using Sick.SafetyScanners.Helpers;

namespace Sick.SafetyScanners.Cola2.Commands;

/// <summary>
/// Command to make the scanner flash/blink to help locate it
/// </summary>
public sealed class FindMeCommand : MethodCommand
{
    private readonly ushort _blinkTime;
    
    public FindMeCommand(ushort blinkTime)
        : base(14) // Method index for FindMe
    {
        _blinkTime = blinkTime;
    }
    
    public ushort BlinkTime => _blinkTime;
    
    public override bool CanBeExecutedWithoutSessionId => true;
    
    protected override ReadOnlyMemory<byte> AddTelegramData()
    {
        // Base method index (2 bytes) + blink time (2 bytes)
        var data = new byte[2 + 2];
        var span = data.AsSpan();
        
        // Write base method index (from MethodCommand.AddTelegramData)
        ReadWriteHelper.WriteUint16LittleEndian(span, 0, MethodIndex);
        
        // Write blink time (offset 2, 2 bytes, little endian)
        ReadWriteHelper.WriteUint16LittleEndian(span, 2, _blinkTime);
        
        return data;
    }
    
    protected override bool ProcessReplyInternal(ReadOnlyMemory<byte> replyData, 
        byte replyCommandType, byte replyCommandMode)
    {
        // According to C++ reference, this inverts the result from base class
        // Error response: 'E' (0x45) and 'I' (0x49)
        if ((replyCommandType == 0x45 && replyCommandMode == 0x49) ||
            (replyCommandType == 'E' && replyCommandMode == 'I'))
        {
            return false;
        }
        
        // Success: 'A' (0x41) and 'I' (0x49)
        return (replyCommandType == 0x41 && replyCommandMode == 0x49) ||
               (replyCommandType == 'A' && replyCommandMode == 'I');
    }
}