#region

using System;
using System.Collections.Generic;
using System.Net;
using Microsoft.SharePoint.Client;
using Nuveen.DMG.Core.Services;
using System.Configuration;
using System.IO;
using System.Linq;

#endregion

namespace Nuveen.DMG.Common.Services
{
    public class SharePointService : IDocumentManagementService
    {
        private readonly ILogger _logger;
        private readonly string _sharePointRoot = ConfigurationManager.AppSettings["SharePointRoot"];

        public SharePointService()
        {
            _logger = ServiceLocator.Current.GetInstance<ILogger>();
        }

        #region Connection Methods()

        /// <summary>
        /// Certifications the validation which will allow code to work for SSL enabled sites.
        /// </summary>
        private void CertificationValidation()
        {
            try
            {
                ServicePointManager.ServerCertificateValidationCallback +=
                (sender, certificate, chain, sslPolicyError) => true;
            }
            catch (Exception ex)
            {
                _logger.Error(ex.Message, ex);
                throw;
            }
        }

        /// <summary>
        /// Networks the credential.
        /// </summary>
        /// <returns></returns>
        private NetworkCredential NetworkCredential()
        {
            try
            {
                var userName = ConfigurationManager.AppSettings["SharePointUsername"];
                var domain = ConfigurationManager.AppSettings["SharePointDomain"];
                var password = ConfigurationManager.AppSettings["SharePointPassword"];

                var networkCredential = new NetworkCredential(userName, password, domain);

                return networkCredential;
            }
            catch (Exception ex)
            {
                _logger.Error(ex.Message, ex);
                throw;
            }

        }

        /// <summary>
        /// Opens the connection to share point.
        /// </summary>
        /// <exception cref="System.ArgumentException">OpehConnectionString:  + exception</exception>
        private ClientContext OpenConnectionToSharePoint()
        {
            try
            {
                CertificationValidation();
                var siteUrl = ConfigurationManager.AppSettings["SharePointUrl"];

                using (var clientContext = new ClientContext(siteUrl))
                {
                    //Comment code uses the local authentication from computer

                    //clientContext.AuthenticationMode = ClientAuthenticationMode.Default;
                    //clientContext.Credentials = CredentialCache.DefaultCredentials;

                    clientContext.Credentials = NetworkCredential();
                    clientContext.ValidateOnClient = true;
                    _logger.Info("Connection to SharePoint was successful.");

                    return clientContext;
                }
            }
            catch (Exception ex)
            {
                _logger.Error(ex.Message, ex);
                throw;
            }

        }

        #endregion

        #region Main Methods()

        /// <summary>
        /// Uploads the file as a stream to a sub-folder.
        /// If the sub-folder, (folderName) is not provided the file will be uploaded to the Root Folder.
        /// </summary>
        /// <param name="file">The file.</param>
        /// <param name="fileName">Name of the file.</param>
        /// <param name="folderName">Name of the folder.</param>
        /// <exception cref="System.Exception">Stream cannot be null</exception>
        public void UploadFile(Stream file, string fileName, string folderName)
        {
            try
            {
                using (var clientContext = OpenConnectionToSharePoint())
                {
                    var list = clientContext.Web.Lists.GetByTitle(_sharePointRoot);

                    clientContext.Load(list.RootFolder);
                    clientContext.Load(list.RootFolder.Folders);
                    clientContext.ExecuteQuery();

                    if (string.IsNullOrEmpty(folderName))
                    {
                        var webContext = clientContext.Web.Context;

                        if (file == null) throw new Exception("Stream cannot be null");
                        if (webContext.HasPendingRequest) webContext.ExecuteQuery();

                        var rootFileUrl = Path.Combine(list.RootFolder.ServerRelativeUrl, fileName);

                        Microsoft.SharePoint.Client.File.SaveBinaryDirect(
                            clientContext, rootFileUrl, file, true);
                    }
                    else
                    {
                        CreateFolderIfDoesNotExist(folderName);

                        var newFolder = Path.Combine(list.RootFolder.ServerRelativeUrl, folderName);
                        var folder = list.RootFolder.Folders.Add(newFolder);
                        clientContext.ExecuteQuery();

                        var fileUrl = Path.Combine(newFolder, fileName);
                        clientContext.Load(folder.Files);
                        clientContext.ExecuteQuery();

                        var existingFile = folder.Files.ToList().FirstOrDefault(x => x.Name == fileName);

                        if (existingFile != null)
                        {
                            clientContext.Load(existingFile);
                            clientContext.ExecuteQuery();
                            clientContext.Load(existingFile.LockedByUser);
                            clientContext.ExecuteQuery();
                        }
                        else
                        {
                            Microsoft.SharePoint.Client.File.SaveBinaryDirect(clientContext, fileUrl, file, true);
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                _logger.Error(ex.Message, ex);
                throw;
            }

