//
//  Casera.swift
//  Casera
//
//  Created by Trey Tartt on 11/5/25.
//

import WidgetKit
import SwiftUI

// MARK: - Date Formatting Helper
/// Parses date strings in either yyyy-MM-dd or ISO8601 (RFC3339) format
/// and returns a user-friendly string like "Today" or "in X days"
private func formatWidgetDate(_ dateString: String) -> String {
    let calendar = Calendar.current
    var date: Date?

    // Try parsing as yyyy-MM-dd first
    let dateOnlyFormatter = DateFormatter()
    dateOnlyFormatter.dateFormat = "yyyy-MM-dd"
    date = dateOnlyFormatter.date(from: dateString)

    // Try parsing as ISO8601 (RFC3339) if that fails
    if date == nil {
        let isoFormatter = ISO8601DateFormatter()
        isoFormatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
        date = isoFormatter.date(from: dateString)

        // Try without fractional seconds
        if date == nil {
            isoFormatter.formatOptions = [.withInternetDateTime]
            date = isoFormatter.date(from: dateString)
        }
    }

    guard let parsedDate = date else {
        return dateString
    }

    let today = calendar.startOfDay(for: Date())
    let dueDay = calendar.startOfDay(for: parsedDate)

    if calendar.isDateInToday(parsedDate) {
        return "Today"
    }

    let components = calendar.dateComponents([.day], from: today, to: dueDay)
    let days = components.day ?? 0

    if days > 0 {
        return days == 1 ? "in 1 day" : "in \(days) days"
    } else {
        let overdueDays = abs(days)
        return overdueDays == 1 ? "1 day ago" : "\(overdueDays) days ago"
    }
}

/// CacheManager reads tasks from the App Group shared container
/// Data is written by the main app via WidgetDataManager
class CacheManager {
    struct CustomTask: Codable {
        let id: Int
        let title: String
        let description: String?
        let priority: String?
        let status: String?
        let dueDate: String?
        let category: String?
        let residenceName: String?
        let isOverdue: Bool

        enum CodingKeys: String, CodingKey {
            case id, title, description, priority, status, category
            case dueDate = "due_date"
            case residenceName = "residence_name"
            case isOverdue = "is_overdue"
        }
    }

    private static let appGroupIdentifier = "group.com.tt.casera.CaseraDev"
    private static let tasksFileName = "widget_tasks.json"

    /// Get the shared App Group container URL
    private static var sharedContainerURL: URL? {
        FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroupIdentifier)
    }

    /// Get the URL for the tasks file
    private static var tasksFileURL: URL? {
        sharedContainerURL?.appendingPathComponent(tasksFileName)
    }

    static func getData() -> [CustomTask] {
        guard let fileURL = tasksFileURL else {
            print("CacheManager: Unable to access shared container")
            return []
        }

        guard FileManager.default.fileExists(atPath: fileURL.path) else {
            print("CacheManager: No cached tasks file found")
            return []
        }

        do {
            let data = try Data(contentsOf: fileURL)
            let tasks = try JSONDecoder().decode([CustomTask].self, from: data)
            print("CacheManager: Loaded \(tasks.count) tasks from shared container")
            return tasks
        } catch {
            print("CacheManager: Error decoding tasks - \(error)")
            return []
        }
    }

    static func getUpcomingTasks() -> [CustomTask] {
        let allTasks = getData()

        // Filter for pending/in-progress tasks, sorted by due date
        let upcoming = allTasks.filter { task in
            let status = task.status?.lowercased() ?? ""
            return status == "pending" || status == "in_progress" || status == "in progress"
        }

        // Sort by due date (earliest first), with overdue at top
        return upcoming.sorted { task1, task2 in
            // Overdue tasks first
            if task1.isOverdue != task2.isOverdue {
                return task1.isOverdue
            }

