BlueWallet/ios/Widgets/PriceWidget/PriceWidget.swift

//
//  PriceWidget.swift
//  PriceWidget
//
//  Created by Marcos Rodriguez on 11/8/20.
//  Copyright © 2020 BlueWallet. All rights reserved.
//

import WidgetKit
import SwiftUI

var marketData: [MarketDataTimeline: MarketData?] = [ .Current: nil, .Previous: nil]
struct PriceWidgetProvider: TimelineProvider {
  typealias Entry = PriceWidgetEntry
  static var lastSuccessfulEntry: PriceWidgetEntry?
  
  func placeholder(in context: Context) -> PriceWidgetEntry {
    return PriceWidgetEntry(date: Date(), currentMarketData: MarketData(nextBlock: "", sats: "", price: "$10,000", rate: 10000, dateString: "2019-09-18T17:27:00+00:00"))
  }
  
  func getSnapshot(in context: Context, completion: @escaping (PriceWidgetEntry) -> ()) {
    let entry: PriceWidgetEntry
    if (context.isPreview) {
      entry = PriceWidgetEntry(date: Date(), currentMarketData: MarketData(nextBlock: "", sats: "", price: "$10,000", rate: 10000, dateString: "2019-09-18T17:27:00+00:00"))
    } else {
      entry = PriceWidgetEntry(date: Date(), currentMarketData: emptyMarketData)
    }
    completion(entry)
  }
  
  func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    var entries: [PriceWidgetEntry] = []
    if (context.isPreview) {
      let entry = PriceWidgetEntry(date: Date(), currentMarketData: MarketData(nextBlock: "", sats: "", price: "$10,000", rate: 10000, dateString: "2019-09-18T17:27:00+00:00"))
      entries.append(entry)
      let timeline = Timeline(entries: entries, policy: .atEnd)
      completion(timeline)
    } else {
      let userPreferredCurrency = WidgetAPI.getUserPreferredCurrency()
      if userPreferredCurrency != WidgetAPI.getLastSelectedCurrency() {
        marketData[.Current] = nil
        marketData[.Previous] = nil
        WidgetAPI.saveNewSelectedCurrency()
      }
      
      WidgetAPI.fetchPrice(currency: userPreferredCurrency) { (data, error) in
        let entry: PriceWidgetEntry
        
        if let data = data, let formattedRate = data.formattedRate {
          let currentMarketData = MarketData(nextBlock: "", sats: "", price: formattedRate, rate: data.rateDouble, dateString: data.lastUpdate)
          marketData[.Previous] = marketData[.Current]
          marketData[.Current] = currentMarketData
          entry = PriceWidgetEntry(date: Date(), currentMarketData: currentMarketData)
          PriceWidgetProvider.lastSuccessfulEntry = entry
        } else {
          // Use the last successful entry if available
          if let lastEntry = PriceWidgetProvider.lastSuccessfulEntry {
            entry = lastEntry
          } else {
            // Fallback to a default entry if no successful entry is available
            entry = PriceWidgetEntry(date: Date(), currentMarketData: emptyMarketData)
          }
        }
        entries.append(entry)
        let timeline = Timeline(entries: entries, policy: .atEnd)
        completion(timeline)
      }
    }}
  }
  
  struct PriceWidgetEntry: TimelineEntry {
    let date: Date
    let currentMarketData: MarketData?
    var previousMarketData: MarketData? {
      return marketData[.Previous] as? MarketData
    }
  }
  
  struct PriceWidgetEntryView : View {
    let entry: PriceWidgetEntry
    var priceView: some View {
      PriceView(currentMarketData: entry.currentMarketData, previousMarketData: marketData[.Previous] ?? emptyMarketData).padding()
    }
    
    var body: some View {
      VStack(content: {
        priceView
      }).background(Color.widgetBackground)
    }
  }
  
  struct PriceWidget: Widget {
    let kind: String = "PriceWidget"
    
    var body: some WidgetConfiguration {
      if #available(iOSApplicationExtension 16.0, *) {
        return StaticConfiguration(kind: kind, provider: PriceWidgetProvider()) { entry in
          PriceWidgetEntryView(entry: entry)
        }
        .configurationDisplayName("Price")
        .description("View the current price of Bitcoin.").supportedFamilies([.systemSmall])
      } else {
        return StaticConfiguration(kind: kind, provider: PriceWidgetProvider()) { entry in
          PriceWidgetEntryView(entry: entry)
        }
        .configurationDisplayName("Price")
        .description("View the current price of Bitcoin.").supportedFamilies([.systemSmall])
      }
    }
  }
  
struct PriceWidget_Previews: PreviewProvider {
  static var previews: some View {
    PriceWidgetEntryView(entry: PriceWidgetEntry(date: Date(), currentMarketData: MarketData(nextBlock: "", sats: "", price: "$10,000", rate: 10000, dateString: "2019-09-18T17:27:00+00:00")))
      .previewContext(WidgetPreviewContext(family: .systemSmall))
  }
}