// Underscore.strings
// (c) 2010 Esa-Matti Suuronen <esa-matti aet suuronen dot org>
// Underscore.strings is freely distributable under the terms of the MIT license.
// Documentation: http://bitbucket.org/epeli/underscore.strings/
// Some code is borrowed from MooTools and Alexandru Marasteanu.

// Version 1.0


(function(){
    // ------------------------- Baseline setup ---------------------------------

    // Establish the root object, "window" in the browser, or "global" on the server.
    var root = this;

    var nativeTrim = String.prototype.trim;

    function str_repeat(i, m) {
        for (var o = []; m > 0; o[--m] = i);
        return o.join('');
    }

    function defaultToWhiteSpace(characters){
        if (characters) {
            return _s.escapeRegExp(characters);
        }
        return '\\s';
    }

    var _s;
    _s = root._s = {

        capitalize : function(str) {
            return str.charAt(0).toUpperCase() + str.substring(1).toLowerCase();
          },

        join: function(sep) {
            // TODO: Could this be faster by converting 
            // arguments to Array and using array.join(sep)?
            sep = String(sep);
            var str = "";
            for (var i=1; i < arguments.length; i += 1) {
                str += String(arguments[i]);
                if ( i !== arguments.length-1 ) {
                    str += sep;
                }
            }
            return str;
          },

        escapeRegExp: function(str){
            // From MooTools core 1.2.4
            return str.replace(/([-.*+?^${}()|[\]\/\\])/g, '\\$1');
        },

        reverse: function(str){
            return Array.prototype.reverse.apply(str.split('')).join('');
        },  

        contains: function(str, needle){
            return str.indexOf(needle) !== -1;
        },

        clean: function(str){
            return _s.strip(str.replace(/\s+/g, ' '));
        },

        trim: function(str, characters){
            if (!characters && nativeTrim) {
                return nativeTrim.call(str);
            }
            characters = defaultToWhiteSpace(characters);
            return str.replace(new RegExp('\^[' + characters + ']+|[' + characters + ']+$', 'g'), '');
        },



        ltrim: function(str, characters){
            characters = defaultToWhiteSpace(characters);
            return str.replace(new RegExp('\^[' + characters + ']+', 'g'), '');
        },

        rtrim: function(str, characters){
            characters = defaultToWhiteSpace(characters);
            return str.replace(new RegExp('[' + characters + ']+$', 'g'), '');
        },


        startsWith: function(str, starts){
            return str.length >= starts.length && str.substring(0, starts.length) === starts;
        },


        endsWith: function(str, ends){
            return str.length >= ends.length && str.substring(str.length - ends.length) === ends;
        },


        /**
         * Credits for this function goes to
         * http://www.diveintojavascript.com/projects/sprintf-for-javascript
         *
         * Copyright (c) Alexandru Marasteanu <alexaholic [at) gmail (dot] com>
         * All rights reserved.
         * */
        sprintf: function(){

            var i = 0, a, f = arguments[i++], o = [], m, p, c, x, s = '';
            while (f) {
                if (m = /^[^\x25]+/.exec(f)) {
                    o.push(m[0]);
                }
                else if (m = /^\x25{2}/.exec(f)) {
                    o.push('%');
                }
                else if (m = /^\x25(?:(\d+)\$)?(\+)?(0|'[^$])?(-)?(\d+)?(?:\.(\d+))?([b-fosuxX])/.exec(f)) {
                    if (((a = arguments[m[1] || i++]) == null) || (a == undefined)) {
                        throw('Too few arguments.');
                    }
                    if (/[^s]/.test(m[7]) && (typeof(a) != 'number')) {
                        throw('Expecting number but found ' + typeof(a));
                    }
                    switch (m[7]) {
                        case 'b': a = a.toString(2); break;
                        case 'c': a = String.fromCharCode(a); break;
                        case 'd': a = parseInt(a); break;
                        case 'e': a = m[6] ? a.toExponential(m[6]) : a.toExponential(); break;
                        case 'f': a = m[6] ? parseFloat(a).toFixed(m[6]) : parseFloat(a); break;
                        case 'o': a = a.toString(8); break;
                        case 's': a = ((a = String(a)) && m[6] ? a.substring(0, m[6]) : a); break;
                        case 'u': a = Math.abs(a); break;
                        case 'x': a = a.toString(16); break;
                        case 'X': a = a.toString(16).toUpperCase(); break;
                    }
                    a = (/[def]/.test(m[7]) && m[2] && a >= 0 ? '+'+ a : a);
                    c = m[3] ? m[3] == '0' ? '0' : m[3].charAt(1) : ' ';
                    x = m[5] - String(a).length - s.length;
                    p = m[5] ? str_repeat(c, x) : '';
                    o.push(s + (m[4] ? a + p : p + a));
                }
                else {
                    throw('Huh ?!');
                }
                f = f.substring(m[0].length);
            }
            return o.join('');
        }
    }

    // Some aliases
    root._s.strip = _s.trim;
    root._s.lstrip = _s.ltrim;
    root._s.rstrip = _s.rtrim;


	// Integrate with Underscore.js
    if (root._) {
        root._.mixin(root._s);
    }

}());