//
//  Date+.swift
//  UMobile
//
//  Created by John Eris Villanueva on 30/08/2017.
//  Copyright © 2017 Donn Carlo Gamboa. All rights reserved.
//
import Foundation
extension Date {

    public var apiFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kDateAPIRequestFormat
        return dateFormatter.string(from: self)
    }

    public var timeFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "hh:mma"
        return dateFormatter.string(from: self)
    }

    public var time24HourFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "HH:mm"
        return dateFormatter.string(from: self)
    }

    public var successDisplayFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kDateAPISuccessDisplayFormat
        return dateFormatter.string(from: self)
    }

    public var successNoSecondsDisplayFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kDateAPISuccessNoSecondsDisplayFormat
        return dateFormatter.string(from: self)
    }

    public var successDisplayDateOnlyFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kDateOnlyAPISuccessDisplayFormat
        return dateFormatter.string(from: self)
    }

    public var successDisplayTimeOnlyFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kTimeOnlyAPISuccessDisplayFormat
        return dateFormatter.string(from: self)
    }

    public var successDisplayFullDateFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kDateAPIResponseFormat
        return dateFormatter.string(from: self)
    }

    public var lastLoginDisplayFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kDateLastLoginDisplayFormat
        return dateFormatter.string(from: self)
    }

    public var monthDayYearDisplayFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kMonthDayYearDisplayFormat
        return dateFormatter.string(from: self)
    }

    public var monthYearDisplayFormat: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = kMonthYearDisplayFormat
        return dateFormatter.string(from: self)
    }

    /// Returns the amount of years from another date
    public func years(from date: Date) -> Int {
        return Calendar.current.dateComponents([.year], from: date, to: self).year ?? 0
    }

    /// Returns the amount of months from another date
    public func months(from date: Date) -> Int {
        return Calendar.current.dateComponents([.month], from: date, to: self).month ?? 0
    }

    /// Returns the amount of weeks from another date
    public func weeks(from date: Date) -> Int {
        return Calendar.current.dateComponents([.weekOfYear], from: date, to: self).weekOfYear ?? 0
    }

    /// Returns the amount of days from another date
    public func days(from date: Date) -> Int {
        return Calendar.current.dateComponents([.day], from: date, to: self).day ?? 0
    }

    /// Returns the amount of hours from another date
    public func hours(from date: Date) -> Int {
        return Calendar.current.dateComponents([.hour], from: date, to: self).hour ?? 0
    }

    /// Returns the amount of minutes from another date
    public func minutes(from date: Date) -> Int {
        return Calendar.current.dateComponents([.minute], from: date, to: self).minute ?? 0
    }

    /// Returns the amount of seconds from another date
    public func seconds(from date: Date) -> Int {
        return Calendar.current.dateComponents([.second], from: date, to: self).second ?? 0
    }

    public func format(format: String) -> String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = format
        return dateFormatter.string(from: self)
    }

    public func daySuffix() -> String {
        let calendar = Calendar.current
        let dayOfMonth = calendar.component(.day, from: self)
        switch dayOfMonth {
        case 1, 21, 31: return "st"
        case 2, 22: return "nd"
        case 3, 23: return "rd"
        default: return "th"
        }
    }

    public func dateOffset(from date: Date) -> String {
        if self.years(from: date) > 0 {
            let years = self.years(from: date)
            return "\(years) year\(years > 1 ? "s" : "") ago"
        }
        if self.months(from: date)  > 0 {
            let months = self.months(from: date)
            return "\(months) month\(months > 1 ? "s" : "") ago"
        }
        if self.weeks(from: date)   > 0 {
            let weeks = self.weeks(from: date)
            return "\(weeks) week\(weeks > 1 ? "s" : "") ago"
        }
        if self.days(from: date)    > 0 {
            let days = self.days(from: date)
            if days == 1 {
                return "Yesterday"
            }
            return "\(days) day\(days > 1 ? "s" : "") ago"
        }
        if self.hours(from: date)   > 0 {
            let hours = self.hours(from: date)
            return "\(hours) hour\(hours > 1 ? "s" : "") ago"
        }
        if self.minutes(from: date) > 0 {
            let minutes = self.minutes(from: date)
            if minutes == 1 {
                return "a minute ago"
            }
            if minutes < 10 {
                return "moments ago"
            }
            return "\(minutes) minute\(minutes > 1 ? "s" : "") ago"
        }
        return "just now"
    }

    public func notifDateOffset(from date: Date) -> String {
        // Greater than 7 days:
        // format: 19 August 2017 (dd MMMM yyyy)
        if self.weeks(from: date) > 0 {
            let toFormatter = DateFormatter()
            toFormatter.dateFormat = "dd MMMM yyyy"
            return toFormatter.string(from: date)
        }

        // Yesterday and x days ago:
        // possible formats:
        //    - Yesterday
        //    - 6 days ago
        if self.days(from: date) > 0 {
            let days = self.days(from: date)
            if days == 1 {
                return "Yesterday"
            }
            return "\(days) day\(days > 1 ? "s" : "") ago"
        }

        // Today - Greater than an hour:
        // format: 4 hours ago
        if self.hours(from: date)   > 0 {
            let hours = self.hours(from: date)
            return "\(hours) hour\(hours > 1 ? "s" : "") ago"
        }

        // Today - Less than an hour:
        // possible formats:
        //    - just now
        //    - moments ago
        //    - a minute ago
        //    - 30 minutes ago
        if self.minutes(from: date) > 0 {
            let minutes = self.minutes(from: date)
            if minutes == 1 {
                return "A minute ago"
            }
            if minutes < 10 {
                return "Moments ago"
            }
            return "\(minutes) minute\(minutes > 1 ? "s" : "") ago"
        }
        return "Just now"
    }

    public var dayOfTheWeek: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "EEEE"
        return dateFormatter.string(from: self)
    }

    public var dateOfTheMonth: String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "dd"
        return dateFormatter.string(from: self)
    }
}