import WidgetKit
import SwiftUI
import SwiftData
import AppIntents

struct AndromidaWidgetProvider: AppIntentTimelineProvider {
    func placeholder(in context: Context) -> WidgetEntry {
        WidgetEntry(
            date: Date(),
            configuration: ConfigurationAppIntent(),
            completionRate: 0.75,
            currentStreak: 5,
            nextHabits: [
                HabitEntry(id: UUID(), title: "Morning Meditation", symbolName: "figure.mind.and.body", ritualTitle: "Mindfulness", isCompleted: false),
                HabitEntry(id: UUID(), title: "Drink Water", symbolName: "drop.fill", ritualTitle: "Health", isCompleted: true)
            ],
            weeklyTrend: [0.5, 0.7, 0.6, 0.9, 0.8, 0.75, 0.0],
            currentTimeOfDay: "Morning",
            currentTimeOfDaySymbol: "sunrise.fill",
            currentTimeOfDayRange: "Before 11am",
            nextRitualInfo: "Next: Drink Water (Midday)"
        )
    }

    func snapshot(for configuration: ConfigurationAppIntent, in context: Context) async -> WidgetEntry {
        await fetchLatestData(for: configuration, at: Date())
    }

    func timeline(for configuration: ConfigurationAppIntent, in context: Context) async -> Timeline<WidgetEntry> {
        // Create entries for each time-of-day boundary for the next 24 hours.
        // This ensures the widget displays the correct rituals at each time period.
        var entries: [WidgetEntry] = []
        let calendar = Calendar.current
        let now = Date()
        
        // Create an entry for right now
        let currentEntry = await fetchLatestData(for: configuration, at: now)
        entries.append(currentEntry)
        
        // Create entries at each upcoming time-of-day boundary
        let boundaryDates = upcomingTimeOfDayBoundaries(from: now, count: 5)
        for boundaryDate in boundaryDates {
            let entry = await fetchLatestData(for: configuration, at: boundaryDate)
            entries.append(entry)
        }
        
        // Request a new timeline after the last entry (roughly 24 hours)
        let lastEntryDate = entries.last?.date ?? now
        let nextRefresh = calendar.date(byAdding: .hour, value: 1, to: lastEntryDate) ?? lastEntryDate
        
        return Timeline(entries: entries, policy: .after(nextRefresh))
    }
    
    /// Returns the next N time-of-day boundary dates.
    /// Boundaries are at 11:00, 14:00, 17:00, 21:00, and 00:00.
    private func upcomingTimeOfDayBoundaries(from startDate: Date, count: Int) -> [Date] {
        let calendar = Calendar.current
        let boundaryHours = [0, 11, 14, 17, 21] // midnight, morning end, midday end, afternoon end, evening end
        
        var boundaries: [Date] = []
        var checkDate = startDate
        
        while boundaries.count < count {
            let currentHour = calendar.component(.hour, from: checkDate)
            let startOfDay = calendar.startOfDay(for: checkDate)
            
            // Find the next boundary hour after the current hour
            for hour in boundaryHours {
                if hour > currentHour {
                    if let boundaryDate = calendar.date(bySettingHour: hour, minute: 0, second: 0, of: startOfDay) {
                        boundaries.append(boundaryDate)
                        if boundaries.count >= count { break }
                    }
                }
            }
            
            // Move to the next day for remaining boundaries
            if let nextDay = calendar.date(byAdding: .day, value: 1, to: startOfDay) {
                checkDate = nextDay
            } else {
                break
            }
        }
        
        return boundaries
    }

    @MainActor
    private func fetchLatestData(for configuration: ConfigurationAppIntent, at targetDate: Date) -> WidgetEntry {
        let schema = Schema([Ritual.self, RitualArc.self, ArcHabit.self])
        let configurationURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: AppIdentifiers.appGroupIdentifier)?
            .appendingPathComponent("Andromida.sqlite") ?? URL.documentsDirectory.appendingPathComponent("Andromida.sqlite")
        
        let modelConfig = ModelConfiguration(schema: schema, url: configurationURL)

        do {
            let container = try ModelContainer(for: schema, configurations: [modelConfig])
            let context = container.mainContext
            
            let descriptor = FetchDescriptor<Ritual>()
            let rituals = try context.fetch(descriptor)
            
