// Copyright (C) 2007, Fredrik Kuivinen <frekui@gmail.com>
//               2007, Petr Baudis <pasky@suse.cz>
//          2008-2011, Jakub Narebski <jnareb@gmail.com>

/**
 * @fileOverview Generic JavaScript code (helper functions)
 * @license GPLv2 or later
 */


/* ============================================================ */
/* ............................................................ */
/* Padding */

/**
 * pad number N with nonbreakable spaces on the left, to WIDTH characters
 * example: padLeftStr(12, 3, '\u00A0') == '\u00A012'
 *          ('\u00A0' is nonbreakable space)
 *
 * @param {Number|String} input: number to pad
 * @param {Number} width: visible width of output
 * @param {String} str: string to prefix to string, e.g. '\u00A0'
 * @returns {String} INPUT prefixed with (WIDTH - INPUT.length) x STR
 */
function padLeftStr(input, width, str) {
        var prefix = '';

        width -= input.toString().length;
        while (width > 0) {
                prefix += str;
                width--;
        }
        return prefix + input;
}

/**
 * Pad INPUT on the left to SIZE width, using given padding character CH,
 * for example padLeft('a', 3, '_') is '__a'.
 *
 * @param {String} input: input value converted to string.
 * @param {Number} width: desired length of output.
 * @param {String} ch: single character to prefix to string.
 *
 * @returns {String} Modified string, at least SIZE length.
 */
function padLeft(input, width, ch) {
        var s = input + "";
        while (s.length < width) {
                s = ch + s;
        }
        return s;
}


/* ............................................................ */
/* Ajax */

/**
 * Create XMLHttpRequest object in cross-browser way
 * @returns XMLHttpRequest object, or null
 */
function createRequestObject() {
        try {
                return new XMLHttpRequest();
        } catch (e) {}
        try {
                return window.createRequest();
        } catch (e) {}
        try {
                return new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {}
        try {
                return new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}

        return null;
}


/* ............................................................ */
/* time and data */

/**
 * used to extract hours and minutes from timezone info, e.g '-0900'
 * @constant
 */
var tzRe = /^([+-])([0-9][0-9])([0-9][0-9])$/;

/**
 * convert numeric timezone +/-ZZZZ to offset from UTC in seconds
 *
 * @param {String} timezoneInfo: numeric timezone '(+|-)HHMM'
 * @returns {Number} offset from UTC in seconds for timezone
 *
 * @globals tzRe
 */
function timezoneOffset(timezoneInfo) {
        var match = tzRe.exec(timezoneInfo);
        var tz_sign = (match[1] === '-' ? -1 : +1);
        var tz_hour = parseInt(match[2],10);
        var tz_min  = parseInt(match[3],10);

        return tz_sign*(((tz_hour*60) + tz_min)*60);
}

/**
 * return date in local time formatted in iso-8601 like format
 * 'yyyy-mm-dd HH:MM:SS +/-ZZZZ' e.g. '2005-08-07 21:49:46 +0200'
 *
 * @param {Number} epoch: seconds since '00:00:00 1970-01-01 UTC'
 * @param {String} timezoneInfo: numeric timezone '(+|-)HHMM'
 * @returns {String} date in local time in iso-8601 like format
 */
function formatDateISOLocal(epoch, timezoneInfo) {
        // date corrected by timezone
        var localDate = new Date(1000 * (epoch +
                timezoneOffset(timezoneInfo)));
        var localDateStr = // e.g. '2005-08-07'
                localDate.getUTCFullYear()                 + '-' +
                padLeft(localDate.getUTCMonth()+1, 2, '0') + '-' +
                padLeft(localDate.getUTCDate(),    2, '0');
        var localTimeStr = // e.g. '21:49:46'
                padLeft(localDate.getUTCHours(),   2, '0') + ':' +
                padLeft(localDate.getUTCMinutes(), 2, '0') + ':' +
                padLeft(localDate.getUTCSeconds(), 2, '0');

        return localDateStr + ' ' + localTimeStr + ' ' + timezoneInfo;
}


/* ............................................................ */
/* unquoting/unescaping filenames */

/**#@+
 * @constant
 */
var escCodeRe = /\\([^0-7]|[0-7]{1,3})/g;
var octEscRe = /^[0-7]{1,3}$/;
var maybeQuotedRe = /^\"(.*)\"$/;
/**#@-*/

/**
 * unquote maybe git-quoted filename
 * e.g. 'aa' -> 'aa', '"a\ta"' -> 'a    a'
 *
 * @param {String} str: git-quoted string
 * @returns {String} Unquoted and unescaped string
 *
 * @globals escCodeRe, octEscRe, maybeQuotedRe
 */
function unquote(str) {
        function unq(seq) {
                var es = {
                        // character escape codes, aka escape sequences (from C)
                        // replacements are to some extent JavaScript specific
                        t: "\t",   // tab            (HT, TAB)
                        n: "\n",   // newline        (NL)
                        r: "\r",   // return         (CR)
                        f: "\f",   // form feed      (FF)
                        b: "\b",   // backspace      (BS)
                        a: "\x07", // alarm (bell)   (BEL)
                        e: "\x1B", // escape         (ESC)
                        v: "\v"    // vertical tab   (VT)
                };

                if (seq.search(octEscRe) !== -1) {
                        // octal char sequence
                        return String.fromCharCode(parseInt(seq, 8));
                } else if (seq in es) {
                        // C escape sequence, aka character escape code
                        return es[seq];
                }
                // quoted ordinary character
                return seq;
        }

        var match = str.match(maybeQuotedRe);
        if (match) {
                str = match[1];
                // perhaps str = eval('"'+str+'"'); would be enough?
                str = str.replace(escCodeRe,
                        function (substr, p1, offset, s) { return unq(p1); });
        }
        return str;
}

/* end of common-lib.js */