/*	$calcurse: recur.c,v 1.1 2006/07/31 21:00:03 culot Exp $	*/

/*
 * Calcurse - text-based organizer
 * Copyright (c) 2004-2006 Frederic Culot
 *
 * 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.
 *
 * Send your feedback or comments to : calcurse@culot.org
 * Calcurse home page : http://culot.org/calcurse
 *
 */

#include <ncurses.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <time.h>

#include "i18n.h"
#include "utils.h"
#include "apoint.h"
#include "event.h"
#include "recur.h"

struct recur_apoint_s *recur_alist;
struct recur_event_s *recur_elist;

/* Insert a new recursive appointment in the general linked list */
struct recur_apoint_s *recur_apoint_new(char *mesg, long start, long dur, 
	int type, int freq, long until)
{
	struct recur_apoint_s *o, **i;
	o = (struct recur_apoint_s *) malloc(sizeof(struct recur_apoint_s));
	o->rpt = (struct rpt_s *) malloc(sizeof(struct rpt_s));
	o->exc = (struct days_s *) malloc(sizeof(struct days_s));
	o->mesg = (char *) malloc(strlen(mesg) + 1);
	strcpy(o->mesg, mesg);
	o->start = start;
	o->dur = dur;
	o->rpt->type = type;
	o->rpt->freq = freq;
	o->rpt->until = until;
	i = &recur_alist;
	for (;;) {
		if (*i == 0 || (*i)->start > start) {
			o->next = *i;
			*i = o;
			break;
		}
		i = &(*i)->next;
	}
	return o;
}

/* Insert a new recursive event in the general linked list */
struct recur_event_s *recur_event_new(char *mesg, long day, int id, 
	int type, int freq, long until)
{
	struct recur_event_s *o, **i;
	o = (struct recur_event_s *) malloc(sizeof(struct recur_event_s));
	o->rpt = (struct rpt_s *) malloc(sizeof(struct rpt_s));
	o->exc = (struct days_s *) malloc(sizeof(struct days_s));
	o->mesg = (char *) malloc(strlen(mesg) + 1);
	strcpy(o->mesg, mesg);
	o->day = day;
	o->id = id;
	o->rpt->type = type;
	o->rpt->freq = freq;
	o->rpt->until = until;
	i = &recur_elist;
	for (;;) {
		if (*i == 0 || (*i)->day > day) {
			o->next = *i;
			*i = o;
			break;
		}
		i = &(*i)->next;
	}
	return o;
}

/* 
 * Correspondance between the defines on recursive type, 
 * and the letter to be written in file. 
 */
char recur_def2char(int define){
	char recur_char;

	switch (define) {
	case 1:
		recur_char = 'D';
		break;	
	case 2:
		recur_char = 'W';
		break;
	case 3:
		recur_char = 'M';
		break;
	case 4:
		recur_char = 'Y';
		break;
	}
	return recur_char;
}

/* 
 * Correspondance between the letters written in file and the defines
 * concerning the recursive type.
 */
int recur_char2def(char type){
	int recur_def;

	switch (type) {
	case 'D':
		recur_def = RECUR_DAILY;
		break;	
	case 'W':
		recur_def = RECUR_WEEKLY;
		break;
	case 'M':
		recur_def = RECUR_MONTHLY;
		break;
	case 'Y':
		recur_def = RECUR_YEARLY;
		break;
	}
	return recur_def;
}

/* Writting of a recursive appointment into file. */
void recur_apoint_write(struct recur_apoint_s *o, FILE *f)
{
	struct tm *lt;
	time_t t;

	t = o->start;
	lt = localtime(&t);
	fprintf(f, "%02u/%02u/%04u @ %02u:%02u",
		lt->tm_mon + 1, lt->tm_mday, 1900 + lt->tm_year,
		lt->tm_hour, lt->tm_min);

	t = o->start + o->dur;
	lt = localtime(&t);
	fprintf(f, " -> %02u/%02u/%04u @ %02u:%02u",
		lt->tm_mon + 1, lt->tm_mday, 1900 + lt->tm_year,
		lt->tm_hour, lt->tm_min);

	t = o->rpt->until;
	if (t == 0) { /* We have an endless recurrent appointment. */
		fprintf(f, " {%d%c} |%s\n", o->rpt->freq, 
			recur_def2char(o->rpt->type), o->mesg);
	} else {
		lt = localtime(&t);
		fprintf(f, " {%d%c -> %02u/%02u/%04u} |%s\n",
			o->rpt->freq, recur_def2char(o->rpt->type),
			lt->tm_mon + 1, lt->tm_mday, 1900 + lt->tm_year,
			o->mesg);
	}
}

/* Writting of a recursive event into file. */
void recur_event_write(struct recur_event_s *o, FILE *f)
{
	struct tm *lt;
	time_t t;
	int st_mon, st_day, st_year;
	int end_mon, end_day, end_year;

	t = o->day;
	lt = localtime(&t);
	st_mon = lt->tm_mon + 1;
	st_day = lt->tm_mday;
	st_year = lt->tm_year + 1900;
	t = o->rpt->until;
	if (t == 0) { /* We have an endless recurrent event. */
		fprintf(f, "%02u/%02u/%04u [%d] {%d%c} %s\n",
			st_mon, st_day, st_year, o->id, o->rpt->freq,
			recur_def2char(o->rpt->type), o->mesg);
	} else {
		lt = localtime(&t);
		end_mon = lt->tm_mon + 1;
		end_day = lt->tm_mday;
		end_year = lt->tm_year + 1900;
		fprintf(f, "%02u/%02u/%04u [%d] {%d%c -> %02u/%02u/%04u} %s\n",
			st_mon, st_day, st_year, o->id, 
			o->rpt->freq, recur_def2char(o->rpt->type),
			end_mon, end_day, end_year, o->mesg);
	}
}

