path: root/src/ical.c

/*
 * Calcurse - text-based organizer
 *
 * Copyright (c) 2004-2015 calcurse Development Team <misc@calcurse.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the
 *        following disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the
 *        following disclaimer in the documentation and/or other
 *        materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Send your feedback or comments to : misc@calcurse.org
 * Calcurse home page : http://calcurse.org
 *
 */

#include <strings.h>
#include <sys/types.h>

#include "calcurse.h"

#define ICALDATEFMT      "%Y%m%d"
#define ICALDATETIMEFMT  "%Y%m%dT%H%M%S"

typedef enum {
	ICAL_VEVENT,
	ICAL_VTODO,
	ICAL_TYPES
} ical_types_e;

typedef enum {
	UNDEFINED,
	APPOINTMENT,
	EVENT
} ical_vevent_e;

typedef struct {
	enum recur_type type;
	int freq;
	long until;
	unsigned count;
} ical_rpt_t;

static void ical_export_header(FILE *);
static void ical_export_recur_events(FILE *);
static void ical_export_events(FILE *);
static void ical_export_recur_apoints(FILE *);
static void ical_export_apoints(FILE *);
static void ical_export_todo(FILE *);
static void ical_export_footer(FILE *);

static const char *ical_recur_type[RECUR_TYPES] =
    { "", "DAILY", "WEEKLY", "MONTHLY", "YEARLY" };

/* iCal alarm notification. */
static void ical_export_valarm(FILE * stream)
{
	fputs("BEGIN:VALARM\n", stream);
	pthread_mutex_lock(&nbar.mutex);
	fprintf(stream, "TRIGGER:-P%dS\n", nbar.cntdwn);
	pthread_mutex_unlock(&nbar.mutex);
	fputs("ACTION:DISPLAY\n", stream);
	fputs("END:VALARM\n", stream);
}

/* Export header. */
static void ical_export_header(FILE * stream)
{
	fputs("BEGIN:VCALENDAR\n", stream);
	fprintf(stream, "PRODID:-//calcurse//NONSGML v%s//EN\n", VERSION);
	fputs("VERSION:2.0\n", stream);
}

/* Export footer. */
static void ical_export_footer(FILE * stream)
{
	fputs("END:VCALENDAR\n", stream);
}

/* Export recurrent events. */
static void ical_export_recur_events(FILE * stream)
{
	llist_item_t *i, *j;
	char ical_date[BUFSIZ];

	LLIST_FOREACH(&recur_elist, i) {
		struct recur_event *rev = LLIST_GET_DATA(i);
		date_sec2date_fmt(rev->day, ICALDATEFMT, ical_date);
		fputs("BEGIN:VEVENT\n", stream);
		fprintf(stream, "DTSTART:%s\n", ical_date);
		fprintf(stream, "RRULE:FREQ=%s;INTERVAL=%d",
			ical_recur_type[rev->rpt->type], rev->rpt->freq);

		if (rev->rpt->until != 0) {
			date_sec2date_fmt(rev->rpt->until, ICALDATEFMT,
					  ical_date);
			fprintf(stream, ";UNTIL=%s\n", ical_date);
		} else {
			fputc('\n', stream);
		}

		if (LLIST_FIRST(&rev->exc)) {
			fputs("EXDATE:", stream);
			LLIST_FOREACH(&rev->exc, j) {
				struct excp *exc = LLIST_GET_DATA(j);
				date_sec2date_fmt(exc->st, ICALDATEFMT,
						  ical_date);
				fprintf(stream, "%s", ical_date);
				fputc(LLIST_NEXT(j) ? ',' : '\n', stream);
			}
		}

		fprintf(stream, "SUMMARY:%s\n", rev->mesg);
		fputs("END:VEVENT\n", stream);
	}
}

/* Export events. */
static void ical_export_events(FILE * stream)
{
	llist_item_t *i;
	char ical_date[BUFSIZ];

	LLIST_FOREACH(&eventlist, i) {
		struct event *ev = LLIST_TS_GET_DATA(i);
		date_sec2date_fmt(ev->day, ICALDATEFMT, ical_date);
		fputs("BEGIN:VEVENT\n", stream);
		fprintf(stream, "DTSTART:%s\n", ical_date);
		fprintf(stream, "SUMMARY:%s\n", ev->mesg);
		fputs("END:VEVENT\n", stream);
	}
}

/* Export recurrent appointments. */
static void ical_export_recur_apoints(FILE * stream)
{
	llist_item_t *i, *j;
	char ical_datetime[BUFSIZ];
	char ical_date[BUFSIZ];

