#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;
using System.Diagnostics.CodeAnalysis;

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>
[SuppressMessage("Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses", Justification = "Reflection")]
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 <see langword="true"/> if the <paramref name="targetType"/> is
  /// assignable from a <see cref="string"/> type.
  /// </para>
  /// </remarks>
  public bool CanConvertTo(Type targetType) => 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="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>
  /// <see langword="true"/> if the <paramref name="sourceType"/> is
  /// the <see cref="string"/> type.
  /// </returns>
  public bool CanConvertFrom(Type sourceType) => 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);
  }
}
