import Foundation

extension Date {
    func addingDays(_ days: Int) -> Date {
        Calendar.current.date(byAdding: .day, value: days, to: self)!
    }

    func addingMinutes(_ minutes: Int) -> Date {
        Calendar.current.date(byAdding: .minute, value: minutes, to: self)!
    }

    func startOfWeek() -> Date {
        let calendar = Calendar.current
        var cal = calendar
        cal.firstWeekday = 2 // Monday
        let components = cal.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)
        return cal.date(from: components) ?? self
    }

    func dayOfWeekIndex() -> Int {
        let calendar = Calendar.current
        let weekday = calendar.component(.weekday, from: self)
        // Convert to 0=Monday format
        return (weekday + 5) % 7
    }

    var isToday: Bool {
        Calendar.current.isDateInToday(self)
    }

    var isPast: Bool {
        self < Calendar.current.startOfDay(for: Date())
    }

    func formattedWeekRange() -> String {
        let endDate = self.addingDays(6)
        let formatter = DateFormatter()
        formatter.locale = Locale.current

        let dayFormatter = DateFormatter()
        dayFormatter.dateFormat = "d"

        let monthFormatter = DateFormatter()
        monthFormatter.dateFormat = "MMM"

        let startDay = dayFormatter.string(from: self)
        let endDay = dayFormatter.string(from: endDate)
        let month = monthFormatter.string(from: endDate)

        return "\(startDay)-\(endDay) \(month)"
    }

    func startOfMonth() -> Date {
        let calendar = Calendar.current
        let components = calendar.dateComponents([.year, .month], from: self)
        return calendar.date(from: components) ?? self
    }

    func addingMonths(_ months: Int) -> Date {
        Calendar.current.date(byAdding: .month, value: months, to: self) ?? self
    }

    func monthYearLabel(locale: Locale = .current) -> String {
        let formatter = DateFormatter()
        formatter.locale = locale
        formatter.setLocalizedDateFormatFromTemplate("LLLL yyyy")
        return formatter.string(from: self)
    }
}

func combineDateAndTime(date: Date, time: Date) -> Date {
    let calendar = Calendar.current
    let dateComponents = calendar.dateComponents([.year, .month, .day], from: date)
    let timeComponents = calendar.dateComponents([.hour, .minute], from: time)

    var combined = DateComponents()
    combined.year = dateComponents.year
    combined.month = dateComponents.month
    combined.day = dateComponents.day
    combined.hour = timeComponents.hour
    combined.minute = timeComponents.minute

    return calendar.date(from: combined) ?? date
}