Gallery Server Pro - An ASP.NET Gallery for Sharing Photos, Video, Audio and Other Media

using System;
using System.Web;
using GalleryServerPro.Business;
using GalleryServerPro.Business.Interfaces;

namespace GalleryServerPro.Web.Controller
{
	/// <summary>
	/// Contains functionality for interacting with gallery objects (that is, media objects and albums). Typically web pages 
	/// directly call the appropriate business layer objects, but when a task involves multiple steps or the functionality 
	/// does not exist in the business layer, the methods here are used.
	/// </summary>
	public static class GalleryObjectController
	{
		#region Public Static Methods

		/// <summary>
		/// Persist the gallery object to the data store. This method updates the audit fields before saving. The currently logged
		/// on user is recorded as responsible for the changes. All gallery objects should be
		/// saved through this method rather than directly invoking the gallery object's Save method, unless you want to 
		/// manually update the audit fields yourself.
		/// </summary>
		/// <param name="galleryObject">The gallery object to persist to the data store.</param>
		/// <remarks>When no user name is available through Util.UserName, the string &lt;unknown&gt; is
		/// substituted. Since GSP requires users to be logged on to edit objects, there will typically always be a user name 
		/// available. However, in some cases one won't be available, such as when an error occurs during self registration and
		/// the exception handling code needs to delete the just-created user album.</remarks>
		public static void SaveGalleryObject(IGalleryObject galleryObject)
		{
			string userName = (String.IsNullOrEmpty(Util.UserName) ? Resources.GalleryServerPro.Site_Missing_Data_Text : Util.UserName);
			SaveGalleryObject(galleryObject, userName);
		}

		/// <summary>
		/// Persist the gallery object to the data store. This method updates the audit fields before saving. All gallery objects should be
		/// saved through this method rather than directly invoking the gallery object's Save method, unless you want to
		/// manually update the audit fields yourself.
		/// </summary>
		/// <param name="galleryObject">The gallery object to persist to the data store.</param>
		/// <param name="userName">The user name to be associated with the modifications. This name is stored in the internal
		/// audit fields associated with this gallery object.</param>
		public static void SaveGalleryObject(IGalleryObject galleryObject, string userName)
		{
			DateTime currentTimestamp = DateTime.Now;

			if (galleryObject.IsNew)
			{
				galleryObject.CreatedByUserName = userName;
				galleryObject.DateAdded = currentTimestamp;
			}

			if (galleryObject.HasChanges)
			{
				galleryObject.LastModifiedByUserName = userName;
				galleryObject.DateLastModified = currentTimestamp;
			}

			// Verify that any role needed for album ownership exists and is properly configured.
			RoleController.ValidateRoleExistsForAlbumOwner(galleryObject as IAlbum);

			// Persist to data store.
			galleryObject.Save();
		}

		/// <summary>
		/// Move the specified object to the specified destination album. This method moves the physical files associated with this
		/// object to the destination album's physical directory. The object's Save() method is invoked to persist the changes to the
		/// data store. When moving albums, all the album's children, grandchildren, etc are also moved. 
		/// The audit fields are automatically updated before saving.
		/// </summary>
		/// <param name="galleryObjectToMove">The gallery object to move.</param>
		/// <param name="destinationAlbum">The album to which the current object should be moved.</param>
		public static void MoveGalleryObject(IGalleryObject galleryObjectToMove, IAlbum destinationAlbum)
		{
			string currentUser = Util.UserName;
			DateTime currentTimestamp = DateTime.Now;

			galleryObjectToMove.LastModifiedByUserName = currentUser;
			galleryObjectToMove.DateLastModified = currentTimestamp;

			galleryObjectToMove.MoveTo(destinationAlbum);
		}

		/// <summary>
		/// Copy the specified object and place it in the specified destination album. This method creates a completely separate copy
		/// of the original, including copying the physical files associated with this object. The copy is persisted to the data
		/// store and then returned to the caller. When copying albums, all the album's children, grandchildren, etc are also copied.
		/// The audit fields of the copied objects are automatically updated before saving.
		/// </summary>
		/// <param name="galleryObjectToCopy">The gallery object to copy.</param>
		/// <param name="destinationAlbum">The album to which the current object should be copied.</param>
		/// <returns>
		/// Returns a new gallery object that is an exact copy of the original, except that it resides in the specified
		/// destination album, and of course has a new ID. Child objects are recursively copied.
		/// </returns>
		public static IGalleryObject CopyGalleryObject(IGalleryObject galleryObjectToCopy, IAlbum destinationAlbum)
		{
			string currentUser = Util.UserName;

			return galleryObjectToCopy.CopyTo(destinationAlbum, currentUser);
		}

		/// <summary>
		/// Return the requested display object from the specified media object. If Unknown is passed in the 
		/// displayType parameter, and the object is an image, return the optimized object. If an optimized 
		/// version does not exist, return the original object. If Unknown is passed in the displayType parameter, 
		/// and the object is NOT an image, return the original object. If a thumbnail is requested, always 
		/// return a thumbnail object.
		/// </summary>
		/// <param name="mediaObject">The media object containing the display object to return.</param>
		/// <param name="displayType">One of the DisplayObjectType enumeration values indicating which object to return.</param>
		/// <returns>Returns the requested display object from the specified media object.</returns>
		public static IDisplayObject GetDisplayObject(IGalleryObject mediaObject, DisplayObjectType displayType)
		{
			IDisplayObject displayObject = null;

			if (displayType == DisplayObjectType.Thumbnail)
			{
				displayObject = mediaObject.Thumbnail;
			}
			else if (mediaObject is GalleryServerPro.Business.Image)
			{
				displayObject = GetDisplayObjectForImage(mediaObject, displayType);
			}
			else
			{
				displayObject = mediaObject.Original;
			}

			return displayObject;
		}

		#endregion

		#region Private Static Methods

		/// <summary>
		/// Return the requested display object from the specified image object. If Unknown is passed in the 
		/// displayType parameter, return the optimized object. If an optimized version does not exist, return 
		/// the original object. If a thumbnail is requested, always return a thumbnail object.
		/// </summary>
		/// <param name="mediaObject">The media object containing the display object to return.</param>
		/// <param name="displayType">One of the DisplayObjectType enumeration values indicating which object to return.</param>
		/// <returns>Returns the requested display object from the specified image object.</returns>
		/// <exception cref="System.ArgumentException">Thrown when the parameter mediaObject is not of type 
		/// GalleryServerPro.Business.Image.</exception>
		private static IDisplayObject GetDisplayObjectForImage(IGalleryObject mediaObject, DisplayObjectType displayType)
		{
			if (!(mediaObject is GalleryServerPro.Business.Image))
			{
				throw new ArgumentException("The parameter 'mediaObject' in function GspPage.GetDisplayObjectForImage must be of type GalleryServerPro.Business.Image, but it was not.");
			}

			IDisplayObject displayObject;
			switch (displayType)
			{
				case DisplayObjectType.Thumbnail:
					{
						displayObject = mediaObject.Thumbnail;
						break;
					}
				case DisplayObjectType.Unknown:
				case DisplayObjectType.Optimized:
					{
						if (mediaObject.Optimized.FileName == mediaObject.Original.FileName)
						{
							// No optimized version is available
							displayObject = mediaObject.Original;
						}
						else
						{
							displayObject = mediaObject.Optimized;
						}
						break;
					}
				case DisplayObjectType.Original:
					{
						displayObject = mediaObject.Original;
						break;
					}
				default:
					{
						displayObject = mediaObject.Optimized;
						break;
					}
			}

			return displayObject;
		}

		#endregion

	}
}