// For now we are using a simple parser adapted from htm (https://github.com/developit/htm/blob/master/src/build.mjs)
// If we find any issues we can switch to something more sophisticated like
// - https://github.com/acrazing/html5parser
// - https://github.com/fb55/htmlparser2

const MODE_SLASH = 0
const MODE_TEXT = 1
const MODE_WHITESPACE = 2
const MODE_TAGNAME = 3
const MODE_COMMENT = 4
const MODE_ATTRIBUTE = 5

export function parseHTML(
  markup: string,
  onClass: (startIndex: number, endIndex: number, quote: string) => false | unknown,
): void {
  let mode = MODE_TEXT
  let startIndex = 0
  let quote = ''
  let attributeName = ''

  const commit = (currentIndex: number): void => {
    if (mode == MODE_ATTRIBUTE && attributeName == 'class') {
      if (onClass(startIndex, currentIndex, quote) === false) {
        markup = ''
      }
    }
  }

  for (let position = 0; position < markup.length; position++) {
    const char = markup[position]

    if (mode == MODE_TEXT) {
      if (char == '<') {
        mode = markup.substr(position + 1, 3) == '!--' ? MODE_COMMENT : MODE_TAGNAME
      }
    } else if (mode == MODE_COMMENT) {
      // Ignore everything until the last three characters are '-', '-' and '>'
      if (char == '>' && markup.slice(position - 2, position) == '--') {
        mode = MODE_TEXT
      }
    } else if (quote) {
      if (char == quote && markup[position - 1] != '\\') {
        commit(position)
        mode = MODE_WHITESPACE
        quote = ''
      }
    } else if (char == '"' || char == "'") {
      quote = char
      startIndex += 1
    } else if (char == '>') {
      commit(position)
      mode = MODE_TEXT
    } else if (!mode) {
      // MODE_SLASH
      // Ignore everything until the tag ends
    } else if (char == '=') {
      attributeName = markup.slice(startIndex, position)
      mode = MODE_ATTRIBUTE
      startIndex = position + 1
    } else if (char == '/' && (mode < MODE_ATTRIBUTE || markup[position + 1] == '>')) {
      commit(position)
      mode = MODE_SLASH
    } else if (/\s/.test(char)) {
      // <a class=font-bold>
      commit(position)
      mode = MODE_WHITESPACE
      startIndex = position + 1
    }
  }
}

export function fixClassList(value: string, quote: string): string {
  // const value = markup.slice(startIndex, endIndex)

  // Lets handle some special react cases:
  //   * arbitrary values for `content-`
  //     <span class="before:content-[&#x27;asas&#x27;]"></span>
  //     <span class="before:content-[&quot;asas&quot;]"></span>
  //
  //   * self-referenced groups
  //     <span class="flex(&amp; col)"></span>
  //
  //     If a class name contains `'`, `"`, or `&` those will be replaced with HTML entities
  //     To fix this we replace those for depending on the actual symbol that is being used
  //     As an alternative we could always escape class names direcly in twind like react does
  //     but this works for now
  return (
    quote == `"`
      ? // `'` -> &#39; &apos; &#x27;
        value.replace(/(=|\[)(?:&#39;|&apos;|&#x27;)|(?:&#39;|&apos;|&#x27;)(])/g, `$1'$2`)
      : quote == `'`
      ? // `"` -> &#34; &quot; &#x22;
        value.replace(/(=|\[)(?:&#34;|&quot;|&#x22;)|(?:&#34;|&quot;|&#x22;)(])/g, `$1"$2`)
      : value
  ).replace(/(&#38;|&amp;|&#x26;)/g, '&')
}