#pragma once // ensure that a given header file is included only once in a
             // single compilation unit
#include "arena.h"
#include "base.h"
#include "lf_mpmc.h"

#include "arena.c"

// xxhash include
#define XXH_STATIC_LINKING_ONLY
#include "xxh_x86dispatch.h"

// ----------------------------- Config -------------------------------------
#define FILE_HASHES_TXT "file_hashes.txt"
#define HASH_STRLEN 33 // 128-bit hex (32 chars) + null
#define MAX_PATHLEN 4096
#define READ_BLOCK (KiB(64))

// ----------------------------- Globals ------------------------------------
static atomic_uint_fast64_t g_files_found = 0;
static atomic_uint_fast64_t g_files_hashed = 0;
static atomic_uint_fast64_t g_bytes_processed = 0;
static atomic_int g_scan_done = 0;

// ================== OS-agnostic functions abstraction =====================
// ----------------------------- Timer functions --------------
typedef struct {
  u64 start;
  u64 now;
} HiResTimer;

#if defined(_WIN32) || defined(_WIN64)

static LARGE_INTEGER g_freq;

static void timer_init(void) { QueryPerformanceFrequency(&g_freq); }

static void timer_start(HiResTimer *t) {
  LARGE_INTEGER v;
  QueryPerformanceCounter(&v);
  t->start = v.QuadPart;
}

static double timer_elapsed(HiResTimer *t) {
  LARGE_INTEGER v;
  QueryPerformanceCounter(&v);
  t->now = v.QuadPart;

  return (double)(t->now - t->start) / (double)g_freq.QuadPart;
}

#elif defined(__linux__)

void timer_init(void) {}

void timer_start(HiResTimer *t) {
  struct timespec ts;
  clock_gettime(CLOCK_MONOTONIC, &ts);
  t->start = ts.tv_sec * 1000000000ULL + ts.tv_nsec;
}

double timer_elapsed(HiResTimer *t) {
  struct timespec ts;
  clock_gettime(CLOCK_MONOTONIC, &ts);

  uint64_t now = ts.tv_sec * 1000000000ULL + ts.tv_nsec;

  return (double)(now - t->start) / 1e9;
}

#endif

// ----------------------------- Get HW info --------------
#if defined(_WIN32) || defined(_WIN64)

size_t platform_physical_cores(void) {
  DWORD len = 0;
  GetLogicalProcessorInformation(NULL, &len);

  SYSTEM_LOGICAL_PROCESSOR_INFORMATION buf[len];

  GetLogicalProcessorInformation(buf, &len);
  DWORD count = 0;
  DWORD n = len / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION);
  for (DWORD i = 0; i < n; i++) {
    if (buf[i].Relationship == RelationProcessorCore)
      count++;
  }
  return count ? count : 1;
}

#elif defined(__linux__)

size_t platform_physical_cores(void) {
  long n = sysconf(_SC_NPROCESSORS_ONLN);
  return n > 0 ? (size_t)n : 1;
}

#endif

const char *get_xxhash_instruction_set(void) {
  int vecID = XXH_featureTest();

  switch (vecID) {
  case XXH_SCALAR:
    return "Scalar (portable C)";
  case XXH_SSE2:
    return "SSE2";
  case XXH_AVX2:
    return "AVX2";
  case XXH_AVX512:
    return "AVX-512";
  default:
    return "Unknown";
  }
}

// -------------------- File IO -------------------

#if defined(_WIN32) || defined(_WIN64)
typedef HANDLE FileHandle;
#define INVALID_FILE_HANDLE INVALID_HANDLE_VALUE

// File open function
static FileHandle os_file_open(const char *path) {
  return CreateFileA(path, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE,
                     NULL, OPEN_EXISTING, FILE_FLAG_SEQUENTIAL_SCAN, NULL);
}

// File read function
static int os_file_read(FileHandle handle, void *buf, size_t count,
                        uint64_t *bytes_read) {
  DWORD read = 0;
  BOOL result = ReadFile(handle, buf, (DWORD)count, &read, NULL);
  *bytes_read = read;
  return (result && read > 0) ? 0 : -1;
}

// File close function
static void os_file_close(FileHandle handle) { CloseHandle(handle); }

#elif defined(__linux__)
typedef int FileHandle;
#define INVALID_FILE_HANDLE (-1)

// File open function
static FileHandle os_file_open(const char *path) {
  return open(path, O_RDONLY | O_NOFOLLOW);
}

// File read function
static int os_file_read(FileHandle handle, void *buf, size_t count,
                        uint64_t *bytes_read) {
  ssize_t result = read(handle, buf, count);
  if (result >= 0) {
    *bytes_read = (uint64_t)result;
    return 0;
  }
  *bytes_read = 0;
  return -1;
}

// File close function
static void os_file_close(FileHandle handle) { close(handle); }

#endif

// -------------------- Thread abstraction -------------------
// Threads context
typedef struct {
  u8 num_threads;

  mem_arena *path_arena;
  mem_arena *meta_arena;

  MPMCQueue *dir_queue;
  MPMCQueue *file_queue;
} ScannerContext;

typedef struct {
  mem_arena *arena;
  MPMCQueue *file_queue;
} WorkerContext;

