Create complications for Apple Watch

// CLKComplicationDataSource - Required
class ComplicationController: NSObject, CLKComplicationDataSource {

    func getCurrentTimelineEntry(
        for complication: CLKComplication, 
        withHandler handler: @escaping (CLKComplicationTimelineEntry?) -> Void)     
    {
        // Call the handler with the current timeline entry
        handler(createTimelineEntry(forComplication: complication, date: Date()))
    }
}

// CLKComplicationDataSource - Timeline Support
extension ComplicationController {

    func getTimelineEndDate(
        for complication: CLKComplication, 
        withHandler handler: @escaping (Date?) -> Void) 
    {
        handler(timeline(for: complication)?.endDate)
    }

    func getTimelineEntries(
        for complication: CLKComplication, 
        after date: Date, 
        limit: Int, 
        withHandler handler: @escaping ([CLKComplicationTimelineEntry]?) -> Void) 
    {
       handler(timeline(for: complication)?.entries(after: date, limit: limit))
    }
}

let longDate: Date = DateComponents(year: 2020, month: 9, day: 23).date ?? Date()
let units: NSCalendar.Unit = [.weekday, .month, .day]
let textProvider = CLKDateTextProvider(date: longDate, units: units)

let timerStart: Date = …
let units: NSCalendar.Unit = [.hour, .minute, .second]
let textProvider = CLKRelativeDateTextProvider(date: timerStart, style: .timer, units: units)

// CLKComplicationDataSource - Multiple Complication Support
extension ComplicationController {
    var descriptors : [CLKComplicationDescriptor] = []
    var dataDict = Dictionary<AnyHashable, Any>()
        
    for station in data.stations {
        dataDict = [“name": station.name, “shortName": station.shortName]
        descriptors.append(
            CLKComplicationDescriptor(
                identifier: station.name,
                displayName: station.name,
                supportedFamilies: CLKComplicationFamily.allCases,
                userInfo: dataDict))
    }
    
    descriptors.append(
        CLKComplicationDescriptor(
            identifier: "LogSighting",
            displayName: "Log Sighting",
            supportedFamilies: CLKComplicationFamily.allCases))

    descriptors.append(
        CLKComplicationDescriptor(
            identifier: "SeasonData",
            displayName: "Season Data",
            supportedFamilies: [.graphicRectangular]))
        
    // Call the handler with the currently supported complication descriptors
    handler(descriptors)
}

func getLocalizableSampleTemplate(
    for complication: CLKComplication, 
    withHandler handler: @escaping (CLKComplicationTemplate?) -> Void) 
{
    let template = createSampleTemplate(forComplication: complication)
    handler(template)
}

func createTimelineEntry(
    forComplication complication: CLKComplication, 
    date: Date) -> CLKComplicationTimelineEntry? 
{
    guard let template = createTemplate(forComplication: complication, date: date) else {
        return nil
    }
    return CLKComplicationTimelineEntry(date: date, complicationTemplate: template)
}

func createTemplate(
    forComplication complication: CLKComplication, 
    date: Date) -> CLKComplicationTemplate? 
{
    var station: Station? = nil
    if let stationName = complication.userInfo?["name"] as? String {
        station = data.stations.first(where: { $0.name == stationName })
    }
    
    let image = UIImage(named: "Spout-small")!
    let spoutFullColorImageProvider = CLKFullColorImageProvider(fullColorImage: image)
    let logSightingTextProvider = CLKSimpleTextProvider(
        text: "Log Sighting", 
        shortText: "Log")

    let defaultTemplate: (CLKComplicationFamily) -> CLKComplicationTemplate = { family -> CLKComplicationTemplate in
      // Return a default complication template for the given family
    }
  
    switch (complication.family, complication.identifier) {

    case (.graphicRectangular, "SeasonData"):
        return CLKComplicationTemplateGraphicRectangularFullView(
            ChartView(
                seriesData: data.last7DaysSightings, 
                seriesColor: .turquoise)

    case (.graphicCircular, "LogSighting"):
        return CLKComplicationTemplateGraphicCircularStackImage(
            line1ImageProvider: spoutFullColorImageProvider, 
            line2TextProvider: logSightingTextProvider)

    case (.graphicCircular, _):
        guard let station = station else { return defaultTemplate(.graphicCircular) }
        return CLKComplicationTemplateGraphicCircularView(
            SightingTypeView(station: station))
          
    case (.graphicCorner, _):
        guard let station = station else { return defaultTemplate(.graphicCorner) }
        return CLKComplicationTemplateGraphicCornerTextImage(
            textProvider: station.timeAndShortLocTextProvider, 
            imageProvider: station.whaleActivityFullColorProvider)
                
    case (.graphicExtraLarge, _):
        guard let station = station else { return defaultTemplate(.graphicExtraLarge) }
        return CLKComplicationTemplateGraphicExtraLargeCircularStackText(
            line1TextProvider: station.timeAndLocationTextProvider, 
            line2TextProvider: station.shortLocationTextProvider)

    default:
        return defaultTemplate(complication.family)
    }
}