            // Use targetDate for time-of-day calculation, but today for completion data
            let today = Calendar.current.startOfDay(for: targetDate)
            let dayID = RitualAnalytics.dayIdentifier(for: today)
            let timeOfDay = TimeOfDay.current(for: targetDate)
            
            // Filter rituals for the target time of day
            let activeRituals = rituals.filter { ritual in
                guard ritual.activeArc(on: today) != nil else {
                    return false
                }
                return ritual.timeOfDay == .anytime || ritual.timeOfDay == timeOfDay
            }
            .sorted { lhs, rhs in
                if lhs.timeOfDay != rhs.timeOfDay {
                    return lhs.timeOfDay < rhs.timeOfDay
                }
                return lhs.sortIndex < rhs.sortIndex
            }
            
            var visibleHabits: [HabitEntry] = []
            for ritual in activeRituals {
                if let arc = ritual.activeArc(on: today) {
                    // Sort habits within each ritual by their sortIndex
                    let sortedHabits = (arc.habits ?? []).sorted { $0.sortIndex < $1.sortIndex }
                    for habit in sortedHabits {
                        visibleHabits.append(HabitEntry(
                            id: habit.id,
                            title: habit.title,
                            symbolName: habit.symbolName,
                            ritualTitle: ritual.title,
                            isCompleted: habit.completedDayIDs.contains(dayID)
                        ))
                    }
                }
            }
            
            // Calculate overall progress across ALL rituals for today
            let overallRate = RitualAnalytics.overallCompletionRate(on: today, from: rituals)
            
            // Next habits (limit to 3) - still filtered by current time of day for the list
            let nextHabits = visibleHabits.prefix(3)
            
            // Streak calculation
            let streak = RitualAnalytics.calculateCurrentStreak(rituals: rituals)
            
            // Next ritual info
            var nextRitualString: String? = nil
            if let nextContext = RitualAnalytics.nextUpcomingRitualContext(from: rituals, currentDate: targetDate) {
                if nextContext.isTomorrow {
                    let format = String(localized: "Next ritual: Tomorrow %@ (%@)")
                    nextRitualString = String.localizedStringWithFormat(
                        format,
                        nextContext.ritual.timeOfDay.displayName,
                        nextContext.ritual.timeOfDay.timeRange
                    )
                } else {
                    let format = String(localized: "Next ritual: %@ (%@)")
                    nextRitualString = String.localizedStringWithFormat(
                        format,
                        nextContext.ritual.timeOfDay.displayName,
                        nextContext.ritual.timeOfDay.timeRange
                    )
                }
            }
            
            return WidgetEntry(
                date: targetDate,
                configuration: configuration,
                completionRate: overallRate,
                currentStreak: streak,
                nextHabits: Array(nextHabits),
                weeklyTrend: [],
                currentTimeOfDay: timeOfDay.displayName,
                currentTimeOfDaySymbol: timeOfDay.symbolName,
                currentTimeOfDayRange: timeOfDay.timeRange,
                nextRitualInfo: nextRitualString
            )
        } catch {
            // Return a default entry instead of placeholder(in: .preview)
            return WidgetEntry(
                date: Date(),
                configuration: configuration,
                completionRate: 0.0,
                currentStreak: 0,
                nextHabits: [],
                weeklyTrend: [],
                currentTimeOfDay: "Today",
                currentTimeOfDaySymbol: "clock.fill",
                currentTimeOfDayRange: "",
                nextRitualInfo: nil
            )
        }
    }
}