#include <stdint.h>
#include <stddef.h>
#include "vfs/vfs.h"
#include "spinlock/spinlock.h"
#include "util/util.h"
#include "fs/portlfs/portlfs.h"
#include "storedev/storedev.h"
#include "baseimg/baseimg.h"
#include "dlmalloc/malloc.h"
#include "std/string.h"
#include "kprintf.h"
#include "errors.h"
#include "hshtb.h"

VfsTable VFS_TABLE;
VfsBusyObjs VFS_BUSY_VOBJS;

#define CHECK_BUSY_VFSOBJ() \
  char *tmpbuf = dlmalloc(VFS_MOUNTPOINT_LABEL_MAX+1+VFS_PATH_MAX); \
  \
  memset(tmpbuf, 0, VFS_MOUNTPOINT_LABEL_MAX+1+VFS_PATH_MAX); \
  strcat(tmpbuf, mountpoint); \
  strcat(tmpbuf, ":"); \
  strcat(tmpbuf, path); \
  \
  bool busy = false; \
  VfsObj *vobj, *vobjtmp; \
  spinlock_acquire(&VFS_BUSY_VOBJS.spinlock); \
  LL_FOREACH_SAFE(VFS_BUSY_VOBJS.vobjs, vobj, vobjtmp) { \
    if (strcmp(vobj->path, tmpbuf) == 0) { \
      busy = true; \
      break; \
    } \
  } \
  spinlock_release(&VFS_BUSY_VOBJS.spinlock); \
  \
  dlfree(tmpbuf);

void vfs_init_littlefs(VfsMountPoint *mp, bool format) {
  struct lfs_config *cfg = dlmalloc(sizeof(*cfg));
  memset(cfg, 0, sizeof(*cfg));
  cfg->context = mp;
  cfg->read = &portlfs_read;
  cfg->prog = &portlfs_prog;
  cfg->erase = &portlfs_erase;
  cfg->sync = &portlfs_sync;
  cfg->block_size = LITTLEFS_BLOCK_SIZE;
  cfg->block_count = mp->backingsd->capacity(mp->backingsd) / LITTLEFS_BLOCK_SIZE;
  cfg->read_size = LITTLEFS_BLOCK_SIZE;
  cfg->prog_size = LITTLEFS_BLOCK_SIZE;
  cfg->block_cycles = 16;
  cfg->cache_size = LITTLEFS_BLOCK_SIZE;
  cfg->lookahead_size = LITTLEFS_BLOCK_SIZE;
  cfg->read_buffer = NULL;
  cfg->prog_buffer = NULL;
  cfg->lookahead_buffer = NULL;
  cfg->name_max = 0;
  cfg->file_max = 0;
  cfg->attr_max = 0;
  if (format) {
    lfs_format(&mp->fs.littlefs.instance, cfg);
  }
  int err = lfs_mount(&mp->fs.littlefs.instance, cfg);
  if (err < 0) {
    ERR("vfs", "Little FS mount failed %d\n", err);
  }

  mp->cleanup     = &littlefs_cleanup;
  mp->open        = &littlefs_open;
  mp->stat        = &littlefs_stat;
  mp->fetchdirent = &littlefs_fetchdirent;
  mp->mkdir       = &littlefs_mkdir;
  mp->delete      = &littlefs_delete;
}

int32_t vfs_stat(char *mountpoint, const char *path, FsStat *stat) {
  VfsMountPoint *mp = NULL;

  spinlock_acquire(&VFS_TABLE.spinlock);
  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
  spinlock_release(&VFS_TABLE.spinlock);

  if (mp == NULL) {
    return E_NOENTRY;
  }

  return mp->stat(mp, path, stat);
}

int32_t vfs_mkdir(char *mountpoint, const char *path) {
  VfsMountPoint *mp = NULL;

  spinlock_acquire(&VFS_TABLE.spinlock);
  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
  spinlock_release(&VFS_TABLE.spinlock);

  if (mp == NULL) {
    return E_NOENTRY;
  }

  return mp->mkdir(mp, path);
}

int32_t vfs_fetchdirent(char *mountpoint, const char *path, FsDirent *direntbuf, size_t idx) {
  VfsMountPoint *mp = NULL;

  spinlock_acquire(&VFS_TABLE.spinlock);
  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
  spinlock_release(&VFS_TABLE.spinlock);

  if (mp == NULL) {
    return E_NOENTRY;
  }

  return mp->fetchdirent(mp, path, direntbuf, idx);
}

int32_t vfs_delete(char *mountpoint, const char *path) {
  CHECK_BUSY_VFSOBJ()

