Trio/Dependencies/LoopKit/LoopKitUI/Views/ChartPointsTouchHighlightLayerViewCache.swift

//
//  StatusChartHighlightLayer.swift
//  Naterade
//
//  Created by Nathan Racklyeft on 2/28/16.
//  Copyright © 2016 Nathan Racklyeft. All rights reserved.
//

import Foundation
import SwiftCharts
import UIKit

final class ChartPointsTouchHighlightLayerViewCache {
    private lazy var containerView = UIView(frame: .zero)

    private lazy var xAxisOverlayView = UIView()

    private lazy var point = ChartPointEllipseView(center: .zero, diameter: 16)

    private lazy var labelY: UILabel = {
        let label = UILabel()
        label.font = UIFont.monospacedDigitSystemFont(ofSize: 15, weight: UIFont.Weight.bold)

        return label
    }()

    private lazy var labelX: UILabel = {
        let label = UILabel()
        label.font = self.axisLabelSettings.font
        label.textColor = self.axisLabelSettings.fontColor

        return label
    }()

    private let axisLabelSettings: ChartLabelSettings

    private(set) var highlightLayer: ChartPointsTouchHighlightLayer<ChartPoint, UIView>!

    init(xAxisLayer: ChartAxisLayer, yAxisLayer: ChartAxisLayer, axisLabelSettings: ChartLabelSettings, chartPoints: [ChartPoint], tintColor: UIColor, gestureRecognizer: UIGestureRecognizer? = nil, onCompleteHighlight: (() -> Void)? = nil) {

        self.axisLabelSettings = axisLabelSettings

        highlightLayer = ChartPointsTouchHighlightLayer(
            xAxis: xAxisLayer.axis,
            yAxis: yAxisLayer.axis,
            chartPoints: chartPoints,
            gestureRecognizer: gestureRecognizer,
            onCompleteHighlight: onCompleteHighlight,
            modelFilter: { (screenLoc, chartPointModels) -> ChartPointLayerModel<ChartPoint>? in
                if let index = chartPointModels.map({ $0.screenLoc.x }).findClosestElementIndex(matching: screenLoc.x) {
                    return chartPointModels[index]
                } else {
                    return nil
                }
            },
            viewGenerator: { [weak self] (chartPointModel, layer, chart) -> UIView? in
                guard let strongSelf = self else {
                    return nil
                }

                let containerView = strongSelf.containerView
                containerView.frame = chart.contentView.bounds
                containerView.alpha = 1  // This is animated to 0 when touch last ended

                let xAxisOverlayView = strongSelf.xAxisOverlayView
                if xAxisOverlayView.superview == nil {
                    xAxisOverlayView.frame = CGRect(
                        origin: CGPoint(x: containerView.bounds.minX,
                                        y: containerView.bounds.maxY + 1), // Don't clip X line
                        size: xAxisLayer.frame.size
                    )
                    xAxisOverlayView.backgroundColor = .systemBackground
                    xAxisOverlayView.isOpaque = true
                    containerView.addSubview(xAxisOverlayView)
                }

                let point = strongSelf.point
                point.center = chartPointModel.screenLoc
                if point.superview == nil {
                    point.fillColor = tintColor.withAlphaComponent(0.5)
                    containerView.addSubview(point)
                }

                if let text = chartPointModel.chartPoint.y.labels.first?.text {
                    let label = strongSelf.labelY

                    label.text = text
                    label.sizeToFit()
                    label.center.y = containerView.frame.minY - 21
                    label.center.x = chartPointModel.screenLoc.x
                    label.frame.origin.x = min(max(label.frame.origin.x, containerView.bounds.minX), containerView.bounds.maxX - label.frame.size.width)
                    label.frame.origin.makeIntegralInPlaceWithDisplayScale(chart.view.traitCollection.displayScale)

                    if label.superview == nil {
                        label.textColor = tintColor

                        containerView.addSubview(label)
                    }
                }

                if let text = chartPointModel.chartPoint.x.labels.first?.text {
                    let label = strongSelf.labelX
                    label.text = text
                    label.sizeToFit()
                    label.center = CGPoint(x: chartPointModel.screenLoc.x, y: xAxisOverlayView.center.y)
                    label.frame.origin.makeIntegralInPlaceWithDisplayScale(chart.view.traitCollection.displayScale)

                    if label.superview == nil {
                        containerView.addSubview(label)
                    }
                }
                
                return containerView
            }
        )
    }
}