using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;
using System.Xml;

namespace Differ
{
	public class File
	{
		public File() {
			this.Path = "";
			this.Name = "";
			this.Hash = "";
			this.Parent = null;
		}
		public File(string path, Folder parent = null) {
			this.Name = (new FileInfo(path).Name);
			this.Path = path;
			this.Parent = parent;
			this.Hash = GetHash();
		}

		public string Name { get; private set; }
		public string Path { get; private set; }
		public Folder Parent { get; internal set; }
		public string Hash { get; private set; }

		protected bool Diffed = false;

		public string GetHash() {
			MD5CryptoServiceProvider provider = null;
			ASCIIEncoding encoder = null;
			FileStream fileStream = null;

			try
			{
				provider = new MD5CryptoServiceProvider();
				encoder = new ASCIIEncoding();
				fileStream = new FileStream(this.Path, FileMode.Open, FileAccess.Read);

				provider.Initialize();
				byte[] hash = provider.ComputeHash(fileStream);
				StringBuilder hashBuilder = new StringBuilder();

				foreach (var b in hash)
				{
					hashBuilder.Append(b.ToString("x2"));
				}

				return hashBuilder.ToString();
			}
			catch (Exception)
			{
				return "";
			}
			finally {
				// Dispose objects.
				if(fileStream != null)
					fileStream.Dispose();
				if(provider != null)
					provider.Dispose();
			}
		}
		public XmlNode GetNode(XmlDocument document) {
			XmlNode toReturn = document.CreateNode(XmlNodeType.Element, "File", "");

			XmlAttribute hashAttribute = document.CreateAttribute("Hash");
			hashAttribute.InnerText = Hash;
			XmlAttribute nameAttribute = document.CreateAttribute("Name");
			nameAttribute.InnerText = this.Name;

			toReturn.Attributes.Append(nameAttribute);
			toReturn.Attributes.Append(hashAttribute);

			return toReturn;
		}
		public bool Matches(File file) {
			return (file.Name == this.Name) 
				&& (file.Hash == this.Hash);
		}
		public string GetRelativePath() {
			StringBuilder builder = new StringBuilder();
			builder.Append(this.Parent.GetRelativePath())
				.AppendFormat("\\{0}", this.Name);

			return builder.ToString();
		}

		public void ParseFromXmlNode(XmlNode node) {
			foreach (XmlAttribute attribute in node.Attributes) {
				switch (attribute.Name) {
					case "Name":
						this.Name = attribute.InnerText;
						break;
					case "Hash":
						this.Hash = attribute.InnerText;
						break;
					default:
						break;
				}
			}
		}
	}
}