#if defined(_WIN32) || defined(_WIN64)
typedef HANDLE ThreadHandle;
typedef DWORD(WINAPI *ThreadFunc)(void *);
#define THREAD_RETURN DWORD WINAPI
#define THREAD_RETURN_VALUE 0;

typedef struct {
  ThreadHandle handle;
  int valid; // Track if thread was successfully created
} Thread;

// Thread function wrapper to handle different return types
#define THREAD_FUNCTION(name) DWORD WINAPI name(LPVOID arg)

// Thread creation function
static int thread_create(Thread *thread, ThreadFunc func, void *arg) {
  thread->handle =
      CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)func, arg, 0, NULL);
  return (thread->handle != NULL) ? 0 : -1;
}

// Thread join function
static int thread_join(Thread *thread) {
  return (WaitForSingleObject(thread->handle, INFINITE) == WAIT_OBJECT_0) ? 0
                                                                          : -1;
}

// Thread close/detach function
static void thread_close(Thread *thread) { CloseHandle(thread->handle); }

// Wait for multiple threads
static int thread_wait_multiple(Thread *threads, size_t count) {
  HANDLE handles[64]; // Max 64 threads for Windows
  for (size_t i = 0; i < count; i++) {
    handles[i] = threads[i].handle;
  }
  return (WaitForMultipleObjects((DWORD)count, handles, TRUE, INFINITE) ==
          WAIT_OBJECT_0)
             ? 0
             : -1;
}

#elif defined(__linux__)
typedef pthread_t ThreadHandle;
typedef void *(*ThreadFunc)(void *);
#define THREAD_RETURN void *
#define THREAD_RETURN_VALUE NULL;

typedef struct {
  ThreadHandle handle;
  int valid; // Track if thread was successfully created
} Thread;

// Thread function wrapper to handle different return types
typedef struct {
  void *(*func)(void *);
  void *arg;
} ThreadWrapper;

static void *thread_start_routine(void *arg) {
  ThreadWrapper *wrapper = (ThreadWrapper *)arg;
  void *result = wrapper->func(wrapper->arg);
  free(wrapper);
  return result;
}

// Thread creation function
static int thread_create(Thread *thread, ThreadFunc func, void *arg) {
  int ret = pthread_create(&thread->handle, NULL, func, arg);
  if (ret == 0) {
    thread->valid = 1;
  }
  return ret;
}

// Thread join function
static int thread_join(Thread *thread) {
  int ret = pthread_join(thread->handle, NULL);
  thread->valid = 0;
  return ret;
}

// Thread close/detach function
static void thread_close(Thread *thread) {
  if (thread->valid) {
    pthread_detach(thread->handle);
    thread->valid = 0;
  }
}

// Wait for multiple threads
static int thread_wait_multiple(Thread *threads, size_t count) {
  for (size_t i = 0; i < count; i++) {
    if (thread_join(&threads[i]) != 0) {
      return -1;
    }
  }
  return 0;
}

#endif

// ======================== Get file metadata ========================
// -------------------- Path parsing -------------------
static void normalize_path(char *p) {
  char *src = p;
  char *dst = p;
  int prev_slash = 0;

  while (*src) {
    char c = *src++;

    if (c == '\\' || c == '/') {
      if (!prev_slash) {
        *dst++ = '/';
        prev_slash = 1;
      }
    } else {
      *dst++ = c;
      prev_slash = 0;
    }
  }

  *dst = '\0';
}

static int parse_paths(char *line, char folders[][MAX_PATHLEN],
                       int max_folders) {
  int count = 0;
  char *p = line;

  while (*p && count < max_folders) {

    while (*p && isspace((unsigned char)*p))
      p++;

    if (!*p)
      break;

    char *start;
    char quote = 0;

    if (*p == '"' || *p == '\'') {
      quote = *p++;
      start = p;

      while (*p && *p != quote)
        p++;
    } else {
      start = p;

      while (*p && !isspace((unsigned char)*p))
        p++;
    }

    size_t len = p - start;
    if (len >= MAX_PATHLEN)
      len = MAX_PATHLEN - 1;

    memcpy(folders[count], start, len);
    folders[count][len] = 0;

    normalize_path(folders[count]);

    count++;

    if (quote && *p == quote)
      p++;
  }
  return count;
}

// ----------------------------- File time -------------------------
#if defined(_WIN32) || defined(_WIN64)
static void format_time(uint64_t t, char *out, size_t out_sz) {
  if (t == 0) {
    snprintf(out, out_sz, "N/A");
    return;
  }

  time_t tt = (time_t)t;
  struct tm tm;

  localtime_s(&tm, &tt);

  strftime(out, out_sz, "%Y-%m-%d %H:%M:%S", &tm);
}
// ----------------------------- Convert filetime to epoch --------------
static uint64_t filetime_to_epoch(const FILETIME *ft) {
  ULARGE_INTEGER ull;
  ull.LowPart = ft->dwLowDateTime;
  ull.HighPart = ft->dwHighDateTime;

  // Windows epoch (1601) ￢ﾆﾒ Unix epoch (1970)
  return (ull.QuadPart - 116444736000000000ULL) / 10000000ULL;
}

void platform_get_file_times(const char *path, uint64_t *out_created,
                             uint64_t *out_modified) {
  WIN32_FILE_ATTRIBUTE_DATA fad;
  if (GetFileAttributesExA(path, GetFileExInfoStandard, &fad)) {
    *out_created = filetime_to_epoch(&fad.ftCreationTime);
    *out_modified = filetime_to_epoch(&fad.ftLastWriteTime);
  } else {
    *out_created = 0;
    *out_modified = 0;
  }
}

