import WidgetKit
import SwiftUI

struct Provider: TimelineProvider {
    
    private func getDataFromFlutter() -> SimpleEntry {
        let userDefault = UserDefaults(suiteName: "group.attendance")
        let checkInTimeString = userDefault?.string(forKey: "checkInTime") ?? ""
        
        let timerText: String
        if !checkInTimeString.isEmpty {
            timerText = getElapsedTimeString(from: checkInTimeString)
        } else {
            timerText = "00:00:00"
        }
        
        let checkInStatus = userDefault?.bool(forKey: "status") ?? false
        let checkInLoading = userDefault?.bool(forKey: "onLoading") ?? false
        return SimpleEntry(date: Date(), timer: timerText, status: checkInStatus, checkInLoading: checkInLoading)
    }
    
    func getElapsedTimeString(from dateString: String) -> String {
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
        formatter.timeZone = TimeZone.current

        guard let pastDate = formatter.date(from: dateString) else {
            return "00:00:00"
        }

        let now = Date()
        let elapsed = now.timeIntervalSince(pastDate)

        if elapsed < 0 {
            return "00:00:00" // Date is in the future
        }

        let hours = Int(elapsed) / 3600
        let minutes = (Int(elapsed) % 3600) / 60
        let seconds = Int(elapsed) % 60

        return String(format: "%02d:%02d:%02d", hours, minutes, seconds)
    }
    
    // preview in widget gallery
    func placeholder(in context: Context) -> SimpleEntry {
        SimpleEntry(date: Date(), timer: "00:00:00", status: false, checkInLoading: false)
    }
    
    // widget gallery/selection preview
    func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> ()) {
        let entry = SimpleEntry(date: Date(), timer: "00:00:00", status: false, checkInLoading: false)
        completion(entry)
    }
    
    // actual widget
    func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
        let entry = getDataFromFlutter()
        
        let nextUpdate = Calendar.current.date(byAdding: .second, value: 10, to: Date())!
        let timeline = Timeline(entries: [entry], policy: .after(nextUpdate))
        completion(timeline)
    }
    
    //    func relevances() async -> WidgetRelevances<Void> {
    //        // Generate a list containing the contexts this widget is relevant in.
    //    }
}

struct SimpleEntry: TimelineEntry {
    let date: Date
    let timer: String
    let status: Bool
    var checkInStatusText: String {
        status ? "Check Out" : "Check In"
    }
    let checkInLoading: Bool
}

struct AttendanceWidgetEntryView : View {
    var entry: Provider.Entry
    
    var body: some View {
        VStack(spacing: 16) {
            Text("Work Time")
                .font(.headline)
                .foregroundColor(.black)
            
            HStack(spacing: 8) {
                Image(systemName: "clock")
                    .foregroundColor(.black)
                Text(entry.timer)
                    .font(.system(size: 36, weight: .bold, design: .monospaced))
                    .foregroundColor(.black)
            }
            
            Link(destination: URL(string: "homeWidget://checkout")!) {
                RoundedRectangle(cornerRadius: 12)
                    .fill(Color.white.opacity(0.2))
                    .overlay(
                        HStack {
                            Image(systemName: "arrow.right.circle.fill")
                                .foregroundColor(.white)
                            
                            Text(entry.checkInStatusText)
                                .font(.system(size: 16, weight: .semibold))
                                .foregroundColor(.white)
                        }
                            .frame(maxWidth: .infinity)
                            .padding(.vertical, 12)
                            .background(Color(red: 0/255, green: 222/255, blue: 156/255))
                            .cornerRadius(12)
                            .padding(.horizontal, 16)
                    )
                    .frame(height: 44)
            }
        }
    
        .background(Color.clear)
        .cornerRadius(20)
        .containerBackground(.fill.tertiary, for: .widget)
    }
}

struct AttendanceWidget: Widget {
    let kind: String = "AttendanceWidget"
    
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: Provider()) { entry in
            if #available(iOS 17.0, *) {
                AttendanceWidgetEntryView(entry: entry)
                    .containerBackground(.fill.tertiary, for: .widget)
            } else {
                AttendanceWidgetEntryView(entry: entry)
                    .padding()
                    .background()
            }
        }
        .configurationDisplayName("My Widget")
        .description("This is an example widget.")
    }
}

#Preview(as: .systemSmall) {
    AttendanceWidget()
} timeline: {
    SimpleEntry(date: .now, timer: "00:00:00", status: false, checkInLoading: false)
    SimpleEntry(date: .now, timer: "00:00:00", status: false, checkInLoading: false)
}