/**
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.

 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA

 * RRDtool 1.4.5  Copyright by Tobi Oetiker, 1997-2010
 *
 * Convert to javascript: Manuel Sanmartin <manuel.luis at gmail.com>
 **/

"use strict";

/**
 * RrdTimeError
 * @constructor
 */
var RrdTimeError = function (message)
{
	this.name = "RrdTimeError";
	this.message = (message) ? message : "Error";
};
RrdTimeError.prototype = new Error();

/**
 * RrdTime
 * @constructor
 */
var RrdTime = function(tspec) /* parser */
{
	var date = new Date();
	var hr = 0;

	this.tspec = tspec;

	this.tokens = (tspec+'').match(/[0-9]+|[A-Za-z]+|[:.+-\/]/g);
	this.toklen = this.tokens.length;
	this.tokidx = 0;

	this.token = null;
	this.tokid = 0;

	this.specials = RrdTime.VARIOUSWORDS;

	/* establish the default time reference */
	this.type = RrdTime.ABSOLUTE_TIME;
	this.offset = 0;
	this.tm_sec = date.getSeconds();
	this.tm_min = date.getMinutes();
	this.tm_hour = date.getHours();
	this.tm_mday = date.getDate();
	this.tm_mon = date.getMonth();
	this.tm_year = date.getFullYear()-1900;
	this.tm_wday = date.getDay();

	this.gettok();
	switch (this.tokid) {
		case RrdTime.PLUS:
		case RrdTime.MINUS:
			break;          /* jump to OFFSET-SPEC part */
		case RrdTime.EPOCH:
			this.type = RrdTime.RELATIVE_TO_EPOCH;
			/* falls through */
		case RrdTime.START:
		case RrdTime.END:
			if (this.tokid === RrdTime.EPOCH)
				this.type = RrdTime.RELATIVE_TO_START_TIME;
			else
				this.type = RrdTime.RELATIVE_TO_END_TIME;
			this.tm_sec = 0;
			this.tm_min = 0;
			this.tm_hour = 0;
			this.tm_mday = 0;
			this.tm_mon = 0;
			this.tm_year = 0;
			/* falls through */
		case RrdTime.NOW:
			var time_reference = this.tokid;
			this.gettok();
			if (this.tokid == RrdTime.PLUS || this.tokid == RrdTime.MINUS)
				break;
			if (time_reference != RrdTime.NOW) {
				throw new RrdTimeError("'start' or 'end' MUST be followed by +|- offset");
			} else if (this.tokid != RrdTime.EOF) {
				throw new RrdTimeError("if 'now' is followed by a token it must be +|- offset");
			}
			break;
		case RrdTime.NUMBER: /* Only absolute time specifications below */
			var hour_sv = this.tm_hour;
			var year_sv = this.tm_year;
			this.tm_hour = 30;
			this.tm_year = 30000;
			this.tod();
			this.day();
			if (this.tm_hour == 30 && this.tm_year != 30000)
				this.tod();
			if (this.tm_hour == 30)
				this.tm_hour = hour_sv;
			if (this.tm_year == 30000)
				this.tm_year = year_sv;
			break;
		case RrdTime.JAN:
		case RrdTime.FEB:
		case RrdTime.MAR:
		case RrdTime.APR:
		case RrdTime.MAY:
		case RrdTime.JUN:
		case RrdTime.JUL:
		case RrdTime.AUG:
		case RrdTime.SEP:
		case RrdTime.OCT:
		case RrdTime.NOV:
		case RrdTime.DEC:
			this.day();
			if (this.tokid != RrdTime.NUMBER)
				break;
			this.tod();
			break;
		case RrdTime.TEATIME:
			hr += 4;
			/* falls through */
		case RrdTime.NOON:
			hr += 12;
			/* falls through */
		case RrdTime.MIDNIGHT:
			this.tm_hour = hr;
			this.tm_min = 0;
			this.tm_sec = 0;
			this.gettok();
			this.day();
			break;
		default:
			throw new RrdTimeError("unparsable time: "+this.token+" "+this.sct);
	} /* ugly case statement */

	/*
	 * the OFFSET-SPEC part
	 * (NOTE, the sc_tokid was prefetched for us by the previous code)
	 */
	if (this.tokid == RrdTime.PLUS || this.tokid == RrdTime.MINUS) {
		this.specials = RrdTime.TIMEMULTIPLIERS; /* switch special words context */
		while (this.tokid == RrdTime.PLUS || this.tokid == RrdTime.MINUS || this.tokid == RrdTime.NUMBER) {
			if (this.tokid == RrdTime.NUMBER) {
				this.plus_minus(-1);
			} else {
				this.plus_minus(this.tokid);
			}
			this.gettok();    /* We will get EOF eventually but that's OK, since token() will return us as many EOFs as needed */
		}
	}