	LLIST_TS_LOCK(&recur_alist_p);
	LLIST_TS_FOREACH(&recur_alist_p, i) {
		struct recur_apoint *rapt = LLIST_TS_GET_DATA(i);

		date_sec2date_fmt(rapt->start, ICALDATETIMEFMT,
				  ical_datetime);
		fputs("BEGIN:VEVENT\n", stream);
		fprintf(stream, "DTSTART:%s\n", ical_datetime);
		fprintf(stream, "DURATION:PT0H0M%ldS\n", rapt->dur);
		fprintf(stream, "RRULE:FREQ=%s;INTERVAL=%d",
			ical_recur_type[rapt->rpt->type], rapt->rpt->freq);

		if (rapt->rpt->until != 0) {
			date_sec2date_fmt(rapt->rpt->until + HOURINSEC,
					  ICALDATEFMT, ical_date);
			fprintf(stream, ";UNTIL=%s\n", ical_date);
		} else {
			fputc('\n', stream);
		}

		if (LLIST_FIRST(&rapt->exc)) {
			fputs("EXDATE:", stream);
			LLIST_FOREACH(&rapt->exc, j) {
				struct excp *exc = LLIST_GET_DATA(j);
				date_sec2date_fmt(exc->st, ICALDATEFMT,
						  ical_date);
				fprintf(stream, "%s", ical_date);
				fputc(LLIST_NEXT(j) ? ',' : '\n', stream);
			}
		}

		fprintf(stream, "SUMMARY:%s\n", rapt->mesg);
		if (rapt->state & APOINT_NOTIFY)
			ical_export_valarm(stream);
		fputs("END:VEVENT\n", stream);
	}
	LLIST_TS_UNLOCK(&recur_alist_p);
}

/* Export appointments. */
static void ical_export_apoints(FILE * stream)
{
	llist_item_t *i;
	char ical_datetime[BUFSIZ];

	LLIST_TS_LOCK(&alist_p);
	LLIST_TS_FOREACH(&alist_p, i) {
		struct apoint *apt = LLIST_TS_GET_DATA(i);
		date_sec2date_fmt(apt->start, ICALDATETIMEFMT,
				  ical_datetime);
		fputs("BEGIN:VEVENT\n", stream);
		fprintf(stream, "DTSTART:%s\n", ical_datetime);
		fprintf(stream, "DURATION:P%ldDT%ldH%ldM%ldS\n",
			apt->dur / DAYINSEC,
			(apt->dur / HOURINSEC) % DAYINHOURS,
			(apt->dur / MININSEC) % HOURINMIN,
			apt->dur % MININSEC);
		fprintf(stream, "SUMMARY:%s\n", apt->mesg);
		if (apt->state & APOINT_NOTIFY)
			ical_export_valarm(stream);
		fputs("END:VEVENT\n", stream);
	}
	LLIST_TS_UNLOCK(&alist_p);
}

/* Export todo items. */
static void ical_export_todo(FILE * stream)
{
	llist_item_t *i;

	LLIST_FOREACH(&todolist, i) {
		struct todo *todo = LLIST_TS_GET_DATA(i);
		if (todo->id < 0)	/* completed items */
			continue;

		fputs("BEGIN:VTODO\n", stream);
		fprintf(stream, "PRIORITY:%d\n", todo->id);
		fprintf(stream, "SUMMARY:%s\n", todo->mesg);
		fputs("END:VTODO\n", stream);
	}
}

/* Print a header to describe import log report format. */
static void ical_log_init(FILE * log, int major, int minor)
{
	const char *header =
	    "+-------------------------------------------------------------------+\n"
	    "| Calcurse icalendar import log.                                    |\n"
	    "|                                                                   |\n"
	    "| Items imported from icalendar file, version %d.%d                   |\n"
	    "| Some items could not be imported, they are described hereafter.   |\n"
	    "| The log line format is as follows:                                |\n"
	    "|                                                                   |\n"
	    "|       TYPE [LINE]: DESCRIPTION                                    |\n"
	    "|                                                                   |\n"
	    "| where:                                                            |\n"
	    "|  * TYPE represents the item type ('VEVENT' or 'VTODO')            |\n"
	    "|  * LINE is the line in the input stream at which this item begins |\n"
	    "|  * DESCRIPTION indicates why the item could not be imported       |\n"
	    "+-------------------------------------------------------------------+\n\n";

	if (log)
		fprintf(log, header, major, minor);
}

/*
 * Used to build a report of the import process.
 * The icalendar item for which a problem occurs is mentioned (by giving its
 * first line inside the icalendar file), together with a message describing the
 * problem.
 */
static void ical_log(FILE * log, ical_types_e type, unsigned lineno,
		     char *msg)
{
	const char *typestr[ICAL_TYPES] = { "VEVENT", "VTODO" };

