#region Copyright notice and license

// 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.

#endregion

using System;
using System.Collections.Generic;
using System.IO;
using System.Text.RegularExpressions;
using Google.ProtocolBuffers.DescriptorProtos;
using Google.ProtocolBuffers.Descriptors;

namespace Google.ProtocolBuffers.ProtoGen {
  /// <summary>
  /// All the configuration required for the generator - where to generate
  /// output files, the location of input files etc. While this isn't immutable
  /// in practice, the contents shouldn't be changed after being passed to
  /// the generator.
  /// </summary>
  public sealed class GeneratorOptions {
    public IList<string> InputFiles { get; set; }

    /// <summary>
    /// Attempts to validate the options, but doesn't throw an exception if they're invalid.
    /// Instead, when this method returns false, the output variable will contain a collection
    /// of reasons for the validation failure.
    /// </summary>
    /// <param name="reasons">Variable to receive a list of reasons in case of validation failure.</param>
    /// <returns>true if the options are valid; false otherwise</returns>
    public bool TryValidate(out IList<string> reasons) {
      List<string> tmpReasons = new List<string>();

      ParseArguments(tmpReasons);

      // Output directory validation
      if (string.IsNullOrEmpty(FileOptions.OutputDirectory)) {
        tmpReasons.Add("No output directory specified");
      }
      else {
        if (!Directory.Exists(FileOptions.OutputDirectory)) {
          tmpReasons.Add("Specified output directory (" + FileOptions.OutputDirectory + " doesn't exist.");
        }
      }

      // Input file validation (just in terms of presence)
      if (InputFiles == null || InputFiles.Count == 0) {
        tmpReasons.Add("No input files specified");
      }
      else {
        foreach (string input in InputFiles) {
          FileInfo fi = new FileInfo(input);
          if (!fi.Exists) {
            tmpReasons.Add("Input file " + input + " doesn't exist.");
          }
        }
      }

      if (tmpReasons.Count != 0) {
        reasons = tmpReasons;
        return false;
      }

      reasons = null;
      return true;
    }

    /// <summary>
    /// Validates that all the options have been set and are valid,
    /// throwing an exception if they haven't.
    /// </summary>
    /// <exception cref="InvalidOptionsException">The options are invalid.</exception>
    public void Validate() {
      IList<string> reasons;
      if (!TryValidate(out reasons)) {
        throw new InvalidOptionsException(reasons);
      }
    }

    // Raw arguments, used to provide defaults for proto file options
    public IList<string> Arguments { get; set; }

    [Obsolete("Please use GeneratorOptions.FileOptions.OutputDirectory instead")]
    public string OutputDirectory {
      get { return FileOptions.OutputDirectory; }
      set {
        CSharpFileOptions.Builder bld = FileOptions.ToBuilder();
        bld.OutputDirectory = value;
        FileOptions = bld.Build();
      }
    }

    private static readonly Regex ArgMatch = new Regex(@"^[-/](?<name>[\w_]+?)[:=](?<value>.*)$");
    private CSharpFileOptions fileOptions;

    public CSharpFileOptions FileOptions {
      get { return fileOptions ?? (fileOptions = CSharpFileOptions.DefaultInstance); }
      set { fileOptions = value; }
    }

    private void ParseArguments(IList<string> tmpReasons) {
      bool doHelp = Arguments.Count == 0;

      InputFiles = new List<string>();
      CSharpFileOptions.Builder builder = FileOptions.ToBuilder();
      Dictionary<string, FieldDescriptor> fields =
        new Dictionary<string, FieldDescriptor>(StringComparer.OrdinalIgnoreCase);
      foreach (FieldDescriptor fld in builder.DescriptorForType.Fields) {
        fields.Add(fld.Name, fld);
      }

      foreach (string argument in Arguments) {
        if (StringComparer.OrdinalIgnoreCase.Equals("-help", argument) ||
            StringComparer.OrdinalIgnoreCase.Equals("/help", argument) ||
            StringComparer.OrdinalIgnoreCase.Equals("-?", argument) ||
            StringComparer.OrdinalIgnoreCase.Equals("/?", argument)) {
          doHelp = true;
          break;
        }

        Match m = ArgMatch.Match(argument);
        if (m.Success) {
          FieldDescriptor fld;
          string name = m.Groups["name"].Value;
          string value = m.Groups["value"].Value;

          if (fields.TryGetValue(name, out fld)) {
            object obj;
            if (TryCoerceType(value, fld, out obj, tmpReasons)) {
              builder[fld] = obj;
            }
          }
          else if (!File.Exists(argument)) {
            doHelp = true;
            tmpReasons.Add("Unknown argument '" + name + "'.");
          }
          else {
            InputFiles.Add(argument);
          }
        }
        else {
          InputFiles.Add(argument);
        }
      }

      if (doHelp || InputFiles.Count == 0) {
        tmpReasons.Add("Arguments:");
        foreach (KeyValuePair<string, FieldDescriptor> field in fields) {
          tmpReasons.Add(String.Format("-{0}=[{1}]", field.Key, field.Value.FieldType));
        }
        tmpReasons.Add("followed by one or more file paths.");
      }
      else {
        FileOptions = builder.Build();
      }
    }

    private static bool TryCoerceType(string text, FieldDescriptor field, out object value, IList<string> tmpReasons) {
      value = null;

      switch (field.FieldType) {
        case FieldType.Int32:
        case FieldType.SInt32:
        case FieldType.SFixed32:
          value = Int32.Parse(text);
          break;

        case FieldType.Int64:
        case FieldType.SInt64:
        case FieldType.SFixed64:
          value = Int64.Parse(text);
          break;

        case FieldType.UInt32:
        case FieldType.Fixed32:
          value = UInt32.Parse(text);
          break;

        case FieldType.UInt64:
        case FieldType.Fixed64:
          value = UInt64.Parse(text);
          break;

        case FieldType.Float:
          value = float.Parse(text);
          break;

        case FieldType.Double:
          value = Double.Parse(text);
          break;

        case FieldType.Bool:
          value = Boolean.Parse(text);
          break;

        case FieldType.String:
          value = text;
          break;

        case FieldType.Enum: {
          EnumDescriptor enumType = field.EnumType;

          int number;
          if (int.TryParse(text, out number)) {
            value = enumType.FindValueByNumber(number);
            if (value == null) {
              tmpReasons.Add(
                "Enum type \"" + enumType.FullName +
                "\" has no value with number " + number + ".");
              return false;
            }
          }
          else {
            value = enumType.FindValueByName(text);
            if (value == null) {
              tmpReasons.Add(
                "Enum type \"" + enumType.FullName +
                "\" has no value named \"" + text + "\".");
              return false;
            }
          }

          break;
        }

        case FieldType.Bytes:
        case FieldType.Message:
        case FieldType.Group:
          tmpReasons.Add("Unhandled field type " + field.FieldType.ToString() + ".");
          return false;
      }

      return true;
    }
  }
}