using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using JD.Interfaces.Composition;
using JD.Interfaces.Composition.Units;

namespace JD.Core
{
    /// <summary>
    /// Manager handling task creation. This manager is able to overload tasks according to the framework components availability. 
    /// </summary>
    public class TaskManager
    {
        static TaskManager()
        {
            Instance = new TaskManager();
        }

        public static TaskManager Instance { get; }

        private readonly IEnumerable<ITaskOverload> _availableOverloads;
        protected TaskManager()
        {
            _availableOverloads = Objects.GetAllInstances<ITaskOverload>();
        }

        public Task CreateTask(Action action) 
        {
            return new Task(OverloadTask(action));
        }

        public Task CreateTask(Action action, CancellationToken cancellationToken)
        {
            return new Task(OverloadTask(action), cancellationToken);
        }

        public Task CreateTask(Action action, TaskCreationOptions creationOptions)
        {
            return new Task(OverloadTask(action), creationOptions);
        }

        public Task CreateTask(Action action, CancellationToken cancellationToken, TaskCreationOptions creationOptions)
        {
            return new Task(OverloadTask(action), cancellationToken, creationOptions);
        }

        public Task CreateTask(Action<object> action, object state)
        {
            return new Task(OverloadTask(action), state);
        }

        public Task CreateTask(Action<object> action, object state, CancellationToken cancellationToken)
        {
            return new Task(OverloadTask(action), state, cancellationToken);
        }

        public Task CreateTask(Action<object> action, object state, TaskCreationOptions creationOptions)
        {
            return new Task(OverloadTask(action), state, creationOptions);
        }

        public Task CreateTask(Action<object> action, object state, CancellationToken cancellationToken, TaskCreationOptions creationOptions)
        {
            return new Task(OverloadTask(action), state, cancellationToken, creationOptions);
        }

        private Action OverloadTask(Action action)
        {
            foreach (var overload in _availableOverloads)
            {
                action = overload.OverloadTask(action);
            }
            return action;
        }

        private Action<object> OverloadTask(Action<object> action)
        {
            foreach (var overload in _availableOverloads)
            {
                action = overload.OverloadTask(action);
            }
            return action;
        }
    }
}