Repo created

iphone/Maps/UI/PlacePage/Components/ElevationProfile/ElevationProfileFormatter.swift

@@ -0,0 +1,67 @@
+import Chart
+import CoreApi
+
+final class ElevationProfileFormatter {
+
+  private enum Constants {
+    static let metricToImperialMultiplier: CGFloat = 0.3048
+    static var metricAltitudeStep: CGFloat = 50
+    static var imperialAltitudeStep: CGFloat = 100
+  }
+
+  private let distanceFormatter: DistanceFormatter.Type
+  private let altitudeFormatter: AltitudeFormatter.Type
+  private let unitSystemMultiplier: CGFloat
+  private let altitudeStep: CGFloat
+  private let units: Units
+
+  init(units: Units = SettingsBridge.measurementUnits()) {
+    self.units = units
+    self.distanceFormatter = DistanceFormatter.self
+    self.altitudeFormatter = AltitudeFormatter.self
+    switch units {
+    case .metric:
+      self.altitudeStep = Constants.metricAltitudeStep
+      self.unitSystemMultiplier = 1
+    case .imperial:
+      self.altitudeStep = Constants.imperialAltitudeStep
+      self.unitSystemMultiplier = Constants.metricToImperialMultiplier
+    @unknown default:
+      fatalError("Unsupported units")
+    }
+  }
+}
+
+extension ElevationProfileFormatter: ChartFormatter {
+  func xAxisString(from value: Double) -> String {
+    distanceFormatter.distanceString(fromMeters: value)
+  }
+
+  func yAxisString(from value: Double) -> String {
+    altitudeFormatter.altitudeString(fromMeters: value)
+  }
+
+  func yAxisLowerBound(from value: CGFloat) -> CGFloat {
+    floor((value / unitSystemMultiplier) / altitudeStep) * altitudeStep * unitSystemMultiplier
+  }
+
+  func yAxisUpperBound(from value: CGFloat) -> CGFloat {
+    ceil((value / unitSystemMultiplier) / altitudeStep) * altitudeStep * unitSystemMultiplier
+  }
+
+  func yAxisSteps(lowerBound: CGFloat, upperBound: CGFloat) -> [CGFloat] {
+    let lower = yAxisLowerBound(from: lowerBound)
+    let upper = yAxisUpperBound(from: upperBound)
+    let range = upper - lower
+    var stepSize = altitudeStep
+    var stepsCount = Int((range / stepSize).rounded(.up))
+
+    while stepsCount > 6 {
+      stepSize *= 2 // Double the step size to reduce the step count
+      stepsCount = Int((range / stepSize).rounded(.up))
+    }
+
+    let steps = stride(from: lower, through: upper, by: stepSize)
+    return Array(steps)
+  }
+}