  if (busy) {
    return E_NOTYET;
  }

  VfsMountPoint *mp = NULL;

  spinlock_acquire(&VFS_TABLE.spinlock);
  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
  spinlock_release(&VFS_TABLE.spinlock);

  if (mp == NULL) {
    return E_NOENTRY;
  }

  return mp->delete(mp, path);
}

int32_t vfs_mount(char *mountpoint, int32_t fstype, StoreDev *backingsd, bool format) {
  VfsMountPoint *mp = NULL;

  spinlock_acquire(&VFS_TABLE.spinlock);
  HSHTB_ALLOC(VFS_TABLE.mountpoints, label, mountpoint, mp);
  spinlock_release(&VFS_TABLE.spinlock);

  if (mp == NULL) {
    return E_NOMEMORY;
  }

  memcpy(mp->label, mountpoint, strlen(mountpoint));
  mp->backingsd = backingsd;
  mp->fstype = fstype;
  switch (fstype) {
    case VFS_LITTLEFS:
      vfs_init_littlefs(mp, format);
      break;
    default:
      return E_UNKNOWN_FSTYPE;
  }

  return E_OK;
}

int32_t vfs_unmount(char *mountpoint) {
  VfsMountPoint *mp = NULL;

  spinlock_acquire(&VFS_TABLE.spinlock);
  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
  spinlock_release(&VFS_TABLE.spinlock);

  if (mp == NULL) {
    return E_NOENTRY;
  }

  spinlock_acquire(&mp->spinlock);
  int32_t err = mp->cleanup(mp);
  if (err != E_OK) {
    spinlock_release(&mp->spinlock);
    return err;
  }
  memset(mp, 0, sizeof(*mp));
  spinlock_release(&mp->spinlock);
  return E_OK;
}

VfsObj *vfs_open(char *mountpoint, const char *path, uint32_t flags) {
  CHECK_BUSY_VFSOBJ()

  if (busy) {
    return NULL;
  }

  VfsMountPoint *mp = NULL;

  spinlock_acquire(&VFS_TABLE.spinlock);
  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
  spinlock_release(&VFS_TABLE.spinlock);

  if (mp == NULL) {
    return NULL;
  }

  VfsObj *vobj1 = mp->open(mp, path, flags);
  if (vobj1 == NULL) {
    return NULL;
  }

  strcat(vobj1->path, mountpoint);
  strcat(vobj1->path, ":");
  strcat(vobj1->path, path);

  spinlock_acquire(&VFS_BUSY_VOBJS.spinlock);
  LL_APPEND(VFS_BUSY_VOBJS.vobjs, vobj1);
  spinlock_release(&VFS_BUSY_VOBJS.spinlock);

  return vobj1;
}

void vfs_close(VfsObj *vobj) {
  spinlock_acquire(&VFS_BUSY_VOBJS.spinlock);
  LL_REMOVE(VFS_BUSY_VOBJS.vobjs, vobj);
  spinlock_release(&VFS_BUSY_VOBJS.spinlock);
  vobj->cleanup(vobj);
}

void vfs_init(void) {
  memset(&VFS_TABLE, 0, sizeof(VFS_TABLE));
  spinlock_init(&VFS_TABLE.spinlock);
  memset(&VFS_BUSY_VOBJS, 0, sizeof(VFS_BUSY_VOBJS));
  spinlock_init(&VFS_BUSY_VOBJS.spinlock);

  {
    RamSdInitExtra extra = { .capacity = baseimg_getsize(), .preallocbuffer = (uint8_t *)baseimg_getaddr() };
    StoreDev *backingsd = storedev_create(STOREDEV_RAMSD, "ramsd-0", &extra);
    if (backingsd == NULL) {
      return;
    }
    vfs_mount("base", VFS_LITTLEFS, backingsd, false);
  }

  {
    RamSdInitExtra extra = { .capacity = (1024*1024*10) };
    StoreDev *backingsd = storedev_create(STOREDEV_RAMSD, "ramsd-1", &extra);
    if (backingsd == NULL) {
      return;
    }
    vfs_mount("temp", VFS_LITTLEFS, backingsd, true);
  }

  LOG("vfs", "init\n");

  for (size_t i = 0; i < LEN(VFS_TABLE.mountpoints); i++) {
    if (VFS_TABLE.mountpoints[i]._hshtbstate != HSHTB_TAKEN) continue;
    VfsMountPoint *vmp = &VFS_TABLE.mountpoints[i];
    LOG("vfs", "mount point %s: %s, backing device: %s\n",
        vmp->label, vfs_strings[vmp->fstype], storedev_strings[vmp->backingsd->sdtype]);
  }
}