import AppIntents
import Foundation
import SwiftUI
import WidgetKit

struct MomentProvider: TimelineProvider {
    func placeholder(in context: Context) -> MomentEntry {
        MomentEntry(date: .now, lastRating: nil, lastRecordedAt: nil)
    }

    func getSnapshot(in context: Context, completion: @escaping (MomentEntry) -> Void) {
        completion(currentEntry())
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<MomentEntry>) -> Void) {
        completion(Timeline(entries: [currentEntry()], policy: .never))
    }

    private func currentEntry() -> MomentEntry {
        let defaults = MomentWidgetStorage.defaults
        let lastRating = defaults.string(forKey: MomentWidgetStorage.lastRatingKey)
            .flatMap(MomentRatingValue.init(rawValue:))
        let lastRecordedAt = defaults.object(forKey: MomentWidgetStorage.lastRecordedAtKey) as? Date

        return MomentEntry(date: .now, lastRating: lastRating, lastRecordedAt: lastRecordedAt)
    }
}

struct MomentEntry: TimelineEntry {
    let date: Date
    let lastRating: MomentRatingValue?
    let lastRecordedAt: Date?
}

struct MomentEntryView: View {
    let entry: MomentEntry

    private let ratings: [MomentRatingValue] = [
        .veryGood,
        .good,
        .middle,
        .bad,
        .veryBad
    ]

    var body: some View {
        VStack(alignment: .leading, spacing: 14) {
            HStack(alignment: .firstTextBaseline) {
                Text("Wie geht es dir?")
                    .font(.system(size: 18, weight: .bold))
                    .foregroundStyle(.white)
                    .lineLimit(1)
                    .minimumScaleFactor(0.82)
                    .shadow(color: .black.opacity(0.12), radius: 2, y: 1)

                Spacer(minLength: 6)

                if showsSavedState {
                    Text("Gespeichert")
                        .font(.system(size: 10, weight: .bold))
                        .foregroundStyle(.white)
                        .lineLimit(1)
                        .minimumScaleFactor(0.75)
                }
            }

            HStack(spacing: 7) {
                ForEach(ratings, id: \.self) { rating in
                    Button(intent: TrackMomentIntent(rating: rating)) {
                        ZStack(alignment: .topTrailing) {
                            Text(rating.emoji)
                                .font(.system(size: entry.lastRating == rating ? 28 : 25, weight: .bold))
                                .frame(maxWidth: .infinity)
                                .frame(height: 42)
                                .background(buttonBackground(for: rating), in: RoundedRectangle(cornerRadius: 8))

                            if showsSavedState, entry.lastRating == rating {
                                Image(systemName: "checkmark.circle.fill")
                                    .font(.system(size: 12, weight: .bold))
                                    .foregroundStyle(.white, Color.green)
                                    .offset(x: 4, y: -4)
                            }
                        }
                    }
                    .buttonStyle(.plain)
                    .accessibilityLabel(Text(rating.rawValue))
                }
            }
        }
        .padding(14)
        .containerBackground(for: .widget) {
            LinearGradient(
                colors: [
                    Color(red: 0.82, green: 0.90, blue: 0.76),
                    Color(red: 0.66, green: 0.78, blue: 0.60)
                ],
                startPoint: .topLeading,
                endPoint: .bottomTrailing
            )
        }
    }

    private var showsSavedState: Bool {
        guard let lastRecordedAt = entry.lastRecordedAt else { return false }
        return Date.now.timeIntervalSince(lastRecordedAt) < 90
    }

    private func buttonBackground(for rating: MomentRatingValue) -> Color {
        guard showsSavedState, entry.lastRating == rating else {
            return .white.opacity(0.68)
        }

        return .white.opacity(0.92)
    }
}

struct Moment: Widget {
    nonisolated static let kind = "Moment"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: Self.kind, provider: MomentProvider()) { entry in
            MomentEntryView(entry: entry)
        }
        .configurationDisplayName("Momentaufnahme")
        .description("Tracke deine Stimmung direkt vom Homescreen.")
        .supportedFamilies([.systemSmall, .systemMedium])
    }
}

#Preview(as: .systemSmall) {
    Moment()
} timeline: {
    MomentEntry(date: .now, lastRating: .good, lastRecordedAt: .now)
}