'use client'

import type { RawContentMatch } from '@admin/utils/editor/raw-content-match'

const mathBlockEnvironmentNames = new Set([
  'align',
  'align*',
  'aligned',
  'alignedat',
  'alignedat*',
  'array',
  'bmatrix',
  'cases',
  'equation',
  'equation*',
  'gather',
  'gather*',
  'gathered',
  'matrix',
  'multline',
  'multline*',
  'pmatrix',
  'smallmatrix',
  'split',
  'vmatrix'
])

export function matchBlockMath(src: string): RawContentMatch | null {
  const bracketMatch = /^\\\[[\s\S]*?\\\][ \t]*(?:\n|$)/.exec(src)
  if (bracketMatch) {
    return {
      kind: 'math',
      raw: bracketMatch[0].trimEnd()
    }
  }

  const dollarMatch = /^\$\$[\s\S]*?\$\$[ \t]*(?:\n|$)/.exec(src)
  if (dollarMatch) {
    return {
      kind: 'math',
      raw: dollarMatch[0].trimEnd()
    }
  }

  const environmentMatch = /^\\begin\{([^}]+)\}[\s\S]*?\\end\{\1\}[ \t]*(?:\n|$)/.exec(src)
  if (environmentMatch && mathBlockEnvironmentNames.has(environmentMatch[1])) {
    return {
      kind: 'math',
      raw: environmentMatch[0].trimEnd()
    }
  }

  return null
}