using Microsoft.WindowsAzure.Storage.Blob;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tango.Web.Storage
{
    public static class ExtensionMethods
    {
        public static CloudBlockBlob CreateEmptyBlob(this CloudBlobContainer container, String name)
        {
            CloudBlockBlob emptyBlob = container.GetBlockBlobReference(name);
            using (MemoryStream ms = new MemoryStream())
            {
                emptyBlob.UploadFromStream(ms);//Empty memory stream. Will create an empty blob.
            }

            return emptyBlob;
        }

        public static CloudBlockBlob UploadNewBlob(this CloudBlobContainer container, Stream stream, String name)
        {
            CloudBlockBlob emptyBlob = container.GetBlockBlobReference(name);
            emptyBlob.UploadFromStream(stream);
            return emptyBlob;
        }

        public static String GenerateReadSignature(this CloudBlockBlob blob, TimeSpan duration)
        {
            String signature = blob.GetSharedAccessSignature(new SharedAccessBlobPolicy()
            {
                SharedAccessStartTime = DateTime.UtcNow,
                SharedAccessExpiryTime = DateTime.UtcNow.Add(duration),
                Permissions = SharedAccessBlobPermissions.Read
            });

            return new Uri(blob.Uri + signature).ToString();
        }

        public static String GenerateWriteSignature(this CloudBlockBlob blob, TimeSpan duration)
        {
            String signature = blob.GetSharedAccessSignature(new SharedAccessBlobPolicy()
            {
                SharedAccessStartTime = DateTime.UtcNow,
                SharedAccessExpiryTime = DateTime.UtcNow.Add(duration),
                Permissions = SharedAccessBlobPermissions.Write
            });

            return new Uri(blob.Uri + signature).ToString();
        }
    }
}