/**
 * @author Titus Wormer
 * @copyright 2015 Titus Wormer
 * @license MIT
 * @module remark:parse:tokenize:heading-atx
 * @fileoverview Tokenise an ATX-style heading.
 */

'use strict';

module.exports = atxHeading;

var C_NEWLINE = '\n';
var C_TAB = '\t';
var C_SPACE = ' ';
var C_HASH = '#';

var MAX_ATX_COUNT = 6;

/* Tokenise an ATX-style heading. */
function atxHeading(eat, value, silent) {
  var self = this;
  var settings = self.options;
  var length = value.length + 1;
  var index = -1;
  var now = eat.now();
  var subvalue = '';
  var content = '';
  var character;
  var queue;
  var depth;

  /* Eat initial spacing. */
  while (++index < length) {
    character = value.charAt(index);

    if (character !== C_SPACE && character !== C_TAB) {
      index--;
      break;
    }

    subvalue += character;
  }

  /* Eat hashes. */
  depth = 0;

  while (++index <= length) {
    character = value.charAt(index);

    if (character !== C_HASH) {
      index--;
      break;
    }

    subvalue += character;
    depth++;
  }

  if (depth > MAX_ATX_COUNT) {
    return;
  }

  if (
    !depth ||
    (!settings.pedantic && value.charAt(index + 1) === C_HASH)
  ) {
    return;
  }

  length = value.length + 1;

  /* Eat intermediate white-space. */
  queue = '';

  while (++index < length) {
    character = value.charAt(index);

    if (character !== C_SPACE && character !== C_TAB) {
      index--;
      break;
    }

    queue += character;
  }

  /* Exit when not in pedantic mode without spacing. */
  if (
    !settings.pedantic &&
    queue.length === 0 &&
    character &&
    character !== C_NEWLINE
  ) {
    return;
  }

  if (silent) {
    return true;
  }

  /* Eat content. */
  subvalue += queue;
  queue = '';
  content = '';

  while (++index < length) {
    character = value.charAt(index);

    if (!character || character === C_NEWLINE) {
      break;
    }

    if (
      character !== C_SPACE &&
      character !== C_TAB &&
      character !== C_HASH
    ) {
      content += queue + character;
      queue = '';
      continue;
    }

    while (character === C_SPACE || character === C_TAB) {
      queue += character;
      character = value.charAt(++index);
    }

    while (character === C_HASH) {
      queue += character;
      character = value.charAt(++index);
    }

    while (character === C_SPACE || character === C_TAB) {
      queue += character;
      character = value.charAt(++index);
    }

    index--;
  }

  now.column += subvalue.length;
  now.offset += subvalue.length;
  subvalue += content + queue;

  return eat(subvalue)({
    type: 'heading',
    depth: depth,
    children: self.tokenizeInline(content, now)
  });
}