//******************************************************************************************************
//  AppSettingsBase.cs - Gbtc
//
//  Copyright © 2012, Grid Protection Alliance.  All Rights Reserved.
//
//  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See
//  the NOTICE file distributed with this work for additional information regarding copyright ownership.
//  The GPA licenses this file to you under the MIT License (MIT), 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.opensource.org/licenses/MIT
//
//  Unless agreed to in writing, the subject software distributed under the License is distributed on an
//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the
//  License for the specific language governing permissions and limitations.
//
//  Code Modification History:
//  ----------------------------------------------------------------------------------------------------
//  01/30/2009 - J. Ritchie Carroll
//       Generated original version of source code.
//  03/31/2009 - J. Ritchie Carroll
//       Made initialize during constructor optional for languages that do not initialize
//       member variables before call to constructor (e.g., Visual Basic.NET).
//  09/14/2009 - Stephen C. Wills
//       Added new header and license agreement.
//  12/14/2012 - Starlynn Danyelle Gilliam
//       Modified Header.
//
//******************************************************************************************************

using System;
using System.ComponentModel;
using System.Configuration;

namespace GSF.Configuration
{
    /// <summary>
    /// Represents the base class for application settings that are synchronized with the "appSettings" section in a configuration file.
    /// </summary>
    /// <remarks>
    /// <para>
    /// In order to make custom types serializable for the configuration file, implement a <see cref="System.ComponentModel.TypeConverter"/> for the type.<br/>
    /// See <a href="http://msdn.microsoft.com/en-us/library/ayybcxe5.aspx">MSDN</a> for details.
    /// </para>
    /// <example>
    /// Here is an example class derived from <see cref="AppSettingsBase"/> that automatically
    /// serializes its fields and properties to the configuration file.
    /// <code>
    ///    public enum MyEnum
    ///     {
    ///         One,
    ///         Two,
    ///         Three
    ///     }
    /// 
    ///     public class MySettings : AppSettingsBase
    ///     {
    ///         // Private property fields (private fields will not be serialized)
    ///         private double m_doubleVal;
    /// 
    ///         // Public settings fields
    ///         public bool BoolVal = true;
    ///         public int IntVal = 1;
    ///         public float FloatVal = 3.14F;
    ///         public string StrVal = "This is a test...";
    ///         public MyEnum EnumVal = MyEnum.Three;
    ///         
    ///         [SettingName("UserOptions"), EncryptSetting()]
    ///         public string Password = "default";
    /// 
    ///         // Mark this field to not be serialized to INI file...
    ///         [SerializeSetting(false)]
    ///         public decimal DecimalVal;
    /// 
    ///         [Category("OtherSettings"), DefaultValue(1.159D)]
    ///         public double DoubleVal
    ///         {
    ///             get
    ///             {
    ///                 return m_doubleVal;
    ///             }
    ///             set
    ///             {
    ///                 m_doubleVal = value;
    ///             }
    ///         }
    /// 
    ///         [SerializeSetting(false)]
    ///         public bool DontSerializeMe { get; set; }
    ///     }
    /// </code>
    /// </example>
    /// </remarks>
    public abstract class AppSettingsBase : SettingsBase
    {
        #region [ Members ]

        // Fields
        private ConfigurationFile m_configFile;

        #endregion

        #region [ Constructors ]

        /// <summary>
        /// Creates a new instance of the <see cref="AppSettingsBase"/> class for the application's configuration file.
        /// </summary>
        protected AppSettingsBase()
            : this(ConfigurationFile.Current, false, true)
        {
        }

        /// <summary>
        /// Creates a new instance of the <see cref="AppSettingsBase"/> class for the application's configuration file.
        /// </summary>
        /// <param name="configFile">Configuration file used for accessing settings.</param>
        /// <param name="requireSerializeSettingAttribute">
        /// Assigns flag that determines if <see cref="SerializeSettingAttribute"/> is required
        /// to exist before a field or property is serialized to the configuration file.
        /// </param>
        /// <param name="initialize">Determines if <see cref="SettingsBase.Initialize"/> method should be called from constructor.</param>
        /// <remarks>
        /// Note that some .NET languages (e.g., Visual Basic) will not initialize member elements before call to constuctor,
        /// in this case <paramref name="initialize"/> should be set to <c>false</c>, then the <see cref="SettingsBase.Initialize"/>
        /// method should be called manually after all properties have been initialized. Alternately, consider using the
        /// <see cref="DefaultValueAttribute"/> on the fields or properties and this will be used to initialize the values.
        /// </remarks>
        protected AppSettingsBase(ConfigurationFile configFile, bool requireSerializeSettingAttribute, bool initialize)
            : base(requireSerializeSettingAttribute)
        {
            m_configFile = configFile;

            // Make sure settings exist and load current values
            if (initialize)
                Initialize();
        }

        #endregion

        #region [ Properties ]

        /// <summary>
        /// Gets or sets reference to working configuration file.
        /// </summary>
        /// <exception cref="NullReferenceException">value cannot be null.</exception>
        protected ConfigurationFile ConfigFile
        {
            get
            {
                return m_configFile;
            }
            set
            {
                if ((object)value == null)
                    throw new NullReferenceException("value cannot be null");

                m_configFile = value;
            }
        }

        #endregion

        #region [ Methods ]

        /// <summary>
        /// Create setting in configuration file if it doesn't already exist.
        /// This method is for internal use.
        /// </summary>
        /// <param name="name">Field or property name, if useful (can be different from setting name).</param>
        /// <param name="setting">Setting name.</param>
        /// <param name="value">Setting value.</param>
        [EditorBrowsable(EditorBrowsableState.Never)]
        protected override void CreateSetting(string name, string setting, string value)
        {
            KeyValueConfigurationCollection settings = m_configFile.Configuration.AppSettings.Settings;

            if ((object)settings[setting] == null)
                settings.Add(setting, value);
        }

        /// <summary>
        /// Retrieves setting from configuration file.
        /// This method is for internal use.
        /// </summary>
        /// <param name="name">Field or property name, if useful (can be different from setting name).</param>
        /// <param name="setting">Setting name.</param>
        /// <returns>Setting value.</returns>
        [EditorBrowsable(EditorBrowsableState.Never)]
        protected override string RetrieveSetting(string name, string setting)
        {
            return m_configFile.Configuration.AppSettings.Settings[setting].Value;
        }

        /// <summary>
        /// Stores setting to configuration file.
        /// This method is for internal use.
        /// </summary>
        /// <param name="name">Field or property name, if useful (can be different from setting name).</param>
        /// <param name="setting">Setting name.</param>
        /// <param name="value">Setting value.</param>
        [EditorBrowsable(EditorBrowsableState.Never)]
        protected override void StoreSetting(string name, string setting, string value)
        {
            m_configFile.Configuration.AppSettings.Settings[setting].Value = value;
        }

        /// <summary>
        /// Persist any pending changes to configuration file.
        /// This method is for internal use.
        /// </summary>
        [EditorBrowsable(EditorBrowsableState.Never)]
        protected override void PersistSettings()
        {
            m_configFile.Save();
        }

        #endregion
    }
}