/* Pretty handling of time axes.

Copyright (c) 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);