#elif defined(__linux__)
static void format_time(uint64_t t, char *out, size_t out_sz) {
  if (t == 0) {
    snprintf(out, out_sz, "N/A");
    return;
  }

  time_t tt = (time_t)t;
  struct tm tm;

  localtime_r(&tt, &tm);

  strftime(out, out_sz, "%Y-%m-%d %H:%M:%S", &tm);
}

void platform_get_file_times(const char *path, uint64_t *out_created,
                             uint64_t *out_modified) {
  struct stat st;
  if (stat(path, &st) == 0) {
    *out_created = (uint64_t)st.st_ctime;
    *out_modified = (uint64_t)st.st_mtime;
  } else {
    *out_created = 0;
    *out_modified = 0;
  }
}

#endif

// ----------------------------- File owner ---------------------
#if defined(_WIN32) || defined(_WIN64)
static void get_file_owner(const char *path, char *out, size_t out_sz) {
  PSID sid = NULL;
  PSECURITY_DESCRIPTOR sd = NULL;

  if (GetNamedSecurityInfoA(path, SE_FILE_OBJECT, OWNER_SECURITY_INFORMATION,
                            &sid, NULL, NULL, NULL, &sd) == ERROR_SUCCESS) {

    char name[64], domain[64];
    DWORD name_len = sizeof(name);
    DWORD domain_len = sizeof(domain);
    SID_NAME_USE use;

    if (LookupAccountSidA(NULL, sid, name, &name_len, domain, &domain_len,
                          &use)) {
      snprintf(out, out_sz, "%s\\%s", domain, name);
    } else {
      snprintf(out, out_sz, "UNKNOWN");
    }
  } else {
    snprintf(out, out_sz, "UNKNOWN");
  }

  if (sd)
    LocalFree(sd);
}

void platform_get_file_owner(const char *path, char *out_owner,
                             size_t out_owner_size) {
  get_file_owner(path, out_owner, out_owner_size);
}

#elif defined(__linux__)
static void get_file_owner(uid_t uid, char *out, size_t out_sz) {
  struct passwd *pw = getpwuid(uid);
  if (pw) {
    snprintf(out, out_sz, "%s", pw->pw_name);
  } else {
    snprintf(out, out_sz, "UNKNOWN");
  }
}

void platform_get_file_owner(const char *path, char *out_owner,
                             size_t out_owner_size) {
  struct stat st;
  if (stat(path, &st) == 0) {
    get_file_owner(st.st_uid, out_owner, out_owner_size);
  } else {
    snprintf(out_owner, out_owner_size, "UNKNOWN");
  }
}

#endif

// ----------------------------- Scan helpers -----------------------------
typedef struct FileEntry {
  char *path;

  uint64_t size_bytes;
  uint64_t created_time;  // epoch
  uint64_t modified_time; // epoch seconds
  char owner[128];        // resolved owner name
} FileEntry;

typedef struct {
  char buffer[MAX_PATHLEN];
  char *base_end;     // Points to end of base path
  char *filename_pos; // Points to where filename should be written
  size_t base_len;
} PathBuilder;

static void path_builder_init(PathBuilder *pb, const char *base) {
  pb->base_len = strlen(base);
  memcpy(pb->buffer, base, pb->base_len);
  pb->base_end = pb->buffer + pb->base_len;

#if defined(_WIN32) || defined(_WIN64)
  *pb->base_end = '\\';
#elif defined(__linux__)
  *pb->base_end = '/';
#endif

  // Ensure null termination
  *(pb->base_end + 1) = '\0';
  pb->filename_pos = pb->base_end + 1;
}

static void path_builder_set_filename(PathBuilder *pb, const char *filename,
                                      size_t name_len) {
  memcpy(pb->filename_pos, filename, name_len);
  pb->filename_pos[name_len] = '\0'; // Ensure null termination
}

static char *path_builder_dup_arena(PathBuilder *pb, mem_arena *arena,
                                    bool zero) {
  // Calculate total length including base + separator + filename + null
  // terminator
  size_t total_len =
      (pb->filename_pos - pb->buffer) + strlen(pb->filename_pos) + 1;
  char *dup = arena_push(&arena, total_len, zero);
  memcpy(dup, pb->buffer, total_len);
  return dup;
}

#if defined(_WIN32) || defined(_WIN64)
void scan_folder(const char *base, ScannerContext *ctx) {
  PathBuilder pb;
  path_builder_init(&pb, base);

  char search[MAX_PATHLEN];
  memcpy(search, pb.buffer, pb.base_len + 1); // Copy base + separator
  memcpy(search + pb.base_len + 1, "*", 2);   // Add "*" and null

  WIN32_FIND_DATAA fd;
  HANDLE h = FindFirstFileA(search, &fd);
  if (h == INVALID_HANDLE_VALUE)
    return;

  do {
    // Skip . and ..
    if (fd.cFileName[0] == '.' &&
        (fd.cFileName[1] == 0 ||
         (fd.cFileName[1] == '.' && fd.cFileName[2] == 0)))
      continue;

    if (fd.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)
      continue;

    size_t name_len = strlen(fd.cFileName);
    path_builder_set_filename(&pb, fd.cFileName, name_len);

    if (fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
      char *dir = path_builder_dup_arena(&pb, ctx->path_arena, false);
      mpmc_push_work(ctx->dir_queue, dir);
    } else {
      atomic_fetch_add(&g_files_found, 1);

