#ident "$Id: luach-ical.c,v 1.29 2007/03/11 14:31:07 rl Exp $"
/*
 * Hebrew - Gregorian Calendar (iCalendar)
 *
 * Author:
 *      Dr. Zvi Har'El,                             ד"ר צבי הראל
 *      Department of Mathematics,              הפקולטה למתמטיקה
 *      Technion, Israel Institute of Technology, הטכניון - מט"ל
 *      Haifa 32000, Israel.                   חיפה 32000, ישראל
 *      E-Mail: rl@math.technion.ac.il
 *
 * See:
 *	Dawson, F. and D. Stenerson, Internet Calendaring and Scheduling Core
 *	Object Specification (iCalendar), RFC2445, November 1998.
 */
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
extern int Gauss(int year, int g, int* day);
extern void alef(int n, int i, char* s);
static char* holidays(int month, int length, int wd, bool dflag, bool hflag,
	int year);
static char* reading(int month, int length, bool leap, bool dflag, bool hflag);
static char* omer(int day, int month, bool hflag);
static void vcalendar_begin(char *desc, bool g);
static void vcalendar_end();
static void vevent(char* desc, int year, int month, int day);

static int Hlen[13] = {
    30, 0, 0, 29, 30, 30, 29, 30, 29, 30, 29, 30, 29
};
static int Glen[12] = {
    31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
static char *Hmonth[13][2] = {
    { "Tishri",  "תשרי" },
    { "Heshvan", "חשון" },
    { "Kislev",  "כסלו" },
    { "Tevet",    "טבת" },
    { "Shevat",   "שבט" },
    { "Adar I", "אדר א" },
    { "",            "" },
    { "Nisan",   "ניסן" },
    { "Iyyar",    "איר" },
    { "Sivan",   "סיון" },
    { "Tammuz",  "תמוז" },
    { "Av",        "אב" },
    { "Elul",     "אלול"}
};
static const char *portion[54][2] = {
    { "Bereshit",           "בראשית" },
    { "Noach",                  "נח" },
    { "Lech-Lecha",          "לך־לך" },
    { "Vayera",               "וירא" },
    { "Chayei-Sarah",      "חיי־שרה" },
    { "Toldot",              "תולדת" },
    { "Vayetze",              "ויצא" },
    { "Vayishlach",          "וישלח" },
    { "Vayeshev",             "וישב" },
    { "Miketz",                "מקץ" },
    { "Vayigash",             "ויגש" },
    { "Vayechi",              "ויחי" },
    { "Shemot",               "שמות" },
    { "Vaera",                "וארא" },
    { "Bo",                     "בא" },
    { "Beshalach",            "בשלח" },
    { "Yitro",                "יתרו" },
    { "Mishpatim",          "משפטים" },
    { "Teruma",              "תרומה" },
    { "Tetzave",              "תצוה" },
    { "Ki-Tisa",            "כי־תשא" },
    { "Vayakhel",            "ויקהל" },
    { "Pekudei",             "פקודי" },
    { "Vayikra",             "ויקרא" },
    { "Tzav",                   "צו" },
    { "Shemini",             "שמיני" },
    { "Tazri’a",             "תזריע" },
    { "Metzora",              "מצרע" },
    { "Acharei-Mot",      "אחרי־מות" },
    { "Kedoshim",            "קדשים" },
    { "Emor",                  "אמר" },
    { "Behar",                 "בהר" },
    { "Bechukotai",          "בחקתי" },
    { "Bamidbar",            "במדבר" },
    { "Naso",                  "נשא" },
    { "Beha’alotcha",       "בהעלתך" },
    { "Shelach",               "שלח" },
    { "Korach",                "קרח" },
    { "Chukat",                "חקת" },
    { "Balak",                 "בלק" },
    { "Pinchas",             "פינחס" },
    { "Matot",                "מטות" },
    { "Mase’ei",              "מסעי" },
    { "Devarim",             "דברים" },
    { "Vaetchanan",         "ואתחנן" },
    { "Ekev",                  "עקב" },
    { "Re’e",                  "ראה" },
    { "Shoftim",             "שפטים" },
    { "Ki-Tetze",           "כי־תצא" },
