/* Pretty handling of time axes.

Copyright © 2007-2013 IOLA and Ole Laursen. Licensed under the MIT license.

Set axis.mode to “time” to enable. See the section “Time series data” in API.txt for details.

*/

(function($) {

var options = {
        xaxis: {
                timezone: null,         // "browser" for local to the client or timezone for timezone-js
                timeformat: null,       // format string to use
                twelveHourClock: false, // 12 or 24 time in time mode
                monthNames: null        // list of names of months
        }
};

// round to nearby lower multiple of base

function floorInBase(n, base) {
        return base * Math.floor(n / base);
}

// Returns a string with the date d formatted according to fmt.
// A subset of the Open Group's strftime format is supported.

function formatDate(d, fmt, monthNames, dayNames) {

        if (typeof d.strftime == "function") {
                return d.strftime(fmt);
        }

        var leftPad = function(n, pad) {
                n = "" + n;
                pad = "" + (pad == null ? "0" : pad);
                return n.length == 1 ? pad + n : n;
        };

        var r = [];
        var escape = false;
        var hours = d.getHours();
        var isAM = hours < 12;

        if (monthNames == null) {
                monthNames = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
        }

        if (dayNames == null) {
                dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
        }

        var hours12;

        if (hours > 12) {
                hours12 = hours - 12;
        } else if (hours == 0) {
                hours12 = 12;
        } else {
                hours12 = hours;
        }

        for (var i = 0; i < fmt.length; ++i) {

                var c = fmt.charAt(i);

                if (escape) {
                        switch (c) {
                                case 'a': c = "" + dayNames[d.getDay()]; break;
                                case 'b': c = "" + monthNames[d.getMonth()]; break;
                                case 'd': c = leftPad(d.getDate()); break;
                                case 'e': c = leftPad(d.getDate(), " "); break;
                                case 'h':       // For back-compat with 0.7; remove in 1.0
                                case 'H': c = leftPad(hours); break;
                                case 'I': c = leftPad(hours12); break;
                                case 'l': c = leftPad(hours12, " "); break;
                                case 'm': c = leftPad(d.getMonth() + 1); break;
                                case 'M': c = leftPad(d.getMinutes()); break;
                                // quarters not in Open Group's strftime specification
                                case 'q':
                                        c = "" + (Math.floor(d.getMonth() / 3) + 1); break;
                                case 'S': c = leftPad(d.getSeconds()); break;
                                case 'y': c = leftPad(d.getFullYear() % 100); break;
                                case 'Y': c = "" + d.getFullYear(); break;
                                case 'p': c = (isAM) ? ("" + "am") : ("" + "pm"); break;
                                case 'P': c = (isAM) ? ("" + "AM") : ("" + "PM"); break;
                                case 'w': c = "" + d.getDay(); break;
                        }
                        r.push(c);
                        escape = false;
                } else {
                        if (c == "%") {
                                escape = true;
                        } else {
                                r.push(c);
                        }
                }
        }

        return r.join("");
}

// To have a consistent view of time-based data independent of which time
// zone the client happens to be in we need a date-like object independent
// of time zones.  This is done through a wrapper that only calls the UTC
// versions of the accessor methods.

function makeUtcWrapper(d) {

        function addProxyMethod(sourceObj, sourceMethod, targetObj, targetMethod) {
                sourceObj[sourceMethod] = function() {
                        return targetObj[targetMethod].apply(targetObj, arguments);
                };
        };

        var utc = {
                date: d
        };

        // support strftime, if found

        if (d.strftime != undefined) {
                addProxyMethod(utc, "strftime", d, "strftime");
        }

        addProxyMethod(utc, "getTime", d, "getTime");
        addProxyMethod(utc, "setTime", d, "setTime");

        var props = ["Date", "Day", "FullYear", "Hours", "Milliseconds", "Minutes", "Month", "Seconds"];

        for (var p = 0; p < props.length; p++) {
                addProxyMethod(utc, "get" + props[p], d, "getUTC" + props[p]);
                addProxyMethod(utc, "set" + props[p], d, "setUTC" + props[p]);
        }

        return utc;
};

// select time zone strategy.  This returns a date-like object tied to the
// desired timezone

function dateGenerator(ts, opts) {
        if (opts.timezone == "browser") {
                return new Date(ts);
        } else if (!opts.timezone || opts.timezone == "utc") {
                return makeUtcWrapper(new Date(ts));
        } else if (typeof timezoneJS != "undefined" && typeof timezoneJS.Date != "undefined") {
                var d = new timezoneJS.Date();
                // timezone-js is fickle, so be sure to set the time zone before
                // setting the time.
                d.setTimezone(opts.timezone);
                d.setTime(ts);
                return d;
        } else {
                return makeUtcWrapper(new Date(ts));
        }
}

