import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
import adapter from '@sveltejs/adapter-static';
import fs from 'fs';

import { mdsvex, escapeSvelte } from 'mdsvex';
import remarkAlert from './src/lib/markdown.js'
import relativeImages from 'mdsvex-relative-images'
import remarkToc from 'remark-toc'
import rehypeSlug from 'rehype-slug'
import { getHighlighter } from 'shiki'
import rehypeKatexSvelte from "rehype-katex-svelte";
import remarkMath from 'remark-math'

const contentDir = process.env?.CHRYSOBLOG_CONTENT ?? "src/content";

const metadata = await fs.promises.readFile(contentDir + "/metadata.json")
                         .then((file) => JSON.parse(file.toString()));
const langs = metadata?.markdown.highlighterLangs ?? [
   "javascript",
   "lean",
   "lisp",
   "nix",
   "python",
   "rust",
   "toml",
   "typescript",
   "yaml",
   "c",
   "c++",
   "sh",
];
const katexOptions = metadata?.markdown.katex ?? {
   macros: {
      "\\Nat": "\\mathbb N",
      "\\Complex": "\\mathbb C",
      "\\vec": "\\boldsymbol",
      "\\mat": "\\boldsymbol",
      "\\rv": "\\mathrm",
   },
};
const highlightingThemes = {
   light: 'vitesse-light',
   dark: 'vitesse-dark',
};

const themes = Object.keys(highlightingThemes).map(function(k){ return highlightingThemes[k] });
const highlighter = await getHighlighter({
   themes,
   langs,
})
await highlighter.loadLanguage(...langs);

/** @type {import('@sveltejs/kit').Config} */
const config = {
	// Consult https://kit.svelte.dev/docs/integrations#preprocessors
	// for more information about preprocessors
	preprocess: [
      mdsvex({
         extensions: ['.md'],
         remarkPlugins: [
            remarkAlert,
            relativeImages,
            [remarkToc, {tight: true}],
            remarkMath,
         ],
         rehypePlugins: [
            [ rehypeKatexSvelte, katexOptions ],
            rehypeSlug,
         ],
         highlight: {
		      highlighter: async (code, lang = 'text') => {
			      const html = escapeSvelte(highlighter.codeToHtml(code, {
                  lang,
                  themes: highlightingThemes,
               }))
			      return `{@html \`${html}\` }`
		      }
	      },
      }),
      vitePreprocess(),
   ],
   extensions: [".svelte", ".md"],

	kit: {
		// adapter-auto only supports some environments, see https://kit.svelte.dev/docs/adapter-auto for a list.
		// If your environment is not supported, or you settled on a specific environment, switch out the adapter.
		// See https://kit.svelte.dev/docs/adapters for more information about adapters.
		adapter: adapter({
         pages: "build",
         assets: "build",
         fallback: null,
         precompress: false,
         trailingSlash: 'always',
      }),
      prerender: {
         crawl: true,
         entries: ['*'],
      },
		alias: {
         $content: contentDir,
			"@/*": "./*",
		},
	}
};

export default config;