    { "Ki-Tavo",           "כי־תבוא" },
    { "Nitzavim",            "נצבים" },
    { "Vayelech",             "וילך" },
    { "Ha’azinu",           "האזינו" },
    { "Vezot-Habracha", "וזאת־הברכה" }
};
int
main(int argc, const char **argv)
{
    bool dflag = false; //Israel/Diaspora style
    bool hflag = false; //English/Hebrew printout
    bool jflag = false; //Gregorian/Julian calendar
    bool xflag = false; //Exclude date and readings
    while (--argc > 0) {
	const char *p;
	int Hy; //Hebrew year (A.M.)
	if (*(p = *++argv) == '-') {
	    while (*++p) switch(*p) {
	    case 'e': //English printout
		hflag = false;
		break;
	    case 'h': //Hebrew printout
		hflag = true;
		break;
	    case 'i': //reading Israel style
		dflag = false;
	    break;
	    case 'd': //reading Diaspora style, second holidays
		dflag = true;
		break;
	    case 'g': //Gregorian calendar
		jflag = false;
		break;
	    case 'j': //Julian Calendar
		jflag = true;
		break;
	    case 'x': //Exclude dates and readings
		xflag = true;
		break;
	    case 'a': //All items
		xflag = false;
		break;
	    default:
		fprintf(stderr,"illegal option: %s\n", *argv);
		exit(1);
	    }
	} else if ((Hy = atoi(*argv))) {
	    bool g = !jflag && Hy>= 5343; //Gregorian flag
	    int Wd; //day in the week (mod. 7)
	    int Gd = Gauss(Hy - 1, g, &Wd);
		    //day in the Gregorian month (1:Glen[Gm])
	    int kvia = Gauss(Hy, g, NULL) - Gd + 365 - 353;
		    //excess of length of the Hebrew year over 353
	    int Gy = Hy - 3760; //Gregorian year
	    Glen[1] = 28;
	    if ((Gy % 4 == 0 && (!g || Gy%100 != 0))
		    || Gy % 400 == 0) {
		kvia++;
		Glen[1]++;
	    }
	    Gy--;
	    if (hflag) {
		Hmonth[6][1] = (kvia >= 30) ? "אדר ב" : "אדר";
	    } else {
		Hmonth[6][0] = (kvia >= 30) ? "Adar II" : "Adar";
	    }
	    Hlen[1] = (kvia % 30 == 2) ? 30 : 29;
	    Hlen[2] = (kvia % 30 == 0) ? 29 : 30;
	    Wd+=2;
	    if (Wd >= 7)
		Wd -= 7;
	    int Gm; //month in the Gregorian year (0:11)
	    if (Gd <= 21) {
		Gd += 10;
		Gm = 7;
	    } else if (Gd <= 51) {
		Gd -= 21;
		Gm = 8;
	    } else {
		Gd -= 51;
		Gm = 9;
	    }
	    int Hm = 0; //month in the Hebrew year (0:12)
	    int Hd = 1; //day in the Hebrew month (1:Hlen[Hm])
	    if (g && Hy == 5343)
		Gd -= 10;
	    char desc[100] = "";
	    if (hflag) {
		strcat(desc, "לוח עברי לשנת ");
		alef(Hy, 0, desc);
		strcat(desc, " נוסח ");
		strcat(desc, dflag? "הגולה" : "ישראל");
	    } else {
		sprintf(desc, "Hebrew Calendar for %d ", Hy);
		strcat(desc, dflag? "Diaspora" : "Israel");
		strcat(desc, " Style");
	    }
	    vcalendar_begin(desc, g);
	    for (int i = 0; i < kvia + 353; i++) {
		desc[0] = '\0';
		if (hflag) {
		    alef(Hd, 0, desc);
		    strcat(desc, " ");
		    strcat(desc, Hmonth[Hm][1]);
		    strcat(desc, " ");
		    alef(Hy, 0, desc);
		} else {
		    sprintf(desc, "%d %s %d", Hd, Hmonth[Hm][0], Hy);
		}
		if (!xflag)
		    vevent(desc, Gy, Gm + 1, Gd);
		char *s =  holidays(Hd, Hm, Wd, dflag, hflag, Hy);
		vevent(s, Gy, Gm + 1, Gd);
		if (Wd == 0 && !xflag) {
		    s = reading(Hd, Hm, kvia >= 30, dflag, hflag);
		    vevent(s, Gy, Gm + 1, Gd);
		}
		if (!xflag) {
		    s = omer(Hd, Hm, hflag);
		    vevent(s, Gy, Gm + 1, Gd);
		}

		if (Wd++ == 6) Wd = 0;
		if (Hd++ == Hlen[Hm]) {
		    Hd = 1;
		    Hm++;
		    if (kvia < 30 && Hm == 5)
			Hm++;
		}
		if (Gd++ == Glen[Gm]) {
		    Gd = 1;
		    if (Gm++ == 11) {
			Gm = 0;
			Gy++;
		    }
		}
		if (g && Hy == 5343 && Hm == 0 && Hd == 19)
		    Gd += 10;
	    }
	    vcalendar_end();
	} else {
	    fprintf(stderr,"illegal argument: %s\n",*argv);
	    exit(1);
	}
    }
    exit(0);
}