// map of app. size of time units in milliseconds

var timeUnitSize = {
        "second": 1000,
        "minute": 60 * 1000,
        "hour": 60 * 60 * 1000,
        "day": 24 * 60 * 60 * 1000,
        "month": 30 * 24 * 60 * 60 * 1000,
        "quarter": 3 * 30 * 24 * 60 * 60 * 1000,
        "year": 365.2425 * 24 * 60 * 60 * 1000
};

// the allowed tick sizes, after 1 year we use
// an integer algorithm

var baseSpec = [
        [1, "second"], [2, "second"], [5, "second"], [10, "second"],
        [30, "second"], 
        [1, "minute"], [2, "minute"], [5, "minute"], [10, "minute"],
        [30, "minute"], 
        [1, "hour"], [2, "hour"], [4, "hour"],
        [8, "hour"], [12, "hour"],
        [1, "day"], [2, "day"], [3, "day"],
        [0.25, "month"], [0.5, "month"], [1, "month"],
        [2, "month"]
];

// we don't know which variant(s) we'll need yet, but generating both is
// cheap

var specMonths = baseSpec.concat([[3, "month"], [6, "month"],
        [1, "year"]]);
var specQuarters = baseSpec.concat([[1, "quarter"], [2, "quarter"],
        [1, "year"]]);

function init(plot) {
        plot.hooks.processOptions.push(function (plot, options) {
                $.each(plot.getAxes(), function(axisName, axis) {

                        var opts = axis.options;

                        if (opts.mode == "time") {
                                axis.tickGenerator = function(axis) {

                                        var ticks = [];
                                        var d = dateGenerator(axis.min, opts);
                                        var minSize = 0;

                                        // make quarter use a possibility if quarters are
                                        // mentioned in either of these options

                                        var spec = (opts.tickSize && opts.tickSize[1] ===
                                                "quarter") ||
                                                (opts.minTickSize && opts.minTickSize[1] ===
                                                "quarter") ? specQuarters : specMonths;

                                        if (opts.minTickSize != null) {
                                                if (typeof opts.tickSize == "number") {
                                                        minSize = opts.tickSize;
                                                } else {
                                                        minSize = opts.minTickSize[0] * timeUnitSize[opts.minTickSize[1]];
                                                }
                                        }

                                        for (var i = 0; i < spec.length - 1; ++i) {
                                                if (axis.delta < (spec[i][0] * timeUnitSize[spec[i][1]]
                                                                                  + spec[i + 1][0] * timeUnitSize[spec[i + 1][1]]) / 2
                                                        && spec[i][0] * timeUnitSize[spec[i][1]] >= minSize) {
                                                        break;
                                                }
                                        }

                                        var size = spec[i][0];
                                        var unit = spec[i][1];

                                        // special-case the possibility of several years

                                        if (unit == "year") {

                                                // if given a minTickSize in years, just use it,
                                                // ensuring that it's an integer

                                                if (opts.minTickSize != null && opts.minTickSize[1] == "year") {
                                                        size = Math.floor(opts.minTickSize[0]);
                                                } else {

                                                        var magn = Math.pow(10, Math.floor(Math.log(axis.delta / timeUnitSize.year) / Math.LN10));
                                                        var norm = (axis.delta / timeUnitSize.year) / magn;

                                                        if (norm < 1.5) {
                                                                size = 1;
                                                        } else if (norm < 3) {
                                                                size = 2;
                                                        } else if (norm < 7.5) {
                                                                size = 5;
                                                        } else {
                                                                size = 10;
                                                        }

                                                        size *= magn;
                                                }

                                                // minimum size for years is 1

                                                if (size < 1) {
                                                        size = 1;
                                                }
                                        }

                                        axis.tickSize = opts.tickSize || [size, unit];
                                        var tickSize = axis.tickSize[0];
                                        unit = axis.tickSize[1];

                                        var step = tickSize * timeUnitSize[unit];

                                        if (unit == "second") {
                                                d.setSeconds(floorInBase(d.getSeconds(), tickSize));
                                        } else if (unit == "minute") {
                                                d.setMinutes(floorInBase(d.getMinutes(), tickSize));
                                        } else if (unit == "hour") {
                                                d.setHours(floorInBase(d.getHours(), tickSize));
                                        } else if (unit == "month") {
                                                d.setMonth(floorInBase(d.getMonth(), tickSize));
                                        } else if (unit == "quarter") {
                                                d.setMonth(3 * floorInBase(d.getMonth() / 3,
                                                        tickSize));
                                        } else if (unit == "year") {
                                                d.setFullYear(floorInBase(d.getFullYear(), tickSize));
                                        }

