//
//  MPParsedSummand.m
//  MathPad
//
//  Created by Kim Wittenburg on 10.09.14.
//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
//

#import "MPParsedProduct.h"

@implementation MPParsedProduct {
    NSMutableArray *_factors;
}

- (instancetype)init
{
    self = [super init];
    if (self) {
        _factors = [[NSMutableArray alloc] init];
    }
    return self;
}

- (instancetype)initWithFactor:(id<MPParsedFactor>)factor
{
    self = [super init];
    if (self) {
        _factors = [[NSMutableArray alloc] initWithObjects:factor, nil];
    }
    return self;
}

- (NSArray *)factors
{
    return _factors;
}

- (void)addFactor:(id<MPParsedFactor>)factor
{
    [_factors addObject:factor];
}

- (NSDecimalNumber *)evaluateWithError:(MPParseError *__autoreleasing *)error
{
    if (_factors.count == 0) {
        return [NSDecimalNumber zero];
    }
    NSDecimalNumber *value = [NSDecimalNumber one];
    for (id<MPParsedFactor> factor in _factors) {
        NSDecimalNumber *factorValue = [factor evaluateWithError:error];
        if (!factorValue) {
            return nil;
        }
        value = [value decimalNumberByMultiplyingBy:factorValue];
    }
    return value;
}

- (NSString *)description
{
    return [NSString stringWithFormat:@"MPParsedProduct<%@>", [_factors componentsJoinedByString:@"*"]];
}

@end