#include <stdint.h>
#include <stddef.h>
#include "vfs.h"
#include "kprintf.h"
#include "spinlock/spinlock.h"
#include "hal/hal.h"
#include "util/util.h"
#include "hshtb.h"
#include "assert.h"
#include "errors.h"
#include "fs/kvfs/kvfs.h"
#include "storedev/storedev.h"

VfsTable VFS_TABLE;

void vfs_init_kvfs(VfsMountPoint *mp) {
  mp->read = &kvfs_read;
  mp->write = &kvfs_write;
  mp->remove = &kvfs_remove;
  mp->check = &kvfs_check;
  mp->cleanup = &kvfs_cleanup;
}

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

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

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

  hal_memcpy(mp->label, mountpoint, hal_strlen(mountpoint));
  mp->backingsd = backingsd;
  mp->fstype = fstype;
  switch (fstype) {
    case VFS_KVFS:
      vfs_init_kvfs(mp);
      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, mountpoint, label, 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;
  }
  hal_memset(mp, 0, sizeof(*mp));
  spinlock_release(&mp->spinlock);
  return E_OK;
}

int32_t vfs_read(char *mountpoint, const char *path, uint8_t *const buffer, size_t n, size_t off) {
  VfsMountPoint *mp = NULL;

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

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

  return mp->read(mp, path, buffer, n, off);
}

int32_t vfs_write(char *mountpoint, const char *path, const uint8_t *const buffer, size_t n, size_t off) {
  VfsMountPoint *mp = NULL;

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

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

  return mp->write(mp, path, buffer, n, off);
}

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

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

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

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

int32_t tmpvars_init(void) {
  RamSdInitExtra extra = { .capacity = KVFS_NODES_MAX * KVFS_BUFFER_SIZE };
  StoreDev *backingsd = storedev_create(STOREDEV_RAMSD, &extra);
  if (backingsd == NULL) {
    return E_NOMEMORY;
  }
  return vfs_mount("tmpvars", VFS_KVFS, backingsd);
}

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

  tmpvars_init();

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

  for (size_t i = 0; i < LEN(VFS_TABLE.mountpoints); i++) {
    if (!VFS_TABLE.mountpoints[i].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]);
    if (vmp->check != NULL) {
      LOG("vfs", "check = %s\n", vmp->check() ? "OK" : "FAIL");
    } else {
      LOG("vfs", "check skipped\n");
    }
  }
}