      FileEntry *fe = arena_push(&ctx->meta_arena, sizeof(FileEntry), true);

      // Create a temporary copy for normalization to avoid corrupting pb.buffer
      char temp_path[MAX_PATHLEN];
      memcpy(temp_path, pb.buffer,
             (pb.filename_pos - pb.buffer) + name_len + 1);
      normalize_path(temp_path);

      fe->path = arena_push(&ctx->path_arena, strlen(temp_path) + 1, false);
      strcpy(fe->path, temp_path);

      platform_get_file_times(pb.buffer, &fe->created_time, &fe->modified_time);
      platform_get_file_owner(pb.buffer, fe->owner, sizeof(fe->owner));
      fe->size_bytes = ((uint64_t)fd.nFileSizeHigh << 32) | fd.nFileSizeLow;

      mpmc_push(ctx->file_queue, fe);
    }

  } while (FindNextFileA(h, &fd));

  FindClose(h);
}

#elif defined(__linux__)
static int platform_get_file_times_fd(int dir_fd, const char *name,
                                      time_t *created, time_t *modified) {
  struct stat st;
  if (fstatat(dir_fd, name, &st, 0) == 0) {
    *created = st.st_ctime; // or st.st_birthtime on systems that support it
    *modified = st.st_mtime;
    return 0;
  }
  return -1;
}

static int platform_get_file_owner_fd(int dir_fd, const char *name, char *owner,
                                      size_t owner_size) {
  struct stat st;
  if (fstatat(dir_fd, name, &st, 0) == 0) {
    struct passwd pw;
    struct passwd *result;
    char buffer[4096]; // Sufficiently large buffer for passwd data

    // Reentrant version (thread-safe)
    if (getpwuid_r(st.st_uid, &pw, buffer, sizeof(buffer), &result) == 0 &&
        result != NULL && result->pw_name != NULL) {
      strncpy(owner, result->pw_name, owner_size - 1);
      owner[owner_size - 1] = '\0';
    } else {
      // Fallback to uid
      snprintf(owner, owner_size, "uid:%d", st.st_uid);
    }
    return 0;
  }
  return -1;

  void scan_folder(const char *base, ScannerContext *ctx) {
    PathBuilder pb;
    path_builder_init(&pb, base);

    int dir_fd = open(base, O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
    if (dir_fd == -1)
      return;

    DIR *dir = fdopendir(dir_fd);
    if (!dir) {
      close(dir_fd);
      return;
    }

    struct dirent *entry;

    while ((entry = readdir(dir)) != NULL) {
      if (entry->d_name[0] == '.' &&
          (entry->d_name[1] == 0 ||
           (entry->d_name[1] == '.' && entry->d_name[2] == 0)))
        continue;

      size_t name_len = strlen(entry->d_name);
      path_builder_set_filename(&pb, entry->d_name, name_len);

      int file_type = DT_UNKNOWN;
#ifdef _DIRENT_HAVE_D_TYPE
      file_type = entry->d_type;
#endif

      // Fast path using d_type
      if (file_type != DT_UNKNOWN) {
        if (file_type == DT_LNK)
          continue; // Skip symlinks

        if (file_type == DT_DIR) {
          char *dir_path = path_builder_dup_arena(&pb, ctx->path_arena, false);
          mpmc_push_work(ctx->dir_queue, dir_path);
          continue;
        }

        if (file_type == DT_REG) {
          atomic_fetch_add(&g_files_found, 1);
          FileEntry *fe = arena_push(&ctx->meta_arena, sizeof(FileEntry), true);

          // Use fstatat for file info
          struct stat st;
          if (fstatat(dir_fd, entry->d_name, &st, 0) == 0) {
            // Convert times using fd variant
            platform_get_file_times_fd(dir_fd, entry->d_name, &fe->created_time,
                                       &fe->modified_time);
            platform_get_file_owner_fd(dir_fd, entry->d_name, fe->owner,
                                       sizeof(fe->owner));
            fe->size_bytes = (uint64_t)st.st_size;

            // Normalize path
            char temp_path[MAX_PATHLEN];
            memcpy(temp_path, pb.buffer,
                   (pb.filename_pos - pb.buffer) + name_len + 1);
            normalize_path(temp_path);

            fe->path =
                arena_push(&ctx->path_arena, strlen(temp_path) + 1, false);
            strcpy(fe->path, temp_path);

            mpmc_push(ctx->file_queue, fe);
          }
          continue;
        }
      }

      // Fallback for unknown types
      struct stat st;
      if (fstatat(dir_fd, entry->d_name, &st, AT_SYMLINK_NOFOLLOW) == 0) {
        if (S_ISLNK(st.st_mode))
          continue;

        if (S_ISDIR(st.st_mode)) {
          char *dir_path = path_builder_dup_arena(&pb, ctx->path_arena, false);
          mpmc_push_work(ctx->dir_queue, dir_path);
        } else if (S_ISREG(st.st_mode)) {
          atomic_fetch_add(&g_files_found, 1);
          FileEntry *fe = arena_push(&ctx->meta_arena, sizeof(FileEntry), true);

          platform_get_file_times(pb.buffer, &fe->created_time,
                                  &fe->modified_time);
          platform_get_file_owner(pb.buffer, fe->owner, sizeof(fe->owner));
          fe->size_bytes = (uint64_t)st.st_size;

