namespace XFEEDToolBox.Plugin;

internal static unsafe partial class Navigation
{
    private static nuint dockingZeroAxisRoot;
    private static ulong dockingZeroAxisVersion,dockingZeroAxisCommits,dockingZeroAxisRestoresSkipped;
    private static void RememberDockingZero(nuint root)
    {dockingZeroAxisRoot=root;dockingZeroAxisVersion++;dockingZeroAxisCommits++;}
    private static void RestoreOverlayAxis(nuint root,int axis,float previous,float written,ulong version)
    {
        // FSD can run inside an input-evaluation overlay. A durable original
        // zero must also survive restoration of that outer invocation.
        if(axis==0&&root==dockingZeroAxisRoot&&version!=dockingZeroAxisVersion)
        {dockingZeroAxisRestoresSkipped++;return;}
        var address=root+0x70+(nuint)axis*0x10;
        if(Read<float>(address)==written)Write(address,previous);
    }
    // SetSpeedZero updates the original controller, but an SCA exit can leave
    // its last .75 value in the newly materialised ship's input buffer. Commit
    // the requested zero only after overlays have been released. The caller
    // has already checked the current main ship, owner, target and ATC grant.
    private static bool CommitOriginalDockingZeroAxis(nuint inputRoot,nuint controller,float sampledThrottle,
        bool originalInputConfirmed,bool inputLeaseReleased,out bool committed)
    {
        committed=false;
        if(!originalInputConfirmed||!inputLeaseReleased||inputRoot<0x10000||controller<0x10000
            ||!float.IsFinite(sampledThrottle)||Math.Abs(sampledThrottle)>1.001f
            ||Pointer(inputRoot+0x2F8)!=controller||Read<float>(controller+0x680)!=0)return false;
        var current=Read<float>(inputRoot+0x70);
        if(current==0){RememberDockingZero(inputRoot);return true;}
        // A changed sample may be a player input. Never overwrite it.
        if(current!=sampledThrottle)return false;
        Write(inputRoot+0x70,0f);
        committed=Read<float>(inputRoot+0x70)==0;
        if(committed)RememberDockingZero(inputRoot);
        return committed;
    }
}