backwards compatibility

packages/utils/markdown/html-block.ts

@@ -0,0 +1,128 @@
+import { defineComarkPlugin } from 'comark/parse'
+import { Parser as HtmlTagParser } from 'htmlparser2'
+import type Token from 'markdown-it/lib/token.mjs'
+
+import type MarkdownIt = require('markdown-it')
+
+// This is here to keep backwards compatibility
+// Comark closes most open html tags when it hits a blank line,
+// we make it only do that if we can't find a closing tag, in order to mimic the side effect of
+// markdown-it emitting html entirely raw (which your browser is then lenient with unclosed tags)
+// whereas comark does its fancy AST which means it can't just emit the html raw
+// Thank you for coming to my TED talk -chyz
+
+type RuleBlock = MarkdownIt.ParserBlock.RuleBlock
+type StateBlock = MarkdownIt.StateBlock
+
+// If you know a better way to do this go ahead
+function findHtmlBlockRuleFn(md: MarkdownIt): RuleBlock | undefined {
+	const rules = (md.block.ruler as unknown as { __rules__: { name: string; fn: RuleBlock }[] })
+		.__rules__
+	return rules?.find((r) => r.name === 'comark_html_block')?.fn
+}
+
+function extractOpenTagName(line: string): string | undefined {
+	return /^<([a-zA-Z][a-zA-Z0-9-]*)/.exec(line)?.[1]?.toLowerCase()
+}
+
+function parseOpenTagAttrs(line: string): [string, string][] {
+	const attrs: [string, string][] = []
+	const parser = new HtmlTagParser({
+		onopentag(_name, attrObj) {
+			for (const [key, value] of Object.entries(attrObj)) attrs.push([key, value])
+		},
+	})
+	parser.write(line)
+	parser.end()
+	return attrs
+}
+
+function markdownItModrinthHtmlBlock(md: MarkdownIt) {
+	const htmlBlockFn = findHtmlBlockRuleFn(md)
+	if (!htmlBlockFn) return
+
+	md.block.ruler.before(
+		'comark_html_block',
+		'modrinth_html_block',
+		(state: StateBlock, startLine: number, endLine: number, silent: boolean) => {
+			if (silent) return htmlBlockFn(state, startLine, endLine, true)
+
+			const tokensBefore = state.tokens.length
+			const lineBefore = state.line
+			const matched = htmlBlockFn(state, startLine, endLine, false)
+			if (!matched) return false
+
+			const token = state.tokens[state.tokens.length - 1]
+			if (token.type !== 'html_block' || !token.map) return true
+
+			const firstLine = (token.content.split('\n')[0] ?? '').trim()
+			if (firstLine.endsWith('/>')) return true
+
+			const tagName = extractOpenTagName(firstLine)
+			if (!tagName) return true
+
+			const openLineRe = new RegExp(`^<${tagName}(\\s|/?>|$)`, 'i')
+			const closeLineRe = new RegExp(`^</${tagName}\\s*>$`, 'i')
+			let depth = 0
+			let closeLine = -1
+			for (let line = startLine + 1; line < endLine; line++) {
+				if (state.sCount[line] < state.blkIndent) break
+				const p = state.bMarks[line] + state.tShift[line]
+				const mx = state.eMarks[line]
+				const text = state.src.slice(p, mx).trim()
+				if (openLineRe.test(text) && !text.endsWith('/>')) {
+					depth++
+					continue
+				}
+				if (closeLineRe.test(text)) {
+					if (depth > 0) {
+						depth--
+						continue
+					}
+					closeLine = line
+					break
+				}
+			}
+			if (closeLine === -1 || closeLine < token.map[1]) return true
+
+			state.tokens.length = tokensBefore
+			state.line = lineBefore
+
+			const attrs = parseOpenTagAttrs(firstLine)
+			const oldParent = state.parentType
+			const oldLineMax = state.lineMax
+			state.parentType = 'comark_block' as StateBlock['parentType']
+			state.lineMax = closeLine
+
+			const tokenOpen: Token & { block?: boolean } = state.push('mdc_block_open', tagName, 1)
+			tokenOpen.block = true
+			tokenOpen.map = [startLine, closeLine + 1]
+			for (const [key, value] of attrs) tokenOpen.attrSet(key, value)
+
+			const blkIndent = state.blkIndent
+			state.blkIndent = 0
+			// eslint-disable-next-line @typescript-eslint/no-explicit-any
+			const env = state.env as any
+			env.comarkBlockTokens ||= []
+			env.comarkBlockTokens.unshift(tokenOpen)
+			state.md.block.tokenize(state, startLine + 1, closeLine)
+			state.blkIndent = blkIndent
+			env.comarkBlockTokens.shift()
+
+			const tokenClose: Token & { block?: boolean } = state.push('mdc_block_close', tagName, -1)
+			tokenClose.map = [startLine, closeLine + 1]
+			tokenClose.block = true
+
+			state.parentType = oldParent
+			state.lineMax = oldLineMax
+			state.line = closeLine + 1
+			return true
+		},
+		{ alt: ['paragraph', 'reference', 'blockquote'] },
+	)
+}
+
+export const modrinthHtmlBlock = defineComarkPlugin(() => ({
+	name: 'modrinth-html-block',
+	markdownItPlugins: [markdownItModrinthHtmlBlock],
+}))