#include <time.h>
#include <objc/objc.h>
#include "dates.h"
#include "gscal.h"

char *days[] = {
	"Sun",
	"Mon",
	"Tue",
	"Wed",
	"Thu",
	"Fri",
	"Sat"
};

char *months[] = {
	"January",
	"February",
	"March",
	"April",
	"May",
	"June",
	"July",
	"August",
	"Septemeber",
	"October",
	"November",
	"December"
};

int days_in_month[] = {
	31,
	28,
	31,
	30,
	31,
	30,
	31,
	31,
	30,
	31,
	30,
	31
};

NSString *read_line(FILE *fp)
{
	char buf[81];
	if(!fgets(buf,81,fp)) {
		return [[NSString alloc] initWithString:@" "];
	}
	buf[strlen(buf)-1] = '\0';
	return [[NSString alloc] initWithCString:buf length:strlen(buf)];
}

NSComparisonResult compare(NSString *a, NSString *b, void *c)
{
	return [a compare:b];
}

int findMonth(int month, int year)
{
	struct tm t;
	t.tm_mday = 1;
	t.tm_mon = month;
	t.tm_year = year - 1900;
	t.tm_hour = t.tm_min = t.tm_sec = t.tm_isdst = 0;
	mktime(&t);
	return t.tm_wday;
}

char* referenceLetter(int i)
{
	char c, *ret;
	ret = malloc(sizeof(*ret) * 2);
	c = 'A';
	ret[0] =  c + i;
	ret[1] = 0;
	return ret;
}

id findToday(id arrayOfDates, int month, int day, int year)
{
	int i;
	id aString, newString;
	newString = [[NSMutableString alloc] init];
	for(i=0;i<[arrayOfDates count];i++) {
		if(aString = [[arrayOfDates objectAtIndex:i] isToday:month day:day year:year]) {
			newString = [newString stringByAppendingString:[NSString stringWithCString:referenceLetter(i)]];
		}
	}
	return newString;
}

@implementation GSCalendar

-initWithFile: (NSString*)fname
{
	FILE *fp;
	NSString *aString;
	fp = fopen([fname cString],"r");;
	fileContents = [[NSMutableArray alloc] init];
	while(aString = read_line(fp)) {
		if([aString isEqualToString:@" "]) {
			break;
		}
		[fileContents addObject:aString];
	}
	[aString release];
	fclose(fp);
	return self;
}

-drawCalendar:(NSString*)fname month:(int)month year:(int)year
{
	[self writeTitle:fname month:month year:year];
	[self drawWeeks:fname month:month year:year];
	[self printReferenceTable:fname month:month year:year];
	return self;
}

-writeTitle:(NSString*)fname month:(int)month year:(int)year
{
	FILE *fp;
	int i=0;
	fp = fopen([fname cString],"a");
	for(i=0;i<71;i++) {
		fprintf(fp,"-");
	}
	fprintf(fp,"\n");
	fprintf(fp,"|%-10s",months[month]);
	for(i=0;i<55;i++) {
		fprintf(fp," ");
	}
	fprintf(fp,"%4i|\n",year);
	for(i=0;i<71;i++) {
		fprintf(fp,"-");
	}
	fprintf(fp,"\n");
	fclose(fp);
	return self;
}

-writeWeek:(NSString*)fname
{
	FILE *fp;
	int i=0, isDay=MONDAY;
	char ch[11], num[3];
	fp = fopen([fname cString],"a");
	while(i<70){
		snprintf(num,3,"%i",i);
		if((num[1] == '0') || (strcmp(num,"0")==0)) {
			strncpy(ch,"|",3);
		} else if((num[1] == '1') || (strcmp(num,"1")==0)) {
			strncpy(ch,days[isDay++],11);
		} else {
			strncpy(ch," ",3);
		}
		i+=strlen(ch);
		fprintf(fp,"%s",ch);
	}
	fprintf(fp,"|\n");
	for(i=0;i<71;i++) {
		fprintf(fp,"-");
	}
	fprintf(fp,"\n");
	fclose(fp);
	return self;
}

-sortData
{
	[fileContents sortUsingFunction:compare context:NULL];
	return self;
}

-printReferenceTable:(NSString*)fname month:(int)month year:(int)year
{
	int i;
	id anObject, arrayOfDates, date, parsedStrings, enumerator;
	FILE *fp;
	fp = fopen([fname cString],"a");
	enumerator = [fileContents objectEnumerator];
	arrayOfDates = [[NSMutableArray alloc] init];
	while(anObject = [enumerator nextObject]) {
		parsedStrings = [anObject componentsSeparatedByString:@":"];
		date = [[DateEntry alloc] 
			initWithString:[parsedStrings objectAtIndex:0] 
			descr:[parsedStrings objectAtIndex:1]];
		[arrayOfDates addObject:date];
	}
	for(i=0;i<[arrayOfDates count];i++) {
		fprintf(fp,"%s: %s %i, %i\n\t\%s\n",
			referenceLetter(i),
			months[[[arrayOfDates objectAtIndex:i] getMonth]-1],
			[[arrayOfDates objectAtIndex:i] getDay],
			[[arrayOfDates objectAtIndex:i] getYear],
			[[[arrayOfDates objectAtIndex:i] getDescription] cString]);
	}
	fclose(fp);
}

-drawWeeks:(NSString*)fname month:(int)month year:(int)year
{
	FILE *fp;
	int monthStartsOn, i, day=1, j, k;
	BOOL monthStarted = NO;
	id anObject;
	DateEntry *date;
	NSArray *parsedStrings;
	NSMutableArray *arrayOfDates;
	NSEnumerator *enumerator = [fileContents objectEnumerator];
	fp = fopen([fname cString],"a");
	[self sortData];
	monthStartsOn = findMonth(month,year);
	arrayOfDates = [[NSMutableArray alloc] init];
	while(anObject = [enumerator nextObject]) {
		parsedStrings = [anObject componentsSeparatedByString:@":"];
		date = [[DateEntry alloc] 
			initWithString:[parsedStrings objectAtIndex:0] 
			descr:[parsedStrings objectAtIndex:1]];
		[arrayOfDates addObject:date];
	}
	anObject = [NSString stringWithString:@" "];
	for(i=0;i<6;i++) {	
		for(j=0;j<7;j++) {
			fprintf(fp,"|");
			if(j==monthStartsOn) {
				monthStarted = YES;
			}
			if(day>days_in_month[month]) {
				monthStarted = NO;
				anObject = [NSString stringWithString:@" "];
			}
		if(monthStarted) {
				anObject = [NSString stringWithFormat:@"%i:%s",day++,[findToday(arrayOfDates,month+1,day,year) cString]];
			}
			fprintf(fp,"%-9s",[anObject cString]);
		}
		fprintf(fp,"|\n");
		for(k=0;k<71;k++) {
			fprintf(fp,"-");
		}
		fprintf(fp,"\n");
	}
	[arrayOfDates release];
	fclose(fp);
	return self;
}

@end