//
//  MaterialShowcase+Calculations.swift
//  MaterialShowcase
//
//  Created by Andrei Tulai on 2017-11-16.
//  Copyright © 2017 Aromajoin. All rights reserved.
//

import Foundation
import UIKit

extension MaterialShowcase {
    
    func isInGutter(center: CGPoint) -> Bool {
        return center.y < offsetThreshold || containerView.frame.height - center.y < offsetThreshold
    }
    
    func getOuterCircleCenterPoint(for target: UIView) -> CGPoint {
        if isInGutter(center: target.center) {
            return target.center
        }
        
        let targetRadius = max(target.frame.width, target.frame.height) / 2 + TARGET_PADDING
        let totalTextHeight = instructionView.frame.height
        
        let onTop = getTargetPosition(target: targetView, container: containerView) == .below
        
        let left = min(instructionView.frame.minX, target.frame.minX - targetRadius)
        let right = max(instructionView.frame.maxX, target.frame.maxX + targetRadius)
        let titleHeight = instructionView.primaryLabel.frame.height
        let centerY = onTop ? target.center.y - TARGET_HOLDER_RADIUS - TARGET_PADDING - totalTextHeight + titleHeight
            : target.center.y + TARGET_HOLDER_RADIUS + TARGET_PADDING + titleHeight
        
        return CGPoint(x: (left + right) / 2, y: centerY)
    }
    
    func getOuterCircleRadius(center: CGPoint, textBounds: CGRect, targetBounds: CGRect) -> CGFloat {
        let targetCenterX = targetBounds.midX
        let targetCenterY = targetBounds.midY
        
        let expandedRadius = 1.1 * TARGET_HOLDER_RADIUS
        let expandedBounds = CGRect(x: targetCenterX, y: targetCenterY, width: 0, height: 0)
        expandedBounds.insetBy(dx: -expandedRadius, dy: -expandedRadius);
        
        let textRadius = maxDistance(from: center, to: textBounds)
        let targetRadius = maxDistance(from: center, to: expandedBounds)
        return max(textRadius, targetRadius) + 40
    }
    
    func maxDistance(from point: CGPoint, to rect: CGRect) -> CGFloat {
        let tl = distance(point, CGPoint(x: rect.minX, y: rect.minY))
        let tr = distance(point, CGPoint(x: rect.maxX, y: rect.minY))
        let bl = distance(point, CGPoint(x: rect.minX, y: rect.maxY))
        let br = distance(point, CGPoint(x: rect.maxX, y: rect.maxY))
        return max(tl, max(tr, max(bl, br)))
    }
    
    func distance(_ a: CGPoint, _ b: CGPoint) -> CGFloat {
        let xDist = a.x - b.x
        let yDist = a.y - b.y
        return CGFloat(sqrt((xDist * xDist) + (yDist * yDist)))
    }
}