// 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.Collections.Generic;
using System.IO;

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 string OutputDirectory { get; set; }
    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>();

      // Output directory validation
      if (string.IsNullOrEmpty(OutputDirectory)) {
        tmpReasons.Add("No output directory specified");
      } else {
        if (!Directory.Exists(OutputDirectory)) {
          tmpReasons.Add("Specified output directory (" + 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);
      }
    }
  }
}