// SPDX-FileCopyrightText: 2025-2026 Kat Suricata <https://KatSuricata.com/>
// SPDX-License-Identifier: (CC-BY-4.0+ OR Apache-2.0+)

import adapter from '@sveltejs/adapter-static';
import { sveltekit } from '@sveltejs/kit/vite';
import { mkdirSync, readFileSync, writeFileSync } from 'node:fs';
import { dirname, resolve } from 'node:path';
import { fileURLToPath } from 'node:url';
import { defineConfig, type Plugin } from 'vite';
import { toTokensCss } from './src/lib/palette.ts';

const generatedTokens = fileURLToPath(new URL('./src/lib/generated/tokens.css', import.meta.url));
const specMarkdown = fileURLToPath(
	new URL('./Digital Rust Syntax Highlighting Specification.md', import.meta.url)
);

// The version lives in the spec's version history. Inlining it at build time
// keeps the whole markdown document out of the client bundle.
function readSpecVersion(): string {
	const markdown = readFileSync(specMarkdown, 'utf8');
	const match = /- \*\*(v\d+\.\d+\.\d+)\*\*/.exec(markdown);
	if (!match) {
		throw new Error(
			'Spec version not found. The syntax specification must keep a "- **vX.Y.Z**" entry in its version history.'
		);
	}
	return match[1];
}

// Local date, so the site reports the day the build actually ran here.
function buildDate(): string {
	const now = new Date();
	const month = String(now.getMonth() + 1).padStart(2, '0');
	const day = String(now.getDate()).padStart(2, '0');
	return `${now.getFullYear()}-${month}-${day}`;
}

// Keeps src/lib/generated/tokens.css in sync with src/lib/palette.ts so the
// site has a single palette source.
function paletteTokens(): Plugin {
	const write = () => {
		mkdirSync(dirname(generatedTokens), { recursive: true });
		writeFileSync(generatedTokens, toTokensCss());
	};
	return {
		name: 'digital-rust-tokens',
		buildStart: write,
		configureServer(server) {
			server.watcher.add(resolve('./src/lib/palette.ts'));
			server.watcher.on('change', (file) => {
				if (file.endsWith('palette.ts')) write();
			});
		}
	};
}

export default defineConfig({
	define: {
		__SPEC_VERSION__: JSON.stringify(readSpecVersion()),
		__BUILD_DATE__: JSON.stringify(buildDate())
	},
	plugins: [
		paletteTokens(),
		sveltekit({
			compilerOptions: {
				// Force runes mode for the project, except for libraries. Can be removed in svelte 6.
				runes: ({ filename }) =>
					filename.split(/[/\\]/).includes('node_modules') ? undefined : true,
				experimental: { async: true }
			},
			adapter: adapter(),
			experimental: { remoteFunctions: true, forkPreloads: true }
		})
	]
});