            // Then by due date
            guard let date1 = task1.dueDate, let date2 = task2.dueDate else {
                return task1.dueDate != nil
            }
            return date1 < date2
        }
    }
}

struct Provider: AppIntentTimelineProvider {
    func placeholder(in context: Context) -> SimpleEntry {
        SimpleEntry(
            date: Date(),
            configuration: ConfigurationAppIntent(),
            upcomingTasks: []
        )
    }
    
    func snapshot(for configuration: ConfigurationAppIntent, in context: Context) async -> SimpleEntry {
        let tasks = CacheManager.getUpcomingTasks()
        return SimpleEntry(
            date: Date(),
            configuration: configuration,
            upcomingTasks: tasks
        )
    }
    
    func timeline(for configuration: ConfigurationAppIntent, in context: Context) async -> Timeline<SimpleEntry> {
        let tasks = CacheManager.getUpcomingTasks()
        
        // Update every hour
        let currentDate = Date()
        let nextUpdate = Calendar.current.date(byAdding: .hour, value: 1, to: currentDate)!
        let entry = SimpleEntry(
            date: currentDate,
            configuration: configuration,
            upcomingTasks: tasks
        )
        
        return Timeline(entries: [entry], policy: .after(nextUpdate))
    }
}

struct SimpleEntry: TimelineEntry {
    let date: Date
    let configuration: ConfigurationAppIntent
    let upcomingTasks: [CacheManager.CustomTask]
    
    var taskCount: Int {
        upcomingTasks.count
    }
    
    var nextTask: CacheManager.CustomTask? {
        upcomingTasks.first
    }
}

struct CaseraEntryView : View {
    var entry: Provider.Entry
    @Environment(\.widgetFamily) var family

    var body: some View {
        switch family {
        case .systemSmall:
            SmallWidgetView(entry: entry)
        case .systemMedium:
            MediumWidgetView(entry: entry)
        case .systemLarge:
            LargeWidgetView(entry: entry)
        default:
            SmallWidgetView(entry: entry)
        }
    }
}

// MARK: - Small Widget View
struct SmallWidgetView: View {
    let entry: SimpleEntry
    
    var body: some View {
        VStack(alignment: .leading, spacing: 0) {
            // Task Count
            VStack(alignment: .leading, spacing: 4) {
                Text("\(entry.taskCount)")
                    .font(.system(size: 36, weight: .bold))
                    .foregroundStyle(.blue)
                
                if entry.taskCount > 0 {
                    Text(entry.taskCount == 1 ? "upcoming task" : "upcoming tasks")
                        .font(.system(size: 12, weight: .medium))
                        .foregroundStyle(.secondary)
                }
            }
            
            // Next Task
            if let nextTask = entry.nextTask {
                VStack(alignment: .leading, spacing: 4) {
                    Text("NEXT UP")
                        .font(.system(size: 9, weight: .semibold))
                        .foregroundStyle(.secondary)
                        .tracking(0.5)
                    
                    Text(nextTask.title)
                        .font(.system(size: 12, weight: .semibold))
                        .lineLimit(2)
                        .foregroundStyle(.primary)
                    
                    if let dueDate = nextTask.dueDate {
                        HStack(spacing: 4) {
                            Image(systemName: "calendar")
                                .font(.system(size: 9))
                            Text(formatWidgetDate(dueDate))
                                .font(.system(size: 10, weight: .medium))
                        }
                        .foregroundStyle(.orange)
                    }
                }
                .padding(.top, 8)
                .padding(.horizontal, 10)
                .padding(.vertical, 8)
                .frame(maxWidth: .infinity, alignment: .leading)
                .background(
                    RoundedRectangle(cornerRadius: 8)
                        .fill(Color.blue.opacity(0.1))
                )
            } else {
                HStack {
                    Image(systemName: "checkmark.circle.fill")
                        .font(.system(size: 16))
                        .foregroundStyle(.green)
                    //                    Text("All caught up!")
                    //                        .font(.system(size: 11, weight: .medium))
                    //                        .foregroundStyle(.secondary)
                }
                .frame(maxWidth: .infinity)
                .padding(.vertical, 8)
                .background(
                    RoundedRectangle(cornerRadius: 8)
                        .fill(Color.green.opacity(0.1))
                )
            }
        }
        .padding(16)
    }
}