	/* now we should be at EOF */
	if (this.tokid != RrdTime.EOF)
		throw new RrdTimeError("unparsable trailing text: '..."+this.token+"'");
//	if (this.type == RrdTime.ABSOLUTE_TIME)
//		if (mktime(&ptv->tm) == -1)  // FIXME ??
//			panic(e("the specified time is incorrect (out of range?)"));
};

RrdTime.EOF = -1;
RrdTime.MIDNIGHT = 0;
RrdTime.NOON = 1;
RrdTime.TEATIME = 2;
RrdTime.PM = 3;
RrdTime.AM = 4;
RrdTime.YESTERDAY = 5;
RrdTime.TODAY = 6;
RrdTime.TOMORROW = 7;
RrdTime.NOW = 8;
RrdTime.START = 9;
RrdTime.END = 10;
RrdTime.EPOCH = 11;
RrdTime.SECONDS = 12;
RrdTime.MINUTES = 13;
RrdTime.HOURS = 14;
RrdTime.DAYS = 15;
RrdTime.WEEKS = 16;
RrdTime.MONTHS = 17;
RrdTime.YEARS = 18;
RrdTime.MONTHS_MINUTES = 19;
RrdTime.NUMBER = 20;
RrdTime.PLUS = 21;
RrdTime.MINUS = 22;
RrdTime.DOT = 23;
RrdTime.COLON = 24;
RrdTime.SLASH = 25;
RrdTime.ID = 26;
RrdTime.JUNK = 27;
RrdTime.JAN = 28;
RrdTime.FEB = 29;
RrdTime.MAR = 30;
RrdTime.APR = 31;
RrdTime.MAY = 32;
RrdTime.JUN = 33;
RrdTime.JUL = 34;
RrdTime.AUG = 35;
RrdTime.SEP = 36;
RrdTime.OCT = 37;
RrdTime.NOV = 38;
RrdTime.DEC = 39;
RrdTime.SUN = 40;
RrdTime.MON = 41;
RrdTime.TUE = 42;
RrdTime.WED = 43;
RrdTime.THU = 44;
RrdTime.FRI = 45;
RrdTime.SAT = 46;

RrdTime.VARIOUSWORDS = {
	"midnight": RrdTime.MIDNIGHT, /* 00:00:00 of today or tomorrow */
	"noon": RrdTime.NOON,     /* 12:00:00 of today or tomorrow */
	"teatime": RrdTime.TEATIME,   /* 16:00:00 of today or tomorrow */
	"am": RrdTime.AM,         /* morning times for 0-12 clock */
	"pm": RrdTime.PM,         /* evening times for 0-12 clock */
	"tomorrow": RrdTime.TOMORROW,
	"yesterday": RrdTime.YESTERDAY,
	"today": RrdTime.TODAY,
	"now": RrdTime.NOW,
	"n": RrdTime.NOW,
	"start": RrdTime.START,
	"s": RrdTime.START,
	"end": RrdTime.END,
	"e": RrdTime.END,
	"epoch": RrdTime.EPOCH,
	"jan": RrdTime.JAN,
	"feb": RrdTime.FEB,
	"mar": RrdTime.MAR,
	"apr": RrdTime.APR,
	"may": RrdTime.MAY,
	"jun": RrdTime.JUN,
	"jul": RrdTime.JUL,
	"aug": RrdTime.AUG,
	"sep": RrdTime.SEP,
	"oct": RrdTime.OCT,
	"nov": RrdTime.NOV,
	"dec": RrdTime.DEC,
	"january": RrdTime.JAN,
	"february": RrdTime.FEB,
	"march": RrdTime.MAR,
	"april": RrdTime.APR,
//	"may": RrdTime.MAY,
	"june": RrdTime.JUN,
	"july": RrdTime.JUL,
	"august": RrdTime.AUG,
	"september": RrdTime.SEP,
	"october": RrdTime.OCT,
	"november": RrdTime.NOV,
	"december": RrdTime.DEC,
	"sunday": RrdTime.SUN,
	"sun": RrdTime.SUN,
	"monday": RrdTime.MON,
	"mon": RrdTime.MON,
	"tuesday": RrdTime.TUE,
	"tue": RrdTime.TUE,
	"wednesday": RrdTime.WED,
	"wed": RrdTime.WED,
	"thursday": RrdTime.THU,
	"thu": RrdTime.THU,
	"friday": RrdTime.FRI,
	"fri": RrdTime.FRI,
	"saturday": RrdTime.SAT,
	"sat": RrdTime.SAT
};

