//-----------------------------------------------------------------------
// <copyright file="PassThruMsg.cs" company="bedug.com">
//     Copyright © 2012 Nils Hammar. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------
/*
 * Software to access vehicle information via the OBD-II connector.
 * 
 * Copyright © 2012 Nils Hammar
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 * 
 * Alternative licensing is possible, see the licensing document.
 * 
 * The above text may not be removed or modified.
 */

namespace DeviceApi
{
    using global::SharedObjects.Api;
    using global::SharedObjects.Misc;
    using global::SharedObjects.Protocol;

    /// <summary>
    /// Envelope class for one message.
    /// This is much like the PASSTHRU_MSG struct
    /// but is 'pure' C# to avoid unsafe pointers.
    /// </summary>
    public class PassThruMsg : IPassThruMsg
    {
        /// <summary>
        /// Gets or sets the Protocol ID.
        /// </summary>
        public int ProtocolID { get; set; }

        /// <summary>
        /// Gets or sets the RX Status Flags.
        /// </summary>
        public int RxStatus { get; set; }

        /// <summary>
        /// Gets or sets the TX Flags.
        /// </summary>
        public int TxFlags { get; set; }

        /// <summary>
        /// Gets or sets the Message Timestamp.
        /// </summary>
        public int Timestamp { get; set; }

        /// <summary>
        /// Gets or sets the size of the data.
        /// </summary>
        public int DataSize { get; set; }

        /// <summary>
        /// Gets or sets the index of extra data.
        /// </summary>
        public int ExtraDataIndex { get; set; }

        /// <summary>
        /// Gets or sets the array of data.
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1819:PropertiesShouldNotReturnArrays", Justification = "Intentional for use with DLL API")]
        public byte[] Data { get; set; }

        /// <summary>
        /// Gets a value indicating whether this is a message sent from the application,
        /// which is applicable when replaying raw data through the simulator.
        /// </summary>
        public bool isSentData { get; private set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="PassThruMsg" /> class.
        /// </summary>
        /// <param name="isSentData">'true' if this message is for data sent to the vehicle from the application.</param>
        /// <param name="ProtocolID">ID of protocol used.</param>
        /// <param name="RxStatus">Receive status flags.</param>
        /// <param name="TxFlags">Transmit flags</param>
        /// <param name="Timestamp">Timestamp value</param>
        /// <param name="DataSize">Size of data (payload)</param>
        /// <param name="ExtraDataIndex">Index of extra data.</param>
        /// <param name="Data">Payload data.</param>
        public PassThruMsg(
            bool isSentData,
            int ProtocolID,
            int RxStatus,
            int TxFlags,
            int Timestamp,
            int DataSize,
            int ExtraDataIndex,
            byte[] Data)
        {
            this.isSentData = isSentData;
            this.ProtocolID = ProtocolID;
            this.RxStatus = RxStatus;
            this.TxFlags = TxFlags;
            this.Timestamp = Timestamp;
            this.DataSize = DataSize;
            this.ExtraDataIndex = ExtraDataIndex;
            this.Data = Data;
        }

        /// <summary>
        /// Get one empty message that can be populated.
        /// </summary>
        /// <param name="protocol">Protocol to set on message.</param>
        /// <returns>Message instance.</returns>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Justification = "Reviewed, intentional.")]
        public static IPassThruMsg getMaskedMsg(Protocols protocol)
        {
            return getMaskedMsg((int)protocol.id);
        }

        /// <summary>
        /// Get one empty message that can be populated.
        /// </summary>
        /// <param name="protocolid">ID of protocol to set on message.</param>
        /// <returns>Message instance.</returns>
        public static IPassThruMsg getMaskedMsg(int protocolid)
        {
            IPassThruMsg txmsg = new PassThruMsg(false, protocolid, 0, 0, 0, 0, 0, new byte[PassThruConstants.MAX_DATA_SIZE]);

