using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.Core;

namespace Tango.Integration.Storage
{
    public class StorageFileHandler : ExtendedObject
    {
        private Action _cancelAction;

        public event EventHandler<StorageFileHandlerProgressEventArgs> Progress;
        public event EventHandler Completed;
        public event EventHandler Canceled;
        public event EventHandler<Exception> Failed;

        internal StorageFileHandler()
        {

        }

        internal StorageFileHandler(StorageFile storageFile, Action cancelAction)
        {
            _cancelAction = cancelAction;
            StorageFile = storageFile;
        }

        public StorageFile StorageFile { get; set; }

        private StorageFileHandlerStatus _status;
        public StorageFileHandlerStatus Status
        {
            get { return _status; }
            private set { _status = value; RaisePropertyChangedAuto(); }
        }

        private long _current;
        public long Current
        {
            get { return _current; }
            internal set
            {
                long previous = _current;
                _current = value; RaisePropertyChangedAuto();
                Progress?.Invoke(this, new StorageFileHandlerProgressEventArgs()
                {
                    Current = _current,
                    Total = _total,
                    Delta = _current - previous,
                });

                if (Status != StorageFileHandlerStatus.Active)
                {
                    Status = StorageFileHandlerStatus.Active;
                }
            }
        }

        private long _total;
        public long Total
        {
            get { return _total; }
            internal set { _total = value; RaisePropertyChangedAuto(); }
        }

        public bool IsPaused { get; set; }

        public Task Cancel()
        {
            return Task.Factory.StartNew(() =>
            {
                _cancelAction.Invoke();
                Status = StorageFileHandlerStatus.Canceled;
            });
        }

        internal void RaiseCompleted()
        {
            Status = StorageFileHandlerStatus.Completed;
            Completed?.Invoke(this, new EventArgs());
        }

        internal void RaiseCanceled()
        {
            Status = StorageFileHandlerStatus.Canceled;
            Canceled?.Invoke(this, new EventArgs());
        }

        internal void RaiseFailed(Exception ex)
        {
            Status = StorageFileHandlerStatus.Failed;
            Failed?.Invoke(this, ex);
        }
    }
}