using System;
using System.Collections.Generic;
using System.Diagnostics.Contracts;
using System.IO;
using System.Linq;
using System.Text;

namespace Pithos.Interfaces
{
    [ContractClass(typeof(ICloudClientContract))]
    public interface ICloudClient
    {
        string ApiKey { get; set; }
        string UserName { get; set; }
        string StorageUrl { get; set; }
        string Token { get; set; }
        void Authenticate(string userName,string apiKey);
        
        IList<ContainerInfo> ListContainers();
        IList<ObjectInfo> ListObjects(string container);
        bool ContainerExists(string container);
        ContainerInfo GetContainerInfo(string container);
        void CreateContainer(string container);
        
        Stream GetObject(string container, string objectName);
        void PutObject(string container, string objectName, Stream file,long fileSize);
        void DeleteObject(string container, string objectName);
        void MoveObject(string container, string oldObjectName, string newObjectName);
        bool ObjectExists(string container,string objectName);
        ObjectInfo GetObjectInfo(string container, string objectName);
    }


    [ContractClassFor(typeof(ICloudClient))]
    public abstract class ICloudClientContract:ICloudClient
    {
        public string ApiKey { get; set; }
        public string UserName { get; set; }
        public string StorageUrl { get; set; }
        public string Token { get; set; }

        public void Authenticate(string userName, string apiKey)
        {
            Contract.Requires<ArgumentNullException>(!String.IsNullOrWhiteSpace(apiKey), "ApiKey must be filled before calling Authenticate");
            Contract.Requires<ArgumentNullException>(!String.IsNullOrWhiteSpace(userName), "UserName must be filled before calling Authenticate");


            Contract.Ensures(apiKey==ApiKey);
            Contract.Ensures(userName==UserName);
            Contract.Ensures(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Ensures(!String.IsNullOrWhiteSpace(Token));
            
        }

        public IList<ContainerInfo> ListContainers()
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));

            return default(IList<ContainerInfo>);
        }

        public IList<ObjectInfo> ListObjects(string container)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));

            return default(IList<ObjectInfo>);
        }

        public bool ContainerExists(string container)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));

            return default(bool);
        }

        public ContainerInfo GetContainerInfo(string container)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));

            return default(ContainerInfo);
        }

        public void CreateContainer(string container)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));
        }

        public Stream GetObject(string container, string objectName)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));
            Contract.Requires(!String.IsNullOrWhiteSpace(objectName));

            return default(Stream);
        }

        public void PutObject(string container, string objectName, Stream file,long fileSize)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));
            Contract.Requires(file!=null);
            Contract.Requires(file.CanRead);
            Contract.Requires(fileSize>=0);            
            Contract.Requires(!String.IsNullOrWhiteSpace(objectName));
        }

        public void DeleteObject(string container, string objectName)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));
            Contract.Requires(!String.IsNullOrWhiteSpace(objectName));
        }

        public void MoveObject(string container, string oldObjectName, string newObjectName)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));
            Contract.Requires(!String.IsNullOrWhiteSpace(oldObjectName));
            Contract.Requires(!String.IsNullOrWhiteSpace(newObjectName));
        }

        public bool ObjectExists(string container,string objectName)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));
            Contract.Requires(!String.IsNullOrWhiteSpace(objectName));

            return default(bool);
        }

        public ObjectInfo GetObjectInfo(string container,string objectName)
        {
            Contract.Requires(!String.IsNullOrWhiteSpace(Token));
            Contract.Requires(!String.IsNullOrWhiteSpace(StorageUrl));
            Contract.Requires(!String.IsNullOrWhiteSpace(container));
            Contract.Requires(!String.IsNullOrWhiteSpace(objectName));

            return default(ObjectInfo);
        }
    }

    public class ContainerInfo
    {
        public string Name { get; set; }
        public long Count { get; set; }
        public long Bytes { get; set; }

        public static ContainerInfo Empty=new ContainerInfo();
    }
    
    public class ObjectInfo
    {
        public string Name { get; set; }
        public string Hash { get; set; }
        public long Bytes { get; set; }
        public string Content_Type { get; set; }
        public DateTime Last_Modified { get; set; }

        public static ObjectInfo Empty=new ObjectInfo {Name=String.Empty,Hash=String.Empty,Bytes=0,Content_Type=String.Empty,Last_Modified=DateTime.MinValue};
    }
}