/**
 * @class Ext.util.Format
 * Reusable data formatting functions
 * @singleton
 */
Ext.util.Format = function() {
    var trimRe         = /^\s+|\s+$/g,
        stripTagsRE    = /<\/?[^>]+>/gi,
        stripScriptsRe = /(?:<script.*?>)((\n|\r|.)*?)(?:<\/script>)/ig,
        nl2brRe        = /\r?\n/g;

    return {
        /**
         * Truncate a string and add an ellipsis ('...') to the end if it exceeds the specified length
         * @param {String} value The string to truncate
         * @param {Number} length The maximum length to allow before truncating
         * @param {Boolean} word True to try to find a common work break
         * @return {String} The converted text
         */
        ellipsis : function(value, len, word) {
            if (value && value.length > len) {
                if (word) {
                    var vs    = value.substr(0, len - 2),
                        index = Math.max(vs.lastIndexOf(' '), vs.lastIndexOf('.'), vs.lastIndexOf('!'), vs.lastIndexOf('?'));
                    if (index == -1 || index < (len - 15)) {
                        return value.substr(0, len - 3) + "...";
                    } else {
                        return vs.substr(0, index) + "...";
                    }
                } else {
                    return value.substr(0, len - 3) + "...";
                }
            }
            return value;
        },

        /**
         * Checks a reference and converts it to empty string if it is undefined
         * @param {Mixed} value Reference to check
         * @return {Mixed} Empty string if converted, otherwise the original value
         */
        undef : function(value) {
            return value !== undefined ? value : "";
        },

        /**
         * Checks a reference and converts it to the default value if it's empty
         * @param {Mixed} value Reference to check
         * @param {String} defaultValue The value to insert if it's undefined (defaults to "")
         * @return {String}
         */
        defaultValue : function(value, defaultValue) {
            if (!defaultValue && defaultValue !== 0) {
                defaultValue = '';
            }
            return value !== undefined && value !== '' ? value : defaultValue;
        },

        /**
         * Convert certain characters (&, <, >, and ') to their HTML character equivalents for literal display in web pages.
         * @param {String} value The string to encode
         * @return {String} The encoded text
         */
        htmlEncode : function(value) {
            return !value ? value : String(value).replace(/&/g, "&amp;").replace(/>/g, "&gt;").replace(/</g, "&lt;").replace(/"/g, "&quot;");
        },

        /**
         * Convert certain characters (&, <, >, and ') from their HTML character equivalents.
         * @param {String} value The string to decode
         * @return {String} The decoded text
         */
        htmlDecode : function(value) {
            return !value ? value : String(value).replace(/&gt;/g, ">").replace(/&lt;/g, "<").replace(/&quot;/g, '"').replace(/&amp;/g, "&");
        },

        /**
         * Trims any whitespace from either side of a string
         * @param {String} value The text to trim
         * @return {String} The trimmed text
         */
        trim : function(value) {
            return String(value).replace(trimRe, "");
        },

        /**
         * Returns a substring from within an original string
         * @param {String} value The original text
         * @param {Number} start The start index of the substring
         * @param {Number} length The length of the substring
         * @return {String} The substring
         */
        substr : function(value, start, length) {
            return String(value).substr(start, length);
        },

        /**
         * Converts a string to all lower case letters
         * @param {String} value The text to convert
         * @return {String} The converted text
         */
        lowercase : function(value) {
            return String(value).toLowerCase();
        },

        /**
         * Converts a string to all upper case letters
         * @param {String} value The text to convert
         * @return {String} The converted text
         */
        uppercase : function(value) {
            return String(value).toUpperCase();
        },

        /**
         * Converts the first character only of a string to upper case
         * @param {String} value The text to convert
         * @return {String} The converted text
         */
        capitalize : function(value) {
            return !value ? value : value.charAt(0).toUpperCase() + value.substr(1).toLowerCase();
        },

        // private
        call : function(value, fn) {
            if (arguments.length > 2) {
                var args = Array.prototype.slice.call(arguments, 2);
                args.unshift(value);
                return eval(fn).apply(window, args);
            } else {
                return eval(fn).call(window, value);
            }
        },

        /**
         * Format a number as US currency
         * @param {Number/String} value The numeric value to format
         * @return {String} The formatted currency string
         */
        usMoney : function(v) {
            v = (Math.round((v-0)*100))/100;
            v = (v == Math.floor(v)) ? v + ".00" : ((v*10 == Math.floor(v*10)) ? v + "0" : v);
            v = String(v);
            var ps = v.split('.'),
                whole = ps[0],
                sub = ps[1] ? '.'+ ps[1] : '.00',
                r = /(\d+)(\d{3})/;
            while (r.test(whole)) {
                whole = whole.replace(r, '$1' + ',' + '$2');
            }
            v = whole + sub;
            if (v.charAt(0) == '-') {
                return '-$' + v.substr(1);
            }
            return "$" +  v;
        },

        /**
         * Parse a value into a formatted date using the specified format pattern.
         * @param {String/Date} value The value to format (Strings must conform to the format expected by the javascript Date object's <a href="http://www.w3schools.com/jsref/jsref_parse.asp">parse()</a> method)
         * @param {String} format (optional) Any valid date format string (defaults to 'm/d/Y')
         * @return {String} The formatted date string
         */
        date : function(v, format) {
            if (!v) {
                return "";
            }
            if (!Ext.isDate(v)) {
                v = new Date(Date.parse(v));
            }
            return v.dateFormat(format || "m/d/Y");
        },

        /**
         * Returns a date rendering function that can be reused to apply a date format multiple times efficiently
         * @param {String} format Any valid date format string
         * @return {Function} The date formatting function
         */
        dateRenderer : function(format) {
            return function(v) {
                return Ext.util.Format.date(v, format);
            };
        },

