acuminous/yadda

'use strict';

var $ = require('../Array');
var StringUtils = require('../StringUtils');
var COLUMN_SEPARATOR_REGEX = /[\|\u2506]/;
var OUTER_BORDERS_REGEX = /^[\|\u2506]|[\|\u2506]$/g;
var DASH_REGEX = /^[\\|\u2506]?-{3,}/;

module.exports = function table_converter(value, next) {
  var rows = value.split(/\n/);
  var headings = parse_headings(rows.shift());
  var handler = is_horizinal_separator(rows[0]) ? handle_multiline_row : handle_single_line_row;
  var table = $();

  try {
    $(rows).each(handler);
    next(null, collapse(table));
  } catch (err) {
    next(err);
  }

  function handle_single_line_row(row) {
    if (is_horizinal_separator(row)) throw new Error('Dashes are unexpected at this time');
    start_new_row();
    parse_fields(row);
  }

  function handle_multiline_row(row) {
    if (is_horizinal_separator(row)) return start_new_row();
    parse_fields(row);
  }

  function parse_headings(row) {
    return $(row.replace(OUTER_BORDERS_REGEX, '').split(COLUMN_SEPARATOR_REGEX))
      .collect(function (value) {
        return { text: StringUtils.trim(value), indentation: StringUtils.indentation(value) };
      })
      .naked();
  }

  function is_horizinal_separator(row) {
    return DASH_REGEX.test(row);
  }

  function start_new_row() {
    table.push({});
  }

  function parse_fields(row) {
    var fields = table.last();
    $(row.replace(OUTER_BORDERS_REGEX, '').split(COLUMN_SEPARATOR_REGEX)).each(function (field, index) {
      var column = headings[index].text;
      var indentation = headings[index].indentation;
      var text = StringUtils.rtrim(field.substr(indentation));
      if (StringUtils.isNotBlank(field) && StringUtils.indentation(field) < indentation) throw new Error('Indentation error');
      fields[column] = (fields[column] || []).concat(text);
    });
  }

  function collapse(table) {
    return table
      .collect(function (row) {
        var new_row = {};
        for (var heading in row) {
          new_row[heading] = row[heading].join('\n');
        }
        return new_row;
      })
      .naked();
  }
};