//
//  MPExpressionLayout.m
//  MathPad
//
//  Created by Kim Wittenburg on 07.08.14.
//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
//

#import "MPExpressionLayout.h"
#import "MPFunctionLayout.h"

@interface MPExpressionLayout (MPPathGeneration)

- (NSBezierPath *)bezierPathForChildAtIndex:(NSUInteger)index;
- (NSBezierPath *)generateBezierPathForString:(NSString *)aString;


@end

@implementation MPExpressionLayout (MPPathGeneration)

- (NSBezierPath *)bezierPathForChildAtIndex:(NSUInteger)index
{
    id symbol = [self.expression elementAtIndex:index];
    if ([symbol isString]) {
        return [self cachableObjectForIndex:index
                                  generator:^id{
            return [self generateBezierPathForString:symbol];
        }];
    } else {
        MPLayout *layout = [self childLayoutAtIndex:index];
        return layout.bezierPath;
    }
}

- (NSBezierPath *)generateBezierPathForString:(NSString *)aString
{
    NSAttributedString *text = [[NSAttributedString alloc] initWithString:aString
                                                               attributes:@{NSFontAttributeName: [NSFont fontWithName:@"Lucida Grande" size:18.0]}];
    self.textStorage.attributedString = text;
    NSRange glyphRange = [self.layoutManager glyphRangeForTextContainer:self.textContainer];
    NSGlyph glyphs[glyphRange.length+1];
    NSUInteger actualGlyphCount = [self.layoutManager getGlyphs:glyphs
                                                          range:glyphRange];
    NSBezierPath *path = [NSBezierPath bezierPath];
    [path moveToPoint:NSZeroPoint];
    [path appendBezierPathWithGlyphs:glyphs
                               count:actualGlyphCount
                              inFont:[NSFont fontWithName:@"Lucida Grande" size:18.0]];
    return path;
}

@end

@implementation MPExpressionLayout

# pragma mark Creation Methods
- (instancetype)initRootLayoutWithExpressionStorage:(MPExpressionStorage *)expressionStorage
{
    self = [super init];
    if (self) {
        _expressionStorage = expressionStorage;
    }
    return self;
}

#pragma mark Properties
@synthesize expressionStorage = _expressionStorage;
- (MPExpressionStorage *)expressionStorage
{
    if (_expressionStorage) {
        return _expressionStorage;
    }
    return self.parent.expressionStorage;
}

- (MPExpression *)expression
{
    return [self.expressionStorage elementAtIndexPath:self.path];
}

#pragma mark Cache Methods
- (MPLayout *)childLayoutAtIndex:(NSUInteger)index
{
    id cachedObject = [self cachableObjectForIndex:index generator:^id{
        NSIndexPath *indexPath = [self.path indexPathByAddingIndex:index];
        MPFunctionLayout *layout = [MPFunctionLayout functionLayoutForFunctionAtIndexPath:indexPath
                                                                                   parent:self];
        return layout;
    }];
    if ([cachedObject isKindOfClass:[NSBezierPath class]]) {
        return nil;
    }
    return cachedObject;
}

- (NSSize)sizeForChildAtIndex:(NSUInteger)index
{
    id symbol = [self.expression elementAtIndex:index];
    if ([symbol isString]) {
        return [self bezierPathForChildAtIndex:index].bounds.size;
    } else {
        return [self childLayoutAtIndex:index].size;
    }
}

#pragma mark Drawing Methods
- (NSBezierPath *)generateBezierPath
{
    NSBezierPath *fullPath = [NSBezierPath bezierPath];
    [fullPath moveToPoint:NSZeroPoint];
    NSUInteger x = 0;
    for (NSInteger index = 0; index < self.expression.numberOfElements; ++index) {
        NSAffineTransform *transform = [NSAffineTransform transform];
        // TODO: Translate by the right amount
        [transform translateXBy:x yBy:0];
        NSBezierPath *path = [self bezierPathForChildAtIndex:index].copy;
        [path transformUsingAffineTransform:transform];
        [fullPath appendBezierPath:path];
        x += path.bounds.size.width;
    }
    return fullPath;
}

@end