	RETURN_IF(type < 0 || type >= ICAL_TYPES, _("unknown ical type"));
	if (!log)
		return;

	fprintf(log, "%s [%d]: %s\n", typestr[type], lineno, msg);
}

static void ical_store_todo(int priority, char *mesg, char *note, int list)
{
	struct todo *todo = todo_add(mesg, priority, note);
	if (list) {
		char *hash = todo_hash(todo);
		printf("%s\n", hash);
		mem_free(hash);
	}
	mem_free(mesg);
	erase_note(&note);
}

static void
ical_store_event(char *mesg, char *note, long day, long end,
		 ical_rpt_t * rpt, llist_t * exc, int list)
{
	const int EVENTID = 1;
	struct event *ev;
	struct recur_event *rev;

	if (rpt) {
		rev = recur_event_new(mesg, note, day, EVENTID, rpt->type,
				      rpt->freq, rpt->until, exc);
		mem_free(rpt);
		if (list) {
			char *hash = recur_event_hash(rev);
			printf("%s\n", hash);
			mem_free(hash);
		}
		goto cleanup;
	}

	if (end == 0 || end - day <= DAYINSEC) {
		ev = event_new(mesg, note, day, EVENTID);
		if (list) {
			char *hash = event_hash(ev);
			printf("%s\n", hash);
			mem_free(hash);
		}
		goto cleanup;
	}

	/*
	 * Here we have an event that spans over several days.
	 *
	 * In iCal, the end specifies when the event is supposed to end, in
	 * calcurse, the end specifies the time that the last occurrence of the
	 * event starts, so we need to do some conversion here.
	 */
	end = day + ((end - day - 1) / DAYINSEC) * DAYINSEC;
	rpt = mem_malloc(sizeof(ical_rpt_t));
	rpt->type = RECUR_DAILY;
	rpt->freq = 1;
	rpt->count = 0;
	rpt->until = end;
	rev = recur_event_new(mesg, note, day, EVENTID, rpt->type,
			      rpt->freq, rpt->until, exc);
	mem_free(rpt);
	if (list) {
		char *hash = recur_event_hash(rev);
		printf("%s\n", hash);
		mem_free(hash);
	}

cleanup:
	mem_free(mesg);
	erase_note(&note);
}

static void
ical_store_apoint(char *mesg, char *note, long start, long dur,
		  ical_rpt_t * rpt, llist_t * exc, int has_alarm, int list)
{
	char state = 0L;
	struct apoint *apt;
	struct recur_apoint *rapt;

	if (has_alarm)
		state |= APOINT_NOTIFY;
	if (rpt) {
		rapt = recur_apoint_new(mesg, note, start, dur, state,
					rpt->type, rpt->freq, rpt->until, exc);
		mem_free(rpt);
		if (list) {
			char *hash = recur_apoint_hash(rapt);
			printf("%s\n", hash);
			mem_free(hash);
		}
	} else {
		apt = apoint_new(mesg, note, start, dur, state);
		if (list) {
			char *hash = apoint_hash(apt);
			printf("%s\n", hash);
			mem_free(hash);
		}
	}
	mem_free(mesg);
	erase_note(&note);
}

/*
 * Returns an allocated string representing the string given in argument once
 * unformatted.
 *
 * Note:
 * Even if the RFC2445 recommends not to have more than 75 octets on one line of
 * text, I prefer not to restrict the parsing to this size, thus I use a buffer
 * of size BUFSIZ.
 *
 * Extract from RFC2445:
 * Lines of text SHOULD NOT be longer than 75 octets, excluding the line
 * break.
 */
static char *ical_unformat_line(char *line)
{
	char *p, uline[BUFSIZ];
	int len;

	if (strlen(line) >= BUFSIZ)
		return NULL;

	memset(uline, 0, BUFSIZ);
	for (len = 0, p = line; *p; p++) {
		switch (*p) {
		case '\\':
			switch (*(p + 1)) {
			case 'n':
				uline[len++] = '\n';
				p++;
				break;
			case 't':
				uline[len++] = '\t';
				p++;
				break;
			case ';':
			case ':':
			case ',':
				uline[len++] = *(p + 1);
				p++;
				break;
			default:
				uline[len++] = *p;
				break;
			}
			break;
		default:
			uline[len++] = *p;
			break;
		}
	}

	return mem_strdup(uline);
}

static void
ical_readline_init(FILE * fdi, char *buf, char *lstore, unsigned *ln)
{
	char *eol;

