//
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// SwiftDate
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// Parse, validate, manipulate, and display dates, time and timezones in Swift
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//
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// Created by Daniele Margutti
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// - Web: https://www.danielemargutti.com
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// - Twitter: https://twitter.com/danielemargutti
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// - Mail: hello@danielemargutti.com
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//
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// Copyright © 2019 Daniele Margutti. Licensed under MIT License.
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//
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import Foundation
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/// Time periods are represented by the TimePeriodProtocol protocol.
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/// Required variables and method impleementations are bound below.
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/// An inheritable implementation of the TimePeriodProtocol is available through the TimePeriod class.
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open class TimePeriod: TimePeriodProtocol {
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/// The start date for a TimePeriod representing the starting boundary of the time period
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public var start: DateInRegion?
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/// The end date for a TimePeriod representing the ending boundary of the time period
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public var end: DateInRegion?
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// MARK: - Initializers
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public init() { }
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/// Create a new time period with given date range.
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///
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/// - Parameters:
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/// - start: start date
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/// - end: end date
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public init(start: DateInRegion?, end: DateInRegion?) {
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self.start = start
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self.end = end
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}
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/// Create a new time period with given start and a length specified in number of seconds.
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///
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/// - Parameters:
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/// - start: start of the period
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/// - duration: duration of the period expressed in seconds
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public init(start: DateInRegion, duration: TimeInterval) {
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self.start = start
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self.end = DateInRegion(start.date.addingTimeInterval(duration), region: start.region)
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}
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/// Create a new time period which ends at given date and start date is back on time by given interval.
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///
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/// - Parameters:
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/// - end: end date
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/// - duration: duration expressed in seconds (it will be subtracted from start date)
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public init(end: DateInRegion, duration: TimeInterval) {
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self.end = end
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self.start = end.addingTimeInterval(-duration)
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}
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/// Return a new instance of the TimePeriod that starts on the provided start date and is of the
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/// size provided.
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///
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/// - Parameters:
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/// - start: start of the period
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/// - duration: length of the period (ie. `2.days` or `14.hours`...)
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public init(start: DateInRegion, duration: DateComponents) {
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self.start = start
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self.end = (start + duration)
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}
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/// Return a new instance of the TimePeriod that starts at end time minus given duration.
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///
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/// - Parameters:
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/// - end: end date
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/// - duration: duration (it will be subtracted from end date in order to provide the start date)
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public init(end: DateInRegion, duration: DateComponents) {
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self.start = (end - duration)
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self.end = end
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}
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/// Returns a new instance of DTTimePeriod that represents the largest time period available.
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/// The start date is in the distant past and the end date is in the distant future.
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///
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/// - Returns: a new time period
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public static func infinity() -> TimePeriod {
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return TimePeriod(start: DateInRegion.past(), end: DateInRegion.future())
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}
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// MARK: - Shifted
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/// Shift the `TimePeriod` by a `TimeInterval`
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///
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/// - Parameter timeInterval: The time interval to shift the period by
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/// - Returns: The new, shifted `TimePeriod`
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public func shifted(by timeInterval: TimeInterval) -> TimePeriod {
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let timePeriod = TimePeriod()
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timePeriod.start = start?.addingTimeInterval(timeInterval)
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timePeriod.end = end?.addingTimeInterval(timeInterval)
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return timePeriod
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}
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/// Shift the `TimePeriod` by the specified components value.
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/// ie. `let shifted = period.shifted(by: 3.days)`
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///
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/// - Parameter components: components to shift
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/// - Returns: new period
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public func shifted(by components: DateComponents) -> TimePeriod {
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let timePeriod = TimePeriod()
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timePeriod.start = (hasStart ? (start! + components) : nil)
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timePeriod.end = (hasEnd ? (end! + components) : nil)
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return timePeriod
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}
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// MARK: - Lengthen / Shorten
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/// Lengthen the `TimePeriod` by a `TimeInterval`
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///
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/// - Parameters:
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/// - timeInterval: The time interval to lengthen the period by
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/// - anchor: The anchor point from which to make the change
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/// - Returns: The new, lengthened `TimePeriod`
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public func lengthened(by timeInterval: TimeInterval, at anchor: TimePeriodAnchor) -> TimePeriod {
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let timePeriod = TimePeriod()
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switch anchor {
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case .beginning:
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timePeriod.start = start
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timePeriod.end = end?.addingTimeInterval(timeInterval)
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case .center:
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timePeriod.start = start?.addingTimeInterval(-timeInterval)
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timePeriod.end = end?.addingTimeInterval(timeInterval)
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case .end:
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timePeriod.start = start?.addingTimeInterval(-timeInterval)
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timePeriod.end = end
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}
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return timePeriod
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}
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/// Shorten the `TimePeriod` by a `TimeInterval`
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///
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/// - Parameters:
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/// - timeInterval: The time interval to shorten the period by
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/// - anchor: The anchor point from which to make the change
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/// - Returns: The new, shortened `TimePeriod`
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public func shortened(by timeInterval: TimeInterval, at anchor: TimePeriodAnchor) -> TimePeriod {
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let timePeriod = TimePeriod()
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switch anchor {
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case .beginning:
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timePeriod.start = start
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timePeriod.end = end?.addingTimeInterval(-timeInterval)
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case .center:
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timePeriod.start = start?.addingTimeInterval(-timeInterval / 2)
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timePeriod.end = end?.addingTimeInterval(timeInterval / 2)
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case .end:
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timePeriod.start = start?.addingTimeInterval(timeInterval)
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timePeriod.end = end
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}
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return timePeriod
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}
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// MARK: - Operator Overloads
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/// Default anchor = beginning
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/// Operator overload for lengthening a `TimePeriod` by a `TimeInterval`
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public static func + (leftAddend: TimePeriod, rightAddend: TimeInterval) -> TimePeriod {
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return leftAddend.lengthened(by: rightAddend, at: .beginning)
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}
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/// Default anchor = beginning
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/// Operator overload for shortening a `TimePeriod` by a `TimeInterval`
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public static func - (minuend: TimePeriod, subtrahend: TimeInterval) -> TimePeriod {
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return minuend.shortened(by: subtrahend, at: .beginning)
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}
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/// Operator overload for checking if a `TimePeriod` is equal to a `TimePeriodProtocol`
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public static func == (left: TimePeriod, right: TimePeriodProtocol) -> Bool {
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return left.equals(right)
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}
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}
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public extension TimePeriod {
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/// The start date of the time period
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var startDate: Date? {
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return start?.date
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}
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/// The end date of the time period
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var endDate: Date? {
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return end?.date
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}
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/// Create a new time period with the given start date, end date and region (default is UTC)
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convenience init(startDate: Date, endDate: Date, region: Region = Region.UTC) {
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let start = DateInRegion(startDate, region: region)
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let end = DateInRegion(endDate, region: region)
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self.init(start: start, end: end)
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}
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}
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