#include <Arch/DTB.h>
#include <OS/Panic.h>
#include <OS/Log.h>
#include <Lib/Bytes.h>
#include <Lib/Align.h>
#include <Lib/String.h>

void DTBParse(Pointer dtb) {
    FDTHeader* header = (FDTHeader*)dtb;
    if (BytesSwap32(header->magic) != kFDTHeaderMagic) {
        OSPanic("Invalid DTB magic");
    }

    UInt32 offStruct = BytesSwap32(header->offDtStruct);
    UInt32 offStrings = BytesSwap32(header->offDtStrings);

    BytePointer structs = (BytePointer)dtb + offStruct;
    ASCII* strings = (ASCII*)dtb + offStrings;
    ASCII* currentNode = "";

    while (true) {
        UInt32 token = BytesSwap32(*(UInt32*)structs);
        structs += 4;

        switch (token) {
            case FDTTokenBeginNode: {
                currentNode = (ASCII*)structs;

                UInt32 nameLength = StringGetLength(currentNode);
                structs += (nameLength + 1);
                structs = (BytePointer)AlignUp64((Address)structs, 4);

                break;
            }
            case FDTTokenProperty: {
                UInt32 propertyLength = BytesSwap32(*(UInt32*)structs);
                UInt32 nameOffset = BytesSwap32(*(UInt32*)(structs + 4));
                structs += 8;

                ASCII* propertyName = strings + nameOffset;
                if (StringCompare(propertyName, "reg") == 0 && StringStartsWith(currentNode, "memory")) {
                    UInt32* cells = (UInt32*)structs;
                    
                    UInt64 base = Merge32To64(BytesSwap32(cells[0]), BytesSwap32(cells[1]));
                    UInt64 size = Merge32To64(BytesSwap32(cells[2]), BytesSwap32(cells[3]));

                    OSLog("Memory: base=0x%x, size=0x%x\n", base, size);
                }
                structs += propertyLength;
                structs = (BytePointer)AlignUp64((Address)structs, 4);

                break;
            }

            case FDTTokenEndNode: break;
            case FDTTokenNOP: continue;
            case FDTTokenEnd: return;
            default:
                OSPanic("Invalid DTB token");
        }
    }

}