	*buf = *lstore = '\0';
	if (fgets(lstore, BUFSIZ, fdi)) {
		if ((eol = strchr(lstore, '\n')) != NULL) {
			if (*(eol - 1) == '\r')
				*(eol - 1) = '\0';
			else
				*eol = '\0';
		}
		(*ln)++;
	}
}

static int ical_readline(FILE * fdi, char *buf, char *lstore, unsigned *ln)
{
	char *eol;

	strncpy(buf, lstore, BUFSIZ);
	(*ln)++;

	while (fgets(lstore, BUFSIZ, fdi) != NULL) {
		if ((eol = strchr(lstore, '\n')) != NULL) {
			if (*(eol - 1) == '\r')
				*(eol - 1) = '\0';
			else
				*eol = '\0';
		}
		if (*lstore != SPACE && *lstore != TAB)
			break;
		strncat(buf, lstore + 1, BUFSIZ - strlen(buf) - 1);
		(*ln)++;
	}

	if (feof(fdi)) {
		*lstore = '\0';
		if (*buf == '\0')
			return 0;
	}

	return 1;
}

static int
ical_chk_header(FILE * fd, char *buf, char *lstore, unsigned *lineno,
		int *major, int *minor)
{
	if (!ical_readline(fd, buf, lstore, lineno))
		return 0;

	if (!starts_with_ci(buf, "BEGIN:VCALENDAR"))
		return 0;

	while (!sscanf(buf, "VERSION:%d.%d", major, minor)) {
		if (!ical_readline(fd, buf, lstore, lineno))
			return 0;
	}

	return 1;
}

/*
 * iCalendar date-time format is based on the ISO 8601 complete
 * representation. It should be something like : DATE 'T' TIME
 * where DATE is 'YYYYMMDD' and TIME is 'HHMMSS'.
 * The time and 'T' separator are optional (in the case of an day-long event).
 *
 * Optionally, if the type pointer is given, specify if it is an event
 * (no time is given, meaning it is an all-day event), or an appointment
 * (time is given).
 *
 * The timezone is not yet handled by calcurse.
 */
static time_t ical_datetime2time_t(char *datestr, ical_vevent_e * type)
{
	const int FORMAT_DATE = 3, FORMAT_DATETIME = 6, FORMAT_DATETIMEZ = 7;
	struct date date;
	unsigned hour, min, sec;
	char c;
	int format;

	format = sscanf(datestr, "%04u%02u%02uT%02u%02u%02u%c",
			&date.yyyy, &date.mm, &date.dd, &hour, &min, &sec, &c);
	if (format == FORMAT_DATE) {
		if (type)
			*type = EVENT;
		return date2sec(date, 0, 0);
	} else if (format == FORMAT_DATETIME || format == FORMAT_DATETIMEZ) {
		if (type)
			*type = APPOINTMENT;
		if (format == FORMAT_DATETIMEZ && c == 'Z')
			return utcdate2sec(date, hour, min);
		else
			return date2sec(date, hour, min);
	}
	return 0;
}

static long ical_durtime2long(char *timestr)
{
	char *p;
	int bytes_read;
	unsigned hour = 0, min = 0, sec = 0;

	if ((p = strchr(timestr, 'T')) == NULL)
		return 0;

	p++;
	if (strchr(p, 'H')) {
		if (sscanf(p, "%uH%n", &hour, &bytes_read) != 1)
			return 0;
		p += bytes_read;
	}
	if (strchr(p, 'M')) {
		if (sscanf(p, "%uM%n", &min, &bytes_read) != 1)
			return 0;
		p += bytes_read;
	}
	if (strchr(p, 'S')) {
		if (sscanf(p, "%uM%n", &sec, &bytes_read) != 1)
			return 0;
		p += bytes_read;
	}

	if (hour == 0 && min == 0 && sec == 0)
		return 0;

