#include <windows.h>
#include <winternl.h>
#include <stdio.h>
#include <stdint.h>

typedef struct _S_LDR_DATA_TABLE_ENTRY {
    LIST_ENTRY InMemoryOrderModuleList;
    LIST_ENTRY InInitializationOrderModuleList;
    LPVOID DllBase;
    LPVOID EntryPoint;
    ULONG  SizeOfImage;
    UNICODE_STRING FullDllName;
    UNICODE_STRING BaseDllName;
} S_LDR_DATA_TABLE_ENTRY;

typedef struct _S_PEB_LDR_DATA {
    DWORD      Length;
    DWORD      Initialized;
    LPVOID     SsHandle;
    LIST_ENTRY InLoadOrderModuleList;
    LIST_ENTRY InMemoryOrderModuleList;
} S_PEB_LDR_DATA;

typedef struct _S_PEB {
    BYTE    Reserved1[2];
    BYTE    BeingDebugged;
    BYTE    Reserved2;
#ifdef _WIN64
    BYTE    Reserved3[4];
#endif
    LPVOID  Reserved4[1];
    LPVOID  ImageBaseAddress;
    S_PEB_LDR_DATA *Ldr;
} S_PEB;

static inline S_PEB *GetPeb(void) {
#ifdef _WIN64
    return (S_PEB *)__readgsqword(0x60);
#else
    return (S_PEB *)__readfsdword(0x30);
#endif
}

static DWORD StubHash(const char *str) {
    DWORD h = 0x4E67C6A7;
    while (*str) {
        h = ((h << 5) + h) ^ (unsigned char)*str++;
    }
    return h;
}

static DWORD StubHashW(const WCHAR *str, USHORT lenBytes) {
    DWORD h = 0x4E67C6A7;
    const char *raw = (const char *)str;
    for (USHORT i = 0; i < lenBytes; i++) {
        char c = raw[i];
        if (c >= 'a' && c <= 'z') c -= 0x20;
        h = ((h << 5) + h) ^ (unsigned char)c;
    }
    return h;
}

int main(void) {
    printf("=== PEB Module Walk ===\n");
    S_PEB_LDR_DATA *ldr = GetPeb()->Ldr;
    S_LDR_DATA_TABLE_ENTRY *first = (S_LDR_DATA_TABLE_ENTRY *)ldr->InMemoryOrderModuleList.Flink;
    S_LDR_DATA_TABLE_ENTRY *entry = first;
    do {
        if (entry->BaseDllName.Buffer) {
            DWORD h = StubHashW(entry->BaseDllName.Buffer, entry->BaseDllName.Length);
            printf("  Module: %.*S  hash=0x%08X  base=%p\n",
                   entry->BaseDllName.Length / 2, entry->BaseDllName.Buffer,
                   h, entry->DllBase);
        }
        entry = (S_LDR_DATA_TABLE_ENTRY *)entry->InMemoryOrderModuleList.Flink;
    } while (entry != first);

    printf("\n=== Expected Hashes ===\n");
    printf("  FH_KERNEL32 = 0x52B1CB57\n");
    printf("  FH_NTDLL    = 0x1EBCC013\n");

    /* Try to resolve a function */
    LPVOID k32 = NULL;
    LPVOID ntdll = NULL;
    entry = first;
    do {
        if (entry->BaseDllName.Buffer) {
            DWORD h = StubHashW(entry->BaseDllName.Buffer, entry->BaseDllName.Length);
            if (h == 0x52B1CB57) k32 = entry->DllBase;
            if (h == 0x1EBCC013) ntdll = entry->DllBase;
        }
        entry = (S_LDR_DATA_TABLE_ENTRY *)entry->InMemoryOrderModuleList.Flink;
    } while (entry != first);

    printf("\n=== Resolution ===\n");
    printf("  kernel32 base: %p %s\n", k32, k32 ? "FOUND" : "NOT FOUND!");
    printf("  ntdll base:    %p %s\n", ntdll, ntdll ? "FOUND" : "NOT FOUND!");

    if (k32) {
        /* Try resolving LoadLibraryA by hash */
        LPBYTE base = (LPBYTE)k32;
        PIMAGE_DOS_HEADER dos = (PIMAGE_DOS_HEADER)base;
        PIMAGE_NT_HEADERS nt = (PIMAGE_NT_HEADERS)(base + dos->e_lfanew);
        PIMAGE_EXPORT_DIRECTORY exp = (PIMAGE_EXPORT_DIRECTORY)(
            base + nt->OptionalHeader.DataDirectory[0].VirtualAddress);
        LPDWORD names = (LPDWORD)(base + exp->AddressOfNames);
        int found = 0;
        for (DWORD i = 0; i < exp->NumberOfNames && i < 5; i++) {
            const char *name = (const char *)(base + names[i]);
            DWORD h = StubHash(name);
            if (i < 3) printf("  Export[%d]: %-30s hash=0x%08X\n", i, name, h);
        }
        /* Find LoadLibraryA specifically */
        for (DWORD i = 0; i < exp->NumberOfNames; i++) {
            const char *name = (const char *)(base + names[i]);
            DWORD h = StubHash(name);
            if (h == 0x32B72ABF) {
                printf("  LoadLibraryA: FOUND (hash 0x32B72ABF matched \"%s\")\n", name);
                found = 1;
                break;
            }
        }
        if (!found) printf("  LoadLibraryA: NOT FOUND!\n");
    }

    return 0;
}