const { shim } = require("lib/shim");
const katex = require("katex");
const katexCss = require("lib/csstojs/katex.css.js");
const Setting = require("lib/models/Setting");

class MdToHtml_Katex {
	name() {
		return "katex";
	}

	processContent(renderedTokens, content, tagType) {
		try {
			let renderered = katex.renderToString(content);

			if (tagType === "block") renderered = "<p>" + renderered + "</p>";

			renderedTokens.push(renderered);
		} catch (error) {
			renderedTokens.push("Cannot render Katex content: " + error.message);
		}
		return renderedTokens;
	}

	extraCss() {
		return katexCss;
	}

	async loadAssets() {
		// In node, the fonts are simply copied using copycss to where Katex expects to find them, which is under app/gui/note-viewer/fonts

		// In React Native, it's more complicated and we need to download and copy them to the right directory. Ideally, we should embed
		// them as an asset and copy them from there (or load them from there by modifying Katex CSS), but for now that will do.

		if (shim.isReactNative()) {
			// Fonts must go under the resourceDir directory because this is the baseUrl of NoteBodyViewer
			const baseDir = Setting.value("resourceDir");
			await shim.fsDriver().mkdir(baseDir + "/fonts");

			await shim.fetchBlob("https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-beta1/fonts/KaTeX_Main-Regular.woff2", { overwrite: false, path: baseDir + "/fonts/KaTeX_Main-Regular.woff2" });
			await shim.fetchBlob("https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-beta1/fonts/KaTeX_Math-Italic.woff2", { overwrite: false, path: baseDir + "/fonts/KaTeX_Math-Italic.woff2" });
			await shim.fetchBlob("https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-beta1/fonts/KaTeX_Size1-Regular.woff2", { overwrite: false, path: baseDir + "/fonts/KaTeX_Size1-Regular.woff2" });
		}
	}
}

module.exports = MdToHtml_Katex;