#region Apache License
//
// Licensed to the Apache Software Foundation (ASF) under one or more 
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership. 
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with 
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion

using System;

namespace log4net.Util.TypeConverters
{
  /// <summary>
  /// Convert between string and <see cref="PatternString"/>
  /// </summary>
  /// <remarks>
  /// <para>
  /// Supports conversion from string to <see cref="PatternString"/> type, 
  /// and from a <see cref="PatternString"/> type to a string.
  /// </para>
  /// <para>
  /// The string is used as the <see cref="PatternString.ConversionPattern"/> 
  /// of the <see cref="PatternString"/>.
  /// </para>
  /// </remarks>
  /// <seealso cref="ConverterRegistry"/>
  /// <seealso cref="IConvertFrom"/>
  /// <seealso cref="IConvertTo"/>
  /// <author>Nicko Cadell</author>
  internal sealed class PatternStringConverter : IConvertTo, IConvertFrom
  {
    /// <summary>
    /// Can the target type be converted to the type supported by this object
    /// </summary>
    /// <param name="targetType">A <see cref="Type"/> that represents the type you want to convert to</param>
    /// <returns>true if the conversion is possible</returns>
    /// <remarks>
    /// <para>
    /// Returns <c>true</c> if the <paramref name="targetType"/> is
    /// assignable from a <see cref="String"/> type.
    /// </para>
    /// </remarks>
    public bool CanConvertTo(Type targetType)
    {
      return (typeof(string).IsAssignableFrom(targetType));
    }

    /// <summary>
    /// Converts the given value object to the specified type, using the arguments
    /// </summary>
    /// <param name="source">the object to convert</param>
    /// <param name="targetType">The Type to convert the value parameter to</param>
    /// <returns>the converted object</returns>
    /// <remarks>
    /// <para>
    /// Uses the <see cref="M:PatternString.Format()"/> method to convert the
    /// <see cref="PatternString"/> argument to a <see cref="String"/>.
    /// </para>
    /// </remarks>
    /// <exception cref="ConversionNotSupportedException">
    /// The <paramref name="source"/> object cannot be converted to the
    /// <paramref name="targetType"/>. To check for this condition use the 
    /// <see cref="CanConvertTo"/> method.
    /// </exception>
    public object ConvertTo(object source, Type targetType)
    {
      if (source is PatternString patternString && CanConvertTo(targetType))
      {
        return patternString.Format();
      }
      throw ConversionNotSupportedException.Create(targetType, source);
    }

    /// <summary>
    /// Can the source type be converted to the type supported by this object
    /// </summary>
    /// <param name="sourceType">the type to convert</param>
    /// <returns>
    /// <c>True</c> if the <paramref name="sourceType"/> is
    /// the <see cref="string"/> type.
    /// </returns>
    public bool CanConvertFrom(System.Type sourceType)
    {
      return (sourceType == typeof(string));
    }

    /// <summary>
    /// Overrides the ConvertFrom method of IConvertFrom.
    /// </summary>
    /// <param name="source">the object to convert to a PatternString</param>
    /// <returns>the PatternString</returns>
    /// <remarks>
    /// <para>
    /// Creates and returns a new <see cref="PatternString"/> using
    /// the <paramref name="source"/> <see cref="String"/> as the
    /// <see cref="PatternString.ConversionPattern"/>.
    /// </para>
    /// </remarks>
    /// <exception cref="ConversionNotSupportedException">
    /// The <paramref name="source"/> object cannot be converted to the
    /// target type. To check for this condition use the <see cref="CanConvertFrom"/>
    /// method.
    /// </exception>
    public object ConvertFrom(object source)
    {
      if (source is string str)
      {
        return new PatternString(str);
      }
      throw ConversionNotSupportedException.Create(typeof(PatternString), source);
    }
  }
}