	return hour * HOURINSEC + min * MININSEC + sec;
}

/*
 * Extract from RFC2445:
 *
 * Value Name: DURATION
 *
 * Purpose: This value type is used to identify properties that contain
 * duration of time.
 *
 * Formal Definition: The value type is defined by the following
 * notation:
 *
 * dur-value  = (["+"] / "-") "P" (dur-date / dur-time / dur-week)
 * dur-date   = dur-day [dur-time]
 * dur-time   = "T" (dur-hour / dur-minute / dur-second)
 * dur-week   = 1*DIGIT "W"
 * dur-hour   = 1*DIGIT "H" [dur-minute]
 * dur-minute = 1*DIGIT "M" [dur-second]
 * dur-second = 1*DIGIT "S"
 * dur-day    = 1*DIGIT "D"
 *
 * Example: A duration of 15 days, 5 hours and 20 seconds would be:
 * P15DT5H0M20S
 * A duration of 7 weeks would be:
 * P7W
 */
static long ical_dur2long(char *durstr)
{
	char *p;
	struct {
		unsigned week, day;
	} date;

	memset(&date, 0, sizeof date);

	p = strchr(durstr, 'P');
	if (!p)
		return -1;
	p++;

	if (*p == '-')
		return -1;
	if (*p == '+')
		p++;

	if (*p == 'T') {
		/* dur-time */
		return ical_durtime2long(p);
	} else if (strchr(p, 'W')) {
		/* dur-week */
		if (sscanf(p, "%u", &date.week) == 1)
			return date.week * WEEKINDAYS * DAYINSEC;
	} else if (strchr(p, 'D')) {
		/* dur-date */
		if (sscanf(p, "%uD", &date.day) == 1) {
			return date.day * DAYINSEC +
				ical_durtime2long(p);
		}
	}

	return -1;
}

/*
 * Compute the vevent repetition end date from the repetition count.
 *
 * Extract from RFC2445:
 * The COUNT rule part defines the number of occurrences at which to
 * range-bound the recurrence. The "DTSTART" property value, if specified,
 * counts as the first occurrence.
 */
static long ical_compute_rpt_until(long start, ical_rpt_t * rpt)
{
	switch (rpt->type) {
	case RECUR_DAILY:
		return date_sec_change(start, 0, rpt->freq * (rpt->count - 1));
	case RECUR_WEEKLY:
		return date_sec_change(start, 0,
				rpt->freq * WEEKINDAYS * (rpt->count - 1));
	case RECUR_MONTHLY:
		return date_sec_change(start, rpt->freq * (rpt->count - 1), 0);
	case RECUR_YEARLY:
		return date_sec_change(start,
				    rpt->freq * 12 * (rpt->count - 1), 0);
	default:
		return 0;
	}
}

/*
 * Read a recurrence rule from an iCalendar RRULE string.
 *
 * Value Name: RECUR
 *
 * Purpose: This value type is used to identify properties that contain
 * a recurrence rule specification.
 *
 * Formal Definition: The value type is defined by the following
 * notation:
 *
 * recur      = "FREQ"=freq *(
 *
 * ; either UNTIL or COUNT may appear in a 'recur',
 * ; but UNTIL and COUNT MUST NOT occur in the same 'recur'
 *
 * ( ";" "UNTIL" "=" enddate ) /
 * ( ";" "COUNT" "=" 1*DIGIT ) /
 *
 * ; the rest of these keywords are optional,
 * ; but MUST NOT occur more than
 * ; once
 *
 * ( ";" "INTERVAL" "=" 1*DIGIT )          /
 * ( ";" "BYSECOND" "=" byseclist )        /
 * ( ";" "BYMINUTE" "=" byminlist )        /
 * ( ";" "BYHOUR" "=" byhrlist )           /
 * ( ";" "BYDAY" "=" bywdaylist )          /
 * ( ";" "BYMONTHDAY" "=" bymodaylist )    /
 * ( ";" "BYYEARDAY" "=" byyrdaylist )     /
 * ( ";" "BYWEEKNO" "=" bywknolist )       /
 * ( ";" "BYMONTH" "=" bymolist )          /
 * ( ";" "BYSETPOS" "=" bysplist )         /
 * ( ";" "WKST" "=" weekday )              /
 * ( ";" x-name "=" text )
 * )
*/
static ical_rpt_t *ical_read_rrule(FILE * log, char *rrulestr,
				   unsigned *noskipped, const int itemline)
{
	const char count[] = "COUNT=";
	const char interv[] = "INTERVAL=";
	char freqstr[BUFSIZ];
	unsigned interval;
	ical_rpt_t *rpt;
	char *p;

	p = strchr(rrulestr, ':');
	if (!p) {
		ical_log(log, ICAL_VEVENT, itemline,
			 _("recurrence rule malformed."));
		(*noskipped)++;
		return NULL;
	}
	p++;