static char *
holidays(int day, //Day the hebrew month (1:Hlen[month])
	int month, //Hebrew Month (0:12)
	int wd, //Week day (0:6)
	bool dflag, //Diaspora second holidays
	bool hflag, //Hebrew printout
	int year)
{
    static char *holiday[30];
    if (day == 1) {
	for (int i = 0; i < 30; i++)
	    holiday[i] = NULL;
	int head = wd; /* Week day of the first day of the month (0:6) */
	holiday[0] = holiday[29] = !hflag ? "Rosh Chodesh" : "ראש חדש";
	switch (month) {
	    int i;
	case 0:
	    holiday[0] = holiday[1] = !hflag ? "Rosh Hashana" : "ראש השנה";
	    holiday[2+(head==5)] = !hflag ? "Tzom Gdalia" : "צום גדליה";
	    holiday[9] = !hflag ? "Yom Kipur" : "יום כפור";
	    for (i = 14; i < 15 + dflag; i++) {
		holiday[i] = !hflag ? "Succot" : "סכות";
	    }
	    for ( ; i < 20; i++) {
		holiday[i] = !hflag ? "Chol Hamoed Succot" : "חול המועד סכות";
	    }
	    holiday[20] = !hflag ? "Hosha’ana Raba" : "הושענא רבה";
	    if (!dflag) {
		holiday[21] = !hflag ? "Shmini Atzeret/Simchat Tora" :
			"שמיני עצרת/שמחת תורה";
	    } else {
		holiday[21] = !hflag ? "Shmini Atzeret" : "שמיני עצרת";
		holiday[22] = !hflag ? "Simchat Tora" : "שמחת תורה";
	    }
	    break;
	case 2:
	    for (i = 24; i < 29; i++) {
		holiday[i] = !hflag ? "Hannuka" : "חנכה";
	    }
	    holiday[29] = !hflag ? "Hannuka/Rosh Chodesh" : "חנכה/ראש חדש";
	    break;
	case 3:
	    holiday[0] = !hflag ? "Hannuka/Rosh Chodesh" : "חנכה/ראש חדש";
	    for (i = 1; i < 2  + (Hlen[2] == 29); i++) {
		holiday[i] = !hflag ? "Hannuka" : "חנכה";
	    }
	    holiday[9+(head==5)] = !hflag ? "Tzom Asara B’Tevet" : "צום עשרה בטבת";
	    break;
	case 4:
	    holiday[14] = !hflag ? "Tu BiShevat" : "ט״ו בשבט";
	    break;
	case 6:
	    holiday[12-2*(head==2)] = !hflag ? "Taanit Ester" : "תענית אסתר";
	    holiday[13] = !hflag ? "Purim" : "פורים";
	    holiday[14] = !hflag ? "Shushan Purim" : "שושן פורים";
	    break;
	case 7:
	    for (i = 14; i < 15 + dflag; i++) {
		holiday[i] = !hflag ? "Pesach" : "פסח";
	    }
	    for ( ; i < 20; i++) {
		holiday[i] = !hflag ? "Chol Hamoed Pesach" : "חול המועד פסח";
	    }
	    for ( ; i < 21 + dflag; i++) {
		holiday[i] = !hflag ? "Pesach" : "פסח";
	    }
	    holiday[26+(head==3)] = !hflag ? "Yom Hashoa" : "יום השואה";
	    break;
	case 8:
	    holiday[i=head==3?1:head==2?2:head==5&&year>=5764?4:3] =
			    !hflag ? "Yom Hazikaron" : "יום הזכרון";
	    holiday[i+1] = !hflag ? "Yom Haatzmaut" : "יום העצמאות";
	    holiday[13] = !hflag ? "Pesach Sheni" : "פסח שני";
	    holiday[17] = !hflag ? "Lag BaOmer" : "ל״ג בעמר";
	    holiday[27] = !hflag ? "Yom Yerushalaim" : "יום ירושלים";
	    break;
	case 9:
	    for (i = 5; i < 6 + dflag; i++) {
		holiday[i] = !hflag ? "Shavuot" : "שבועות";
	    }
	    break;
	case 10:
	    holiday[16+(head==5)] = !hflag ? "Tzom Shiv’a Asar B’Tammuz" :
		    "צום שבעה עשר בתמוז";
	    break;
	case 11:
	    holiday[8+(head==6)] = !hflag ? "Tzom Tish’a B’Av" :
		    "צום תשעה באב";
	    holiday[14] = !hflag ? "Tu B’Av" : "ט״ו באב";
	    break;
	}
    }
    return holiday[day - 1];
}

