#include <utils.h>
#include <msg.h>
#include <main.h>

#include <game.h>

const char *HSR_BASE_MODULE_NAME = "StarRailBase.dll";
const char *HSR_ASSEMBLY_PATH    = "GameAssembly.dll";
const char *HSR_TXS_SECTION_NAME = ".ace";
const char *HSR_TVM_SECTION_NAME = ".tvm0";

enum hsr_region {
    HSR_INVALID,
    HSR_OS,
    HSR_CN
};

struct crc_region_pair {
    uint32_t crc;
    enum hsr_region id;
};

const struct crc_region_pair HSR_REGIONS[] = {
    { 0x9eb3084e, HSR_OS }, // os v1.2.0
    { 0x14be07e9, HSR_CN }  // cn v1.2.0
};

#define JUMP_SIZE (6 + sizeof(void*))

// Temporarily hardcoded offset
// v1.2.0, same for os and cn
#define WTSUD_PATCH_OFFSET 0x16430

char wtsud_original_bytes[JUMP_SIZE];
char *wtsud_patch_addr;

static void _wtsud_stub() {
    // Recover original bytes
    DWORD oldProtect;
    VirtualProtect(wtsud_patch_addr, JUMP_SIZE, PAGE_EXECUTE_READWRITE, &oldProtect);

    memcpy(wtsud_patch_addr, wtsud_original_bytes, JUMP_SIZE);

    VirtualProtect(wtsud_patch_addr, JUMP_SIZE, oldProtect, &oldProtect);
    
    unload_ctr_dec();
}

static void _unityplayer_callback(HMODULE unityModule) {
    if (utils_env_enabled("SRFIX_DISABLE")) {
        msg_info_a("Shared resources fix disabled. The game may not work");
        return;
    }

    // Remove dependency on shared resources by patching WriteTextureStatisticUserData
    unload_ctr_inc();

    wtsud_patch_addr = ((char*)unityModule) + WTSUD_PATCH_OFFSET;

    DWORD oldProtect;
    VirtualProtect(wtsud_patch_addr, JUMP_SIZE, PAGE_EXECUTE_READWRITE, &oldProtect);

    // Save original bytes
    memcpy(wtsud_original_bytes, wtsud_patch_addr, JUMP_SIZE);

    // Write jump
    const char JUMP_INST[] = { 0xFF, 0x25, 0x00, 0x00, 0x00, 0x00 }; // jmp [$ + 6]
    memcpy(wtsud_patch_addr, JUMP_INST, sizeof(JUMP_INST));

    // Write destination address
    void *destAddr = &_wtsud_stub;
    memcpy(wtsud_patch_addr + sizeof(JUMP_INST), &destAddr, sizeof(destAddr));

    VirtualProtect(wtsud_patch_addr, JUMP_SIZE, oldProtect, &oldProtect);
}

void hsr_fill_data(struct game_data *buf) {
    uint32_t crc = utils_file_crc32c(L"UnityPlayer.dll");
    
    enum hsr_region id = HSR_INVALID;
    for (size_t i = 0; i < UTILS_COUNT(HSR_REGIONS); i++) {
        if (HSR_REGIONS[i].crc == crc) {
            id = HSR_REGIONS[i].id;
            break;
        }
    }
    
    if (id == HSR_INVALID) {
        msg_err_a("Invalid UnityPlayer.dll checksum: 0x%08x. This usually happens when the patch is outdated", crc);
    }

    buf->base_module_name = HSR_BASE_MODULE_NAME;
    buf->assembly_path = HSR_ASSEMBLY_PATH;
    buf->txs_section_name = HSR_TXS_SECTION_NAME;
    buf->tvm_section_name = HSR_TVM_SECTION_NAME;

    buf->unityplayer_callback = &_unityplayer_callback;
}