	rpt = mem_malloc(sizeof(ical_rpt_t));
	memset(rpt, 0, sizeof(ical_rpt_t));
	if (sscanf(p, "FREQ=%s", freqstr) != 1) {
		ical_log(log, ICAL_VEVENT, itemline,
			 _("recurrence frequence not found."));
		(*noskipped)++;
		mem_free(rpt);
		return NULL;
	}

	if (starts_with(freqstr, "DAILY")) {
		rpt->type = RECUR_DAILY;
	} else if (starts_with(freqstr, "WEEKLY")) {
		rpt->type = RECUR_WEEKLY;
	} else if (starts_with(freqstr, "MONTHLY")) {
		rpt->type = RECUR_MONTHLY;
	} else if (starts_with(freqstr, "YEARLY")) {
		rpt->type = RECUR_YEARLY;
	} else {
		ical_log(log, ICAL_VEVENT, itemline,
			 _("recurrence frequence not recognized."));
		(*noskipped)++;
		mem_free(rpt);
		return NULL;
	}

	/*
	 * The UNTIL rule part defines a date-time value which bounds the
	 * recurrence rule in an inclusive manner.  If not present, and the
	 * COUNT rule part is also not present, the RRULE is considered to
	 * repeat forever.

	 * The COUNT rule part defines the number of occurrences at which to
	 * range-bound the recurrence.  The "DTSTART" property value, if
	 * specified, counts as the first occurrence.
	 */
	if ((p = strstr(rrulestr, "UNTIL")) != NULL) {
		rpt->until = ical_datetime2time_t(strchr(p, '=') + 1, NULL);
	} else {
		unsigned cnt;
		char *countstr;

		rpt->until = 0;
		if ((countstr = strstr(rrulestr, count))) {
			countstr += sizeof(count) - 1;
			if (sscanf(countstr, "%u", &cnt) == 1)
				rpt->count = cnt;
		}
	}

	rpt->freq = 1;
	if ((p = strstr(rrulestr, interv))) {
		p += sizeof(interv) - 1;
		if (sscanf(p, "%u", &interval) == 1)
			rpt->freq = interval;
	}

	return rpt;
}

static void ical_add_exc(llist_t * exc_head, long date)
{
	if (date == 0)
		return;

	struct excp *exc = mem_malloc(sizeof(struct excp));
	exc->st = date;

	LLIST_ADD(exc_head, exc);
}

/*
 * This property defines the list of date/time exceptions for a
 * recurring calendar component.
 */
static void
ical_read_exdate(llist_t * exc, FILE * log, char *exstr,
		 unsigned *noskipped, const int itemline)
{
	char *p, *q;

	p = strchr(exstr, ':');
	if (!p) {
		ical_log(log, ICAL_VEVENT, itemline,
			 _("recurrence exception dates malformed."));
		(*noskipped)++;
		return;
	}
	p++;

	while ((q = strchr(p, ',')) != NULL) {
		char buf[BUFSIZ];
		const int buflen = q - p;

		strncpy(buf, p, buflen);
		buf[buflen] = '\0';
		ical_add_exc(exc, ical_datetime2time_t(buf, NULL));
		p = ++q;
	}
	ical_add_exc(exc, ical_datetime2time_t(p, NULL));
}

/* Return an allocated string containing the name of the newly created note. */
static char *ical_read_note(char *line, unsigned *noskipped,
			    ical_types_e item_type, const int itemline,
			    FILE * log)
{
	char *p, *notestr, *note;

	p = strchr(line, ':');
	if (!p) {
		ical_log(log, item_type, itemline,
			 _("description malformed."));
		(*noskipped)++;
		return NULL;
	}
	p++;

	notestr = ical_unformat_line(p);
	if (notestr == NULL) {
		ical_log(log, item_type, itemline,
			 _("could not get entire item description."));
		(*noskipped)++;
		return NULL;
	} else if (strlen(notestr) == 0) {
		mem_free(notestr);
		return NULL;
	} else {
		note = generate_note(notestr);
		mem_free(notestr);
		return note;
	}
}

/* Returns an allocated string containing the ical item summary. */
static char *ical_read_summary(char *line)
{
	char *p, *summary;

	p = strchr(line, ':');
	if (!p)
		return NULL;

	summary = ical_unformat_line(p + 1);
	if (!summary)
		return NULL;