          char temp_path[MAX_PATHLEN];
          memcpy(temp_path, pb.buffer,
                 (pb.filename_pos - pb.buffer) + name_len + 1);
          normalize_path(temp_path);

          fe->path = arena_push(&ctx->path_arena, strlen(temp_path) + 1, false);
          strcpy(fe->path, temp_path);

          mpmc_push(ctx->file_queue, fe);
        }
      }
    }

    closedir(dir); // Closes dir_fd automatically
  }

#endif

// ------------------------- Scan worker --------------------------------
static THREAD_RETURN scan_worker(void *arg) {
  ScannerContext *ctx = (ScannerContext *)arg;

  for (;;) {
    char *dir = mpmc_pop(ctx->dir_queue);
    if (!dir)
      break;

    scan_folder(dir, ctx);

    mpmc_task_done(ctx->dir_queue, ctx->num_threads);
  }

  return THREAD_RETURN_VALUE;
}

// ----------------------------- Hashing helpers -----------------------------
static void xxh3_hash_file_stream(const char *path, char *out_hex,
                                  unsigned char *buf) {
  XXH128_hash_t h;
  XXH3_state_t state;
  XXH3_128bits_reset(&state);

  FileHandle handle = os_file_open(path);
  if (handle == INVALID_FILE_HANDLE) {
    strcpy(out_hex, "ERROR");
    return;
  }

  uint64_t bytes_read;
  while (os_file_read(handle, buf, READ_BLOCK, &bytes_read) == 0 &&
         bytes_read > 0) {
    XXH3_128bits_update(&state, buf, (size_t)bytes_read);
    atomic_fetch_add(&g_bytes_processed, bytes_read);
  }

  os_file_close(handle);

  h = XXH3_128bits_digest(&state);
  snprintf(out_hex, HASH_STRLEN, "%016llx%016llx", (unsigned long long)h.high64,
           (unsigned long long)h.low64);
}

// ------------------------- Hash worker --------------------------------
static THREAD_RETURN hash_worker(void *arg) {
  WorkerContext *ctx = (WorkerContext *)arg;
  unsigned char *buf = (unsigned char *)malloc(READ_BLOCK);

  for (;;) {
    FileEntry *fe = mpmc_pop(ctx->file_queue);
    if (!fe)
      break;

    char hash[HASH_STRLEN];
    xxh3_hash_file_stream(fe->path, hash, buf);

    char created[32], modified[32];
    format_time(fe->created_time, created, sizeof(created));
    format_time(fe->modified_time, modified, sizeof(modified));

    double size_kib = (double)fe->size_bytes / 1024.0;

    char stack_buf[1024];

    int len =
        snprintf(stack_buf, sizeof(stack_buf), "%s\t%s\t%.2f\t%s\t%s\t%s\n",
                 hash, fe->path, size_kib, created, modified, fe->owner);

    char *dst = arena_push(&ctx->arena, len, false);
    memcpy(dst, stack_buf, len);

    atomic_fetch_add(&g_files_hashed, 1);
  }

  free(buf);

  return THREAD_RETURN_VALUE;
}

// ------------------------- Progress display ---------------------------
static THREAD_RETURN progress_thread(void *arg) {
  (void)arg;

  HiResTimer progress_timer;
  timer_start(&progress_timer);

  uint64_t last_bytes = 0;
  double last_time = 0.0;
  double displayed_speed = 0.0;
  const double sample_interval = 0.5;

  // Hide cursor to prevent flickering
  printf("\033[?25l");

  for (;;) {
    uint64_t found = atomic_load(&g_files_found);
    uint64_t hashed = atomic_load(&g_files_hashed);
    uint64_t bytes = atomic_load(&g_bytes_processed);
    int scan_done = atomic_load(&g_scan_done);

    double t = timer_elapsed(&progress_timer);
    double dt = t - last_time;

    if (dt >= sample_interval) {
      uint64_t db = (bytes > last_bytes) ? bytes - last_bytes : 0;
      displayed_speed = (double)db / (1024.0 * 1024.0) / dt;
      last_bytes = bytes;
      last_time = t;
    }

    printf("\r");

    if (!scan_done) {
      printf("\033[1mScanning:\033[0m %llu files | Hashed: %llu | \033[32m%.2f "
             "MB/s\033[0m    ",
             (unsigned long long)found, (unsigned long long)hashed,
             displayed_speed);
    } else {
      double pct = found ? (double)hashed / (double)found : 0.0;
      int barw = 40;
      int filled = (int)(pct * barw);

      printf("[");
      // Print filled part in Green (\033[32m)
      printf("\033[32m");
      for (int i = 0; i < filled; i++)
        putchar('#');
      // Reset color for empty part
      printf("\033[0m");
      for (int i = filled; i < barw; i++)
        putchar('.');

      printf("] %6.2f%% (%llu/%llu) \033[32m%.2f MB/s\033[0m    ", pct * 100.0,
             (unsigned long long)hashed, (unsigned long long)found,
             displayed_speed);
    }

    fflush(stdout);

    if (scan_done && hashed == found)
      break;
    sleep_ms(100);
  }

  // Restore cursor (\033[?25h) and move to next line
  printf("\033[?25h\n");

  return THREAD_RETURN_VALUE;
}

// ======================== Hash worker IO Ring ========================
// -------------------------- Configuration ---------------------------
#define NUM_BUFFERS_PER_THREAD 16
#define SUBMIT_TIMEOUT_MS 30000
#define USERDATA_REGISTER 1
#define IORING_READ_BLOCK (KiB(1024))
// Globals
u64 g_ioring_read_block = 4096 * 64;
static atomic_uint_fast64_t g_io_ring_fallbacks = 0;

