// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// http://github.com/jskeet/dotnet-protobufs/
// Original C++/Java/Python code:
// http://code.google.com/p/protobuf/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
using System;
using System.Collections;
using System.Collections.Generic;
using Google.ProtocolBuffers.Descriptors;

namespace Google.ProtocolBuffers.ProtoGen {
  /// <summary>
  /// Generator for the class describing the .proto file in general,
  /// containing things like the message descriptor.
  /// </summary>
  internal sealed class UmbrellaClassGenerator : SourceGeneratorBase<FileDescriptor>, ISourceGenerator {

    internal UmbrellaClassGenerator(FileDescriptor descriptor)
      : base(descriptor) {
    }

    // Recursively searches the given message to see if it contains any extensions.
    private static bool UsesExtensions(IMessage message) {
      // We conservatively assume that unknown fields are extensions.
      if (message.UnknownFields.FieldDictionary.Count > 0) {
        return true;
      }

      foreach (KeyValuePair<FieldDescriptor, object> keyValue in message.AllFields) {
        FieldDescriptor field = keyValue.Key;
        if (field.IsExtension) {
          return true;
        }
        if (field.MappedType == MappedType.Message) {
          if (field.IsRepeated) {
            foreach (IMessage subMessage in (IEnumerable)keyValue.Value) {
              if (UsesExtensions(subMessage)) {
                return true;
              }
            }
          } else {
            if (UsesExtensions((IMessage)keyValue.Value)) {
              return true;
            }
          }
        }
      }
      return false;
    }

    public string UmbrellaClassName {
      get { throw new NotImplementedException(); }
    }

    public void Generate(TextGenerator writer) {
      WriteIntroduction(writer);
      WriteExtensionRegistration(writer);
      WriteChildren(writer, "Extensions", Descriptor.Extensions);
      writer.WriteLine("#region Static variables");
      foreach (MessageDescriptor message in Descriptor.MessageTypes) {
        new MessageGenerator(message).GenerateStaticVariables(writer);
      }
      writer.WriteLine("#endregion");
      WriteDescriptor(writer);
      // The class declaration either gets closed before or after the children are written.
      if (!Descriptor.CSharpOptions.NestClasses) {
        writer.Outdent();
        writer.WriteLine("}");
      }
      WriteChildren(writer, "Enums", Descriptor.EnumTypes);
      WriteChildren(writer, "Messages", Descriptor.MessageTypes);
      WriteChildren(writer, "Services", Descriptor.Services);
      if (Descriptor.CSharpOptions.NestClasses) {
        writer.Outdent();
        writer.WriteLine("}");
      }
      if (Descriptor.CSharpOptions.Namespace != "") {
        writer.Outdent();
        writer.WriteLine("}");
      }
    }

    private void WriteIntroduction(TextGenerator writer) {
      writer.WriteLine("// Generated by the protocol buffer compiler.  DO NOT EDIT!");
      writer.WriteLine();
      Helpers.WriteNamespaces(writer);

      if (Descriptor.CSharpOptions.Namespace != "") {
        writer.WriteLine("namespace {0} {{", Descriptor.CSharpOptions.Namespace);
        writer.Indent();
        writer.WriteLine();
      }    
      if (Descriptor.CSharpOptions.CodeContracts) {
          writer.WriteLine("[global::System.Diagnostics.Contracts.ContractVerificationAttribute(false)]");
      }
      writer.WriteLine("{0} static partial class {1} {{", ClassAccessLevel, Descriptor.CSharpOptions.UmbrellaClassname);
      writer.WriteLine();
      writer.Indent();
    }

    private void WriteExtensionRegistration(TextGenerator writer) {
      writer.WriteLine("#region Extension registration");
      writer.WriteLine("public static void RegisterAllExtensions(pb::ExtensionRegistry registry) {");
      writer.Indent();
      foreach (FieldDescriptor extension in Descriptor.Extensions) {
        new ExtensionGenerator(extension).GenerateExtensionRegistrationCode(writer);
      }
      foreach (MessageDescriptor message in Descriptor.MessageTypes) {
        new MessageGenerator(message).GenerateExtensionRegistrationCode(writer);
      }
      writer.Outdent();
      writer.WriteLine("}");
      writer.WriteLine("#endregion");
    }

    private void WriteDescriptor(TextGenerator writer) {
      writer.WriteLine("#region Descriptor");

      writer.WriteLine("public static pbd::FileDescriptor Descriptor {");
      writer.WriteLine("  get { return descriptor; }");
      writer.WriteLine("}");
      writer.WriteLine("private static pbd::FileDescriptor descriptor;");
      writer.WriteLine();
      writer.WriteLine("static {0}() {{", Descriptor.CSharpOptions.UmbrellaClassname);
      writer.Indent();
      writer.WriteLine("byte[] descriptorData = global::System.Convert.FromBase64String(");
      writer.Indent();
      writer.Indent();

      // TODO(jonskeet): Consider a C#-escaping format here instead of just Base64.
      byte[] bytes = Descriptor.Proto.ToByteArray();
      string base64 = Convert.ToBase64String(bytes);

      while (base64.Length > 60) {
        writer.WriteLine("\"{0}\" + ", base64.Substring(0, 60));
        base64 = base64.Substring(60);
      }
      writer.WriteLine("\"{0}\");", base64);
      writer.Outdent();
      writer.Outdent();
      writer.WriteLine("pbd::FileDescriptor.InternalDescriptorAssigner assigner = delegate(pbd::FileDescriptor root) {");
      writer.Indent();
      writer.WriteLine("descriptor = root;");
      foreach (MessageDescriptor message in Descriptor.MessageTypes) {
        new MessageGenerator(message).GenerateStaticVariableInitializers(writer);
      }
      foreach (FieldDescriptor extension in Descriptor.Extensions) {
        new ExtensionGenerator(extension).GenerateStaticVariableInitializers(writer);
      }

      if (UsesExtensions(Descriptor.Proto)) {
        // Must construct an ExtensionRegistry containing all possible extensions
        // and return it.
        writer.WriteLine("pb::ExtensionRegistry registry = pb::ExtensionRegistry.CreateInstance();");
        writer.WriteLine("RegisterAllExtensions(registry);");
        foreach (FileDescriptor dependency in Descriptor.Dependencies) {
          writer.WriteLine("{0}.RegisterAllExtensions(registry);", DescriptorUtil.GetFullUmbrellaClassName(dependency));
        }
        writer.WriteLine("return registry;");
      } else {
        writer.WriteLine("return null;");
      }
      writer.Outdent();
      writer.WriteLine("};");

      // -----------------------------------------------------------------
      // Invoke internalBuildGeneratedFileFrom() to build the file.
      writer.WriteLine("pbd::FileDescriptor.InternalBuildGeneratedFileFrom(descriptorData,");
      writer.WriteLine("    new pbd::FileDescriptor[] {");
      foreach (FileDescriptor dependency in Descriptor.Dependencies) {
        writer.WriteLine("    {0}.Descriptor, ", DescriptorUtil.GetFullUmbrellaClassName(dependency));
      }
      writer.WriteLine("    }, assigner);");
      writer.Outdent();
      writer.WriteLine("}");
      writer.WriteLine("#endregion");
      writer.WriteLine();
    }
  }
}