var _utils = require('../utils');
var replace = _utils.replace;
var merge = _utils.merge;
var noop = _utils.noop;


/**
 * Block-Level Grammar
 */

var block = {
  newline: /^\n+/,
  code: /^((?: {4}|\t)[^\n]+\n*)+/,
  fences: noop,
  yamlHeader: noop,
  hr: /^( *[-*_]){3,} *(?:\n|$)/,
  heading: /^ *(#{1,6}) *([^\n]+?) *#* *(?:\n|$)/,
  nptable: noop,
  lheading: /^([^\n]+)\n *(=|-){2,} *(?:\n|$)/,
  blockquote: /^( *>[^\n]+(\n(?!def)[^\n]+)*\n*)+/,
  list: /^( *)(bull) [\s\S]+?(?:hr|def|\n{2,}(?! )(?!\1bull )\n*|\s*$)/,
  html: /^ *(?:comment *(?:\n|\s*$)|closed *(?:\n{2,}|\s*$)|closing *(?:\n{2,}|\s*$))/,
  def: /^ *\[([^\]]+)\]: *<?([^\s>]+)>?(?: +["(]([^\n]+)[")])? *(?:\n|$)/,
  footnote: /^\[\^([^\]]+)\]: ([^\n]+)/,
  table: noop,
  paragraph: /^((?:[^\n]+\n?(?!hr|heading|lheading|blockquote|tag|def|math))+)\n*/,
  text: /^[^\n]+/,
  math: /^ *(\${2,}) *([\s\S]+?)\s*\1 *(?:\n|$)/,
};

block._bullet = /(?:[*+-]|\d+\.)/;
block._item = /^( *)(bull) [^\n]*(?:\n(?!\1bull )[^\n]*)*/;
block._item = replace(block._item, 'gm')
  (/bull/g, block._bullet)
  ();

block.list = replace(block.list)
  (/bull/g, block._bullet)
  ('hr', '\\n+(?=\\1?(?:[-*_] *){3,}(?:\\n+|$))')
  ('def', '\\n+(?=' + block.def.source + ')')
  ('footnote', block.footnote)
  ();

block.blockquote = replace(block.blockquote)
  ('def', block.def)
  ();

block._tag = '(?!(?:'
  + 'a|em|strong|small|s|cite|q|dfn|abbr|data|time|code'
  + '|var|samp|kbd|sub|sup|i|b|u|mark|ruby|rt|rp|bdi|bdo'
  + '|span|br|wbr|ins|del|img)\\b)\\w+(?!:\\/|[^\\w\\s@]*@)\\b';

block.html = replace(block.html)
  ('comment', /<!--[\s\S]*?-->/)
  ('closed', /<(tag)[\s\S]+?<\/\1>/)
  ('closing', /<tag(?:"[^"]*"|'[^']*'|[^'">])*?>/)
  (/tag/g, block._tag)
  ();

block.paragraph = replace(block.paragraph)
  ('hr', block.hr)
  ('heading', block.heading)
  ('lheading', block.lheading)
  ('blockquote', block.blockquote)
  ('tag', '<' + block._tag)
  ('def', block.def)
  ('math', block.math)
  ();

/**
 * Normal Block Grammar
 */

block.normal = merge({}, block);

/**
 * GFM Block Grammar
 */

block.gfm = merge({}, block.normal, {
  fences: /^ *(`{3,}|~{3,}) *(\S+)? *\n([\s\S]+?)\s*\1 *(?:\n|$)/,
  paragraph: /^/,
  yamlHeader: /^ *(?=```)/,
});

block.gfm.paragraph = replace(block.paragraph)
  ('(?!', '(?!'
    + block.gfm.fences.source.replace('\\1', '\\2') + '|'
    + block.list.source.replace('\\1', '\\3') + '|')
  ();

/**
 * GFM + Tables Block Grammar
 */

block.tables = merge({}, block.gfm, {
  nptable: /^ *(\S.*\|.*)\n *([-:]+ *\|[-| :]*)\n((?:.*\|.*(?:\n|$))*)\n*/,
  table: /^ *\|(.+)\n *\|( *[-:]+[-| :]*)\n((?: *\|.*(?:\n|$))*)\n*/
});

module.exports = block;