//
//  Subscription.swift
//  Rx
//
//  Created by Krunoslav Zaher on 2/14/15.
//  Copyright © 2015 Krunoslav Zaher. All rights reserved.
//

import Foundation

/**
Records information about subscriptions to and unsubscriptions from observable sequences.
*/
public struct Subscription
    : Equatable
    , Hashable
    , CustomDebugStringConvertible {

    /**
     Subscription virtual time.
    */
    public let subscribe : Int
    /**
     Unsubscription virtual time.
    */
    public let unsubscribe : Int

    /**
     Creates a new subscription object with the given virtual subscription time.
     
     - parameter subscribe: Virtual time at which the subscription occurred.
    */
    public init(_ subscribe: Int) {
        self.subscribe = subscribe
        self.unsubscribe = Int.max
    }

    /**
     Creates a new subscription object with the given virtual subscription and unsubscription time.

     - parameter subscribe: Virtual time at which the subscription occurred.
     - parameter unsubscribe: Virtual time at which the unsubscription occurred.
    */
    public init(_ subscribe: Int, _ unsubscribe: Int) {
        self.subscribe = subscribe
        self.unsubscribe = unsubscribe
    }
    
    /**
     The hash value.
    */
    public var hashValue : Int {
        return subscribe.hashValue ^ unsubscribe.hashValue
    }
}

extension Subscription {
    /** 
    A textual representation of `self`, suitable for debugging.
    */
    public var debugDescription : String {
        let infiniteText = "Infinity"
        return "(\(subscribe) : \(unsubscribe != Int.max ? String(unsubscribe) : infiniteText))"
    }
}

public func == (lhs: Subscription, rhs: Subscription) -> Bool {
    return lhs.subscribe == rhs.subscribe && lhs.unsubscribe == rhs.unsubscribe
}