// MARK: - Medium Widget View
struct MediumWidgetView: View {
    let entry: SimpleEntry
    
    var body: some View {
        HStack(spacing: 16) {
            // Left side - Task count
            VStack(alignment: .leading, spacing: 4) {
                Spacer()
                
                Text("\(entry.taskCount)")
                    .font(.system(size: 42, weight: .bold))
                    .foregroundStyle(.blue)
                
                VStack(alignment: .leading) {
                    Text("upcoming:")
                        .font(.system(size: 11, weight: .medium))
                        .foregroundStyle(.secondary)
                        .lineLimit(2)
                    
                    Text(entry.taskCount == 1 ? "task" : "tasks")
                        .font(.system(size: 11, weight: .medium))
                        .foregroundStyle(.secondary)
                        .lineLimit(2)
                }
                
                Spacer()
            }
            .frame(maxWidth: 75)
            
            Divider()
            
            // Right side - Next tasks
            VStack(alignment: .leading, spacing: 8) {
                if let nextTask = entry.nextTask {
                    Text("NEXT UP")
                        .font(.system(size: 9, weight: .semibold))
                        .foregroundStyle(.secondary)
                        .tracking(0.5)
                }
                
                if entry.nextTask != nil {
                    ForEach(Array(entry.upcomingTasks.prefix(3).enumerated()), id: \.element.id) { index, task in
                        TaskRowView(task: task, index: index)
                    }
                    
                    Spacer()
                } else {
                    Spacer()
                    
                    VStack(spacing: 8) {
                        Image(systemName: "checkmark.circle.fill")
                            .font(.system(size: 24))
                            .foregroundStyle(.green)
                        Text("All caught up!")
                            .font(.system(size: 12, weight: .medium))
                            .foregroundStyle(.secondary)
                    }
                    .frame(maxWidth: .infinity)
                    
                    Spacer()
                }
            }
            .frame(maxWidth: .infinity)
        }
        .padding(16)
    }
}

// MARK: - Task Row
struct TaskRowView: View {
    let task: CacheManager.CustomTask
    let index: Int
    
    var body: some View {
        HStack(spacing: 8) {
            Circle()
                .fill(priorityColor)
                .frame(width: 6, height: 6)
            
            VStack(alignment: .leading, spacing: 2) {
                Text(task.title)
                    .font(.system(size: 11, weight: .semibold))
//                    .lineLimit(1)
                    .foregroundStyle(.primary)
                
                if let dueDate = task.dueDate {
                    HStack(spacing: 3) {
                        Image(systemName: "calendar")
                            .font(.system(size: 8))
                        Text(formatWidgetDate(dueDate))
                            .font(.system(size: 9, weight: .medium))
                    }
                    .foregroundStyle(.secondary)
                }
            }

            Spacer()

            if let priority = task.priority {
                Text(priority.prefix(1).uppercased())
                    .font(.system(size: 9, weight: .bold))
                    .foregroundStyle(.white)
                    .frame(width: 16, height: 16)
                    .background(
                        Circle()
                            .fill(priorityColor)
                    )
            }
        }
        .padding(.vertical, 4)
    }

    private var priorityColor: Color {
        switch task.priority?.lowercased() {
        case "urgent": return .red
        case "high": return .orange
        case "medium": return .blue
        default: return .gray
        }
    }
}

// MARK: - Large Widget View
struct LargeWidgetView: View {
    let entry: SimpleEntry

    private var maxTasksToShow: Int {
        entry.upcomingTasks.count > 6 ? 5 : 6
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 6) {
            // Header
            HStack(spacing: 6) {
                Spacer()
                
                Text("\(entry.taskCount)")
                    .font(.system(size: 22, weight: .bold))
                    .foregroundStyle(.blue)

                Text(entry.taskCount == 1 ? "task" : "tasks")
                    .font(.system(size: 10, weight: .medium))
                    .foregroundStyle(.secondary)
            }

            if entry.upcomingTasks.isEmpty {
                Spacer()