static char*
reading(int day, //Day the hebrew month (1:Hlen[month])
	int month, //Hebrew Month (0:12)
	bool leap, //leap year
	bool dflag, //Israel/Diaspora style
	bool hflag)  //English/Hebrew printout
{
    static bool holiday[5];
    static char *special[5];
    static int seq; //Portion sequence number (1:53)
    static int head; //Week day of the first day of the month (0:6)
    static char result[40];
    if (day <= 7) {
	//Mark Saturdays which fall in a holiday in Tishri, Nisan and Sivan.
	//Mark special Saturday in Tishri.
	//Mark 4 special Saturdays in Adar or its vicinity.
	//Initialize reading sequence in Tishri.
	head = (8 - day) % 7;
	if (month == 0) {
	    holiday[2] = true;
	    if (head == 0) {
		seq = 53;//Haazinu
		holiday[0] = true;
		special[1] = !hflag ? "Shuva" : "שובה";
		holiday[3] = true;
	    } else if (head == 5) {
		seq = 53;//Haazinu
		special[0] = !hflag ? "Shuva" : "שובה";
		holiday[1] = true;
	    } else {
		seq = 52;//Vayelech
		special[0] = !hflag ? "Shuva" : "שובה";
	    }
	} else if (month == 5 || (month == 4 && !leap)) {
	    if (head != 5)
		special[3 + (head == 0)] = !hflag ? "Shekalim" : "שקלים";
	} else if (month == 6) {
	    if (head == 0)
		special[0] = !hflag ? "Shekalim" : "שקלים";
	    special[1] = !hflag ? "Zachor" : "זכור";
	    special[2 + (head == 0 || head == 6)] = !hflag ? "Para" : "פרה";
	    if (head != 6)
		special[3 + (head == 0)] = !hflag ? "Hachodesh" : "החודש";
	} else if (month == 7) {
	    if (head == 0)
		special[0] = !hflag ? "Hachodesh" : "החודש";
	    holiday[2] = true;
	    if (dflag && head == 0) holiday[3] = true;
	} else if (month == 9 && dflag && head == 1) {
	    holiday[0] = true;
	}
    }
    int i = day / 7; //The ordinal number of this Saturday in the month
    if (holiday[i]) {
	holiday[i] = false;
	return NULL;
    }
    // Print reading sequence.
    // Check for possible joined reading.
    strcpy(result, portion[seq-1][hflag]);
    if ((seq == 22 /*Vayakhel/Pekudei*/ &&
		!leap && (head != 0 || i == 4)) ||
	    (seq == 27 /*Tazria/Metzora*/ &&
		!leap) ||
	    (seq == 29 /*Acharei/Kedoshim*/ &&
		!leap) ||
	    (seq == 32 /*Behar/Bechukotai*/ &&
		!leap && (dflag || head != 2)) ||
	    (seq == 39 /*Chukat/Balak*/ &&
		dflag && head == 3) ||
	    (seq == 42 /*Matot/Masei*/ &&
		(!leap || (dflag && month == 11) ||
		(month == 10 && (head == 3 || (head == 1 && i == 3))))) ||
	    (seq == 51 /*Nitzavim/Vayelech*/ &&
		(head == 4 || head == 6))) {
	strcat(result, "/");
	strcat(result, portion[seq++][hflag]);
    }
    if (special[i]) {
	strcat(result, "/");
	strcat(result, special[i]);
	special[i] = NULL;
    }
    if (seq++ == 53)
	seq = 1;
    return result;
}

static char*
omer(int day, //Day the hebrew month (1:Hlen[month])
	int month, //Hebrew Month (0:12)
	bool hflag)  //English/Hebrew printout
{
    static char result[10];
    int count;
    if (month == 7 && day >= 16)
	count = day - 15;
    else if (month == 8)
	count = day + 15;
    else if (month == 9 && day <= 5)
	count = day + 44;
    else
	return NULL;
    if (hflag) {
	result[0] = '\0';
	alef(count, 0, result);
	strcat(result, " בעמר");
    } else {
	sprintf(result, "%d BaOmer", count);
    }
    return result;
}

static void
vevent(char* desc, int year, int month, int day)
{
    if (!desc)
	return;
    printf("BEGIN:VEVENT\r\n");
    printf("SUMMARY:%s\r\n", desc);
    printf("DTSTART;VALUE=DATE:%.4d%.2d%.2d\r\n", year, month, day);
    printf("END:VEVENT\r\n");
}

static void
vcalendar_begin(char* desc, bool g)
{
    printf("BEGIN:VCALENDAR\r\n");
    printf("VERSION:2.0\r\n");
    printf("PRODID:-//Gilead.org.il//NONSGML Luach-iCal $Revision: 1.29 $//EN\r\n");
    printf("X-WR-CALNAME: %s\r\n", desc);
    if (g)
	printf("CALSCALE:GREGORIAN\r\n");
    else
	printf("CALSCALE:JULIAN\r\n");
}

static void
vcalendar_end()
{
    printf("END:VCALENDAR\r\n");
}