// -------------------------- Buffer structure ---------------------------
typedef struct IoBuffer {
  void *data;
  uint64_t offset;
  size_t size;
  size_t bytes_read;
  HRESULT result;
  int buffer_id;
  int completed;
} IoBuffer;

// ============================================================================
// Thread-local I/O Ring context
// ============================================================================
typedef struct ThreadIoContext {
  HIORING ring;
  HANDLE completion_event;
  IoBuffer buffers[NUM_BUFFERS_PER_THREAD];
  int buffer_pool[NUM_BUFFERS_PER_THREAD];
  int free_count;
  int initialized;
} ThreadIoContext;

// -------------------------- File context ---------------------------
typedef struct FileReadContext {
  HANDLE hFile;
  uint64_t file_size;
  XXH3_state_t hash_state;
  char path[MAX_PATH];

  // Completion tracking
  int reads_submitted;
  int reads_completed;
  int reads_hashed;
  uint64_t bytes_hashed;
  int failed_reads;
  int active_reads;
  int buffers_ready; // Count of buffers ready to hash

  // For in-order hashing
  uint64_t next_hash_offset; // Next offset that needs to be hashed
  uint64_t next_read_offset; // Next offset to submit for reading

} FileReadContext;

static _Thread_local ThreadIoContext *g_thread_ctx = NULL;

// ---------------------- Initialize thread context ---------------------------
static ThreadIoContext *io_ring_init_thread(void) {
  if (g_thread_ctx && g_thread_ctx->initialized) {
    return g_thread_ctx;
  }

  if (!g_thread_ctx) {
    g_thread_ctx = (ThreadIoContext *)calloc(1, sizeof(ThreadIoContext));
    if (!g_thread_ctx)
      return NULL;
  }

  // Create I/O Ring
  IORING_CAPABILITIES caps;
  QueryIoRingCapabilities(&caps);

  UINT32 queue_size = min(4096, caps.MaxSubmissionQueueSize);
  IORING_CREATE_FLAGS flags = {0};
  HRESULT hr = CreateIoRing(caps.MaxVersion, flags, queue_size, queue_size * 2,
                            &g_thread_ctx->ring);

  // Create completion event
  g_thread_ctx->completion_event = CreateEvent(NULL, FALSE, FALSE, NULL);
  if (g_thread_ctx->completion_event) {
    SetIoRingCompletionEvent(g_thread_ctx->ring,
                             g_thread_ctx->completion_event);
  }

  // Initialize buffer pool
  IORING_BUFFER_INFO buf_info[NUM_BUFFERS_PER_THREAD];

  u64 buf_pool_size = g_ioring_read_block * NUM_BUFFERS_PER_THREAD;

  // Reserve and Commit the entire memory chunk
  void *base_ptr = plat_mem_reserve(buf_pool_size);
  if (base_ptr) {
    if (!plat_mem_commit(base_ptr, buf_pool_size)) {
      plat_mem_release(base_ptr, 0);
      return NULL;
    }
  } else {
    return NULL;
  }

  for (int i = 0; i < NUM_BUFFERS_PER_THREAD; i++) {

    g_thread_ctx->buffers[i].data = (u8 *)base_ptr + (i * g_ioring_read_block);

    g_thread_ctx->buffer_pool[i] = i;
    g_thread_ctx->buffers[i].buffer_id = i;

    buf_info[i].Address = g_thread_ctx->buffers[i].data;
    buf_info[i].Length = (ULONG)g_ioring_read_block;
  }

  g_thread_ctx->free_count = NUM_BUFFERS_PER_THREAD;

  HRESULT hb = BuildIoRingRegisterBuffers(
      g_thread_ctx->ring, NUM_BUFFERS_PER_THREAD, buf_info, USERDATA_REGISTER);

  if (FAILED(hb)) {
    printf("Buffer registration failed: 0x%lx\n", hb);
    return NULL;
  }

  // Submit registration
  SubmitIoRing(g_thread_ctx->ring, 0, 0, NULL);

  g_thread_ctx->initialized = 1;

  return g_thread_ctx;
}

static void io_ring_cleanup_thread(void) {
  if (!g_thread_ctx)
    return;

  if (g_thread_ctx->completion_event)
    CloseHandle(g_thread_ctx->completion_event);
  if (g_thread_ctx->ring)
    CloseIoRing(g_thread_ctx->ring);
  plat_mem_release(g_thread_ctx->buffers[0].data, 0);
  free(g_thread_ctx);
  g_thread_ctx = NULL;
}

// ---------------------- Get a free buffer from pool ------------------------
static IoBuffer *get_free_buffer(ThreadIoContext *ctx) {

  if (ctx->free_count == 0) {
    return NULL;
  }

  int idx = ctx->buffer_pool[--ctx->free_count];
  IoBuffer *buf = &ctx->buffers[idx];
  buf->completed = 0;
  buf->bytes_read = 0;
  buf->result = E_PENDING;

  return buf;
}

static void return_buffer(ThreadIoContext *ctx, IoBuffer *buf) {
  if (!buf)
    return;

  ctx->buffer_pool[ctx->free_count++] = buf->buffer_id;
}

// -------------------------- Submit async read ---------------------------
static HRESULT submit_read(ThreadIoContext *ctx, FileReadContext *file_ctx,
                           IoBuffer *buf, uint64_t offset, size_t size) {
  buf->offset = offset;
  buf->size = size;

