import CoreML
import SwiftUI


struct ContentView: View {
    @State private var wakeUp = defaultWakeTime
    @State private var sleepAmount = 8.0
    @State private var coffeAmount = 1

    @State private var alertTitle = ""
    @State private var alertMessage = ""
    @State private var showingAlert = false

    static var defaultWakeTime: Date {
        var components = DateComponents()
        components.hour = 7
        components.minute = 0
        return Calendar.current.date(from: components) ?? Date.now
    }

    var body: some View {

        NavigationView {
            Form {
                VStack(alignment: .leading, spacing: 0){
                    Text("When do you want to wake up?")
                        .font(.headline)
                    DatePicker("Please enter a time", selection: $wakeUp, displayedComponents: .hourAndMinute)
                        .labelsHidden()
                }
                VStack(alignment: .leading, spacing: 0){
                    Text("Desired amount of sleep")
                        .font(.headline)
                    Stepper("\(sleepAmount.formatted()) hours", value: $sleepAmount, in: 4...12, step: 0.25)
                }

                VStack(alignment: .leading, spacing: 0){
                    Text("Daily coffe intake")
                        .font(.headline)
                    Stepper(coffeAmount == 1 ? "1 cup" : "\(coffeAmount) cups", value: $coffeAmount, in: 1...20)
                }
            }
            .navigationTitle("Better Rest")
            .toolbar {
                Button("Calculate", action: calculateBedTime)
            }
            .alert(alertTitle, isPresented: $showingAlert) {
                Button("OK") { }
            } message: {
                Text(alertMessage)
            }
        }
    }

    func calculateBedTime() {
        do {
            let config = MLModelConfiguration()
            let model = try SleepCalculator(configuration: config)

            let components = Calendar.current.dateComponents([.hour, .minute], from: wakeUp)
            let hour = (components.hour ?? 0) * 60 * 60
            let minute = (components.minute ?? 0) * 60

            let prediction = try model.prediction(wake: Double(hour + minute), estimatedSleep: sleepAmount, coffee: Double(coffeAmount))

            let sleepTime = wakeUp - prediction.actualSleep
            alertTitle = "Your ideal bed time is..."
            alertMessage = sleepTime.formatted(date: .omitted, time: .shortened)


        } catch {
            alertTitle = "Error"
            alertMessage = "Sorry, there was a problem calculationg your bedtime."
        }
            showingAlert = true
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}