using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace WmData {
	/// <summary>
	/// The WmDataFile object is a two purpose object:
	/// 1) it provides meta data of a certain file, like creation date, size, type, etc.
	/// 2) it provides acces to the real binary file data in the SQL backend
	/// </summary>
	public class WmDataFile : IComparable {
		protected int id;
		protected DateTime created;
		protected DateTime lastAccessed;
		protected DateTime lastUpdated;
		protected string filename;
		protected string fileExtension;
		protected int contentLength;
		protected string contentType;


		protected WmDataFileSupport fileSupport;
		protected static WmDataFileSortBy sortBy;

		public WmDataFile(WmDataFileSupport fileSupport){
			this.fileSupport = fileSupport; // used for retrieval of the bits and byes (binary data)
		}

		public int Id {
			get { return id; }
			set { id = value; }
		}
		public DateTime Created {
			get { return created; }
			set { created = value; }
		}
		public DateTime LastAccessed {
			get { return lastAccessed; }
			set { lastAccessed = value; }
		}
		public DateTime LastUpdated {
			get { return lastUpdated; }
			set { lastUpdated = value; }
		}
		public string Filename {
			get { return filename; }
			set { filename = value; }
		}
		public string FileExtension {
			get { return fileExtension; }
			set { fileExtension = value; }
		}
		public int ContentLength {
			get { return contentLength; }
			set { contentLength = value; }
		}
		public string ContentType {
			get { return contentType; }
			set { contentType = value; }
		}

		public byte[] BinaryData {
			get {
				// first check if this meta object was already stored in the database backend
				if (id == 0) { throw new Exception("WmDataFile: The object instance with meta data must be added to SQL backend before reading binary data"); }
				byte[] binaryData = fileSupport.readBinaryData(this);
				return binaryData;
			}
			set {
				// first check if this meta object was already stored in the database backend
				if (id == 0) { 	throw new Exception("WmDataFile: The object instance with meta data must be added to SQL backend before adding binary data");}
				fileSupport.saveBinaryData(this, value);
			}
		}

		public void saveAs(string path) {
			FileStream fileWriter = new FileStream(path, FileMode.Create);
			byte[] binaryData = BinaryData;
			fileWriter.Write(binaryData, 0, binaryData.Length);
			fileWriter.Close();
		}

		public static WmDataFileSortBy SortBy {
			get { return sortBy; }
			set { sortBy = value; }
		}
		public int CompareTo(object obj) {
			if (!(obj is WmDataFile)) {
				throw new InvalidCastException("This object is not of type WmDataFile");
			}
			WmDataFile other = (WmDataFile)obj;
			switch (sortBy) {
				case WmDataFileSortBy.ID:
					return this.Id.CompareTo(other.Id);
				case WmDataFileSortBy.CREATED:
					return this.Created.CompareTo(other.Created);
				case WmDataFileSortBy.LASTACCESSED:
					return this.LastAccessed.CompareTo(other.LastAccessed);
				case WmDataFileSortBy.LASTUPDATED:
					return this.LastUpdated.CompareTo(other.LastUpdated);
				case WmDataFileSortBy.SIZE:
					return this.ContentLength.CompareTo(other.ContentLength);
				default:
					goto case WmDataFileSortBy.ID;
			}
		}
		
	}

	public enum WmDataFileSortBy {
		ID,CREATED,LASTACCESSED,LASTUPDATED,FILENAME,SIZE
	}
}