elpha-ios/elpha-ios/Date+TimeAgo.swift

//
//  Date+TimeAgo.swift
//  elpha-ios
//
//  Created by Dwayne Harris on 10/1/18.
//  Copyright © 2018 Elpha. All rights reserved.
//

import Foundation

extension Date {
    func timeAgo() -> String {
        let calendar = Calendar.current
        let now = Date()
        let earliest = self < now ? self : now
        let latest = self > now ? self : now
        
        let unitFlags: Set<Calendar.Component> = [.second, .minute, .hour, .day, .weekOfMonth, .month, .year]
        let components: DateComponents = calendar.dateComponents(unitFlags, from: earliest, to: latest)
        
        if let year = components.year {
            if (year >= 2) {
                return "\(year) years"
            } else if (year >= 1) {
                return "last year"
            }
        }
        
        if let month = components.month {
            if (month >= 2) {
                return "\(month) months"
            } else if (month >= 1) {
                return "last month"
            }
        }
        
        if let weekOfMonth = components.weekOfMonth {
            if (weekOfMonth >= 2) {
                return "\(weekOfMonth) weeks"
            } else if (weekOfMonth >= 1) {
                return "last week"
            }
        }
        
        if let day = components.day {
            if (day >= 2) {
                return "\(day) days"
            } else if (day >= 1) {
                return "yesterday"
            }
        }
        
        if let hour = components.hour {
            if (hour >= 2) {
                return "\(hour) hours"
            } else if (hour >= 1) {
                return "an hour ago"
            }
        }
        
        if let minute = components.minute {
            if (minute >= 2) {
                return "\(minute) mins"
            } else if (minute >= 1) {
                return "a minute ago"
            }
        }
        
        if let second = components.second {
            if (second >= 3) {
                return "\(second) seconds"
            }
        }
        
        return "just now"
    }
}