import UIKit

class HistogramView: UIView {
    var barWidth: CGFloat = 3.0
    var barMinHeight: CGFloat = 3.0
    var marginBetweenBars: CGFloat = 2.0

    var bars = [UIView]()

    override init(frame: CGRect) {
        super.init(frame: frame)

        backgroundColor = UIColor.clear

        for i in 0...15 {
            var x = CGFloat(i) * barWidth

            if i > 0 {
                x += CGFloat(i) * marginBetweenBars
            }

            let y = (self.bounds.height - barMinHeight)

            let barRect = CGRect(x: x, y: y,
                                 width: barWidth, height: barMinHeight)

            let v = UIView(frame: barRect)
            v.backgroundColor = UIColor.white
            v.layer.cornerRadius = barWidth / 2

            v.layer.shadowOpacity = 0.8
            v.layer.shadowOffset = CGSize(width: 0.0, height: 0.0)
            v.layer.shadowColor = UIColor.gray.cgColor
            v.layer.shadowRadius = 1.3

            bars.append(v)
            self.addSubview(v)
        }
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func didUpdateHistogramRaw(data: [Int]) {
        let max_pixels = CGFloat(data.max()!)
        let height = CGFloat(self.bounds.height)

        for (i, item) in data.enumerated() {
            var value_height = CGFloat(item) / max_pixels * height

            if value_height < barMinHeight {
                value_height = barMinHeight
            }

            let y = (self.bounds.height - value_height)
            let v = self.bars[i]

            UIView.animate(withDuration: 0.2, animations: {
                v.frame.origin.y = y
                v.frame.size.height = value_height
            })
        }
    }
}