var deburrLetter = require('./internal/deburrLetter'),
    toString = require('./toString');

/** Used to match latin-1 supplementary letters (excluding mathematical operators). */
var reLatin1 = /[\xc0-\xd6\xd8-\xde\xdf-\xf6\xf8-\xff]/g;

/** Used to compose unicode character classes. */
var rsComboMarksRange = '\\u0300-\\u036f\\ufe20-\\ufe23',
    rsComboSymbolsRange = '\\u20d0-\\u20f0';

/** Used to compose unicode capture groups. */
var rsCombo = '[' + rsComboMarksRange + rsComboSymbolsRange + ']';

/**
 * Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks) and
 * [combining diacritical marks for symbols](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks_for_Symbols).
 */
var reComboMark = RegExp(rsCombo, 'g');

/**
 * Deburrs `string` by converting [latin-1 supplementary letters](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
 * to basic latin letters and removing [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).
 *
 * @static
 * @memberOf _
 * @category String
 * @param {string} [string=''] The string to deburr.
 * @returns {string} Returns the deburred string.
 * @example
 *
 * _.deburr('déjà vu');
 * // => 'deja vu'
 */
function deburr(string) {
  string = toString(string);
  return string && string.replace(reLatin1, deburrLetter).replace(reComboMark, '');
}

module.exports = deburr;