RrdTime.TIMEMULTIPLIERS = {
	"second": RrdTime.SECONDS,    /* seconds multiplier */
	"seconds": RrdTime.SECONDS,   /* (pluralized) */
	"sec": RrdTime.SECONDS,   /* (generic) */
	"s": RrdTime.SECONDS,     /* (short generic) */
	"minute": RrdTime.MINUTES,    /* minutes multiplier */
	"minutes": RrdTime.MINUTES,   /* (pluralized) */
	"min": RrdTime.MINUTES,   /* (generic) */
	"m": RrdTime.MONTHS_MINUTES,  /* (short generic) */
	"hour": RrdTime.HOURS,    /* hours ... */
	"hours": RrdTime.HOURS,   /* (pluralized) */
	"hr": RrdTime.HOURS,      /* (generic) */
	"h": RrdTime.HOURS,       /* (short generic) */
	"day": RrdTime.DAYS,      /* days ... */
	"days": RrdTime.DAYS,     /* (pluralized) */
	"d": RrdTime.DAYS,        /* (short generic) */
	"week": RrdTime.WEEKS,    /* week ... */
	"weeks": RrdTime.WEEKS,   /* (pluralized) */
	"wk": RrdTime.WEEKS,      /* (generic) */
	"w": RrdTime.WEEKS,       /* (short generic) */
	"month": RrdTime.MONTHS,  /* week ... */
	"months": RrdTime.MONTHS, /* (pluralized) */
	"mon": RrdTime.MONTHS,    /* (generic) */
	"year": RrdTime.YEARS,    /* year ... */
	"years": RrdTime.YEARS,   /* (pluralized) */
	"yr": RrdTime.YEARS,      /* (generic) */
	"y": RrdTime.YEARS        /* (short generic) */
};

RrdTime.ABSOLUTE_TIME = 0;
RrdTime.RELATIVE_TO_START_TIME = 1;
RrdTime.RELATIVE_TO_END_TIME = 2;
RrdTime.RELATIVE_TO_EPOCH = 3;

RrdTime.prototype.gettok = function ()
{
	if (this.tokidx >= this.toklen) {
		this.tokid = RrdTime.EOF;
	} else {
		this.token = this.tokens[this.tokidx];
		this.tokidx++;
		if (!isNaN(this.token)) {
			this.tokid = RrdTime.NUMBER;
			this.token = parseInt(this.token, 10);
		} else if (this.token === ':') {
			this.tokid = RrdTime.COLON;
		} else if (this.token === '.') {
			this.tokid = RrdTime.DOT;
		} else if (this.token === '+') {
			this.tokid = RrdTime.PLUS;
		} else if (this.token === '/') {
			this.tokid = RrdTime.SLASH;
		} else if (this.token === '-') {
			this.tokid = RrdTime.MINUS;
		} else {
			this.tokid = RrdTime.ID;
			if (this.token in this.specials)
				this.tokid = this.specials[this.token];
		}
	}
	return this.tokid;
};

RrdTime.prototype.plus_minus = function (doop)
{
	var op = RrdTime.PLUS;
	var prev_multiplier = -1;
	var delta;

	if (doop >= 0) {
		op = doop;
		if (this.gettok() != RrdTime.NUMBER)
			throw new RrdTimeError("There should be number after '"+(op == RrdTime.PLUS ? '+' : '-')+"'");
		prev_multiplier = -1;   /* reset months-minutes guessing mechanics */
	}
	/* if doop is < 0 then we repeat the previous op with the prefetched number */
	delta = this.token;
	if (this.gettok() == RrdTime.MONTHS_MINUTES) {
		/* hard job to guess what does that -5m means: -5mon or -5min? */
		switch (prev_multiplier) {
			case RrdTime.DAYS:
			case RrdTime.WEEKS:
			case RrdTime.MONTHS:
			case RrdTime.YEARS:
				this.tokid = RrdTime.MONTHS;
				break;
			case RrdTime.SECONDS:
			case RrdTime.MINUTES:
			case RrdTime.HOURS:
				this.tokid = RrdTime.MINUTES;
				break;
			default:
				if (delta < 6)  /* it may be some other value but in the context of RRD who needs less than 6 min deltas? */
					this.tokid = RrdTime.MONTHS;
				else
					this.tokid = RrdTime.MINUTES;
		}
	}
	prev_multiplier = this.tokid;
	switch (this.tokid) {
		case RrdTime.YEARS:
			this.tm_year += ( op == RrdTime.PLUS) ? delta : -delta;
			return;
		case RrdTime.MONTHS:
			this.tm_mon += ( op == RrdTime.PLUS) ? delta : -delta;
			return;
		case RrdTime.WEEKS:
			delta *= 7;
			/* falls through */
		case RrdTime.DAYS:
			this.tm_mday += ( op == RrdTime.PLUS) ? delta : -delta;
			return;
		case RrdTime.HOURS:
			this.offset += (op == RrdTime.PLUS) ? delta * 60 * 60 : -delta * 60 * 60;
			return;
		case RrdTime.MINUTES:
			this.offset += (op == RrdTime.PLUS) ? delta * 60 : -delta * 60;
			return;
		case RrdTime.SECONDS:
			this.offset += (op == RrdTime.PLUS) ? delta : -delta;
			return;
		default: /*default unit is seconds */
			this.offset += (op == RrdTime.PLUS) ? delta : -delta;
			return;
	}
	throw new RrdTimeError("well-known time unit expected after "+delta);
};

