith("_"))
						.map(
							async (file) =>
								(
									await loader.load({
										path: join(dir, file),
										relativePath: `styles/${file}`,
										source: await readFile(join(dir, file), "utf8"),
									})
								).content ?? "",
						),
				);
				return new Response(css.join("\n"), {
					headers: { "content-type": "text/css; charset=utf-8" },
				});
			});
		},
	};
}

async function sassFiles(dir: string, prefix = ""): Promise<string[]> {
	const files: string[] = [];
	for (const entry of await readdir(dir, { withFileTypes: true })) {
		const relative = `${prefix}${entry.name}`;
		if (entry.isDirectory())
			files.push(...(await sassFiles(join(dir, entry.name), `${relative}/`)));
		else if (/\.s[ac]ss$/i.test(entry.name)) files.push(relative);
	}
	return files.sort();
}