/* Load the recursive appointment description */
struct recur_apoint_s *recur_apoint_scan(FILE * f, struct tm start, 
	struct tm end, char type, int freq, struct tm until)
{
	struct tm *lt;
	char buf[MESG_MAXSIZE], *nl;
	time_t tstart, tend, t, tuntil;

	t = time(NULL);
	lt = localtime(&t);

        /* Read the appointment description */
	fgets(buf, MESG_MAXSIZE, f);
	nl = strchr(buf, '\n');
	if (nl) {
		*nl = '\0';
	}

	start.tm_sec = end.tm_sec = 0;
	start.tm_isdst = end.tm_isdst = -1;
	start.tm_year -= 1900;
	start.tm_mon--;
	end.tm_year -= 1900;
	end.tm_mon--;
	tstart = mktime(&start);
	tend = mktime(&end);

	if (until.tm_year != 0) {
		until.tm_hour = 12;
        	until.tm_min = 0;
		until.tm_sec =  0;
		until.tm_isdst = -1;
		until.tm_year -= 1900;
		until.tm_mon--;
		tuntil = mktime(&until);
	} else {
		tuntil = 0;
	}

	if (tstart == -1 || tend == -1 || tstart > tend || tuntil == -1) {
		fputs(_("FATAL ERROR in apoint_scan: date error in the appointment\n"), stderr);
		exit(EXIT_FAILURE);
	}
      
	return recur_apoint_new(buf, tstart, tend - tstart, 
		recur_char2def(type), freq, tuntil);
}

/* Load the recursive events from file */
struct recur_event_s *recur_event_scan(FILE * f, struct tm start, int id, 
	char type, int freq, struct tm until)
{
	struct tm *lt;
	char buf[MESG_MAXSIZE], *nl;
	time_t tstart, t, tuntil;

	t = time(NULL);
	lt = localtime(&t);

        /* Read the event description */
	fgets(buf, MESG_MAXSIZE, f);
	nl = strchr(buf, '\n');
	if (nl) {
		*nl = '\0';
	}
      
      	start.tm_hour = until.tm_hour = 12;
        start.tm_min = until.tm_min = 0;
	start.tm_sec = until.tm_sec =  0;
	start.tm_isdst = until.tm_isdst = -1;
	start.tm_year -= 1900;
	start.tm_mon--;
	if (until.tm_year != 0) {
		until.tm_year -= 1900;
		until.tm_mon--;
		tuntil = mktime(&until);
	} else {
		tuntil = 0;
	}
	tstart = mktime(&start);
	if ( (tstart == -1) || (tuntil == -1) ) {
		fputs(_("FATAL ERROR in recur_event_scan: date error in the event\n"), stderr);
		exit(EXIT_FAILURE);
	}
	
	return recur_event_new(buf, tstart, id, recur_char2def(type), freq, tuntil);
}

/* Write recursive items to file. */
void recur_save_data(FILE *f)
{
	struct recur_event_s *re;
	struct recur_apoint_s *ra;

	for (re = recur_elist; re != 0; re = re->next)
		recur_event_write(re, f);
	for (ra = recur_alist; ra != 0; ra = ra->next)
		recur_apoint_write(ra, f);
}

/* Check if the recurrent item belongs to the selected day. */
unsigned recur_item_inday(long item_start, int rpt_type, int rpt_freq,
			  long rpt_until, long day_start)
{
	const int DAYINSEC = 86400; 
	long day_end = day_start + DAYINSEC;
	int inday = 0;
	struct tm *lt;
	time_t t;
	char *error = 
		_("FATAL ERROR in recur_item_inday: unknown item type\n");

	if (rpt_until == 0) /* we have an endless recurrent item */
		rpt_until = day_end;
	while (item_start <= day_end && item_start <= rpt_until) {
		if (item_start < day_end && item_start >= day_start) {
			inday = 1;
			break;
		}
		t = item_start;
		lt = localtime(&t);
		if (rpt_type == RECUR_DAILY) {
			lt->tm_mday += rpt_freq;
		} else if (rpt_type == RECUR_WEEKLY) {
			lt->tm_mday += rpt_freq * 7;
		} else if (rpt_type == RECUR_MONTHLY) {
			lt->tm_mon += rpt_freq;
		} else if (rpt_type == RECUR_YEARLY) {
			lt->tm_year += rpt_freq;
		} else { /* NOT REACHED */
			fputs(error, stderr);
			exit(EXIT_FAILURE);
		}
		item_start = date2sec(lt->tm_year + 1900, lt->tm_mon + 1, 
			lt->tm_mday, 0, 0);
	}	
	return inday;
}

/* Returns a structure of type apoint_s given a structure of type recur_apoint_s */
struct apoint_s *recur_apoint_s2apoint_s(struct recur_apoint_s *p)
{
	struct apoint_s *a;

	a = (struct apoint_s *) malloc(sizeof(struct apoint_s));
	a->mesg = (char *) malloc(strlen(p->mesg) + 1);
	a->start = p->start;
	a->dur = p->dur;
	a->mesg = p->mesg;
	return a;
}