import SwiftUI
import WidgetKit

/// Tracks one event for the Event Countdown (Bars) widget via App Group storage.
/// The widget reads these keys directly — no manual widget configuration needed.
enum CountdownTracker {
    static let idKey    = "kisani.widget.trackedEvent"
    static let sinceKey = "kisani.widget.trackedSince"

    static func isTracked(_ task: TaskItem) -> Bool {
        UserDefaults.kisani.string(forKey: idKey) == task.id.uuidString
    }

    static func toggle(_ task: TaskItem) {
        if isTracked(task) {
            UserDefaults.kisani.removeObject(forKey: idKey)
            UserDefaults.kisani.removeObject(forKey: sinceKey)
        } else {
            UserDefaults.kisani.set(task.id.uuidString, forKey: idKey)
            UserDefaults.kisani.set(Date(), forKey: sinceKey)   // Mode A anchor
        }
        WidgetCenter.shared.reloadAllTimelines()
    }
}

/// The unified long-press menu for a task, shared across Today, Matrix, and Calendar.
/// Pass only the closures a given screen needs; the rest default to no-ops.
struct TaskMenuItems: View {
    let task: TaskItem
    /// The quadrant the row currently lives in (so "Move" hides the current one).
    var currentQuadrant: Quadrant? = nil

    var onPin:         (TaskItem) -> Void            = { _ in }
    var onSetDate:     (TaskItem, Date?) -> Void     = { _, _ in }
    var onPostponeMinutes: (TaskItem, Int) -> Void   = { _, _ in }
    var onMove:        (TaskItem, Quadrant) -> Void  = { _, _ in }
    var onSetPriority: (TaskItem, Priority) -> Void  = { _, _ in }
    var onSetCategory: (TaskItem, TaskCategory) -> Void = { _, _ in }
    var onResetMatrixUrgency: ((TaskItem) -> Void)?  = nil
    var onLiveActivity:(TaskItem) -> Void            = { LiveActivityManager.toggle(for: $0) }
    var onEdit:        ((TaskItem) -> Void)?         = nil
    var onDelete:      (TaskItem) -> Void            = { _ in }

    private var cal: Calendar { .current }

    var body: some View {
        Button { onPin(task) } label: {
            Label(task.isPinned ? "Unpin" : "Pin", systemImage: task.isPinned ? "pin.slash" : "pin")
        }

        Menu {
            Button { onSetDate(task, preservingTime(on: Date())) } label: {
                Label("Today", systemImage: "calendar")
            }
            Button { onSetDate(task, preservingTime(on: dayOffset(1))) } label: {
                Label("Tomorrow", systemImage: "sun.max")
            }
            Button { onSetDate(task, preservingTime(on: nextMonday())) } label: {
                Label("Next Monday", systemImage: "calendar.badge.clock")
            }
            Divider()
            if let onEdit {
                Button { onEdit(task) } label: {
                    Label("Pick Date", systemImage: "calendar.badge.plus")
                }
            }
            Button { onSetDate(task, nil) } label: {
                Label("Clear", systemImage: "xmark.square")
            }
        } label: { Label("Date", systemImage: "calendar.badge.clock") }

        Menu {
            Button { onPostponeMinutes(task, 15) } label: {
                Label("Snooze 15 Minutes", systemImage: "clock")
            }
            Button { onPostponeMinutes(task, 30) } label: {
                Label("Snooze 30 Minutes", systemImage: "clock")
            }
            Button { onPostponeMinutes(task, 60) } label: {
                Label("Snooze 1 Hour", systemImage: "clock")
            }
            Button { onPostponeMinutes(task, 120) } label: {
                Label("Snooze 2 Hours", systemImage: "clock")
            }
            Divider()
            Button { onSetDate(task, preservingTime(on: dayOffset(1))) } label: {
                Label("Tomorrow", systemImage: "sun.max")
            }
        } label: { Label("Postpone", systemImage: "clock.arrow.circlepath") }

        Menu {
            // Only the quadrants the task is NOT currently in — you can't move it to where it sits.
            ForEach(Quadrant.allCases.filter { $0 != (currentQuadrant ?? task.quadrant) }) { q in
                Button { onMove(task, q) } label: {
                    Label(q.matrixLabel, systemImage: "arrow.right")
                }
            }
        } label: { Label("Move", systemImage: "arrow.right.square") }

        if task.urgencyOverride != nil, let onResetMatrixUrgency {
            Button { onResetMatrixUrgency(task) } label: {
                Label("Reset Matrix Urgency", systemImage: "arrow.counterclockwise")
            }
        }

        Menu {
            ForEach(Priority.allCases) { p in
                Button { onSetPriority(task, p) } label: {
                    Label(p.label, systemImage: task.priority == p ? "checkmark" : "flag")
                }
            }
        } label: { Label("Priority", systemImage: "flag") }

        Menu {
            ForEach([TaskCategory.reminder, .birthday, .domain, .annual, .custom], id: \.rawValue) { cat in
                Button { onSetCategory(task, cat) } label: {
                    Label(cat.rawValue, systemImage: task.category == cat ? "checkmark" : "tag")
                }
            }
        } label: { Label("Tags", systemImage: "tag") }

        Button { onLiveActivity(task) } label: {
            Label(liveActivityTitle, systemImage: liveActivityIcon)
        }

        Button { CountdownTracker.toggle(task) } label: {
            Label(CountdownTracker.isTracked(task) ? "Stop Tracking Countdown" : "Track Countdown",
                  systemImage: "timer")
        }

        if let onEdit {
            Button { onEdit(task) } label: { Label("Edit", systemImage: "pencil") }
        }

        Divider()

        Button(role: .destructive) { onDelete(task) } label: {
            Label("Delete", systemImage: "trash")
        }
    }

    private var liveActivityTitle: String {
        if #available(iOS 16.1, *), LiveActivityManager.isActive(taskID: task.id.uuidString) {
            return "Remove from Live Activity"
        }
        return "Add to Live Activity"
    }

    private var liveActivityIcon: String {
        if #available(iOS 16.1, *), LiveActivityManager.isActive(taskID: task.id.uuidString) {
            return "pin.slash"
        }
        return "pin.circle"
    }

    private func dayOffset(_ value: Int) -> Date {
        cal.date(byAdding: .day, value: value, to: Date()) ?? Date()
    }

    private func nextMonday() -> Date {
        var comps = DateComponents()
        comps.weekday = 2
        return cal.nextDate(after: Date(), matching: comps, matchingPolicy: .nextTimePreservingSmallerComponents)
            ?? dayOffset(7)
    }

    private func preservingTime(on day: Date) -> Date {
        let base = cal.startOfDay(for: day)
        guard task.hasTime, let due = task.dueDate else { return base }
        let parts = cal.dateComponents([.hour, .minute], from: due)
        return cal.date(bySettingHour: parts.hour ?? 0, minute: parts.minute ?? 0, second: 0, of: base) ?? base
    }
}