//
//  FeelsWidget.swift
//  FeelsWidget
//
//  Created by Trey Tartt on 1/7/22.
//

import WidgetKit
import SwiftUI
import Intents
import CoreData

struct Provider: IntentTimelineProvider {
    /*
     placeholder for widget, no data
     gets redacted auto
     */
    func placeholder(in context: Context) -> SimpleEntry {
        let date = Date()
        let moodEntry = PersistenceController.shared.moodEntries(forStartDate: date, count: 5)
        return SimpleEntry(date: date, configuration: ConfigurationIntent(), mood: moodEntry)
    }
    
    func getSnapshot(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (SimpleEntry) -> ()) {
        if context.isPreview {
            
        }
        let date = Date()
        let moodEntry = PersistenceController.shared.moodEntries(forStartDate: date, count: 5)
        
        let entry = SimpleEntry(date: date, configuration: configuration, mood: moodEntry)
        completion(entry)
    }
    
    func getTimeline(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
        var entries: [SimpleEntry] = []
        
        var calendar = Calendar.current
        calendar.timeZone = NSTimeZone.local
        let todayStart = calendar.startOfDay(for: Date())
        let userEntries = PersistenceController.shared.moodEntries(forStartDate: todayStart, count: 10)
        
        let entry = SimpleEntry(date: Date(), configuration: configuration, mood: userEntries)
        entries.append(entry)
        
        let timeline = Timeline(entries: entries, policy: .after(Random.widgetUpdateTime))
        completion(timeline)
    }
}

struct SimpleEntry: TimelineEntry {
    let date: Date
    let configuration: ConfigurationIntent
    let mood: [MoodEntry]
    let showStats: Bool
    
    init(date: Date, configuration: ConfigurationIntent, mood: [MoodEntry], showStats: Bool = false) {
        self.date = date
        self.configuration = configuration
        self.mood = mood
        self.showStats = showStats
    }
}

struct FeelsWidgetEntryView : View {
    @Environment(\.sizeCategory) var sizeCategory
    @Environment(\.widgetFamily) var family
    
    var entry: Provider.Entry
    
    @ViewBuilder
    var body: some View {
        ZStack {
            Color(UIColor.systemBackground)
            
            switch family {
            case .systemSmall:
                SmallWidgetView(entry: entry)
            case .systemMedium:
                MediumWidgetView(entry: entry)
            case .systemLarge:
                LargeWidgetView(entry: entry)
            @unknown default:
                fatalError()
            }
        }
    }
}

struct SmallWidgetView: View {
    var entry: Provider.Entry
    
    var body: some View {
        VStack {
            EntryCardCollectionView(moodEntries: Array([entry.mood.first!]))
                .padding()
        }
    }
}

struct MediumWidgetView: View {
    var entry: Provider.Entry
    
    var formatter: DateFormatter {
        let dateFormatter = DateFormatter()
        dateFormatter.dateStyle = .medium
        return dateFormatter
    }
    
    var firstGroup: [MoodEntry] {
        Array(self.entry.mood.prefix(5))
    }
    
    var body: some View {
        VStack {
            Spacer()
            
            HStack {
                Text(firstGroup.first?.date ?? Date(), formatter: formatter)
                    .font(.system(.footnote))
                Text(" - ")
                    .font(.system(.footnote))
                Text(firstGroup.last?.date ?? Date(), formatter: formatter)
                    .font(.system(.footnote))
            }
            .frame(minWidth: 0, maxWidth: .infinity)
            .multilineTextAlignment(.leading)
            
            EntryCardCollectionView(moodEntries: firstGroup)
                .frame(minHeight: 0, maxHeight: 55)
                .padding()
            
            Spacer()
        }
    }
}

struct LargeWidgetView: View {
    var entry: Provider.Entry
    
    var formatter: DateFormatter {
        let dateFormatter = DateFormatter()
        dateFormatter.dateStyle = .medium
        return dateFormatter
    }
    
    var firstGroup: [MoodEntry] {
        Array(self.entry.mood.prefix(5))
    }
    
    var lastGroup: [MoodEntry] {
        Array(self.entry.mood.suffix(5))
    }
    
    
    var body: some View {
        VStack {
            Spacer()
            
            HStack {
                Text(firstGroup.first?.date ?? Date(), formatter: formatter)
                    .font(.system(.footnote))
                Text(" - ")
                    .font(.system(.footnote))
                Text(firstGroup.last?.date ?? Date(), formatter: formatter)
                    .font(.system(.footnote))
            }
            .frame(minWidth: 0, maxWidth: .infinity)
            .multilineTextAlignment(.leading)
            
            EntryCardCollectionView(moodEntries: firstGroup)
                .frame(minHeight: 0, maxHeight: 55)
                .padding()
            
            Spacer()
            
            HStack {
                Text(lastGroup.first?.date ?? Date(), formatter: formatter)
                    .font(.system(.footnote))
                Text(" - ")
                Text(lastGroup.last?.date ?? Date(), formatter: formatter)
                    .font(.system(.footnote))
            }
            .frame(minWidth: 0, maxWidth: .infinity)
            .multilineTextAlignment(.leading)
            
            EntryCardCollectionView(moodEntries: lastGroup)
                .frame(minHeight: 0, maxHeight: 55)
                .padding()
            
            Spacer()
        }
    }
}

struct EntryCardCollectionView: View {
    var moodEntries: [MoodEntry]
    
    var body: some View {
        ZStack {
            Color(UIColor.secondarySystemBackground)
            HStack {
                ForEach(moodEntries) { mood in
                    EntryCard(moodEntry: mood)
                }
            }
            .padding()
        }
        .clipShape(RoundedRectangle(cornerRadius: 25, style: .continuous))
    }
}

struct EntryCard: View {
    var moodEntry: MoodEntry
    
    var body: some View {
        moodEntry.mood.icon.font(.system(size: 50))
    }
}

@main
struct FeelsWidget: Widget {
    let kind: String = "FeelsWidget"
    
    var body: some WidgetConfiguration {
        IntentConfiguration(kind: kind,
                            intent: ConfigurationIntent.self,
                            provider: Provider()) { entry in
            FeelsWidgetEntryView(entry: entry)
        }
                            .configurationDisplayName("Feels")
                            .description("")
                            .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
    }
}

struct FeelsWidget_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            FeelsWidgetEntryView(entry: SimpleEntry(date: Date(),
                                                     configuration: ConfigurationIntent(),
                                                     mood: PersistenceController.shared.randomEntries(count: 1)))
                .previewContext(WidgetPreviewContext(family: .systemSmall))
                .environment(\.sizeCategory, .small)
            
            FeelsWidgetEntryView(entry: SimpleEntry(date: Date(),
                                                     configuration: ConfigurationIntent(),
                                                     mood:  PersistenceController.shared.randomEntries(count: 3)))
                .previewContext(WidgetPreviewContext(family: .systemMedium))
                .environment(\.sizeCategory, .medium)
            
            FeelsWidgetEntryView(entry: SimpleEntry(date: Date(),
                                                     configuration: ConfigurationIntent(),
                                                     mood:  PersistenceController.shared.randomEntries(count: 10)))
                .previewContext(WidgetPreviewContext(family: .systemLarge))
                .environment(\.sizeCategory, .large)
        }
    }
}