using Sick.SafetyScanners.Helpers;

namespace Sick.SafetyScanners.Cola2.Commands;

/// <summary>
/// Command to read a variable from the sensor by index
/// </summary>
public sealed class VariableCommand : CommandBase
{
    private readonly ushort _variableIndex;
    
    public VariableCommand(ushort variableIndex) 
        : base(0x52, 0x49) // 'R' and 'I' in ASCII (Read by Index)
    {
        _variableIndex = variableIndex;
    }
    
    public ushort VariableIndex => _variableIndex;
    
    public override bool CanBeExecutedWithoutSessionId => false;
    
    protected override ReadOnlyMemory<byte> AddTelegramData()
    {
        var data = new byte[2];
        var span = data.AsSpan();
        
        // Variable index (2 bytes, little endian)
        ReadWriteHelper.WriteUint16LittleEndian(span, 0, _variableIndex);
        
        return data;
    }
    
    protected override bool ProcessReplyInternal(ReadOnlyMemory<byte> replyData, 
        byte replyCommandType, byte replyCommandMode)
    {
        // Reply should be 'R' (0x52) and 'A' (0x41) for Acknowledge
        if ((replyCommandType == 0x52 && replyCommandMode == 0x41) ||
            (replyCommandType == 'R' && replyCommandMode == 'A'))
        {
            return true;
        }
        
        return false;
    }
}