	/* Event summaries must not contain newlines. */
	for (p = strchr(summary, '\n'); p; p = strchr(p, '\n'))
		*p = ' ';

	return summary;
}

static void
ical_read_event(FILE * fdi, FILE * log, int list, unsigned *noevents,
		unsigned *noapoints, unsigned *noskipped, char *buf,
		char *lstore, unsigned *lineno)
{
	const int ITEMLINE = *lineno;
	ical_vevent_e vevent_type;
	char *p;
	struct {
		llist_t exc;
		ical_rpt_t *rpt;
		char *mesg, *note;
		long start, end, dur;
		int has_alarm;
	} vevent;
	int skip_alarm;

	vevent_type = UNDEFINED;
	memset(&vevent, 0, sizeof vevent);
	LLIST_INIT(&vevent.exc);
	skip_alarm = 0;
	while (ical_readline(fdi, buf, lstore, lineno)) {
		if (skip_alarm) {
			/*
			 * Need to skip VALARM properties because some keywords
			 * could interfere, such as DURATION, SUMMARY,..
			 */
			if (starts_with_ci(buf, "END:VALARM"))
				skip_alarm = 0;
			continue;
		}

		if (starts_with_ci(buf, "END:VEVENT")) {
			if (!vevent.mesg) {
				ical_log(log, ICAL_VEVENT, ITEMLINE,
					 _("could not retrieve item summary."));
				goto cleanup;
			}
			if (vevent.start == 0) {
				ical_log(log, ICAL_VEVENT, ITEMLINE,
					 _("item start date is not defined."));
				goto cleanup;
			}

			if (vevent_type == APPOINTMENT && vevent.dur == 0) {
				if (vevent.end == 0) {
					ical_log(log, ICAL_VEVENT, ITEMLINE,
						 _("could not compute duration "
						  "(no end time)."));
					goto cleanup;
				}

				vevent.dur = vevent.end - vevent.start;
				if (vevent.dur == 0) {
					vevent_type = EVENT;
					vevent.end = 0L;
				} else if (vevent.dur < 0) {
					ical_log(log, ICAL_VEVENT, ITEMLINE,
						_("item has a negative duration."));
					goto cleanup;
				}
			}

			if (vevent.rpt && vevent.rpt->count) {
				vevent.rpt->until =
					ical_compute_rpt_until(vevent.start,
							vevent.rpt);
			}

			switch (vevent_type) {
			case APPOINTMENT:
				ical_store_apoint(vevent.mesg, vevent.note,
						vevent.start, vevent.dur,
						vevent.rpt, &vevent.exc,
						vevent.has_alarm, list);
				(*noapoints)++;
				break;
			case EVENT:
				ical_store_event(vevent.mesg, vevent.note,
						vevent.start, vevent.end,
						vevent.rpt, &vevent.exc, list);
				(*noevents)++;
				break;
			case UNDEFINED:
				ical_log(log, ICAL_VEVENT, ITEMLINE,
					 _("item could not be identified."));
				goto cleanup;
				break;
			}

			return;
		}

		if (starts_with_ci(buf, "DTSTART")) {
			p = strchr(buf, ':');
			if (!p) {
				ical_log(log, ICAL_VEVENT, ITEMLINE,
					 _("event start time malformed."));
				goto cleanup;
			}

			vevent.start = ical_datetime2time_t(++p, &vevent_type);
			if (!vevent.start) {
				ical_log(log, ICAL_VEVENT, ITEMLINE,
					 _("could not retrieve event start time."));
				goto cleanup;
			}
		} else if (starts_with_ci(buf, "DTEND")) {
			p = strchr(buf, ':');
			if (!p) {
				ical_log(log, ICAL_VEVENT, ITEMLINE,
					 _("event end time malformed."));
				goto cleanup;
			}

			vevent.end = ical_datetime2time_t(++p, &vevent_type);
			if (!vevent.end) {
				ical_log(log, ICAL_VEVENT, ITEMLINE,
					 _("could not retrieve event end time."));
				goto cleanup;
			}
		} else if (starts_with_ci(buf, "DURATION")) {
			vevent.dur = ical_dur2long(buf);
			if (vevent.dur <= 0) {
				ical_log(log, ICAL_VEVENT, ITEMLINE,
					 _("item duration malformed."));
				goto cleanup;
			}
		} else if (starts_with_ci(buf, "RRULE")) {
			vevent.rpt = ical_read_rrule(log, buf, noskipped,
					ITEMLINE);
		} else if (starts_with_ci(buf, "EXDATE")) {
			ical_read_exdate(&vevent.exc, log, buf, noskipped,
					ITEMLINE);
		} else if (starts_with_ci(buf, "SUMMARY")) {
			vevent.mesg = ical_read_summary(buf);
		} else if (starts_with_ci(buf, "BEGIN:VALARM")) {
			skip_alarm = vevent.has_alarm = 1;
		} else if (starts_with_ci(buf, "DESCRIPTION")) {
			vevent.note = ical_read_note(buf, noskipped,
					ICAL_VEVENT, ITEMLINE, log);
		}
	}