            // Set first four bytes to zero just in case.
            txmsg.Data[0] = (byte)0;
            txmsg.Data[1] = (byte)0;
            txmsg.Data[2] = (byte)0;
            txmsg.Data[3] = (byte)0;

            return txmsg;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="PassThruMsg" /> class.
        /// </summary>
        /// <param name="pMsg">Pointer to message struct containing data for the message.</param>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Justification = "Provided data shall never be 'null'.")]
        public unsafe PassThruMsg(PASSTHRU_MSG* pMsg)
        {
            this.ProtocolID = pMsg->ProtocolID;
            this.RxStatus = pMsg->RxStatus;
            this.TxFlags = pMsg->TxFlags;
            this.Timestamp = pMsg->Timestamp;
            this.DataSize = pMsg->DataSize;
            this.ExtraDataIndex = pMsg->ExtraDataIndex;
            this.Data = new byte[this.DataSize];

            for (int i = 0; i < this.DataSize && i < PassThruConstants.MAX_DATA_SIZE; i++)
            {
                this.Data[i] = pMsg->Data[i];
            }
        }

        /// <summary>
        /// Calculate hash code for item.
        /// </summary>
        /// <returns>Calculated hash code.</returns>
        public override int GetHashCode()
        {
            int hash = 0;

            Utils.reHash(ref hash, this.ProtocolID.GetHashCode());
            Utils.reHash(ref hash, this.RxStatus.GetHashCode());
            Utils.reHash(ref hash, this.TxFlags.GetHashCode());
            Utils.reHash(ref hash, this.Timestamp.GetHashCode());
            Utils.reHash(ref hash, this.DataSize.GetHashCode());
            Utils.reHash(ref hash, this.ExtraDataIndex.GetHashCode());

            for (int i = 0; i < this.Data.Length; i++)
            {
                Utils.reHash(ref hash, this.Data[i].GetHashCode());
            }

            return hash;
        }

        /// <summary>
        /// Equals compare.
        /// </summary>
        /// <param name="obj">Object to compare with.</param>
        /// <returns>'true' if equals</returns>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily", Justification = "Reviewed, intentional.")]
        public override bool Equals(object obj)
        {
            if (obj is PassThruMsg)
            {
                PassThruMsg passThruMsg = (PassThruMsg)obj;

                if (this.ProtocolID == passThruMsg.ProtocolID
                    && this.RxStatus == passThruMsg.RxStatus
                    && this.TxFlags == passThruMsg.TxFlags
                    && this.Timestamp == passThruMsg.Timestamp
                    && this.DataSize == passThruMsg.DataSize
                    && this.ExtraDataIndex == passThruMsg.ExtraDataIndex)
                {
                    int i = 0;
                    while (i < this.Data.Length && this.Data[i] == passThruMsg.Data[i])
                    {
                        i++;
                    }

                    if (i == this.Data.Length)
                    {
                        return true;
                    }
                }
            }

            return false;
        }

        /// <summary>
        /// Set the values of the struct given as parameter to the values of this object.
        /// Notice that the data area in the struct MUST be allocated to at least
        /// the size of the data area.
        /// </summary>
        /// <param name="pMsg">Pointer to struct to load.</param>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Justification = "Provided data shall never be 'null'.")]
        public unsafe void toStruct(PASSTHRU_MSG* pMsg)
        {
            pMsg->ProtocolID = this.ProtocolID;
            pMsg->RxStatus = this.RxStatus;
            pMsg->TxFlags = this.TxFlags;
            pMsg->Timestamp = this.Timestamp;
            pMsg->DataSize = this.DataSize;
            pMsg->ExtraDataIndex = this.ExtraDataIndex;
            for (int i = 0; i < this.DataSize && i < PassThruConstants.MAX_DATA_SIZE; i++)
            {
                pMsg->Data[i] = this.Data[i];
            }
        }
    }
}