import Foundation

// MARK: - Habit Frequency

enum HabitFrequency: String, Codable, CaseIterable {
    case daily, weekly, monthly, interval, custom
    var displayName: String {
        switch self {
        case .daily: return "Ежедневно"
        case .weekly: return "Еженедельно"
        case .monthly: return "Ежемесячно"
        case .interval: return "Через N дней"
        case .custom: return "Особое"
        }
    }
}

// MARK: - Habit

struct Habit: Codable, Identifiable {
    let id: Int
    var name: String
    var description: String?
    var icon: String?
    var color: String?
    var frequency: HabitFrequency
    var reminderTime: String?
    var targetDays: [Int]?
    var targetCount: Int?
    var currentStreak: Int?
    var longestStreak: Int?
    var completedToday: Bool?
    var totalCompleted: Int?
    var isArchived: Bool?
    var startDate: String?
    var createdAt: String?
    var updatedAt: String?

    var accentColorHex: String { color ?? "00d4aa" }
    var displayIcon: String { icon ?? "🔥" }

    enum CodingKeys: String, CodingKey {
        case id, name, description, icon, color, frequency
        case reminderTime = "reminder_time"
        case targetDays = "target_days"
        case targetCount = "target_count"
        case currentStreak = "current_streak"
        case longestStreak = "longest_streak"
        case completedToday = "completed_today"
        case totalCompleted = "total_completed"
        case isArchived = "is_archived"
        case startDate = "start_date"
        case createdAt = "created_at"
        case updatedAt = "updated_at"
    }

    var frequencyLabel: String {
        switch frequency {
        case .daily: return "Ежедневно"
        case .weekly:
            guard let days = targetDays, !days.isEmpty else { return "Еженедельно" }
            let names = ["Вс","Пн","Вт","Ср","Чт","Пт","Сб"]
            return days.sorted().compactMap { names[safe: $0] }.joined(separator: ", ")
        case .interval:
            let n = targetCount ?? 1
            return "Каждые \(n) дн."
        case .monthly: return "Ежемесячно"
        case .custom: return "Особое"
        }
    }
}

// MARK: - HabitLog

struct HabitLog: Codable, Identifiable {
    let id: Int
    let habitId: Int?
    let completedAt: String?
    let note: String?

    var dateOnly: String { String(completedAt?.prefix(10) ?? "") }

    enum CodingKeys: String, CodingKey {
        case id
        case habitId = "habit_id"
        case completedAt = "completed_at"
        case note
    }
}

// MARK: - HabitFreeze

struct HabitFreeze: Codable, Identifiable {
    let id: Int
    let habitId: Int?
    let startDate: String
    let endDate: String

    enum CodingKeys: String, CodingKey {
        case id
        case habitId = "habit_id"
        case startDate = "start_date"
        case endDate = "end_date"
    }
}

// MARK: - HabitStats

struct HabitStats: Codable {
    let currentStreak: Int
    let longestStreak: Int
    let thisMonth: Int
    let totalCompleted: Int?
    let completionRate: Double?

    var completionPercent: Int { Int((completionRate ?? 0) * 100) }

    enum CodingKeys: String, CodingKey {
        case currentStreak = "current_streak"
        case longestStreak = "longest_streak"
        case thisMonth = "this_month"
        case totalCompleted = "total_completed"
        case completionRate = "completion_rate"
    }
}

// MARK: - HabitsOverallStats

struct HabitsOverallStats: Codable {
    let todayCompleted: Int?
    let activeHabits: Int?

    enum CodingKeys: String, CodingKey {
        case todayCompleted = "today_completed"
        case activeHabits = "active_habits"
    }
}

// MARK: - CompletionDataPoint (for charts)

struct CompletionDataPoint: Identifiable {
    let id = UUID()
    let date: Date
    let rate: Double
    let label: String
}

// MARK: - HabitLogRequest

struct HabitLogRequest: Codable {
    var completedAt: String?
    var note: String?
    enum CodingKeys: String, CodingKey {
        case completedAt = "completed_at"
        case note
    }
}

// MARK: - Safe Array Subscript

extension Array {
    subscript(safe index: Int) -> Element? {
        guard index >= 0, index < count else { return nil }
        return self[index]
    }
}