//
//  CountdownView.swift
//  LeCountdown
//
//  Created by Laurent Morvillier on 25/01/2023.
//

import SwiftUI
import WidgetKit
import CoreData

struct GradientView: View {
    
    private static let backgroundGradientColors: [Color] = [.red, .purple]
    
    var body: some View {
        ZStack {
            GeometryReader { reader in
                let gradient: Gradient = Gradient(colors: GradientView.backgroundGradientColors)
                RadialGradient(gradient: gradient,
                               center: .init(x: 0.0, y: 0.0),
                               startRadius: 0, endRadius: reader.size.width)
            }
        }
    }

}

extension View {
    
    var linearGradient: LinearGradient {
        
        LinearGradient(colors: [Color(red: 255, green: 128, blue: 223), Color(red: 255, green: 180, blue: 78)],
                       startPoint: .topLeading, endPoint: .bottomTrailing)
    }
    
    var radialGradient: some View {
        RadialGradient(colors: [Color(red: 255, green: 128, blue: 223),
                                Color(red: 255, green: 86, blue: 61),
                                Color(red: 255, green: 180, blue: 78)],
                       center: .bottomLeading,
                       startRadius:  Angle.degrees(0).degrees,
                       endRadius: Angle.degrees(90).degrees)
        
    }
    
}

struct SingleTimerView: View {
    
    @Environment(\.widgetFamily) var family: WidgetFamily
    
    var timer: AbstractTimer
    
    var body: some View {
        VStack {
            HStack {
                VStack(alignment: .leading) {
                    Text(timer.displayName.uppercased())
                    if let countdown = timer as? Countdown {
                        Text(countdown.duration.hourMinuteSecond)
                    }
                }
                Spacer()
            }
            Spacer()
        }
        .padding()
        .monospaced()
        .foregroundColor(.white)
        .background(GradientView())
//        .background(.white.opacity(0.5))
        .font(self.font)
        .widgetURL(timer.url)
    }
    
    private var font: Font {
        switch family {
        case .systemSmall, .systemMedium, .systemLarge, .systemExtraLarge:
            return .body
        case .accessoryCircular:
            return .footnote
        default:
            return .body
        }
    }
    
}

struct LockScreenCountdownView: View {
    
    @Environment(\.widgetFamily) var family: WidgetFamily
    
    var timer: AbstractTimer
    
    var body: some View {
        VStack {
            let title = self.timer.displayName.uppercased()
            switch self.family {
            case .accessoryCircular:
                Text(title)
            default:
                Text(title)
                if let countdown = self.timer as? Countdown {
                    Text(countdown.duration.hourMinuteSecond)
                        .monospaced()
                }
            }
        }
        .multilineTextAlignment(.center)
        .foregroundColor(Color.white)
        .font(self.font)
        .widgetURL(self.timer.url)
    }
    
    private var activityName: String {
        switch self.family {
        case .accessoryCircular:
            let reduced = self.timer.displayName
            if reduced.contains(" ") {
                let initials = reduced.components(separatedBy: " ").compactMap { $0.first }.map { String($0) }
                return initials.joined(separator: "")
            } else {
                return String(reduced.prefix(5))
            }
        default:
            return self.timer.displayName
        }
    }
    
    private var font: Font {
        return .system(size: 14.0, weight: .medium)
        
//        return .body
//        switch self.family {
//        case .systemSmall, .systemMedium, .systemLarge, .systemExtraLarge:
//            return .body
//        case .accessoryCircular:
//            return Font.system(.body, weight: .medium)
//        default:
//            return .body
//        }
    }
    
}

struct MultiCountdownView: View {
    
    @Environment(\.widgetFamily) var family: WidgetFamily
    
    private let columns: [GridItem] = [
        GridItem(spacing: 10.0),
        GridItem(spacing: 10.0),
    ]
    
    var timers: [AbstractTimer]
    
    var body: some View {
        
        if self.timers.isEmpty {
            DefaultView()
        } else {
            
            LazyVGrid(
                columns: self.columns,
                spacing: 10.0
            ) {
                
                ForEach(self.timers) { timer in
                    
                    Link(destination: timer.url) {
                        HStack {
                            
                            VStack(alignment: .leading) {
                                Spacer()
                                Text(timer.displayName.uppercased()).lineLimit(1)
                                if let countdown = timer as? Countdown {
                                    Text(countdown.duration.hourMinuteSecond)
                                }
                                Spacer()
                            }
                            Spacer()
                        }
                        .padding(.horizontal, 12.0)
                        .padding(.vertical, 4.0)
                        .font(.footnote)
                        .background(Color.white.opacity(0.1))
                        .foregroundColor(.white)
                        .monospaced()
                        .cornerRadius(16.0)
                    }

                }
            }
            .padding(.horizontal, 12.0)
            .padding(.vertical, 16.0)
            .frame(maxWidth: .infinity, maxHeight: .infinity)
            .background(GradientView())
//            .background(.white.opacity(0.5))

        }
        
    }
    
    private var font: Font {
        switch family {
        case .systemSmall, .systemMedium, .systemLarge, .systemExtraLarge:
            return .title2
        default:
            return .body
        }
    }
    
}

struct CountdownView_Previews: PreviewProvider {
    static var previews: some View {
        
        SingleTimerView(timer: Countdown.fake(context: PersistenceController.preview.container.viewContext)).previewContext(WidgetPreviewContext(family: .systemSmall)).background(.black)
        MultiCountdownView(timers: self.countdowns(context: PersistenceController.preview.container.viewContext)).previewContext(WidgetPreviewContext(family: .systemMedium))
        LockScreenCountdownView(timer: Countdown.fake(context: PersistenceController.preview.container.viewContext)).previewContext(WidgetPreviewContext(family: .accessoryRectangular))
        LockScreenCountdownView(timer: Countdown.fake(context: PersistenceController.preview.container.viewContext)).previewContext(WidgetPreviewContext(family: .accessoryCircular))
    }
    
    static func countdowns(context: NSManagedObjectContext) -> [Countdown] {
        return (0..<4).map { _ in
            Countdown.fake(context: context)
        }
    }
    
}