//
//  MPExpression.h
//  MathPad
//
//  Created by Kim Wittenburg on 10.08.14.
//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
//

@import Foundation;
#import "NSString+MPExpressionElement.h"

@class MPExpression, MPFunction, MPRangePath;
@protocol MPExpressionElement;

@interface MPExpression : NSObject <NSCopying, NSCoding>

#pragma mark Creation Methods
- (instancetype)init; // Convenience
- (instancetype)initWithElement:(id<MPExpressionElement>)element; // Convenience
- (instancetype)initWithElements:(NSArray *)elements; // Designated Initializer

#pragma mark Working With the Expression Tree
@property (nonatomic, weak) MPFunction *parent; // Set automatically, nil for root expression

- (void)fixElements; // Called automatically, removes empty elements, joins subsequent strings

#pragma mark Primitive Methods
- (NSUInteger)length;
- (NSUInteger)numberOfElements;
- (id<MPExpressionElement>)elementAtIndex:(NSUInteger)index;
- (NSArray *)elementsInRange:(NSRange)range;
- (NSUInteger)indexOfElement:(id<MPExpressionElement>)element;
- (void)replaceElementsInRange:(NSRange)range withElements:(NSArray *)elements;
// TODO: - (NSUInteger)indexOfElementAtLocation:(NSUInteger)location;

- (double)doubleValue; // Evaluates Expression

#pragma mark Notifications
// All notification methods should create a new rangePath with the receiver's index added to the beginning of the path and then ascend the message to it's parent
// TODO: More notifications
- (void)didChangeElementsInRangePath:(MPRangePath *)rangePath
                   replacementLength:(NSUInteger)replacementLength;

#pragma mark Basic NSObject Methods
- (BOOL)isEqualToExpression:(MPExpression *)anExpression;

- (NSString *)description;
- (NSUInteger)hash;

@end

@interface MPExpression (MPExpressionExtension)

#pragma mark Working With the Expression Tree
- (id)elementAtIndexPath:(NSIndexPath *)indexPath; // Returns an MPExpression or id<MPExpressionElement>
- (NSArray *)elementsInRangePath:(MPRangePath *)rangePath;

#pragma mark Working With Expressions

- (MPExpression *)subexpressionFromLocation:(NSUInteger)from;
- (MPExpression *)subexpressionToLocation:(NSUInteger)to;
- (MPExpression *)subexpressionWithRange:(NSRange)range;


#pragma mark Mutating Expressions
- (void)appendElement:(id<MPExpressionElement>)anElement;
- (void)appendElements:(NSArray *)elements;

- (void)insertElement:(id<MPExpressionElement>)anElement atLocation:(NSUInteger)index;
- (void)insertElements:(NSArray *)elements atLocation:(NSUInteger)index;

- (void)deleteElementsInRange:(NSRange)range;

#pragma mark Evaluating Expressions
- (float)floatValue;
- (int)intValue;
- (NSInteger)integerValue;
- (long long)longLongValue;

#pragma mark Querying Expressions
- (NSArray *)elements;

@end