                VStack(spacing: 12) {
                    Image(systemName: "checkmark.circle.fill")
                        .font(.system(size: 48))
                        .foregroundStyle(.green)
                    Text("All caught up!")
                        .font(.system(size: 16, weight: .medium))
                        .foregroundStyle(.secondary)
                }
                .frame(maxWidth: .infinity)

                Spacer()
            } else {
                // Show tasks
                ForEach(Array(entry.upcomingTasks.prefix(maxTasksToShow).enumerated()), id: \.element.id) { index, task in
                    LargeTaskRowView(task: task, isOverdue: task.isOverdue)
                }

                if entry.upcomingTasks.count > 6 {
                    Text("+ \(entry.upcomingTasks.count - 5) more tasks")
                        .font(.system(size: 11, weight: .medium))
                        .foregroundStyle(.secondary)
                        .frame(maxWidth: .infinity, alignment: .center)
                        .padding(.top, 2)
                }
            }
        }
        .padding(14)
    }
}

// MARK: - Large Task Row
struct LargeTaskRowView: View {
    let task: CacheManager.CustomTask
    let isOverdue: Bool

    var body: some View {
        HStack(spacing: 8) {
            // Priority indicator
            RoundedRectangle(cornerRadius: 2)
                .fill(priorityColor)
                .frame(width: 3, height: 32)

            VStack(alignment: .leading, spacing: 2) {
                Text(task.title)
                    .font(.system(size: 12, weight: .medium))
                    .lineLimit(1)
                    .foregroundStyle(.primary)

                HStack(spacing: 10) {
                    if let residenceName = task.residenceName {
                        HStack(spacing: 2) {
                            Image("icon")
                                .resizable()
                                .frame(width: 7, height: 7)
                                .font(.system(size: 7))
                            Text(residenceName)
                                .font(.system(size: 9))
                        }
                        .foregroundStyle(.secondary)
                    }

                    if let dueDate = task.dueDate {
                        HStack(spacing: 2) {
                            Image(systemName: "calendar")
                                .font(.system(size: 7))
                            Text(formatWidgetDate(dueDate))
                                .font(.system(size: 9, weight: isOverdue ? .semibold : .regular))
                        }
                        .foregroundStyle(isOverdue ? .red : .secondary)
                    }
                }
            }

            Spacer()

            // Priority badge
            if let priority = task.priority {
                Text(priority.prefix(1).uppercased())
                    .font(.system(size: 8, weight: .bold))
                    .foregroundStyle(.white)
                    .frame(width: 16, height: 16)
                    .background(Circle().fill(priorityColor))
            }
        }
        .padding(.vertical, 4)
        .padding(.horizontal, 6)
        .background(
            RoundedRectangle(cornerRadius: 6)
                .fill(Color.primary.opacity(0.05))
        )
    }

    private var priorityColor: Color {
        switch task.priority?.lowercased() {
        case "urgent": return .red
        case "high": return .orange
        case "medium": return .blue
        default: return .gray
        }
    }
}

struct Casera: Widget {
    let kind: String = "Casera"

    var body: some WidgetConfiguration {
        AppIntentConfiguration(kind: kind, intent: ConfigurationAppIntent.self, provider: Provider()) { entry in
            CaseraEntryView(entry: entry)
                .containerBackground(.fill.tertiary, for: .widget)
        }
    }
}

// MARK: - Previews
#Preview(as: .systemSmall) {
    Casera()
} timeline: {
    SimpleEntry(
        date: .now,
        configuration: ConfigurationAppIntent(),
        upcomingTasks: [
            CacheManager.CustomTask(
                id: 1,
                title: "Fix leaky faucet",
                description: "Kitchen sink needs repair",
                priority: "high",
                status: "pending",
                dueDate: "2024-12-15",
                category: "plumbing",
                residenceName: "Home",
                isOverdue: false
            ),
            CacheManager.CustomTask(
                id: 2,
                title: "Paint living room",
                description: nil,
                priority: "medium",
                status: "pending",
                dueDate: "2024-12-20",
                category: "painting",
                residenceName: "Home",
                isOverdue: false
            )
        ]
    )