  IORING_HANDLE_REF file_ref = IoRingHandleRefFromHandle(file_ctx->hFile);
  IORING_BUFFER_REF buffer_ref =
      IoRingBufferRefFromIndexAndOffset(buf->buffer_id, 0);

  HRESULT hr =
      BuildIoRingReadFile(ctx->ring, file_ref, buffer_ref, (UINT32)size, offset,
                          (UINT_PTR)buf, IOSQE_FLAGS_NONE);

  if (SUCCEEDED(hr)) {
    file_ctx->active_reads++;
    file_ctx->reads_submitted++;
  } else {
    buf->completed = 1;
    return_buffer(ctx, buf);
  }
  return hr;
}

// -------------------------- Process completions ---------------------------
static int process_completions(ThreadIoContext *ctx,
                               FileReadContext *file_ctx) {
  IORING_CQE cqe;
  int processed = 0;

  while (PopIoRingCompletion(ctx->ring, &cqe) == S_OK) {

    if (cqe.UserData == USERDATA_REGISTER || cqe.UserData == 0)
      continue;

    IoBuffer *buf = (IoBuffer *)cqe.UserData;

    if (buf && !buf->completed) {
      buf->result = cqe.ResultCode;
      buf->bytes_read = (DWORD)cqe.Information;
      buf->completed = 1;

      if (SUCCEEDED(cqe.ResultCode) && cqe.Information > 0) {
        file_ctx->active_reads--;
        file_ctx->reads_completed++;
        file_ctx->buffers_ready++;
      } else {
        file_ctx->failed_reads++;
        file_ctx->active_reads--;
        file_ctx->reads_completed++;
      }

      processed++;
    }
  }

  return processed;
}

// -------------------- Hash buffer in sequential order -----------------------
static int hash_sequential_buffers(ThreadIoContext *ctx,
                                   FileReadContext *file_ctx) {
  int hashed = 0;

  // Keep hashing while the next buffer in sequence is ready
  while (file_ctx->next_hash_offset < file_ctx->file_size) {
    // Find the buffer that contains next_hash_offset
    IoBuffer *found_buf = NULL;

    for (int i = 0; i < NUM_BUFFERS_PER_THREAD; i++) {
      IoBuffer *buf = &ctx->buffers[i];
      if (buf->completed && buf->offset == file_ctx->next_hash_offset) {
        found_buf = buf;
        break;
      }
    }

    if (!found_buf)
      break; // Buffer not ready yet

    // Found the correct buffer in order - hash it
    if (SUCCEEDED(found_buf->result) && found_buf->bytes_read > 0) {
      XXH3_128bits_update(&file_ctx->hash_state, found_buf->data,
                          found_buf->bytes_read);
      atomic_fetch_add(&g_bytes_processed, found_buf->bytes_read);

      // Update bytes_hashed for this file!
      file_ctx->bytes_hashed += found_buf->bytes_read;
      file_ctx->reads_hashed++;
      file_ctx->buffers_ready--;

      // Mark as processed and return buffer to pool
      found_buf->completed = 0;
      return_buffer(ctx, found_buf);

      // Move to next offset
      file_ctx->next_hash_offset += found_buf->size;
      hashed++;
    } else if (found_buf->bytes_read == 0 && SUCCEEDED(found_buf->result)) {
      // Read operation failed with an error code
      file_ctx->reads_hashed++;
      file_ctx->buffers_ready--;
      found_buf->completed = 0;
      return_buffer(ctx, found_buf);
      file_ctx->next_hash_offset += found_buf->size;
      hashed++;
    } else {
      // Read failed
      file_ctx->failed_reads++;
      file_ctx->reads_hashed++;
      file_ctx->buffers_ready--;
      found_buf->completed = 0;
      return_buffer(ctx, found_buf);
      file_ctx->next_hash_offset += found_buf->size;
      hashed++;
    }
  }

  return hashed;
}

// ------------- Submit pending reads - fill all free buffers -----------------
static int submit_pending_reads(ThreadIoContext *ctx,
                                FileReadContext *file_ctx) {
  int submitted = 0;

  while (1) {
    // Check if we have more data to read
    uint64_t current_offset = file_ctx->next_read_offset;
    int has_data = (current_offset < file_ctx->file_size);

    if (!has_data)
      break;

    // Get a free buffer
    IoBuffer *buf = get_free_buffer(ctx);
    if (!buf)
      break;

    size_t remaining = file_ctx->file_size - current_offset;

    size_t bytes_to_read;

    if (remaining >= g_ioring_read_block) {
      bytes_to_read = g_ioring_read_block;
    } else {
      // Round UP to sector size (4096)
      bytes_to_read = ALIGN_UP_POW2(remaining, g_pagesize);
    }

