Charts/ChartsDemo-iOS/Swift/Demos/PositiveNegativeBarChartViewController.swift

//
//  PositiveNegativeBarChartViewController.swift
//  ChartsDemo-iOS
//
//  Created by Jacob Christie on 2017-07-09.
//  Copyright © 2017 jc. All rights reserved.
//

#if canImport(UIKit)
    import UIKit
#endif
import Charts

class PositiveNegativeBarChartViewController: DemoBaseViewController {

    @IBOutlet var chartView: BarChartView!

    let dataLabels = ["12-19",
                      "12-30",
                      "12-31",
                      "01-01",
                      "01-02"]
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Do any additional setup after loading the view.
        self.title = "Positive/Negative Bar Chart"
        self.options = [.toggleValues,
                        .toggleHighlight,
                        .animateX,
                        .animateY,
                        .animateXY,
                        .saveToGallery,
                        .togglePinchZoom,
                        .toggleAutoScaleMinMax,
                        .toggleData,
                        .toggleBarBorders]
        
        self.setup(barLineChartView: chartView)
        
        chartView.delegate = self
        
        chartView.setExtraOffsets(left: 70, top: -30, right: 70, bottom: 10)
    
        chartView.drawBarShadowEnabled = false
        chartView.drawValueAboveBarEnabled = true
        
        chartView.chartDescription?.enabled = false
        
        chartView.rightAxis.enabled = false

        let xAxis = chartView.xAxis
        xAxis.labelPosition = .bottom
        xAxis.labelFont = .systemFont(ofSize: 13)
        xAxis.drawAxisLineEnabled = false
        xAxis.labelTextColor = .lightGray
        xAxis.labelCount = 5
        xAxis.centerAxisLabelsEnabled = true
        xAxis.granularity = 1
        xAxis.valueFormatter = self
        
        let leftAxis = chartView.leftAxis
        leftAxis.drawLabelsEnabled = false
        leftAxis.spaceTop = 0.25
        leftAxis.spaceBottom = 0.25
        leftAxis.drawAxisLineEnabled = false
        leftAxis.drawZeroLineEnabled = true
        leftAxis.zeroLineColor = .gray
        leftAxis.zeroLineWidth = 0.7
        
        self.updateChartData()
    }
    
    override func updateChartData() {
        if self.shouldHideData {
            chartView.data = nil
            return
        }
        
        self.setChartData()
    }
    
    func setChartData() {
        let yVals = [BarChartDataEntry(x: 0, y: -224.1),
                     BarChartDataEntry(x: 1, y: 238.5),
                     BarChartDataEntry(x: 2, y: 1280.1),
                     BarChartDataEntry(x: 3, y: -442.3),
                     BarChartDataEntry(x: 4, y: -2280.1)
        ]
        
        let red = UIColor(red: 211/255, green: 74/255, blue: 88/255, alpha: 1)
        let green = UIColor(red: 110/255, green: 190/255, blue: 102/255, alpha: 1)
        let colors = yVals.map { (entry) -> NSUIColor in
            return entry.y > 0 ? red : green
        }
        
        let set = BarChartDataSet(entries: yVals, label: "Values")
        set.colors = colors
        set.valueColors = colors
        
        let data = BarChartData(dataSet: set)
        data.setValueFont(.systemFont(ofSize: 13))
        
        let formatter = NumberFormatter()
        formatter.maximumFractionDigits = 1
        data.setValueFormatter(DefaultValueFormatter(formatter: formatter))
        data.barWidth = 0.8
        
        chartView.data = data
    }
    
    override func optionTapped(_ option: Option) {
        super.handleOption(option, forChartView: chartView)
    }
}

extension PositiveNegativeBarChartViewController: IAxisValueFormatter {
    func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        return dataLabels[min(max(Int(value), 0), dataLabels.count - 1)]
    }
}