import * as fs from "node:fs";
import * as posix from "node:path/posix";
import { prettify, htmlDocument } from "antihtml";
import { pages } from "./content/pages.js";
import type { Page } from "./content/types.js";
import { resolveRefs } from "./utils/resolve-refs.js";
import { createServer } from "./utils/http-server.js";

function pageToHtml(page: Page) {
	if (!page.ref.startsWith("/")) {
		throw new Error(`ref "${page.ref}" for "${page.title}" is not absolute.`);
	}
	return htmlDocument(
		prettify(
			resolveRefs(
				page.content,
				posix.dirname(page.ref),
			)
		)
	)
}

function assembleResources() {
	const webDir = "public";
	const resources = new Map<string, string | Page>();
	for (const entry of fs.readdirSync(webDir, { recursive: true, withFileTypes: true })) {
		if (!entry.isFile())
			continue;
		const parentPath = entry.parentPath.replace(/\\/g, "/");
		const ref = `${parentPath.slice(webDir.length)}/${entry.name}`;
		resources.set(ref, `${parentPath}/${entry.name}`);
	}
	for (const page of pages) {
		if (resources.has(page.ref)) {
			const existing = resources.get(page.ref)!;
			const other = typeof existing === "string" ? "a static resource" : `"${existing.title}"`;
			throw new Error(`ref "${page.ref}" is taken up by both "${page.title}" and ${other}`)
		}
		resources.set(page.ref, page);
	}
	return resources;
}

function build() {
	const outDir = "build/web";
	const dirsCreated = new Set<string>()
	for (const [ref, resource] of assembleResources()) {
		const refDir = `${outDir}${posix.dirname(ref)}`;
		if (!dirsCreated.has(refDir)) {
			fs.mkdirSync(refDir, { recursive: true });
		}
		console.log(`writing ${outDir}${ref}`);
		let content;
		if (typeof resource === "string") {
			content = fs.readFileSync(resource);
		} else {
			content = pageToHtml(resource);
		}
		fs.writeFileSync(`${outDir}${ref}`, content);
	}
}

function serve() {
	const resources = assembleResources();
	const server = createServer(
		(ref) => {
			const resource = resources.get(ref);
			if (resource === undefined)
				return undefined;
			if (typeof resource === "string")
				return fs.readFileSync(resource);
			return Buffer.from(pageToHtml(resource));
		}
	);

	server.listen(8080);
	console.log("Listening on http://localhost:8080");
}

function printUsage() {
	console.log("Usage: cli.js <cmd>");
	console.log("    build - Copy resources and generated pages to build directory.");
	console.log("    serve - Host website on localhost:8080 for development purposes.");
}

function main(runtime: string, script: string, args: string[]) {
	if (!args.length) {
		printUsage();
		process.exitCode = 1;
		return;
	}

	const [command, ...commandArgs] = args;
	if (command === "build") {
		build();
	} else if (command === "serve") {
		serve();
	} else {
		console.log(`Error: Unkown sub-command ${command}`);
		printUsage();
		process.exitCode = 1;
	}
}

const [runtime, script, ...args] = process.argv;
main(runtime, script, args)