    SimpleEntry(
        date: .now,
        configuration: ConfigurationAppIntent(),
        upcomingTasks: []
    )
}

#Preview(as: .systemMedium) {
    Casera()
} timeline: {
    SimpleEntry(
        date: .now,
        configuration: ConfigurationAppIntent(),
        upcomingTasks: [
            CacheManager.CustomTask(
                id: 1,
                title: "Fix leaky faucet",
                description: "Kitchen sink needs repair",
                priority: "high",
                status: "pending",
                dueDate: "2024-12-15",
                category: "plumbing",
                residenceName: "Home",
                isOverdue: true
            ),
            CacheManager.CustomTask(
                id: 2,
                title: "Paint living room",
                description: nil,
                priority: "medium",
                status: "pending",
                dueDate: "2024-12-20",
                category: "painting",
                residenceName: "Cabin",
                isOverdue: false
            ),
            CacheManager.CustomTask(
                id: 3,
                title: "Clean gutters",
                description: "Remove debris",
                priority: "low",
                status: "pending",
                dueDate: "2024-12-25",
                category: "maintenance",
                residenceName: "Home",
                isOverdue: false
            )
        ]
    )

    SimpleEntry(
        date: .now,
        configuration: ConfigurationAppIntent(),
        upcomingTasks: []
    )
}

#Preview(as: .systemLarge) {
    Casera()
} timeline: {
    SimpleEntry(
        date: .now,
        configuration: ConfigurationAppIntent(),
        upcomingTasks: [
            CacheManager.CustomTask(
                id: 1,
                title: "Fix leaky faucet in kitchen",
                description: "Kitchen sink needs repair",
                priority: "high",
                status: "pending",
                dueDate: "2024-12-15",
                category: "plumbing",
                residenceName: "Home",
                isOverdue: true
            ),
            CacheManager.CustomTask(
                id: 2,
                title: "Paint living room walls",
                description: nil,
                priority: "medium",
                status: "pending",
                dueDate: "2024-12-20",
                category: "painting",
                residenceName: "Cabin",
                isOverdue: false
            ),
            CacheManager.CustomTask(
                id: 3,
                title: "Clean gutters",
                description: "Remove debris",
                priority: "low",
                status: "pending",
                dueDate: "2024-12-25",
                category: "maintenance",
                residenceName: "Home",
                isOverdue: false
            ),
            CacheManager.CustomTask(
                id: 4,
                title: "Replace HVAC filter",
                description: nil,
                priority: "medium",
                status: "pending",
                dueDate: "2024-12-28",
                category: "hvac",
                residenceName: "Beach House",
                isOverdue: false
            ),
            CacheManager.CustomTask(
                id: 5,
                title: "Check smoke detectors",
                description: "Replace batteries if needed",
                priority: "high",
                status: "pending",
                dueDate: "2024-12-30",
                category: "safety",
                residenceName: "Home",
                isOverdue: false
            ),
            CacheManager.CustomTask(
                id: 6,
                title: "Service water heater",
                description: nil,
                priority: "medium",
                status: "pending",
                dueDate: "2025-01-05",
                category: "plumbing",
                residenceName: "Cabin",
                isOverdue: false
            ),
            CacheManager.CustomTask(
                id: 7,
                title: "Inspect roof shingles",
                description: nil,
                priority: "low",
                status: "pending",
                dueDate: "2025-01-10",
                category: "exterior",
                residenceName: "Home",
                isOverdue: false
            ),
            CacheManager.CustomTask(
                id: 8,
                title: "Clean dryer vent",
                description: "Fire hazard prevention",
                priority: "urgent",
                status: "pending",
                dueDate: "2025-01-12",
                category: "appliances",
                residenceName: "Beach House",
                isOverdue: false
            )
        ]
    )

    SimpleEntry(
        date: .now,
        configuration: ConfigurationAppIntent(),
        upcomingTasks: []
    )
}