// User-mode regression test for mmap-style native file mappings.

#include <stdint.h>
#include <stddef.h>
#include <string.h>
#include <ntlite/syscall.h>

#define TEST_MAP_SIZE 8192u

static uint8_t gExpected[TEST_MAP_SIZE];

static void print(const char* s) {
    SYS_WRITE_CONSOLE_REQUEST req = { SysSvFromCstr(s) };
    SysWriteConsole(&req);
}

static void print_u64(uint64_t v) {
    char buf[32];
    int i = 0;
    if (v == 0) {
        print("0");
        return;
    }
    while (v && i < (int)sizeof(buf)) {
        buf[i++] = (char)('0' + (v % 10));
        v /= 10;
    }
    while (i--) {
        char c = buf[i];
        SYS_WRITE_CONSOLE_REQUEST req = { SysSvFromParts(&c, 1) };
        SysWriteConsole(&req);
    }
}

static void exit_now(int code) {
    // SysExitProcess should not return, but keep tests from falling through to
    // the synthetic entry frame if a broken kernel build returns anyway.
    while (true)
        SysExitProcess(code);
}

static void fail_status(const char* what, uint32_t status) {
    print("mmap_smoke: ");
    print(what);
    print(" failed status=");
    print_u64(status);
    print("\n");
    exit_now(1);
}

static void fail_msg(const char* msg) {
    print("mmap_smoke: ");
    print(msg);
    print("\n");
    exit_now(1);
}

static uint32_t open_first_existing(uint32_t* fileOut, const char** pathOut) {
    static const char* candidates[] = {
        "mmap_smoke.exe",
        "/apps/mmap_smoke.exe",
        "0:/apps/mmap_smoke.exe",
        "1:/apps/mmap_smoke.exe",

        "/system/init.exe",
        "0:/system/init.exe",
        "1:/system/init.exe",
        "system/init.exe",
    };

    for (size_t i = 0; i < sizeof(candidates) / sizeof(candidates[0]); ++i) {
        uint32_t file = 0;
        SYS_OPEN_FILE_REQUEST openReq = SysMakeOpenFileRequest(SysSvFromCstr(candidates[i]),
                                                               SYS_FILE_ACCESS_READ | SYS_FILE_ACCESS_QUERY,
                                                               SYS_FILE_OPEN_EXISTING,
                                                               SYS_FILE_FLAG_NONE,
                                                               &file);
        uint32_t s = SysOpenFile(&openReq);
        if (s == NTLSTATUS_SUCCESS) {
            *fileOut = file;
            if (pathOut)
                *pathOut = candidates[i];
            return NTLSTATUS_SUCCESS;
        }
    }

    return NTLSTATUS_NOT_FOUND;
}

int main(void) {
    print("mmap_smoke: start\n");

    uint32_t file = 0;
    const char* openedPath = 0;
    uint32_t s = open_first_existing(&file, &openedPath);
    if (s != NTLSTATUS_SUCCESS)
        fail_status("open test file", s);

    print("mmap_smoke: using ");
    print(openedPath ? openedPath : "<unknown>");
    print("\n");

    size_t got = 0;
    memset(gExpected, 0xA5, sizeof(gExpected));

    SYS_FILE_IO_REQUEST ioReq = SysMakeFileIoRequest(file, gExpected, sizeof(gExpected), &got);
    s = SysReadFile(&ioReq);
    if (s != NTLSTATUS_SUCCESS)
        fail_status("read baseline", s);
    if (got < 64)
        fail_msg("baseline read was unexpectedly short");

    print("mmap_smoke: baseline read OK\n");

    uint32_t mapping = 0;
    s = SysCreateFileMapping(file,
                             SYS_VM_READ,
                             SYS_MAP_FLAG_NONE,
                             sizeof(gExpected),
                             &mapping);
    if (s != NTLSTATUS_SUCCESS)
        fail_status("create file mapping", s);

    print("mmap_smoke: mapping created\n");

    // The mapping object must hold its own file reference. Closing the source
    // handle before SysMapFile catches lifetime bugs in the object layer.
    SysCloseHandle(file);
    file = 0;

    print("mmap_smoke: source handle closed\n");

    void* base = 0;
    s = SysMapFile(mapping,
                   0,
                   sizeof(gExpected),
                   SYS_MAP_ACCESS_READ,
                   SYS_MAP_FLAG_NONE,
                   &base);

    SysCloseHandle(mapping);
    mapping = 0;

    if (s != NTLSTATUS_SUCCESS)
        fail_status("map file view", s);
    if (!base)
        fail_msg("map returned null base");

    print("mmap_smoke: view mapped\n");

    volatile uint8_t* view = (volatile uint8_t*)base;

    // Touch both pages before comparing. This ensures the test exercises
    // demand-faulted file-backed VAD pages rather than only VAD creation.
    (void)view[0];
    print("mmap_smoke: first page fault OK\n");

    (void)view[4096];
    print("mmap_smoke: second page fault OK\n");

    for (size_t i = 0; i < got; ++i) {
        if (view[i] != gExpected[i]) {
            print("mmap_smoke: byte mismatch at ");
            print_u64(i);
            print(" expected=");
            print_u64(gExpected[i]);
            print(" got=");
            print_u64(view[i]);
            print("\n");
            SysFreeVm(base);
            exit_now(1);
        }
    }

    print("mmap_smoke: mapped bytes match\n");

    // If the file is shorter than TEST_MAP_SIZE, the mapped tail must be
    // zero-filled rather than exposing stale physical memory.
    for (size_t i = got; i < sizeof(gExpected) && i < got + 64; ++i) {
        if (view[i] != 0) {
            print("mmap_smoke: nonzero EOF fill at ");
            print_u64(i);
            print(" got=");
            print_u64(view[i]);
            print("\n");
            SysFreeVm(base);
            exit_now(1);
        }
    }

    print("mmap_smoke: EOF fill OK\n");

    s = SysFreeVm(base);
    if (s != NTLSTATUS_SUCCESS)
        fail_status("unmap", s);

    print("mmap_smoke: PASS\n");
    exit_now(0);
    return 0;
}