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

#import "MPExpressionStorage.h"
#import "MPExpressionLayout.h"
#import "MPFunctionLayout.h"
#import "MPRangePath.h"

@interface MPExpressionStorage ()
@property (nonatomic, strong) NSLayoutManager *layoutManager;
@property (nonatomic, strong) NSTextContainer *textContainer;
@property (nonatomic, strong) NSTextStorage *textStorage;
@end

@implementation MPExpressionStorage

- (instancetype)initWithSymbols:(NSArray *)symbols
{
    self = [super initWithSymbols:symbols];
    if (self) {
        _expressionLayout = [[MPExpressionLayout alloc] initRootLayoutWithExpressionStorage:self];
    }
    return self;
}

- (NSLayoutManager *)layoutManager
{
    [self ensureTextSystemObjects];
    return _layoutManager;
}

- (NSTextContainer *)textContainer
{
    [self ensureTextSystemObjects];
    return _textContainer;
}

- (NSTextStorage *)textStorage
{
    [self ensureTextSystemObjects];
    return _textStorage;
}

- (void)ensureTextSystemObjects
{
    if (_layoutManager == nil || _textContainer == nil || _textStorage == nil) {
        _textStorage = [[NSTextStorage alloc] init];
        NSTextContainer *textContainer = [[NSTextContainer alloc] initWithContainerSize:NSMakeSize(CGFLOAT_MAX, CGFLOAT_MAX)];
        NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
        [layoutManager addTextContainer:textContainer];
        [_textStorage addLayoutManager:layoutManager];
        _textContainer = textContainer;
        _layoutManager = layoutManager;
    }
}

- (void)symbolsChangedInRangePath:(MPRangePath *)rangePath replacementLength:(NSUInteger)length
{
    if (rangePath.location.length == 0) {
        return;
    }
    id current = self.expressionLayout;
    for (NSUInteger position = 1; position < rangePath.location.length-1; position++) {
        if ([current isKindOfClass:[MPExpressionLayout class]]) {
            current = [(MPExpressionLayout *)current functionLayoutForFunctionAtIndex:position];
        } else {
            current = [(MPFunctionLayout *)current expressionLayoutForChildAtIndex:position];
        }
    }
    if ([current isKindOfClass:[MPExpressionLayout class]]) {
        [(MPExpressionLayout *)current editedExpressionInRange:rangePath.rangeAtLastIndex replacementLength:length];
    } else {
        [(MPFunctionLayout *)current editedChildAtIndex:[rangePath.location indexAtPosition:rangePath.location.length-1]];
    }
}

@end