//******************************************************************************************************
//  ChannelDefinitionBase.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:
//  ----------------------------------------------------------------------------------------------------
//  03/07/2005 - J. Ritchie Carroll
//       Generated original version of source code.
//  09/15/2009 - Stephen C. Wills
//       Added new header and license agreement.
//  10/5/2012 - Gavin E. Holden
//       Added new header and license agreement.
//  12/17/2012 - Starlynn Danyelle Gilliam
//       Modified Header.
//
//******************************************************************************************************

using System;
using System.Collections.Generic;
using System.Runtime.Serialization;
using System.Text;

// ReSharper disable VirtualMemberCallInConstructor
namespace GSF.PhasorProtocols
{
    /// <summary>
    /// Represents the common implementation of the protocol independent definition of any kind of <see cref="IChannel"/> data.
    /// </summary>
    [Serializable]
    public abstract class ChannelDefinitionBase : ChannelBase, IChannelDefinition
    {
        #region [ Members ]

        // Fields
        private IConfigurationCell m_parent;
        private int m_index;
        private string m_label;
        private uint m_scale;
        private double m_offset;

        #endregion

        #region [ Constructors ]

        /// <summary>
        /// Creates a new <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        /// <param name="parent">The <see cref="IConfigurationCell"/> parent of this <see cref="ChannelDefinitionBase"/>.</param>
        protected ChannelDefinitionBase(IConfigurationCell parent)
        {
            m_parent = parent;
        }

        /// <summary>
        /// Creates a new <see cref="ChannelDefinitionBase"/> from specified parameters.
        /// </summary>
        /// <param name="parent">The <see cref="IConfigurationCell"/> parent of this <see cref="ChannelDefinitionBase"/>.</param>
        /// <param name="label">The label of this <see cref="ChannelDefinitionBase"/>.</param>
        /// <param name="scale">The integer scaling value of this <see cref="ChannelDefinitionBase"/>.</param>
        /// <param name="offset">The offset of this <see cref="ChannelDefinitionBase"/>.</param>
        protected ChannelDefinitionBase(IConfigurationCell parent, string label, uint scale, double offset)
        {
            m_parent = parent;
            Label = label;
            m_scale = scale;
            m_offset = offset;
        }

        /// <summary>
        /// Creates a new <see cref="ChannelDefinitionBase"/> from serialization parameters.
        /// </summary>
        /// <param name="info">The <see cref="SerializationInfo"/> with populated with data.</param>
        /// <param name="context">The source <see cref="StreamingContext"/> for this deserialization.</param>
        protected ChannelDefinitionBase(SerializationInfo info, StreamingContext context)
        {
            // Deserialize channel definition
            m_parent = (IConfigurationCell)info.GetValue("parent", typeof(IConfigurationCell));
            m_index = info.GetInt32("index");
            Label = info.GetString("label");
            m_scale = info.GetUInt32("scale");
            m_offset = info.GetDouble("offset");
        }

        #endregion

        #region [ Properties ]

        /// <summary>
        /// Gets or sets the <see cref="IConfigurationCell"/> parent of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        public virtual IConfigurationCell Parent
        {
            get => m_parent;
            set => m_parent = value;
        }

        /// <summary>
        /// Gets the <see cref="PhasorProtocols.DataFormat"/> of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        public abstract DataFormat DataFormat { get; }

        /// <summary>
        /// Gets or sets the index of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        /// <remarks>
        /// Index is automatically maintained by <see cref="ChannelDefinitionCollectionBase{T}"/>.
        /// </remarks>
        public virtual int Index
        {
            get => m_index;
            set => m_index = value;
        }

        /// <summary>
        /// Gets or sets the offset of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        public virtual double Offset
        {
            get => m_offset;
            set => m_offset = value;
        }

        /// <summary>
        /// Gets or sets the conversion factor of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        public virtual double ConversionFactor
        {
            get => ScalingValue * ScalePerBit;
            set
            {
                unchecked
                {
                    ScalingValue = (uint)(value / ScalePerBit);
                }
            }
        }

