love_letter.swift

//
//  love_letter_widget.swift
//  love-letter-widget
//
//  Created by youss on 08/06/2023.
//

import WidgetKit
import SwiftUI
import Intents
import Supabase

struct Message: Identifiable, Hashable, Decodable {
    let id: Int
    let message: String
}


struct MessageEntry: TimelineEntry {
    var message: String
    var date: Date
}

struct MessageFetcher {
    private static var supabase = SupabaseClient(supabaseURL: URL(string: "https://XXX.supabase.co")!, supabaseKey: "XXX")
    
    /// The path where the cached message located
    private static var cachePath: URL {
        URL.cachesDirectory.appending(path: "message.txt")
    }

    /// The cached message
    static var cachedMessage: String? {
        guard let message = try? Data(contentsOf: cachePath) else {
            return  nil
        }
        return String(decoding: message, as: UTF8.self)
    }

    /// Is cached message currently available
    static var cachedMessageAvailable: Bool {
        cachedMessage != nil
    }
    
    static func getMessage() async throws -> Message {
        do {
            let latestMessage: [Message] = try await supabase.database
                .from("messages")
                .select()
                .order(column: "id", ascending: false)
                .limit(count: 1)
                .execute()
                .value
            
            return latestMessage[0]
        } catch {
            throw error
        }
    }

    
    /// Call the Database and then get last message and cache it
    static func fetchLastMessage() async throws -> Message {
        // Parse the JSON data
        let message = try await getMessage()
    
        
        // Spawn another task to cache the downloaded image
        Task {
            try? await cache(message.message.data(using: .utf8)!)
        }
        
        return message
    }
    
    /// Save the message locally
    private static func cache(_ messageData: Data) async throws {
        try messageData.write(to: cachePath)
    }
}


struct Provider: IntentTimelineProvider {
    func placeholder(in context: Context) -> MessageEntry {
        MessageEntry(message: "Je t'aime", date: Date())
    }
    

    func getSnapshot(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (MessageEntry) -> ()) {
        var snapshotMessage: String
        
        if context.isPreview && !MessageFetcher.cachedMessageAvailable {
            snapshotMessage = "Je t'aime"
        } else {
            snapshotMessage = MessageFetcher.cachedMessage!
        }
        let entry = MessageEntry(message: snapshotMessage, date: Date())
        completion(entry)
    }

    func getTimeline(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
        Task {

              // Fetch a random doggy image from server
              guard let message = try? await MessageFetcher.fetchLastMessage() else {
                  return
              }
              
            let entry = MessageEntry(message: message.message, date: Date())
              
              // Next fetch happens 15 minutes later
              let nextUpdate = Calendar.current.date(
                  byAdding: DateComponents(minute: 15),
                  to: Date()
              )!
              
              let timeline = Timeline(
                  entries: [entry],
                  policy: .after(nextUpdate)
              )
              
              completion(timeline)
          }
    }
}


struct love_letter_widgetEntryView : View {
    var entry: Provider.Entry

    var body: some View {
        Text(entry.message)
    }
}

struct love_letter_widget: Widget {
    let kind: String = "love_letter_widget"

    var body: some WidgetConfiguration {
        IntentConfiguration(kind: kind, intent: ConfigurationIntent.self, provider: Provider()) { entry in
            love_letter_widgetEntryView(entry: entry)
        }
        .configurationDisplayName("My Widget")
        .description("This is an example widget.")
    }
}

struct love_letter_widget_Previews: PreviewProvider {
    static var previews: some View {
        love_letter_widgetEntryView(entry: MessageEntry(message: "Je t'aime", date: Date()))
            .previewContext(WidgetPreviewContext(family: .systemSmall))
    }
}