// The two pieces of markdown handling both checks in this directory need, in one
// place rather than two copies that drift.
//
// Shared code, not a shared description. Core's own loader and its schema replay
// use one splitter for the same reason (MODULE_API.md §2.6): two implementations
// of "what counts as a code fence" would disagree eventually, and the check that
// disagreed quietly would be the one still reporting green.

/**
 * The text with every fenced code block blanked out, line count preserved.
 *
 * Fenced blocks are stripped before either check reads anything, because a fence
 * can legitimately contain a path or a link that does not exist: a directory
 * listing of the project the reader has not created yet, a URL in an example. In
 * a repo made entirely of that document type, flagging them makes the check
 * useless.
 *
 * Done by walking lines and toggling on a fence marker rather than by regexp — a
 * fence's own content can contain anything, including a line that looks like the
 * end of one. Lines are replaced by empty strings rather than removed so that
 * line numbers in a report still point at the right place.
 */
function stripFences(text) {
  const out = []
  let fence = null
  for (const line of text.split(/\r?\n/)) {
    const m = /^\s*(```+|~~~+)/.exec(line)
    if (fence) {
      if (m && m[1][0] === fence[0] && m[1].length >= fence.length) fence = null
      out.push('')
      continue
    }
    if (m) {
      fence = m[1]
      out.push('')
      continue
    }
    out.push(line)
  }
  return out.join('\n')
}

/**
 * Every inline code span outside a fenced block, with the 1-based line it is on.
 *
 * `[a](b)` inside backticks is an example rather than a link, and `template/x.js`
 * inside backticks is a claim about this repo's tree — which is why one check
 * throws these away and the other reads only these.
 */
function codeSpans(text) {
  const found = []
  stripFences(text).split(/\r?\n/).forEach((line, i) => {
    for (const m of line.matchAll(/`([^`]+)`/g)) {
      found.push({ text: m[1], line: i + 1 })
    }
  })
  return found
}

module.exports = { stripFences, codeSpans }