        /// <summary>
        /// Gets the scale/bit for the <see cref="ScalingValue"/> of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        /// <remarks>
        /// The base implementation assumes scale/bit of 10^-5.
        /// </remarks>
        public virtual double ScalePerBit => 0.00001D; // Typical scale/bit is 10^-5

        /// <summary>
        /// Gets or sets the integer scaling value of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        public virtual uint ScalingValue
        {
            get => m_scale;
            set
            {
                if (value > MaximumScalingValue)
                    throw new OverflowException($"Scaling value cannot exceed {MaximumScalingValue}");

                m_scale = value;
            }
        }

        /// <summary>
        /// Gets the maximum value for the <see cref="ScalingValue"/> of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        /// <remarks>
        /// The base implementation accommodates maximum scaling factor of 24-bits of space.
        /// </remarks>
        public virtual uint MaximumScalingValue => UInt24.MaxValue; // Typical scaling/conversion factors should fit within 3 bytes (i.e., 24 bits) of space

        /// <summary>
        /// Gets or sets the label of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        public virtual string Label
        {
            get => m_label;
            set
            {
                if (string.IsNullOrEmpty(value))
                    value = "undefined";

                value = value.GetValidLabel();

                if (value.Length > MaximumLabelLength)
                    throw new OverflowException($"Label length cannot exceed {MaximumLabelLength} characters.");

                m_label = value;
            }
        }

        /// <summary>
        /// Gets the binary image of the <see cref="Label"/> of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        public virtual byte[] LabelImage => 
            Encoding.ASCII.GetBytes(MaximumLabelLength < int.MaxValue && AutoPadLabelImage ? Label.PadRight(MaximumLabelLength): Label);

        /// <summary>
        /// Gets the maximum length of the <see cref="Label"/> of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        public virtual int MaximumLabelLength => 16; // Typical label length is 16 bytes

        /// <summary>
        /// Gets flag that indicates if <see cref="LabelImage"/> should auto pad-right value to <see cref="MaximumLabelLength"/>.
        /// </summary>
        /// <remarks>
        /// Padding will only be applied when <see cref="MaximumLabelLength"/> is less than <see cref="int.MaxValue"/>.
        /// </remarks>
        public virtual bool AutoPadLabelImage => true;

        /// <summary>
        /// Gets the length of the <see cref="BodyImage"/>.
        /// </summary>
        protected override int BodyLength => AutoPadLabelImage ? MaximumLabelLength : LabelImage.Length;

        /// <summary>
        /// Gets the binary body image of the <see cref="ChannelDefinitionBase"/> object.
        /// </summary>
        protected override byte[] BodyImage => LabelImage;

        /// <summary>
        /// Gets a <see cref="Dictionary{TKey,TValue}"/> of string based property names and values for this <see cref="ChannelDefinitionBase"/> object.
        /// </summary>
        public override Dictionary<string, string> Attributes
        {
            get
            {
                Dictionary<string, string> baseAttributes = base.Attributes;

                baseAttributes.Add("Label", Label.ToNonNullString("Undefined"));
                baseAttributes.Add("Index", Index.ToString());
                baseAttributes.Add("Offset", Offset.ToString());
                baseAttributes.Add("Data Format", $"{(int)DataFormat}: {DataFormat}");
                baseAttributes.Add("Conversion Factor", ConversionFactor.ToString());
                baseAttributes.Add("Scaling Value", ScalingValue.ToString());
                baseAttributes.Add("Scale per Bit", ScalePerBit.ToString());
                baseAttributes.Add("Maximum Scaling Value", MaximumScalingValue.ToString());
                baseAttributes.Add("Maximum Label Length", MaximumLabelLength.ToString());

                return baseAttributes;
            }
        }

        #endregion

        #region [ Methods ]

        /// <summary>
        /// Parses the binary body image.
        /// </summary>
        /// <param name="buffer">Binary image to parse.</param>
        /// <param name="startIndex">Start index into <paramref name="buffer"/> to begin parsing.</param>
        /// <param name="length">Length of valid data within <paramref name="buffer"/>.</param>
        /// <returns>The length of the data that was parsed.</returns>
        /// <remarks>
        /// The base implementation assumes that all channel definitions begin with a label as this is
        /// the general case, override functionality if this is not the case.
        /// </remarks>
        protected override int ParseBodyImage(byte[] buffer, int startIndex, int length)
        {
            // Length is validated at a frame level well in advance so that low level parsing routines do not have
            // to re-validate that enough length is available to parse needed information as an optimization...

