//
//  MPSumFunction.m
//  MathPad
//
//  Created by Kim Wittenburg on 22.04.14.
//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
//

#import "MPSumFunction.h"
#import "MPExpression.h"

@implementation MPSumFunction

#pragma mark Creation Methods

- (instancetype)init
{
    self = [super init];
    if (self) {
        _startExpression = [[MPExpression alloc] init];
        _startExpression.parent = self;
        _targetExpression = [[MPExpression alloc] init];
        _targetExpression.parent = self;
        _sumExpression = [[MPExpression alloc] init];
        _sumExpression.parent = self;
    }
    return self;
}

#pragma mark Working With the Expression Tree

- (NSUInteger)numberOfChildren
{
    return 3;
}

- (MPExpression *)childAtIndex:(NSUInteger)index
{
    switch (index) {
        case 0:
            return self.startExpression;
        case 1:
            return self.targetExpression;
        case 2:
            return self.sumExpression;
        default:
            return nil;
    }
}

- (NSArray *)children
{
    return @[self.startExpression, self.targetExpression, self.sumExpression];
}

- (void)setChild:(MPExpression *)child
         atIndex:(NSUInteger)index
{
    switch (index) {
            // TODO: Copy child?
        case 0:
            self.startExpression.parent = nil;
            self.startExpression = child;
            break;
        case 1:
            self.targetExpression.parent = nil;
            self.targetExpression = child;
            break;
        case 2:
            self.sumExpression.parent = nil;
            self.sumExpression = child;
            break;
        default:
            return;
    }
    child.parent = self;
}

#pragma mark Evaluating Functions

- (double)doubleValue
{
#warning Implementation
    return 0;
}

#pragma mark Working With Functions

- (BOOL)isEqualToFunction:(MPFunction *)aFunction
{
    if (![aFunction isKindOfClass:[MPSumFunction class]]) {
        return NO;
    }
    MPSumFunction *sumFunction = (MPSumFunction *)aFunction;
    if (![self.startExpression isEqualToExpression:sumFunction.startExpression]) {
        return NO;
    }
    if (![self.targetExpression isEqualToExpression:sumFunction.targetExpression]) {
        return NO;
    }
    return [self.sumExpression isEqualToExpression:sumFunction.sumExpression];
}

- (NSString *)description
{
    return [NSString stringWithFormat:@"Sum(From: %@; To: %@; Using: %@)", self.startExpression, self.targetExpression, self.sumExpression];
}

#pragma mark - NSCopying

- (id)copyWithZone:(NSZone *)zone
{
    MPSumFunction *copy = [[MPSumFunction allocWithZone:zone] init];
    copy.startExpression = [self.startExpression copy];
    copy.targetExpression = [self.targetExpression copy];
    copy.sumExpression = [self.sumExpression copy];
    return copy;
}

@end