#region CPL License
/*
Nuclex Framework
Copyright (C) 2002-2010 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#endregion

#if UNITTEST

using System;
using System.IO;
using System.Text;
using System.Xml;
using System.Xml.Schema;

using NUnit.Framework;

namespace Nuclex.Support {

  /// <summary>Unit Test for the XML helper class</summary>
  [TestFixture]
  public class XmlHelperTest {

    /// <summary>A broken XML schema</summary>
    private const string brokenSchemaXml =
      "This is not a valid schema";

    /// <summary>An XML schema with a syntax error</summary>
    private const string syntaxErrorSchemaXml =
      "<?xml version=\"1.0\" encoding=\"utf-8\" ?>" +
      "<xs:schema" +
      "  elementFormDefault=\"qualified\"" +
      "  xmlns:xs=\"http://www.w3.org/2001/XMLSchema\">" +
      "  <xs:attribute minOccurs=\"0\" maxOccurs=\"2\" name=\"x\" type=\"xs:double\" />" +
      "  <xs:attribute minOccurs=\"0\" maxOccurs=\"2\" name=\"y\" type=\"xs:double\" />" +
      "</xs:schema>";

    /// <summary>A valid XML schema for a list of 2D points</summary>
    private const string pointsSchemaXml =
      "<?xml version=\"1.0\" encoding=\"utf-8\" ?>" +
      "<xs:schema" +
      "  elementFormDefault=\"qualified\"" +
      "  xmlns:xs=\"http://www.w3.org/2001/XMLSchema\">" +
      "  <xs:complexType name=\"vectorType\">" +
      "    <xs:attribute name=\"x\" type=\"xs:double\" />" +
      "    <xs:attribute name=\"y\" type=\"xs:double\" />" +
      "  </xs:complexType>" +
      "  <xs:complexType name=\"pointsType\">" +
      "    <xs:sequence minOccurs=\"0\" maxOccurs=\"unbounded\">" +
      "      <xs:element name=\"point\" type=\"vectorType\" />" +
      "    </xs:sequence>" +
      "  </xs:complexType>" +
      "  <xs:element name=\"points\" type=\"pointsType\" />" +
      "</xs:schema>";

    /// <summary>A broken XML document</summary>
    private const string brokenXml =
      "This is not a valid XML file";

    /// <summary>
    ///   Well-formed XML document that is not conformant to the schema above
    /// </summary>
    private const string unconformantXml =
      "<?xml version=\"1.0\" encoding=\"utf-8\" ?>" +
      "<points" +
      "  xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"" +
      "  xsi:noNamespaceSchemaLocation=\"skin.xsd\">" +
      "  <point x=\"10\" y=\"20\" z=\"30\" />" +
      "  <point x=\"1\" y=\"2\" />" +
      "</points>";

    /// <summary>Well-formed XML document that is conformant to the schema</summary>
    private const string conformantXml =
      "<?xml version=\"1.0\" encoding=\"utf-8\" ?>" +
      "<points" +
      "  xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"" +
      "  xsi:noNamespaceSchemaLocation=\"skin.xsd\">" +
      "  <point x=\"1\" y=\"2\" />" +
      "  <point x=\"10\" y=\"20\" />" +
      "</points>";

    #region TempFileKeeper

    /// <summary>
    ///   Creates a temporary file and automatically deletes it on dispose
    /// </summary>
    private class TempFileKeeper : IDisposable {

      /// <summary>
      ///   Creates a temporary file with the specified contents using the UTF8 encoding
      /// </summary>
      /// <param name="fileContents">
      ///   Contents that will be written into the temporary file
      /// </param>
      public TempFileKeeper(string fileContents) : this(fileContents, Encoding.UTF8) { }

      /// <summary>Creates a temporary file with the specified contents</summary>
      /// <param name="fileContents">
      ///   Contents that will be written into the temporary file
      /// </param>
      /// <param name="encoding">
      ///   Encoding to use for writing the contents into the file
      /// </param>
      public TempFileKeeper(string fileContents, Encoding encoding) {
        string tempFile = Path.GetTempFileName();
        try {
          using(
            FileStream tempFileStream = new FileStream(
              tempFile, FileMode.Truncate, FileAccess.Write, FileShare.None
            )
          ) {
            StreamWriter writer = new StreamWriter(tempFileStream, encoding);
            writer.Write(fileContents);
            writer.Flush();
          }
        }
        catch(Exception) {
          File.Delete(tempFile);
          throw;
        }

        this.tempFilePath = tempFile;
      }

      /// <summary>Called when the instance is collected by the GC</summary>
      ~TempFileKeeper() {
        Dispose();
      }

      /// <summary>Immediately releases all resources used by the instance</summary>
      public void Dispose() {
        if(this.tempFilePath != null) {
          File.Delete(this.tempFilePath);
          this.tempFilePath = null;

          GC.SuppressFinalize(this);
        }
      }

      /// <summary>Implicitely converts a TempFileKeeper into a file path</summary>
      /// <param name="tempFileKeeper">TempFileKeeper that will be converted</param>
      /// <returns>The path to the temporary file managed by the TempFileKeeper</returns>
      public static implicit operator string(TempFileKeeper tempFileKeeper) {
        return tempFileKeeper.tempFilePath;
      }

