Delegation example #2 for the Aya.io tutorial.

delegationExample02.swift

import XCPlayground
XCPlaygroundPage.currentPage.needsIndefiniteExecution = true

protocol CanBuildHouses {
    
    func startWorking()
    
}

protocol CanManageTeams {
    
    func aTeamHasStartedWorking(team: Team)
    
    func aTeamHasFinishedWorking(team: Team)
    
}

class Contractor: CanManageTeams {
    
    var name: String
    
    init(name: String) {
        self.name = name
    }
    
    var employee: CanBuildHouses?
    
    func giveOrders() {
        guard let currentTeam = self.employee else {
            print("\(name): No new team in sight.\n")
            return
        }
        
        print("\(name): Ah! Let's give some work to this team...\n")
        
        currentTeam.startWorking()
    }
    
    func aTeamHasStartedWorking(team: Team) {
        print("\(name): Ok \(team.name), see you later today!\n")
    }
    
    func aTeamHasFinishedWorking(team: Team) {
        if team.taskDuration < 7 {
            print("\(name): Congratulations, \(team.name), work done in \(team.taskDuration) seconds.\n")
        } else {
            print("\(name): Really, \(team.name)? You can do better than \(team.taskDuration) seconds.\n")
        }
        
    }
    
}

class Team: CanBuildHouses {
    
    var name: String
    
    var reportsTo: CanManageTeams?
    
    var taskDuration:UInt32 = 0
    
    init(name: String) {
        self.name = name
    }
    
    func startWorking() {
        if let announce = reportsTo {
            print("\(name): We're going to start in an instant, let's tell the boss...\n")
            announce.aTeamHasStartedWorking(self)
        } else {
            print("\(name): No boss in sight, let's just start working.\n")
        }
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {
            self.taskDuration = arc4random_uniform(10)+2
            sleep(self.taskDuration) // "working" for some time
            dispatch_async(dispatch_get_main_queue()) {
                if let announce = self.reportsTo {
                    print("\(self.name): We're finished, let's tell the boss!\n")
                    announce.aTeamHasFinishedWorking(self)
                } else {
                    print("\(self.name): We're finished! No boss in sight, let's just have a beer.\n")
                }
                
            }
        }
    }
    
}


let boss = Contractor(name: "BOSS")

let teamJohn = Team(name: "JOHN")

let teamJane = Team(name: "JANE")

teamJohn.reportsTo = boss
teamJane.reportsTo = boss

boss.employee = teamJane
boss.giveOrders()

boss.employee = teamJohn
boss.giveOrders()

boss.employee = nil
boss.giveOrders()