        }

        /// <summary>
        /// Downloads all files.
        /// If the sub-folder, (folderName) is not provided -- will download all files from the Root Folder.
        /// Otherwise, will download all the files from a specific sub-folder.
        /// </summary>
        /// <returns></returns>
        public List<MemoryStream> DownloadFiles(string fileName, string folderName, bool downloadAllFile)
        {
            try
            {
                var memoryStreamCollection = new List<MemoryStream>();
​
                using (var clientContext = OpenConnectionToSharePoint())
                {
                    var list = clientContext.Web.Lists.GetByTitle(_sharePointRoot);
                    clientContext.Load(list);
                    clientContext.Load(list.RootFolder);
                    clientContext.Load(list.RootFolder.Folders);
                    clientContext.Load(list.RootFolder.Files);
                    clientContext.ExecuteQuery();
​
                    var folder = list.RootFolder;
                    if (!string.IsNullOrEmpty(folderName))
                    {
                        var folders = list.RootFolder.Folders;
                        folder = folders.First(f => f.Name == folderName);
                    }

                    clientContext.Load(folder.Files);
                    clientContext.ExecuteQuery();
​
                    if (downloadAllFile)
                    {
                        foreach (var file in folder.Files)
                        {
                            var fileReference = file.ServerRelativeUrl;
​
                            GetStream(fileReference, memoryStreamCollection, file.Name, folderName);
                        }
​
                        return memoryStreamCollection;
                    }
                    else
                    {
                        var fileNameCheck = folder.Files.First(f => f.Name == fileName);
                        var fileReference = fileNameCheck.ServerRelativeUrl;
​
                        GetStream(fileReference, memoryStreamCollection, fileName, folderName);
​
                        return memoryStreamCollection;
                    }
                }
            }
            catch (Exception ex)
            {
                _logger.Error(ex.Message, ex);
                throw;
            }
        }

        /// <summary>
        /// Deletes a file from a Sub-folder that matches the fileName.
        /// If the sub-folder, (folderName) is not provided the file will be deleted from the Root Folder.
        /// </summary>
        /// <param name="fileName">Name of the file.</param>
        /// <param name="folderName">Name of the folder.</param>
        public void DeleteFile(List<string> fileName, string folderName)
        {
            try
            {
                using (var clientContext = OpenConnectionToSharePoint())
                {
                    var list = clientContext.Web.Lists.GetByTitle(_sharePointRoot);
                    clientContext.Load(list.RootFolder);
                    clientContext.Load(list.RootFolder.Folders);
                    clientContext.Load(list.RootFolder.Files);
                    clientContext.ExecuteQuery();

                    var files = list.RootFolder.Files;

                    if (string.IsNullOrEmpty(folderName))
                    {
                        foreach (var file in files)
                        {
                            if (fileName.Contains(file.Name))
                            {
                                file.DeleteObject();
                                clientContext.ExecuteQuery();
                                _logger.Info(string.Format("{0}: was deleted from the {1} folder.", fileName, _sharePointRoot));
                            }
                            else
                            {
                                _logger.Error(string.Format("{0}: was not found.", fileName.Contains(file.Name)));
                            }
                        }
                    }
                    else
                    {
                        var folders = list.RootFolder.Folders;
                        var folder = folders.First(f => f.Name == folderName);
                        clientContext.Load(folder.Files);
                        clientContext.ExecuteQuery();

                        var folderFiles = folder.Files;
                        foreach (var ff in folderFiles)
                        {
                            if (fileName.Contains(ff.Name))
                                ff.DeleteObject();
                            clientContext.ExecuteQuery();

                            _logger.Info(string.Format("{0}: was deleted from {1} folder.", fileName.Contains(ff.Name), folderName));
                        }
                    }

                }
            }
            catch (Exception ex)
            {
                _logger.Error(ex.Message, ex);
                throw;
            }
        }

        #endregion

        #region Helper Method()

        /// <summary>
        /// Creates a folder if the folder does not already exist.
        /// </summary>
        /// <param name="folderName">Name of the folder.</param>
        private void CreateFolderIfDoesNotExist(string folderName)
        {
            try
            {
                using (var clientContext = OpenConnectionToSharePoint())
                {
                    var list = clientContext.Web.Lists.GetByTitle(_sharePointRoot);
                    list.EnableFolderCreation = true;

                    clientContext.Load(list);
                    clientContext.Load(list.RootFolder);
                    clientContext.Load(list.RootFolder.Folders);
                    clientContext.ExecuteQuery();

                    var folderCollection = list.RootFolder.Folders;

                    foreach (var folder in folderCollection)
                    {
                        if (folder.Name == folderName)
                        {
                            clientContext.Load(folder.Files);
                            clientContext.ExecuteQuery();
                        }
                        else
                        {
                            var itemCreateInfo = new ListItemCreationInformation
                            {
                                UnderlyingObjectType = FileSystemObjectType.Folder,
                                LeafName = folderName
                            };

                            var newItem = list.AddItem(itemCreateInfo);
                            newItem["Title"] = folderName;
                            newItem.Update();
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                _logger.Error(ex.Message, ex);
                throw;
            }
        }

        /// <summary>
        /// Gets the stream.
        /// </summary>
        /// <param name="fileReference">The file reference.</param>
        /// <param name="memoryStreamCollection">The memory stream collection.</param>
        /// <param name="fileName">Name of the file.</param>
        /// <param name="folderName">Name of the folder.</param>
        /// <returns></returns>
        private void GetStream(string fileReference, ICollection<MemoryStream> memoryStreamCollection, string fileName, string folderName)
        {
            try
             {
                if (string.IsNullOrEmpty(folderName))
                {
                    folderName = _sharePointRoot;
                }
                using (var clientContext = OpenConnectionToSharePoint())
                {
                    var fileInfo = Microsoft.SharePoint.Client.File.OpenBinaryDirect(clientContext, fileReference);
                    var fileStream = new MemoryStream();

                    fileInfo.Stream.CopyTo(fileStream);
                    memoryStreamCollection.Add(fileStream);

                    _logger.Info(string.Format("{0}: was downloaded successfully from {1} folder.", fileName, folderName));
                }
            }
            catch (Exception ex)
            {
                _logger.Error(ex);
                throw;
            }
        }
        #endregion
    }
}