//
//  Calculation.m
//  LeanCalc
//
//  Created by Marc Liyanage on 04.02.05.
//  Copyright 2005 __MyCompanyName__. All rights reserved.
//

#import "Calculation.h"


@implementation Calculation

- (id)init {

	self = [super init];
	if (!self) return nil;
	
	STRING *falseString = makestring("false");
	VALUE falseValue;
	falseValue.v_type = V_STR;
	falseValue.v_subtype = V_NOSUBTYPE;
	falseValue.v_str = falseString;
	setconfig(CONFIG_TILDE, &falseValue);
	setconfig(CONFIG_TAB, &falseValue);
	
	[Calculation setKeys:[NSArray arrayWithObject:@"expression"] triggerChangeNotificationsForDependentKey:@"result"];
	
	return self;
}



- (void)dealloc {
	
	[expression release];
	[next release];
	[super dealloc];
}



- (NSString *)shortcut {

	int historyIndex = [self historyIndex];
	if (historyIndex < 1) return nil;

	unichar ch = 0x2318;
	NSString *str = [NSString stringWithCharacters:&ch length:1];
	return [NSString stringWithFormat:@"%@ %d", str, historyIndex];
}



- (int)historyIndex {
	if (!next) return 0;
	int nextIndex = [next historyIndex];
	if (nextIndex > 8 || nextIndex == -1) return -1;
	return nextIndex + 1;
}


extern jmp_buf calc_jmp_buf;
extern jmp_buf jmpbuf;
extern int calc_jmp;
extern char *calc_error;

- (NSString *)result {

	if (![expression length]) return nil;

	int error;
	if ((error = setjmp(calc_jmp_buf)) != 0) {
		reinitialize();
		calc_jmp = 1;
		return nil;
	}
	calc_jmp = 1;
	
	if ((error = setjmp(jmpbuf)) != 0) {
		reinitialize();
		return nil;
	}	
	reinitialize();

	openstring([expression UTF8String], [expression length]);
	math_divertio();
	getcommands(1);
	char *result = math_getdivertedio();
	NSString *resultString = [[NSString stringWithCString:result] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

	if (result) free(result);

	return resultString;
	
}


- (BOOL)expressionIsEmpty {
	return ![expression length];
}



- (void)encodeWithCoder:(NSCoder *)coder {
	[coder encodeObject:expression forKey:@"expression"];
	[coder encodeObject:next forKey:@"next"];
}


- (id)initWithCoder:(NSCoder *)decoder {

	self = [super init];
	if (!self) return nil;
	
	[self setValue:[decoder decodeObjectForKey:@"expression"] forKey:@"expression"];
	[self setValue:[decoder decodeObjectForKey:@"next"] forKey:@"next"];
	return self;
}





@end