TaskQueue Swift

TaskQueue

import Foundation

struct Task {
    let priority: Int
    let completion: () -> Bool // Returns a Bool indicating success or failure
    let onFailure: () -> Void
    let proceedOnFailure: Bool
}

class TaskQueue {
    private var tasks: [Task] = []
    private let queue = DispatchQueue(label: "taskQueue")
    private var isExecutingTask = false
    private var isStarted = false

    func addTask(_ task: Task) {
        queue.async {
            self.tasks.append(task)
            self.tasks.sort { $0.priority > $1.priority } // Higher priority first
        }
    }

    func startExecution() {
        queue.async {
            guard !self.isStarted else { return }
            self.isStarted = true
            self.executeNextTask()
        }
    }

    private func executeNextTask() {
        guard !isExecutingTask, !tasks.isEmpty else { return }

        isExecutingTask = true
        let nextTask = tasks.removeFirst()

        // Execute task and determine success or failure
        let success = nextTask.completion()

        if success {
            self.queue.async {
                self.isExecutingTask = false
                self.executeNextTask()
            }
        } else {
            nextTask.onFailure()
            self.queue.async {
                self.isExecutingTask = false
                if nextTask.proceedOnFailure {
                    self.executeNextTask()
                } else {
                    self.isStarted = false
                }
            }
        }
    }
}

// Example Usage
let taskQueue = TaskQueue()

taskQueue.addTask(Task(priority: 1,
                       completion: {
                           print("Task with priority 1 executed")
                           return true // Indicate success
                       },
                       onFailure: {
                           print("Task with priority 1 failed")
                       },
                       proceedOnFailure: true))

taskQueue.addTask(Task(priority: 3,
                       completion: {
                           print("Task with priority 3 executed")
                           return false // Indicate failure
                       },
                       onFailure: {
                           print("Task with priority 3 failed")
                       },
                       proceedOnFailure: true))

taskQueue.addTask(Task(priority: 2,
                       completion: {
                           print("Task with priority 2 executed")
                           return true // Indicate success
                       },
                       onFailure: {
                           print("Task with priority 2 failed")
                       },
                       proceedOnFailure: false))

taskQueue.startExecution()