	ical_log(log, ICAL_VEVENT, ITEMLINE,
		 _("The ical file seems to be malformed. "
		   "The end of item was not found."));

cleanup:

	if (vevent.note)
		mem_free(vevent.note);
	if (vevent.mesg)
		mem_free(vevent.mesg);
	if (vevent.rpt)
		mem_free(vevent.rpt);
	LLIST_FREE(&vevent.exc);
	(*noskipped)++;
}

static void
ical_read_todo(FILE * fdi, FILE * log, int list, unsigned *notodos,
	       unsigned *noskipped, char *buf, char *lstore,
	       unsigned *lineno)
{
	const int LOWEST = 9;
	const int ITEMLINE = *lineno;
	struct {
		char *mesg, *note;
		int has_priority, priority;
	} vtodo;
	int skip_alarm;

	memset(&vtodo, 0, sizeof vtodo);
	skip_alarm = 0;
	while (ical_readline(fdi, buf, lstore, lineno)) {
		if (skip_alarm) {
			/*
			 * Need to skip VALARM properties because some keywords
			 * could interfere, such as DURATION, SUMMARY,..
			 */
			if (starts_with_ci(buf, "END:VALARM"))
				skip_alarm = 0;
			continue;
		}

		if (starts_with_ci(buf, "END:VTODO")) {
			if (!vtodo.has_priority)
				vtodo.priority = LOWEST;
			if (!vtodo.mesg) {
				ical_log(log, ICAL_VTODO, ITEMLINE,
					 _("could not retrieve item summary."));
				goto cleanup;
			}

			ical_store_todo(vtodo.priority, vtodo.mesg,
					vtodo.note, list);
			(*notodos)++;
			return;
		}

		if (starts_with_ci(buf, "PRIORITY:")) {
			sscanf(buf, "%d", &vtodo.priority);
			if (vtodo.priority >= 1 && vtodo.priority <= 9) {
				vtodo.has_priority = 1;
			} else {
				ical_log(log, ICAL_VTODO, ITEMLINE,
					 _("item priority is not acceptable "
					  "(must be between 1 and 9)."));
			}
		} else if (starts_with_ci(buf, "SUMMARY")) {
			vtodo.mesg = ical_read_summary(buf);
		} else if (starts_with_ci(buf, "BEGIN:VALARM")) {
			skip_alarm = 1;
		} else if (starts_with_ci(buf, "DESCRIPTION")) {
			vtodo.note = ical_read_note(buf, noskipped, ICAL_VTODO,
					ITEMLINE, log);
		}
	}

	ical_log(log, ICAL_VTODO, ITEMLINE,
		 _("The ical file seems to be malformed. "
		   "The end of item was not found."));

cleanup:
	if (vtodo.note)
		mem_free(vtodo.note);
	if (vtodo.mesg)
		mem_free(vtodo.mesg);
	(*noskipped)++;
}

/* Import calcurse data. */
void
ical_import_data(FILE * stream, FILE * log, int list, unsigned *events,
		 unsigned *apoints, unsigned *todos, unsigned *lines,
		 unsigned *skipped)
{
	char buf[BUFSIZ], lstore[BUFSIZ];
	int major, minor;

	ical_readline_init(stream, buf, lstore, lines);
	RETURN_IF(!ical_chk_header
		  (stream, buf, lstore, lines, &major, &minor),
		  _("Warning: ical header malformed or wrong version number. "
		   "Aborting..."));

	ical_log_init(log, major, minor);

	while (ical_readline(stream, buf, lstore, lines)) {
		(*lines)++;
		if (starts_with_ci(buf, "BEGIN:VEVENT")) {
			ical_read_event(stream, log, list, events, apoints,
					skipped, buf, lstore, lines);
		} else if (starts_with_ci(buf, "BEGIN:VTODO")) {
			ical_read_todo(stream, log, list, todos, skipped, buf,
				       lstore, lines);
		}
	}
}

/* Export calcurse data. */
void ical_export_data(FILE * stream)
{
	ical_export_header(stream);
	ical_export_recur_events(stream);
	ical_export_events(stream);
	ical_export_recur_apoints(stream);
	ical_export_apoints(stream);
	ical_export_todo(stream);
	ical_export_footer(stream);
}