import { marked } from 'marked';
import { MarkdownOptions } from './render';

export interface DescriptionListToken extends marked.Tokens.Generic {
	items: (DescriptionTermToken | DescriptionDetailToken)[];
}

export interface DescriptionTermToken extends marked.Tokens.Generic {
	text: string;
}

export interface DescriptionDetailToken extends marked.Tokens.Generic {
	text: string;
}

export function description_list_ext(renderer: marked.Renderer, opts: MarkdownOptions) : marked.TokenizerExtension & marked.RendererExtension {
	return {
		name: 'description_list',
		level: 'block',
		start: (src) => src.match(/^:[:#-]/)?.index,
		tokenizer(src, tokens) {
			const rule = /^(?::[:#-](?:\s[^\n]*)?(?:\n|$))+/;
			const match = rule.exec(src);

			if (match) {
				const token: DescriptionListToken = {
					type: 'description_list',
					raw: match[0],
					items: [ ]
				};

				const items = token.raw.trim().split('\n');
				const raw_buffer: string[] = [ ];
				const text_buffer: string[] = [ ];

				const flush_buffer = () => {
					if (! raw_buffer.length) {
						return;
					}

					// Grab the second character from the first line to determine the
					// token type (should be "#" or "-")
					const type = raw_buffer[0][1] === '#' ? 'description_term' : 'description_detail';
					
					const sub_token: (DescriptionTermToken | DescriptionDetailToken) = {
						type,
						raw: raw_buffer.join('\n'),
						text: text_buffer.join('\n'),
						tokens: [ ],
					};

					raw_buffer.length = 0;
					text_buffer.length = 0;

					this.lexer.blockTokens(sub_token.text, sub_token.tokens);
					token.items.push(sub_token);
				};

				for (const line of items) {
					const rule = /^:([:#-])(?:\s([^\n]*))?(?:\n|$)/;
					const match = rule.exec(line);
		
					if (match) {
						if (match[1] !== ':') {
							flush_buffer();
						}

						raw_buffer.push(match[0]);
						text_buffer.push(match[2]);
					}
				}

				flush_buffer();
				
				return token;
			}
		},
		renderer(token: DescriptionListToken) {
			const items = token.items.map((item) => {
				const tag = item.type === 'description_term' ? 'dt' : 'dd';
				return `
					<${tag}>
						${this.parser.parse(item.tokens)}
					</${tag}>
				`;
			});

			return `<dl>${items.join('')}</dl>`;
		}
	};
}