// CodeMirror "markdown-math" — a GFM-flavoured Markdown mode that delegates

// the contents of `$...$` (inline) and `$$...$$` (block) math spans to the

// stex (LaTeX) mode. Without this wrapper the standard markdown mode highlights

// `_` as emphasis delimiters even inside math, producing spurious italics for

// subscript expressions like `$\text{F}_\text{A} = \text{F}_\text{B}$` in the

// source view. See https://github.com/marktext/marktext/issues/4121.

//

// The outer mode is `gfm` to preserve the tables / autolinks / task lists

// styling the previous `setMode(cm, 'markdown')` call resolved to via

// `codeMirror/modes.js` (which maps "markdown" → `gfm` / `text/x-gfm`).

//

// All inner modes are loaded eagerly so `getMode` resolves synchronously at

// the time the wrapper is instantiated. `gfm` itself depends on `markdown`.

import 'codemirror/mode/markdown/markdown'

import 'codemirror/mode/gfm/gfm'

import 'codemirror/mode/stex/stex'

// Open guard for inline `$…$`. Mirrors Muya's `inline_math` rule

// (`src/muya/lib/parser/rules.js`): require non-empty content with no inner

// `$`, last char before the closer not being `\`, and the closing `$` not

// followed by another `$` (which would be block math). This stops a single

// stray `$` (e.g. "$5 owed") from flipping the inner mode on forever and keeps

// the source-view tokenization aligned with the inline parse.

const INLINE_MATH_OPEN = /\$(?!\$)(?=[^$\n]*?[^$\\]\$(?!\$))/

// eslint-disable-next-line @typescript-eslint/no-explicit-any

type CodeMirrorLike = any

// eslint-disable-next-line @typescript-eslint/no-explicit-any

type AnyObj = any

const registerMarkdownMathMode = (CodeMirror: CodeMirrorLike): void => {

if (CodeMirror.modes && Object.prototype.hasOwnProperty.call(CodeMirror.modes, 'markdown-math')) {

return

}

CodeMirror.defineMode('markdown-math', function(config: AnyObj) {

const gfmMode = CodeMirror.getMode(config, {

name: 'gfm',

fencedCodeBlocks: true,

strikethrough: true,

taskLists: true

})

const stexMode = CodeMirror.getMode(config, 'stex')

// `$$` must come before `$` so the longer delimiter is matched first.

// Block math (`$$…$$`) intentionally has no lookahead guard: a matching

// closer typically lives on a later line, which CodeMirror's per-line

// tokenizer cannot see from the opener.

return CodeMirror.multiplexingMode(

gfmMode,

{

open: '$$',

close: '$$',

mode: stexMode,

delimStyle: 'formatting formatting-math formatting-math-block math-block',

innerStyle: 'math math-block'

},

{

open: INLINE_MATH_OPEN,

close: '$',

mode: stexMode,

delimStyle: 'formatting formatting-math formatting-math-inline math-inline',

innerStyle: 'math math-inline'

}

)

})

}

export default registerMarkdownMathMode