/*
   Copyright Rasmus Frederiksen <rasmus@vector.dk>
   2017. Some rights reserved.
   Free for non-commercial use with attribution.
*/

class SyntaxError extends Error {
  constructor(message, position) {
    super(message);
    this.name = "SyntaxError";
    this.position = position;
  }
}

var T = {
  NUM:      1,
  LPAREN:   2,
  RPAREN:   5,
  PIPE:     6,
  SLASH:    7,
  END:      8
}

var REGEXP = {
  NUM: /^(\d+)(\[([^\]]*?)\])?(\[([^\]]*?)\])?/
}

var tokenize = function(str) {

  var tokens = [],
        oStr = str,
        i, strL, delta, isNum, num;

  // Get rid of spaces
  str = str.replace(/[ ]*/g, '');

  // Store initial length
  strL = str.length;

  // Convert str to tokens
  while (str.length) {
    isNum = REGEXP.NUM.test(str);
    if (isNum) {
      num = REGEXP.NUM.exec(str);
      tokens.push({type: T.NUM, index: num[1], width: num[3], height: num[5]});
      str = str.substr(num[0].length);
    } else if (str.charAt(0) === '(') {
      tokens.push({type: T.LPAREN});
      str = str.substr(1);
    } else if (str.charAt(0) === ')') {
      tokens.push({type: T.RPAREN});
      str = str.substr(1);
    } else if (str.charAt(0) === '|') {
      tokens.push({type: T.PIPE});
      str = str.substr(1);
    } else if (str.charAt(0) === '/') {
      tokens.push({type: T.SLASH});
      str = str.substr(1);
    } else {
      delta = strL - str.length + 1;
      i = 0;
      while (delta) {
        if (oStr[i] !== ' ') delta--;
        i++;
      }
      throw new SyntaxError(`Illegal char: '${str.charAt(0)}' at position: ${i}`, i);
    }
  }
  tokens.push({type: T.END});
  return tokens;
}

var div = function (opts, contents) {
  var i, keys, node;
  keys = Object.keys(opts);
  node = document.createElement('div');
  for (i = 0; i < keys.length; i++) {
    if (opts.hasOwnProperty(keys[i])) {
      if (opts[keys[i]] !== undefined) {
        node.setAttribute(keys[i], opts[keys[i]]);    
      }
    }
  }
  if (contents !== undefined) {
    if (!Array.isArray(contents)) contents = [contents];
    for (i = 0; i < contents.length; i++) {
      node.appendChild(contents[i]);
    }    
  }
  return node;
}

var parse = function (str) {

  var tokens = tokenize(str);

  var consume = function (type) {
    return (peek() === type) ? tokens.shift() : null;
  }

  var peek = function () {
    return tokens[0].type;
  }

  var rows = function () {
    var val = [];
    val.push(cols());
    while (peek() === T.SLASH) {
      consume(T.SLASH);
      val.push(cols());
    }
    return div({class: 'rows'}, val);
  }

  var cols = function () {
    var val = [];
    val.push(cell());
    while (peek() === T.PIPE) {
      consume(T.PIPE);
      val.push(cell());
    }
    return div({class: 'cols'}, val);
  }

  var cell = function () {
    var val, num;
    if (peek() === T.NUM) {
      num = consume(T.NUM);
      return div({class: 'cell', 'data-index': num.index, 'data-width': num.width, 'data-height': num.height});
    } else if (peek() === T.LPAREN) {
      consume(T.LPAREN);
      val = rows();
      consume(T.RPAREN);
      return val;
    }
  }

  return rows();

}