//
//  MPPowerFunction.m
//  MathPad
//
//  Created by Kim Wittenburg on 30.09.14.
//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
//

#import "MPPowerFunction.h"
#import "MPExpression.h"

@implementation MPPowerFunction

MPFunctionAccessorImplementation(ExponentExpression, _exponentExpression)

- (NSArray *)childrenAccessors
{
    return @[@"exponentExpression"];
}

- (BOOL)validate:(MPParseError *__autoreleasing *)error
{
    if (!self.baseValue) {
        if (error) {
            *error = MPParseError(NSMakeRange([self.parent convertIndex:[self.parent indexOfElement:self]
                                                     fromReferenceFrame:MPElementReferenceFrame
                                                       toReferenceFrame:MPSymbolReferenceFrame], 0), @"No Base for Power");
        }
        return NO;
    }
    return [self.baseValue validate:error] && [[self.exponentExpression parse] validate:error];
}

- (NSDecimalNumber *)evaluate
{
    NSDecimalNumber *base = [self.baseValue evaluate];
    NSDecimalNumber *exponent = [[self.exponentExpression parse] evaluate];
    return [[NSDecimalNumber alloc] initWithDouble:pow(base.doubleValue, exponent.doubleValue)];
}

- (NSString *)description
{
    return [NSString stringWithFormat:@"^%@", self.exponentExpression.description];
}

@end