      /// <summary>Path to the temporary file the TempFileKeeper is managing</summary>
      private string tempFilePath;

    }

    #endregion // class TempFileKeeper

    /// <summary>
    ///   Verifies that an exception is thrown when a schema fails to load
    /// </summary>
    [Test]
    public void TestThrowOnInvalidSchema() {
      using(
        TempFileKeeper tempFile = new TempFileKeeper(brokenSchemaXml)
      ) {
        Assert.Throws<XmlException>(delegate() { XmlHelper.LoadSchema(tempFile); });
      }
    }

    /// <summary>
    ///   Verifies that an exception is thrown when a schema contains a syntax error
    /// </summary>
    [Test]
    public void TestThrowOnSyntaxErrorSchema() {
      using(
        TempFileKeeper tempFile = new TempFileKeeper(syntaxErrorSchemaXml)
      ) {
        Assert.Throws<XmlSchemaException>(delegate() { XmlHelper.LoadSchema(tempFile); });
      }
    }

    /// <summary>
    ///   Verfifies that TryLoadSchema() can fail without throwing an exception
    ///   when the schema is not a valid XML document
    /// </summary>
    [Test]
    public void TestFailOnTryLoadNonExistingFile() {
      XmlSchema schema;
      Assert.IsFalse(XmlHelper.TryLoadSchema("-- hello world --", out schema));
      Assert.IsNull(schema);
    }

    /// <summary>
    ///   Verfifies that TryLoadSchema() can fail without throwing an exception
    ///   when the schema is not a valid XML document
    /// </summary>
    [Test]
    public void TestFailOnTryLoadBrokenSchema() {
      using(
        TempFileKeeper tempFile = new TempFileKeeper(brokenSchemaXml)
      ) {
        XmlSchema schema;
        Assert.IsFalse(XmlHelper.TryLoadSchema(tempFile, out schema));
        Assert.IsNull(schema);
      }
    }

    /// <summary>
    ///   Verfifies that TryLoadSchema() can fail without throwing an exception
    ///   when the schema contains a syntax error
    /// </summary>
    [Test]
    public void TestFailOnTryLoadSyntaxErrorSchema() {
      using(
        TempFileKeeper tempFile = new TempFileKeeper(syntaxErrorSchemaXml)
      ) {
        XmlSchema schema;
        Assert.IsFalse(XmlHelper.TryLoadSchema(tempFile, out schema));
        Assert.IsNull(schema);
      }
    }

    /// <summary>Tests whether a normal, valid schema can be loaded successfully</summary>
    [Test]
    public void TestLoadSchema() {
      using(
        TempFileKeeper tempFile = new TempFileKeeper(pointsSchemaXml)
      ) {
        XmlHelper.LoadSchema(tempFile);
      }
    }

    /// <summary>Tests whether a normal, valid schema can be loaded successfully</summary>
    [Test]
    public void TestTryLoadSchema() {
      using(
        TempFileKeeper tempFile = new TempFileKeeper(pointsSchemaXml)
      ) {
        XmlSchema schema;
        Assert.IsTrue(XmlHelper.TryLoadSchema(tempFile, out schema));
        Assert.NotNull(schema);
      }
    }

    /// <summary>
    ///   Verifies that an exception is thrown when an invalid XML document is loaded
    /// </summary>
    [Test]
    public void TestFailOnLoadInvalidDocument() {
      using(TextReader schemaReader = new StringReader(pointsSchemaXml)) {
        XmlSchema schema = XmlHelper.LoadSchema(schemaReader);
        using(
          TempFileKeeper tempFile = new TempFileKeeper(brokenXml)
        ) {
          Assert.Throws<XmlException>(
            delegate() { XmlHelper.LoadDocument(schema, tempFile); }
          );
        }
      }
    }

    /// <summary>
    ///   Verifies that an exception is thrown when a nonconformant XML document is loaded
    /// </summary>
    [Test]
    public void TestFailOnLoadNonConformingDocument() {
      using(TextReader schemaReader = new StringReader(pointsSchemaXml)) {
        XmlSchema schema = XmlHelper.LoadSchema(schemaReader);
        using(
          TempFileKeeper tempFile = new TempFileKeeper(unconformantXml)
        ) {
          Assert.Throws<XmlSchemaValidationException>(
            delegate() { XmlHelper.LoadDocument(schema, tempFile); }
          );
        }
      }
    }

    /// <summary>
    ///   Tests whether a normal, conformant XML document can be loaded successfully
    /// </summary>
    [Test]
    public void TestLoadConformingDocument() {
      using(TextReader schemaReader = new StringReader(pointsSchemaXml)) {
        XmlSchema schema = XmlHelper.LoadSchema(schemaReader);
        using(
          TempFileKeeper tempFile = new TempFileKeeper(conformantXml)
        ) {
          XmlDocument document = XmlHelper.LoadDocument(schema, tempFile);
        }
      }
    }

  }

} // namespace Nuclex.Support

#endif // UNITTEST