XFEEDToolBox

namespace XFEEDToolBox.Plugin;

internal static unsafe partial class Navigation
{
    // Current ED5A addresses, paired with the old actual provider ctor and
    // typed lookup slots in allegiance-definitions/compatibility.json.
    static bool GalaxyAllegianceSource(nuint source,nuint expectedImage)
    {
        if(source<0x10058)return false;
        var table=Pointer(source);
        return table==expectedImage+0x51BBA70&&Pointer(source-0x58)==expectedImage+0x51BB940&&
            Pointer(source-0x50)==expectedImage+0x51BB970&&Pointer(source+8)==expectedImage+0x51BBB60&&
            Pointer(table)==expectedImage+0x140EA90&&Pointer(table+0x18)==expectedImage+0x140F240&&
            Pointer(table+0x20)==expectedImage+0x140EC60&&Pointer(table+0x48)==expectedImage+0x1410000&&
            Pointer(table+0x50)==expectedImage+0x140FE60;
    }
    static uint GalaxyAllegianceLegacyHash(uint id)
    {
        unchecked
        {
            var hash=id*0x1001;hash=((hash>>22)^hash)*0x11;hash=((hash>>9)^hash)*0x401;
            hash=((hash>>2)^hash)*0x81;return hash^(hash>>12);
        }
    }
    static bool GalaxyAllegianceFindLegacy(nuint map,ulong id,out nuint found)
    {
        found=0;var buckets=Pointer(map);var capacity=Read<ulong>(map+8);var count=Read<ulong>(map+0x18);
        if(buckets<0x10000||capacity==0||capacity>1_048_576||count>4_000_000)return false;
        if(count>0)
        {
            var sentinel=buckets+(nuint)(GalaxyAllegianceLegacyHash((uint)id)%capacity)*8;var node=Pointer(sentinel);
            var maximum=(int)Math.Min(count,256);var ended=false;
            for(var step=0;step<=maximum;step++)
            {
                if(node==sentinel){ended=true;break;}
                if(step==maximum||node<0x10000)return false;
                if(Read<uint>(node+8)==(uint)id){found=node;ended=true;break;}
                var next=Pointer(node);if(next==node)return false;node=next;
            }
            if(!ended)return false;
        }
        return Pointer(map)==buckets&&Read<ulong>(map+8)==capacity&&Read<ulong>(map+0x18)==count;
    }
    static bool FindGalaxyAllegianceDefinition(nuint source,ulong id,out nuint node)
    {
        node=0;
        foreach(var offset in new nuint[]{0x80,0xA8,0xC8,0xE8,0x108})
        {
            if(!GalaxyFactFindHash(source+offset,id,out node))return false;
            if(node!=0)return true;
        }
        return GalaxyAllegianceFindLegacy(source+0x128,id,out node);
    }
    static bool CopyGalaxyAllegianceKey(nuint source,nuint expectedImage,ulong id,out string? key)
    {
        key=null;
        try
        {
            if(!GalaxyAllegianceSource(source,expectedImage))return false;
            // Original3AC56A0 inserts exactly this sentinel under None. Other
            // unresolved IDs are never converted to None; 140F320 rejects Max.
            if(id==ulong.MaxValue){key="None";return true;}
            if(!FindGalaxyAllegianceDefinition(source,id,out var node))return false;
            if(node==0)return true;
            var control=Pointer(node+0x10);var definition=Pointer(node+0x18);
            if(control<0x10000||definition<0x10000||Read<int>(control+0xC)<=0)return true;
            var valid=Read<byte>(definition+0x18);if(valid==0||Read<ulong>(definition)!=id)return true;
            var text=Pointer(definition+8);if(text<0x10000||Read<int>(text+0x10)<=0)return true;
            var length=Read<ulong>(text);var capacity=Read<ulong>(text+8);
            if(length is <1 or >64||capacity<length||capacity>1048576||!GalaxyCString(text+20,(int)length+1,out var candidate)||candidate.Length!=(int)length)return true;
            // These are the actual authored allegiance filter keys. Other
            // faction names may share this service but are not an allegiance.
            if(candidate is not("None" or "Federation" or "Empire" or "Alliance" or "Independent"))return true;
            if(!GalaxyAllegianceSource(source,expectedImage)||!FindGalaxyAllegianceDefinition(source,id,out var confirmed)||confirmed!=node||
               Pointer(node+0x10)!=control||Pointer(node+0x18)!=definition||Read<int>(control+0xC)<=0||
               Read<ulong>(definition)!=id||Read<byte>(definition+0x18)!=valid||Pointer(definition+8)!=text||
               Read<ulong>(text)!=length||Read<ulong>(text+8)!=capacity||Read<int>(text+0x10)<=0||
               !GalaxyCString(text+20,(int)length+1,out var reread)||reread!=candidate)return false;
            key=candidate;return true;
        }
        catch{key=null;return false;}
    }
    static bool TryReadGalaxyAllegianceKey(GalaxyFilterContext context,nuint registry,ulong id,out string? key)
    {
        key=null;
        if(!Enabled()||!inGame||context.expectedImage!=image||context.thread==0||context.thread!=owningThread||
           GetCurrentThreadId()!=context.thread||GetTickCount64()-context.tick>500||registry<0x10000)return false;
        var frame=Current();
        if(!frame.valid||frame.entity!=context.entity||(frame.referenceWorld&0x007FFFFFFFFFFFFFUL)!=context.currentSystem)return false;
        try
        {
            var type=Read<uint>(image+0x5F05E6C);var source=RegisteredComponent(registry,type);
            if(!CopyGalaxyAllegianceKey(source,image,id,out var value))return false;
            if(Read<uint>(image+0x5F05E6C)!=type||RegisteredComponent(registry,type)!=source)return false;
            var current=Current();if(!current.valid||current.entity!=frame.entity||(current.referenceWorld&0x007FFFFFFFFFFFFFUL)!=context.currentSystem)return false;
            key=value;return true;
        }
        catch{return false;}
    }
}