            Label = Encoding.ASCII.GetString(buffer, startIndex, MaximumLabelLength);

            return MaximumLabelLength;
        }

        /// <summary>
        /// Returns a value indicating whether this instance is equal to a specified object.
        /// </summary>
        /// <param name="obj">An object to compare, or null.</param>
        /// <returns>
        /// True if obj is an instance of <see cref="IChannelDefinition"/> and equals the value of this instance;
        /// otherwise, False.
        /// </returns>
        /// <exception cref="ArgumentException">value is not an <see cref="IChannelDefinition"/>.</exception>
        public override bool Equals(object obj)
        {
            return Equals(obj as IChannelDefinition);
        }

        /// <summary>
        /// Returns a value indicating whether this instance is equal to specified <see cref="IChannelDefinition"/> value.
        /// </summary>
        /// <param name="other">A <see cref="IChannelDefinition"/> object to compare to this instance.</param>
        /// <returns>
        /// True if <paramref name="other"/> has the same value as this instance; otherwise, False.
        /// </returns>
        public bool Equals(IChannelDefinition other)
        {
            return CompareTo(other) == 0;
        }

        /// <summary>
        /// Compares this instance to a specified object and returns an indication of their relative values.
        /// </summary>
        /// <param name="obj">An object to compare, or null.</param>
        /// <returns>
        /// A signed number indicating the relative values of this instance and value. Returns less than zero
        /// if this instance is less than value, zero if this instance is equal to value, or greater than zero
        /// if this instance is greater than value.
        /// </returns>
        /// <exception cref="ArgumentException">value is not an <see cref="IChannelDefinition"/>.</exception>
        public virtual int CompareTo(object obj)
        {
            if (obj is IChannelDefinition other)
                return CompareTo(other);

            throw new ArgumentException("ChannelDefinition can only be compared to other IChannelDefinitions");
        }

        /// <summary>
        /// Compares this instance to a specified <see cref="IChannelDefinition"/> object and returns an indication of their
        /// relative values.
        /// </summary>
        /// <param name="other">A <see cref="IChannelDefinition"/> object to compare.</param>
        /// <returns>
        /// A signed number indicating the relative values of this instance and value. Returns less than zero
        /// if this instance is less than value, zero if this instance is equal to value, or greater than zero
        /// if this instance is greater than value.
        /// </returns>
        public int CompareTo(IChannelDefinition other)
        {
            // We sort channel Definitions by index
            return m_index.CompareTo(other.Index);
        }

        /// <summary>
        /// Returns the hash code for this instance.
        /// </summary>
        /// <returns>A 32-bit signed integer hash code.</returns>
        public override int GetHashCode()
        {
            // ReSharper disable once NonReadonlyMemberInGetHashCode
            return m_index.GetHashCode();
        }

        /// <summary>
        /// Gets the string representation of this <see cref="ChannelDefinitionBase"/>.
        /// </summary>
        /// <returns>String representation of this <see cref="ChannelDefinitionBase"/>.</returns>
        public override string ToString()
        {
            return Label;
        }

        /// <summary>
        /// Populates a <see cref="SerializationInfo"/> with the data needed to serialize the target object.
        /// </summary>
        /// <param name="info">The <see cref="SerializationInfo"/> to populate with data.</param>
        /// <param name="context">The destination <see cref="StreamingContext"/> for this serialization.</param>
        public virtual void GetObjectData(SerializationInfo info, StreamingContext context)
        {
            // Serialize channel definition
            info.AddValue("parent", m_parent, typeof(IConfigurationCell));
            info.AddValue("index", m_index);
            info.AddValue("label", m_label);
            info.AddValue("scale", m_scale);
            info.AddValue("offset", m_offset);
        }

        #endregion
    }
}