    HRESULT hr = submit_read(ctx, file_ctx, buf, current_offset, bytes_to_read);

    if (SUCCEEDED(hr)) {
      submitted++;

      file_ctx->next_read_offset += bytes_to_read;
    } else {
      return_buffer(ctx, buf);
      break;
    }
  }

  return submitted;
}

// -------------------------- Wait for completions ---------------------------
static void wait_for_completions(ThreadIoContext *ctx,
                                 FileReadContext *file_ctx) {
  int has_active = (file_ctx->active_reads > 0);

  if (has_active && ctx->completion_event) {
    WaitForSingleObject(ctx->completion_event, SUBMIT_TIMEOUT_MS);
  }
}

// ---------------------- Main parallel hashing function ----------------------
static void xxh3_hash_file_parallel(ThreadIoContext *ctx, const char *path,
                                    char *out_hex, unsigned char *temp_buffer) {

  // Validate I/O Ring
  if (!ctx || !ctx->ring) {
    xxh3_hash_file_stream(path, out_hex, temp_buffer);
    return;
  }

  HANDLE hFile = CreateFileA(
      path, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
      OPEN_EXISTING, FILE_FLAG_OVERLAPPED | FILE_FLAG_NO_BUFFERING, NULL);

  if (hFile == INVALID_HANDLE_VALUE) {
    xxh3_hash_file_stream(path, out_hex, temp_buffer);
    return;
  }

  LARGE_INTEGER file_size;
  if (!GetFileSizeEx(hFile, &file_size)) {
    xxh3_hash_file_stream(path, out_hex, temp_buffer);
    CloseHandle(hFile);
    return;
  }

  FileReadContext file_ctx;
  memset(&file_ctx, 0, sizeof(file_ctx));
  file_ctx.hFile = hFile;
  file_ctx.file_size = file_size.QuadPart;
  file_ctx.next_hash_offset = 0;
  file_ctx.next_read_offset = 0;
  strncpy(file_ctx.path, path, MAX_PATH - 1);
  file_ctx.path[MAX_PATH - 1] = 0;
  XXH3_128bits_reset(&file_ctx.hash_state);

  // Submit initial reads
  submit_pending_reads(ctx, &file_ctx);

  if (file_ctx.reads_submitted > 0) {
    UINT32 submitted = 0;
    SubmitIoRing(ctx->ring, 0, 0, &submitted);
  }

  // Main loop
  while (file_ctx.reads_hashed < file_ctx.reads_submitted) {
    // Process completions
    process_completions(ctx, &file_ctx);

    // Hash buffers in sequential order (critical!)
    hash_sequential_buffers(ctx, &file_ctx);

    // Submit more reads if needed
    if (file_ctx.active_reads < NUM_BUFFERS_PER_THREAD &&
        file_ctx.next_read_offset < file_ctx.file_size) {
      int new_reads = submit_pending_reads(ctx, &file_ctx);
      if (new_reads > 0) {
        UINT32 submitted = 0;
        SubmitIoRing(ctx->ring, 0, 0, &submitted);
      }
    }

    // Wait if nothing to hash and active reads exist
    if (file_ctx.active_reads > 0 && file_ctx.buffers_ready == 0) {
      wait_for_completions(ctx, &file_ctx);
    }
  }

  // Final verification
  if (file_ctx.bytes_hashed == file_ctx.file_size &&
      file_ctx.failed_reads == 0) {
    XXH128_hash_t h = XXH3_128bits_digest(&file_ctx.hash_state);
    snprintf(out_hex, HASH_STRLEN, "%016llx%016llx",
             (unsigned long long)h.high64, (unsigned long long)h.low64);
  } else {
    if (file_ctx.bytes_hashed != file_ctx.file_size) {
      atomic_fetch_add(&g_io_ring_fallbacks, 1);
    }
    xxh3_hash_file_stream(path, out_hex, temp_buffer);
  }

  CloseHandle(hFile);
}

// -------------------------- Hash worker I/O Ring ---------------------------
static THREAD_RETURN hash_worker_io_ring(void *arg) {
  WorkerContext *ctx = (WorkerContext *)arg;
  unsigned char *temp_buffer = (unsigned char *)malloc(READ_BLOCK);
  char hash[HASH_STRLEN];

  if (!temp_buffer)
    return THREAD_RETURN_VALUE;

  // Initialize I/O Ring for this thread
  ThreadIoContext *ring_ctx = io_ring_init_thread();
  if (!ring_ctx || !ring_ctx->ring) {
    printf("Thread %lu: I/O Ring unavailable, using buffered I/O\n",
           GetCurrentThreadId());
    free(temp_buffer);
    return hash_worker(arg);
  }

  for (;;) {
    FileEntry *fe = mpmc_pop(ctx->file_queue);
    if (!fe)
      break;

    // Pass the I/O Ring context to the hashing function
    xxh3_hash_file_parallel(ring_ctx, fe->path, hash, temp_buffer);

    char created[32], modified[32];
    format_time(fe->created_time, created, sizeof(created));
    format_time(fe->modified_time, modified, sizeof(modified));

    double size_kib = (double)fe->size_bytes / 1024.0;

    char stack_buf[1024];
    int len =
        snprintf(stack_buf, sizeof(stack_buf), "%s\t%s\t%.2f\t%s\t%s\t%s\n",
                 hash, fe->path, size_kib, created, modified, fe->owner);

    char *dst = arena_push(&ctx->arena, len, false);
    memcpy(dst, stack_buf, len);
    atomic_fetch_add(&g_files_hashed, 1);
  }

  io_ring_cleanup_thread();
  free(temp_buffer);

  return THREAD_RETURN_VALUE;
}