RrdTime.prototype.tod = function() /* tod() computes the time of day (TIME-OF-DAY-SPEC) */
{
	var hour, minute = 0;
	var tlen;
	/* save token status in  case we must abort */
	var tokid_sv = this.tokid;

	tlen = (this.token+"").length;
	/* first pick out the time of day - we assume a HH (COLON|DOT) MM time */
	if (tlen > 2)
		return;
	hour = this.token;
	this.gettok();
	if (this.tokid == RrdTime.SLASH || this.tokid == RrdTime.DOT) {
		/* guess we are looking at a date */
		this.tokid = tokid_sv;
		this.token = hour;
		return;
	}
	if (this.tokid == RrdTime.COLON) {
		if (this.gettok() != RrdTime.NUMBER)
			throw new RrdTimeError("Parsing HH:MM syntax, expecting MM as number, got none");
		minute = this.token;
		if (minute > 59)
			throw new RrdTimeError("parsing HH:MM syntax, got MM = "+minute+" (>59!)");
		this.gettok();
	}
	/* check if an AM or PM specifier was given */
	if (this.tokid == RrdTime.AM || this.tokid == RrdTime.PM) {
		if (hour > 12) {
			throw new RrdTimeError("there cannot be more than 12 AM or PM hours");
		}
		if (this.tokid == RrdTime.PM) {
			if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */
				hour += 12;
		} else {
			if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */
				hour = 0;
		}
		this.gettok();
	} else if (hour > 23) {
		/* guess it was not a time then ... */
		this.tokid = tokid_sv;
		this.token = hour;
		return;
	}
	this.tm_hour = hour;
	this.tm_min = minute;
	this.tm_sec = 0;
	if (this.tm_hour == 24) {
		this.tm_hour = 0;
		this.tm_mday++;
	}
};

RrdTime.prototype.assign_date = function(mday, mon, year)
{
	if (year > 138) {
		if (year > 1970) {
			year -= 1900;
		} else {
			throw new RrdTimeError("invalid year "+year+" (should be either 00-99 or >1900)");
		}
	} else if (year >= 0 && year < 38) {
		year += 100;    /* Allow year 2000-2037 to be specified as   */
	}
	/* 00-37 until the problem of 2038 year will */
	/* arise for unices with 32-bit time_t :)    */
	if (year < 70)
		throw new RrdTimeError("won't handle dates before epoch (01/01/1970), sorry");

	this.tm_mday = mday;
	this.tm_mon = mon;
	this.tm_year = year;
};

RrdTime.prototype.day = function ()
{
	var mday = 0, wday, mon, year = this.tm_year;

