// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// Copyright (c) 2007 Novell, Inc. (http://www.novell.com)
//
// Authors:
//	Chris Toshok (toshok@ximian.com)
//

using System;
using System.Collections.Generic;
using System.IO;
using System.Xml;
using zipsharp;

namespace System.IO.Packaging {

	class UriComparer : IEqualityComparer<Uri>
	{
		public int GetHashCode(Uri uri)
		{
			return 1;
		}
		
		public bool Equals(Uri x, Uri y)
		{
			return x.OriginalString.Equals (y.OriginalString, StringComparison.OrdinalIgnoreCase);
		}
	}
	
	public sealed class ZipPackage : Package
	{
		private const string ContentNamespace = "http://schemas.openxmlformats.org/package/2006/content-types";
		private const string ContentUri = "[Content_Types].xml";
		
		bool OwnsStream {
			get; set;
		}
		
		Dictionary<Uri, ZipPackagePart> parts;
		internal Dictionary<Uri, MemoryStream> PartStreams = new Dictionary<Uri, MemoryStream> (new  UriComparer());

		internal Stream PackageStream { get; set; }

		Dictionary<Uri, ZipPackagePart> Parts {
			get {
				if (parts == null)
					LoadParts ();
				return parts;
			}
		}
		
		internal ZipPackage (FileAccess access, bool ownsStream, Stream stream)
			: base (access)
		{
			OwnsStream = ownsStream;
			PackageStream = stream;
		}

		internal ZipPackage (FileAccess access, bool ownsStream, Stream stream, bool streaming)
			: base (access, streaming)
		{
			OwnsStream = ownsStream;
			PackageStream = stream;
		}
		
		protected override void Dispose (bool disposing)
		{
			foreach (Stream s in PartStreams.Values)
				s.Close ();
			
			base.Dispose (disposing);
			
			if (OwnsStream)
				PackageStream.Close ();
		}

		protected override void FlushCore ()
		{
			// Ensure that all the data has been read out of the package
			// stream already. Otherwise we'll lose data when we recreate the zip
			foreach (ZipPackagePart part in Parts.Values)
				part.GetStream ().Dispose ();
			
			// Empty the package stream
			PackageStream.Position = 0;
			PackageStream.SetLength (0);

			// Recreate the zip file
			using (ZipArchive archive = new ZipArchive(PackageStream, Append.Create, false)) {

				// Write all the part streams
				foreach (ZipPackagePart part in Parts.Values) {
					Stream partStream = part.GetStream ();
					partStream.Seek (0, SeekOrigin.Begin);
					
					using (Stream destination = archive.GetStream (part.Uri.ToString ().Substring(1), part.CompressionOption)) {
						int count = (int) Math.Min (2048, partStream.Length);
						byte[] buffer = new byte [count];

						while ((count = partStream.Read (buffer, 0, buffer.Length)) != 0)
							destination.Write (buffer, 0, count);
					}
				}

				using (Stream s = archive.GetStream (ContentUri, CompressionOption.Maximum))
					WriteContentType (s);
			}
		}

		protected override PackagePart CreatePartCore (Uri partUri, string contentType, CompressionOption compressionOption)
		{
			ZipPackagePart part = new ZipPackagePart (this, partUri, contentType, compressionOption);
			Parts.Add (part.Uri, part);
			return part;
		}

		protected override void DeletePartCore (Uri partUri)
		{
			Parts.Remove (partUri);
		}

		protected override PackagePart GetPartCore (Uri partUri)
		{
			ZipPackagePart part;
			Parts.TryGetValue (partUri, out part);
			return part;
		}

		protected override PackagePart[] GetPartsCore ()
		{
			ZipPackagePart[] p = new ZipPackagePart [Parts.Count];
			Parts.Values.CopyTo (p, 0);
			return p;
		}
		
		void LoadParts ()
		{
			parts = new Dictionary<Uri, ZipPackagePart> (new  UriComparer());
			try {
				using (UnzipArchive archive = new UnzipArchive (PackageStream)) {

					// Load the content type map file
					XmlDocument doc = new XmlDocument ();
					using (Stream s = archive.GetStream (ContentUri))
						doc.Load (s);

					XmlNamespaceManager manager = new XmlNamespaceManager (doc.NameTable);
					manager.AddNamespace ("content", ContentNamespace);

					// The file names in the zip archive are not prepended with '/'
					foreach (string file in archive.GetFiles ()) {
						if (file.Equals (ContentUri, StringComparison.Ordinal))
							continue;

						XmlNode node;
						CompressionOption compression = archive.GetCompressionLevel (file);

						if (file == RelationshipUri.ToString ().Substring (1))
						{
							CreatePartCore (RelationshipUri, RelationshipContentType, compression);
							continue;
						}

						string xPath = string.Format ("/content:Types/content:Override[@PartName='/{0}']", file);
						node = doc.SelectSingleNode (xPath, manager);

						if (node == null)
						{
							string ext = Path.GetExtension (file);
							if (ext.StartsWith("."))
								ext = ext.Substring (1);
							xPath = string.Format("/content:Types/content:Default[@Extension='{0}']", ext);
							node = doc.SelectSingleNode (xPath, manager);
						}

						// What do i do if the node is null? This means some has tampered with the
						// package file manually
						if (node != null)
							CreatePartCore (new Uri ("/" + file, UriKind.Relative), node.Attributes["ContentType"].Value, compression);
					}
				}
			} catch {
				// The archive is invalid - therefore no parts
			}
		}

		void WriteContentType (Stream s)
		{
			XmlDocument doc = new XmlDocument ();
			XmlNamespaceManager manager = new XmlNamespaceManager (doc.NameTable);
			Dictionary<string, string> mimes = new Dictionary<string, string> ();
			
			manager.AddNamespace ("content", ContentNamespace);

			doc.AppendChild(doc.CreateNode (XmlNodeType.XmlDeclaration, "", ""));
			
			XmlNode root = doc.CreateNode (XmlNodeType.Element, "Types", ContentNamespace);
			doc.AppendChild (root);
			foreach (ZipPackagePart part in Parts.Values)
			{
				XmlNode node = null;
				string existingMimeType;
									
				var extension = Path.GetExtension (part.Uri.OriginalString);
				if (extension.Length > 0)
					extension = extension.Substring (1);
				
				if (!mimes.TryGetValue (extension, out existingMimeType)) {
					node = doc.CreateNode (XmlNodeType.Element, "Default", ContentNamespace);
					
					XmlAttribute ext = doc.CreateAttribute ("Extension");
					ext.Value = extension;
					node.Attributes.Append (ext);
					mimes [extension] = part.ContentType;
				} else if (part.ContentType != existingMimeType) {
					node = doc.CreateNode (XmlNodeType.Element, "Override", ContentNamespace);
					
					XmlAttribute name = doc.CreateAttribute ("PartName");
					name.Value = part.Uri.ToString ();
					node.Attributes.Append (name);
				}
				
				if (node != null) {
					XmlAttribute contentType = doc.CreateAttribute ("ContentType");
					contentType.Value = part.ContentType;
					node.Attributes.Prepend (contentType);
	
					root.AppendChild (node);
				}
			}

			using (XmlTextWriter writer = new XmlTextWriter (s, System.Text.Encoding.UTF8))
				doc.WriteTo (writer);
		}
	}
}