                                        // reset smaller components

                                        d.setMilliseconds(0);

                                        if (step >= timeUnitSize.minute) {
                                                d.setSeconds(0);
                                        }
                                        if (step >= timeUnitSize.hour) {
                                                d.setMinutes(0);
                                        }
                                        if (step >= timeUnitSize.day) {
                                                d.setHours(0);
                                        }
                                        if (step >= timeUnitSize.day * 4) {
                                                d.setDate(1);
                                        }
                                        if (step >= timeUnitSize.month * 2) {
                                                d.setMonth(floorInBase(d.getMonth(), 3));
                                        }
                                        if (step >= timeUnitSize.quarter * 2) {
                                                d.setMonth(floorInBase(d.getMonth(), 6));
                                        }
                                        if (step >= timeUnitSize.year) {
                                                d.setMonth(0);
                                        }

                                        var carry = 0;
                                        var v = Number.NaN;
                                        var prev;

                                        do {

                                                prev = v;
                                                v = d.getTime();
                                                ticks.push(v);

                                                if (unit == "month" || unit == "quarter") {
                                                        if (tickSize < 1) {

                                                                // a bit complicated - we'll divide the
                                                                // month/quarter up but we need to take
                                                                // care of fractions so we don't end up in
                                                                // the middle of a day

                                                                d.setDate(1);
                                                                var start = d.getTime();
                                                                d.setMonth(d.getMonth() +
                                                                        (unit == "quarter" ? 3 : 1));
                                                                var end = d.getTime();
                                                                d.setTime(v + carry * timeUnitSize.hour + (end - start) * tickSize);
                                                                carry = d.getHours();
                                                                d.setHours(0);
                                                        } else {
                                                                d.setMonth(d.getMonth() +
                                                                        tickSize * (unit == "quarter" ? 3 : 1));
                                                        }
                                                } else if (unit == "year") {
                                                        d.setFullYear(d.getFullYear() + tickSize);
                                                } else {
                                                        d.setTime(v + step);
                                                }
                                        } while (v < axis.max && v != prev);

                                        return ticks;
                                };

                                axis.tickFormatter = function (v, axis) {

                                        var d = dateGenerator(v, axis.options);

                                        // first check global format

                                        if (opts.timeformat != null) {
                                                return formatDate(d, opts.timeformat, opts.monthNames, opts.dayNames);
                                        }

                                        // possibly use quarters if quarters are mentioned in
                                        // any of these places

                                        var useQuarters = (axis.options.tickSize &&
                                                        axis.options.tickSize[1] == "quarter") ||
                                                (axis.options.minTickSize &&
                                                        axis.options.minTickSize[1] == "quarter");

                                        var t = axis.tickSize[0] * timeUnitSize[axis.tickSize[1]];
                                        var span = axis.max - axis.min;
                                        var suffix = (opts.twelveHourClock) ? " %p" : "";
                                        var hourCode = (opts.twelveHourClock) ? "%I" : "%H";
                                        var fmt;

                                        if (t < timeUnitSize.minute) {
                                                fmt = hourCode + ":%M:%S" + suffix;
                                        } else if (t < timeUnitSize.day) {
                                                if (span < 2 * timeUnitSize.day) {
                                                        fmt = hourCode + ":%M" + suffix;
                                                } else {
                                                        fmt = "%b %d " + hourCode + ":%M" + suffix;
                                                }
                                        } else if (t < timeUnitSize.month) {
                                                fmt = "%b %d";
                                        } else if ((useQuarters && t < timeUnitSize.quarter) ||
                                                (!useQuarters && t < timeUnitSize.year)) {
                                                if (span < timeUnitSize.year) {
                                                        fmt = "%b";
                                                } else {
                                                        fmt = "%b %Y";
                                                }
                                        } else if (useQuarters && t < timeUnitSize.year) {
                                                if (span < timeUnitSize.year) {
                                                        fmt = "Q%q";
                                                } else {
                                                        fmt = "Q%q %Y";
                                                }
                                        } else {
                                                fmt = "%Y";
                                        }

                                        var rt = formatDate(d, fmt, opts.monthNames, opts.dayNames);

                                        return rt;
                                };
                        }
                });
        });
}

$.plot.plugins.push({
        init: init,
        options: options,
        name: 'time',
        version: '1.0'
});

// Time-axis support used to be in Flot core, which exposed the
// formatDate function on the plot object.  Various plugins depend
// on the function, so we need to re-expose it here.

$.plot.formatDate = formatDate;

})(jQuery);