	switch (this.tokid) {
		case RrdTime.YESTERDAY:
			this.tm_mday--;
			/* falls through */
		case RrdTime.TODAY:
			this.gettok();
			break;
		case RrdTime.TOMORROW:
			this.tm_mday++;
			this.gettok();
			break;
		case RrdTime.JAN:
		case RrdTime.FEB:
		case RrdTime.MAR:
		case RrdTime.APR:
		case RrdTime.MAY:
		case RrdTime.JUN:
		case RrdTime.JUL:
		case RrdTime.AUG:
		case RrdTime.SEP:
		case RrdTime.OCT:
		case RrdTime.NOV:
		case RrdTime.DEC:
			mon = (this.tokid - RrdTime.JAN);
			if (this.gettok() != RrdTime.NUMBER)
				throw new RrdTimeError("the day of the month should follow month name");
			mday = this.token;
			if (this.gettok() == RrdTime.NUMBER) {
				year =	this.token;
				this.gettok();
			} else {
				year = this.tm_year;
			}
			this.assign_date(mday, mon, year);
			break;
		case RrdTime.SUN:
		case RrdTime.MON:
		case RrdTime.TUE:
		case RrdTime.WED:
		case RrdTime.THU:
		case RrdTime.FRI:
		case RrdTime.SAT:
			wday = (this.tokid - RrdTime.SUN);
			this.tm_mday += (wday - this.tm_wday);
			this.gettok();
			break;
		case RrdTime.NUMBER:
			mon = this.token;
			if (mon > 10 * 365 * 24 * 60 * 60) {
				this.localtime(mon);
				this.gettok();
				break;
			}
			if (mon > 19700101 && mon < 24000101) { /*works between 1900 and 2400 */
				var str = this.token + '';
				year = parseInt(str.substr(0,4),10);
				mon = parseInt(str.substr(4,2),10);
				mday = parseInt(str.substr(6,2),10);
				this.gettok();
			} else {
				this.gettok();
				if (mon <= 31 && (this.tokid == RrdTime.SLASH || this.tokid == RrdTime.DOT)) {
					var sep = this.tokid;
					if (this.gettok() != RrdTime.NUMBER)
						throw new RrdTimeError("there should be "+(RrdTime.DOT ? "month" : "day")+" number after '"+(RrdTime.DOT ? '.' : '/')+"'");
					mday = this.token;
					if (this.gettok() == sep) {
						if (this.gettok() != RrdTime.NUMBER)
							throw new RrdTimeError("there should be year number after '"+(sep == RrdTime.DOT ? '.' : '/')+"'");
						year = this.token;
						this.gettok();
					}
					if (sep == RrdTime.DOT) {
						var x = mday;
						mday = mon;
						mon = x;
					}
				}
		}
		mon--;
		if (mon < 0 || mon > 11)
			throw new RrdTimeError("did you really mean month "+(mon+1)+"?");
		if (mday < 1 || mday > 31)
			throw new RrdTimeError("I'm afraid that "+mday+" is not a valid day of the month");
		this.assign_date(mday, mon, year);
		break;
	}
};

RrdTime.prototype.localtime = function (tm)
{
	var date = new Date(tm*1000);
	this.tm_sec = date.getSeconds();
	this.tm_min = date.getMinutes();
	this.tm_hour = date.getHours();
	this.tm_mday = date.getDate();
	this.tm_mon = date.getMonth();
	this.tm_year = date.getFullYear()-1900;
	this.tm_wday = date.getDay();
};

RrdTime.prototype.mktime = function()
{
	var date = new Date(this.tm_year+1900, this.tm_mon, this.tm_mday, this.tm_hour, this.tm_min, this.tm_sec);
	return Math.round(date.getTime()/1000.0);
};

RrdTime.proc_start_end = function(start_t, end_t)
{
	var start, end;

	if (start_t.type == RrdTime.RELATIVE_TO_END_TIME &&  end_t.type == RrdTime.RELATIVE_TO_START_TIME)
		throw new RrdTimeError("the start and end times cannot be specified relative to each other");
	if (start_t.type == RrdTime.RELATIVE_TO_START_TIME)
		throw new RrdTimeError("the start time cannot be specified relative to itself");
	if (end_t.type == RrdTime.RELATIVE_TO_END_TIME)
		throw new RrdTimeError("the end time cannot be specified relative to itself");

	if (start_t.type == RrdTime.RELATIVE_TO_END_TIME) {
		end = end_t.mktime() + end_t.offset;
		var tmtmp = new Date(end*1000);
		tmtmp.setDate(tmtmp.getDate()+start_t.tm_mday);
		tmtmp.setMonth(tmtmp.getMonth()+start_t.tm_mon);
		tmtmp.setFullYear(tmtmp.getFullYear()+start_t.tm_year);
		start = Math.round(tmtmp.getTime()/1000.0) + start_t.offset;
	} else {
		start = start_t.mktime() + start_t.offset;
	}

	if (end_t.type == RrdTime.RELATIVE_TO_START_TIME) {
		start = start_t.mktime() + start_t.offset;
		var tmtmp = new Date(start*1000);
		tmtmp.setDate(tmtmp.getDate()+end_t.tm_mday);
		tmtmp.setMonth(tmtmp.getMonth()+end_t.tm_mon);
		tmtmp.setFullYear(tmtmp.getFullYear()+end_t.tm_year);
		end = Math.round(tmtmp.getTime()/1000.0) + end_t.offset;
	} else {
		end = end_t.mktime() + end_t.offset;
	}

	return [start, end];
};