//
//  MPRootFunctionLayout.m
//  MathPad
//
//  Created by Kim Wittenburg on 11.01.15.
//  Copyright (c) 2015 Kim Wittenburg. All rights reserved.
//

#import "MPRootFunctionLayout.h"

#import "MPRootFunction.h"


#define kRootFunctionTrailingOffset 3

#define kRootFunctionLineWidth 1
#define kRootFunctionLineFragmentLength (self.usesSmallSize ? 3 : 4)
#define kRootFunctionVWidth 5

#define kRootFunctionExpressionXOffset 2
#define kRootFunctionExponentXInset kRootFunctionLineFragmentLength


@implementation MPRootFunctionLayout

- (MPRootFunction *)rootFunction
{
    return (MPRootFunction *)self.function;
}


- (NSUInteger)indexOfLeadingChild
{
    return 1;
}


- (NSUInteger)indexOfTrailingChild
{
    return 1;
}


- (NSUInteger)indexOfChildBelowChildAtIndex:(NSUInteger)index
{
    return 1;
}


- (NSUInteger)indexOfChildAboveChildAtIndex:(NSUInteger)index
{
    return 0;
}


- (NSUInteger)indexOfChildAfterChildAtIndex:(NSUInteger)index
{
    return index == 0 ? 1 : NSNotFound;
}


- (NSIndexSet *)indexesOfRemainingChildren
{
    return [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, 2)];
}


- (BOOL)childAtIndexUsesSmallSize:(NSUInteger)index
{
    return index == 0;
}


- (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
{
    NSRect exponentBounds = [self childLayoutAtIndex:0].bounds;
    NSRect rootBounds = [self childLayoutAtIndex:1].bounds;
    if (index == 0) {
        CGFloat x;
        if (exponentBounds.size.width > kRootFunctionExponentXInset) {
            x = 0;
        } else {
            x = kRootFunctionExponentXInset - exponentBounds.size.width;
        }
        return NSMakePoint(x, rootBounds.size.height / 2.0 + rootBounds.origin.y - exponentBounds.origin.y);
    } else {
        CGFloat rootSymbolXOffset = exponentBounds.size.width > kRootFunctionExponentXInset ? exponentBounds.size.width - kRootFunctionExponentXInset : 0;
        CGFloat x = rootSymbolXOffset + kRootFunctionLineFragmentLength + kRootFunctionVWidth + kRootFunctionExpressionXOffset;
        return NSMakePoint(x, 0);
    }
}


- (NSIndexPath *)indexPathForLocalMousePoint:(NSPoint)point
{
    return [[NSIndexPath indexPathWithIndex:1] indexPathByAddingIndex:0];
}

- (NSRect)generateBounds
{
    CGFloat x, y, width, height;
    NSRect exponentBounds = [self childLayoutAtIndex:0].bounds;
    NSRect rootBounds = [self childLayoutAtIndex:1].bounds;

    x = 0;
    y = rootBounds.origin.y;
    CGFloat rootSymbolXOffset = exponentBounds.size.width > kRootFunctionLineFragmentLength ? exponentBounds.size.width : kRootFunctionLineFragmentLength;
    width = rootSymbolXOffset + kRootFunctionVWidth + kRootFunctionExpressionXOffset + rootBounds.size.width + kRootFunctionTrailingOffset;
    CGFloat heightToExponent = rootBounds.size.height / 2.0 + exponentBounds.size.height;
    height = MAX(heightToExponent, rootBounds.size.height + kRootFunctionLineWidth);
    return NSMakeRect(x, y, width, height);
}


- (void)draw
{
    NSRect exponentBounds = [self childLayoutAtIndex:0].bounds;
    NSRect rootBounds = [self childLayoutAtIndex:1].bounds;
    
    CGFloat rootSymbolXOffset = exponentBounds.size.width > kRootFunctionExponentXInset ? exponentBounds.size.width - kRootFunctionExponentXInset : 0;
    NSBezierPath *rootPath = [NSBezierPath bezierPath];
    NSPoint currentPoint = NSMakePoint(rootSymbolXOffset, rootBounds.size.height / 2.0 + rootBounds.origin.y);
    [rootPath moveToPoint:currentPoint];
    currentPoint.x += kRootFunctionLineFragmentLength;
    [rootPath lineToPoint:currentPoint];
    currentPoint.x += kRootFunctionVWidth / 2.0;
    currentPoint.y = rootBounds.origin.y;
    [rootPath lineToPoint:currentPoint];
    currentPoint.x += kRootFunctionVWidth / 2.0;
    currentPoint.y = rootBounds.size.height + rootBounds.origin.y;
    [rootPath lineToPoint:currentPoint];
    currentPoint.x += rootBounds.size.width;
    [rootPath lineToPoint:currentPoint];
    [rootPath stroke];
}

@end