        /**
         * Strips all HTML tags
         * @param {Mixed} value The text from which to strip tags
         * @return {String} The stripped text
         */
        stripTags : function(v) {
            return !v ? v : String(v).replace(stripTagsRE, "");
        },

        /**
         * Strips all script tags
         * @param {Mixed} value The text from which to strip script tags
         * @return {String} The stripped text
         */
        stripScripts : function(v) {
            return !v ? v : String(v).replace(stripScriptsRe, "");
        },

        /**
         * Simple format for a file size (xxx bytes, xxx KB, xxx MB)
         * @param {Number/String} size The numeric value to format
         * @return {String} The formatted file size
         */
        fileSize : function(size) {
            if (size < 1024) {
                return size + " bytes";
            } else if (size < 1048576) {
                return (Math.round(((size*10) / 1024))/10) + " KB";
            } else {
                return (Math.round(((size*10) / 1048576))/10) + " MB";
            }
        },

        /**
         * It does simple math for use in a template, for example:<pre><code>
         * var tpl = new Ext.Template('{value} * 10 = {value:math("* 10")}');
         * </code></pre>
         * @return {Function} A function that operates on the passed value.
         */
        math : function(){
            var fns = {};
            
            return function(v, a){
                if (!fns[a]) {
                    fns[a] = new Function('v', 'return v ' + a + ';');
                }
                return fns[a](v);
            };
        }(),

        /**
         * Rounds the passed number to the required decimal precision.
         * @param {Number/String} value The numeric value to round.
         * @param {Number} precision The number of decimal places to which to round the first parameter's value.
         * @return {Number} The rounded value.
         */
        round : function(value, precision) {
            var result = Number(value);
            if (typeof precision == 'number') {
                precision = Math.pow(10, precision);
                result = Math.round(value * precision) / precision;
            }
            return result;
        },

        /**
         * Formats the number according to the format string.
         * <div style="margin-left:40px">examples (123456.789):
         * <div style="margin-left:10px">
         * 0 - (123456) show only digits, no precision<br>
         * 0.00 - (123456.78) show only digits, 2 precision<br>
         * 0.0000 - (123456.7890) show only digits, 4 precision<br>
         * 0,000 - (123,456) show comma and digits, no precision<br>
         * 0,000.00 - (123,456.78) show comma and digits, 2 precision<br>
         * 0,0.00 - (123,456.78) shortcut method, show comma and digits, 2 precision<br>
         * To reverse the grouping (,) and decimal (.) for international numbers, add /i to the end.
         * For example: 0.000,00/i
         * </div></div>
         * @param {Number} v The number to format.
         * @param {String} format The way you would like to format this text.
         * @return {String} The formatted number.
         */
        number: function(v, format) {
            if (!format) {
                return v;
            }
            v = Ext.num(v, NaN);
            if (isNaN(v)) {
                return '';
            }
            var comma = ',',
                dec   = '.',
                i18n  = false,
                neg   = v < 0;

            v = Math.abs(v);
            if (format.substr(format.length - 2) == '/i') {
                format = format.substr(0, format.length - 2);
                i18n   = true;
                comma  = '.';
                dec    = ',';
            }

            var hasComma = format.indexOf(comma) != -1,
                psplit   = (i18n ? format.replace(/[^\d\,]/g, '') : format.replace(/[^\d\.]/g, '')).split(dec);

            if (1 < psplit.length) {
                v = v.toFixed(psplit[1].length);
            } else if(2 < psplit.length) {
                throw ('NumberFormatException: invalid format, formats should have no more than 1 period: ' + format);
            } else {
                v = v.toFixed(0);
            }

            var fnum = v.toString();

            psplit = fnum.split('.');

            if (hasComma) {
                var cnum = psplit[0], 
                    parr = [], 
                    j    = cnum.length, 
                    m    = Math.floor(j / 3),
                    n    = cnum.length % 3 || 3,
                    i;

                for (i = 0; i < j; i += n) {
                    if (i != 0) {
                        n = 3;
                    }
                    
                    parr[parr.length] = cnum.substr(i, n);
                    m -= 1;
                }
                fnum = parr.join(comma);
                if (psplit[1]) {
                    fnum += dec + psplit[1];
                }
            } else {
                if (psplit[1]) {
                    fnum = psplit[0] + dec + psplit[1];
                }
            }

            return (neg ? '-' : '') + format.replace(/[\d,?\.?]+/, fnum);
        },

        /**
         * Returns a number rendering function that can be reused to apply a number format multiple times efficiently
         * @param {String} format Any valid number format string for {@link #number}
         * @return {Function} The number formatting function
         */
        numberRenderer : function(format) {
            return function(v) {
                return Ext.util.Format.number(v, format);
            };
        },

        /**
         * Selectively do a plural form of a word based on a numeric value. For example, in a template,
         * {commentCount:plural("Comment")}  would result in "1 Comment" if commentCount was 1 or would be "x Comments"
         * if the value is 0 or greater than 1.
         * @param {Number} value The value to compare against
         * @param {String} singular The singular form of the word
         * @param {String} plural (optional) The plural form of the word (defaults to the singular with an "s")
         */
        plural : function(v, s, p) {
            return v +' ' + (v == 1 ? s : (p ? p : s+'s'));
        },

        /**
         * Converts newline characters to the HTML tag &lt;br/>
         * @param {String} The string value to format.
         * @return {String} The string with embedded &lt;br/> tags in place of newlines.
         */
        nl2br : function(v) {
            return Ext.isEmpty(v) ? '' : v.replace(nl2brRe, '<br/>');
        }
    };
}();