import { marked } from 'marked';
import { create_renderer } from './renderer';
import { mark_ext } from './mark';
import { section_ext } from './section';
import { icon_ext } from './icon';
import { CustomElementHandling, sanitize_html } from './html-sanitize';
import { katex_block_ext, katex_inline_ext } from './katex';
import { footnote_list_ext, footnote_ref_ext } from './footnotes';
import { description_list_ext } from './description-list';
import { resolve_async_bindings } from './async-steps';
import { base_url_walk_tokens } from './base-url';

export interface MarkdownOptions {
	base_url?: string;
	breaks?: boolean;
	inline?: boolean;
	katex_macros?: Record<string, string>;
	extensions?: MarkdownExtension[];
	custom_elements?: CustomElementHandling;
}

export interface MarkdownExtension {
	(renderer: marked.Renderer, opts: MarkdownOptions): marked.TokenizerExtension & marked.RendererExtension
}

export async function render_markdown_to_html(markdown: string, options: MarkdownOptions = { }) {
	const marked_options = marked_opts(options);
	setup_marked(options, marked_options);
	const unsafe_html = options.inline
		? marked.parseInline(markdown, marked_options)
		: marked.parse(markdown, marked_options);

	return sanitize_html(await resolve_async_bindings(unsafe_html), options.custom_elements);
}

export function render_markdown_to_html_inline_sync(markdown: string, options: MarkdownOptions = { }) {
	const marked_options = marked_opts(options);
	setup_marked(options, marked_options);
	const unsafe_html = marked.parseInline(markdown, marked_options);
	return sanitize_html(unsafe_html, options.custom_elements);
}

function marked_opts<T extends boolean>(options: MarkdownOptions) : marked.MarkedOptions {
	return {
		breaks: options.breaks || false,
		renderer: create_renderer(options),
		mangle: false,
		headerIds: false,
	};
}

function setup_marked(options: MarkdownOptions, marked_options: marked.MarkedOptions) {
	marked.use({
		walkTokens(token) {
			base_url_walk_tokens(token, options);
		},
		extensions: [
			katex_block_ext(marked_options.renderer, options),
			katex_inline_ext(marked_options.renderer, options),
			footnote_ref_ext(marked_options.renderer, options),
			footnote_list_ext(marked_options.renderer, options),
			mark_ext(marked_options.renderer, options),
			description_list_ext(marked_options.renderer, options),
			section_ext(marked_options.renderer, options),
			icon_ext(marked_options.renderer, options),
			...(options.extensions || [ ]).map((ext) => {
				return ext(marked_options.renderer, options);
			}),
		],
		tokenizer: {
			url(src) {
				// disable auto-linking; more can be added here to auto-link only sometimes
				// see: https://github.com/markedjs/marked/issues/882#issuecomment-781628889
				return null;
			}
		},
	});
}