/*
  ISC License

  Copyright (c) 2025, Antonio SJ Musumeci <trapexit@spawn.link>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/


#include "fuse_statx.hpp"

#include "config.hpp"
#include "errno.hpp"
#include "fileinfo.hpp"
#include "fs_inode.hpp"
#include "fs_path.hpp"
#include "fs_statx.hpp"
#include "str.hpp"
#include "symlinkify.hpp"
#include "ugid.hpp"

#include "fmt/core.h"

#include "fuse.h"

#include <string>


static
void
_set_stat_if_leads_to_dir(const std::string &path_,
                          struct fuse_statx *st_)
{
  int rv;
  struct fuse_statx st;

  rv = fs::statx(AT_FDCWD,path_,AT_SYMLINK_FOLLOW,STATX_TYPE,&st);
  if(rv < 0)
    return;

  if(S_ISDIR(st.mode))
    *st_ = st;

  return;
}

static
void
_set_stat_if_leads_to_reg(const std::string &path_,
                          struct fuse_statx *st_)
{
  int rv;
  struct fuse_statx st;

  rv = fs::statx(AT_FDCWD,path_,AT_SYMLINK_FOLLOW,STATX_TYPE,&st);
  if(rv < 0)
    return;

  if(S_ISREG(st.mode))
    *st_ = st;

  return;
}

static
int
_statx_fake_root(struct fuse_statx *st_)
{
  st_->ino     = 0;
  st_->mode    = (S_IFDIR|S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
  st_->nlink   = 2;
  st_->uid     = 0;
  st_->gid     = 0;
  st_->size    = 0;
  st_->blocks  = 0;
  st_->atime.tv_sec = 0;
  st_->mtime.tv_sec = 0;
  st_->ctime.tv_sec = 0;

  return 0;
}

static
int
_statx_controlfile(struct fuse_statx *st_)
{
  static const uid_t  uid = ::getuid();
  static const gid_t  gid = ::getgid();
  static const time_t now = ::time(NULL);

  st_->ino     = 0;
  st_->mode    = (S_IFREG|S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH);
  st_->nlink   = 1;
  st_->uid     = uid;
  st_->gid     = gid;
  st_->size    = 0;
  st_->blocks  = 0;
  st_->atime.tv_sec = now;
  st_->mtime.tv_sec = now;
  st_->ctime.tv_sec = now;

  return 0;
}

static
int
_statx(const Policy::Search &searchFunc_,
       const Branches       &branches_,
       const char           *fusepath_,
       const uint32_t        flags_,
       const uint32_t        mask_,
       struct fuse_statx    *st_,
       const bool            symlinkify_,
       const time_t          symlinkify_timeout_,
       FollowSymlinks        followsymlinks_)
{
  int rv;
  std::string fullpath;
  std::vector<Branch*> branches;

  rv = searchFunc_(branches_,fusepath_,branches);
  if(rv < 0)
    return rv;

  fullpath = fs::path::make(branches[0]->path,fusepath_);

  switch(followsymlinks_)
    {
    case FollowSymlinks::ENUM::NEVER:
      rv = fs::statx(AT_FDCWD,fullpath,flags_|AT_SYMLINK_NOFOLLOW,mask_,st_);
      break;
    case FollowSymlinks::ENUM::DIRECTORY:
      rv = fs::statx(AT_FDCWD,fullpath,flags_|AT_SYMLINK_NOFOLLOW,mask_,st_);
      if((rv >= 0) && S_ISLNK(st_->mode))
        ::_set_stat_if_leads_to_dir(fullpath,st_);
      break;
    case FollowSymlinks::ENUM::REGULAR:
      rv = fs::statx(AT_FDCWD,fullpath,flags_|AT_SYMLINK_NOFOLLOW,mask_,st_);
      if((rv >= 0) && S_ISLNK(st_->mode))
        ::_set_stat_if_leads_to_reg(fullpath,st_);
      break;
    case FollowSymlinks::ENUM::ALL:
      rv = fs::statx(AT_FDCWD,fullpath,flags_|AT_SYMLINK_FOLLOW,mask_,st_);
      if(rv < 0)
        rv = fs::statx(AT_FDCWD,fullpath,flags_|AT_SYMLINK_NOFOLLOW,mask_,st_);
      break;
    }

  if(rv < 0)
    return rv;

  if(symlinkify_ && symlinkify::can_be_symlink(*st_,symlinkify_timeout_))
    symlinkify::convert(fullpath,st_);

  fs::inode::calc(branches[0]->path,fusepath_,st_);

  return 0;
}

static
int
_statx(const char        *fusepath_,
       const uint32_t     flags_,
       const uint32_t     mask_,
       struct fuse_statx *st_,
       fuse_timeouts_t   *timeout_)
{
  int rv;
  Config::Read cfg;
  const fuse_context *fc = fuse_get_context();
  const ugid::Set     ugid(fc->uid,fc->gid);

  rv = ::_statx(cfg->func.getattr.policy,
                cfg->branches,
                fusepath_,
                flags_,
                mask_,
                st_,
                cfg->symlinkify,
                cfg->symlinkify_timeout,
                cfg->follow_symlinks);
  if((rv < 0) && Config::is_rootdir(fusepath_))
    return ::_statx_fake_root(st_);

  timeout_->entry = ((rv >= 0) ?
                     cfg->cache_entry :
                     cfg->cache_negative_entry);
  timeout_->attr  = cfg->cache_attr;

  return rv;
}

int
FUSE::statx(const char        *fusepath_,
            const uint32_t     flags_,
            const uint32_t     mask_,
            struct fuse_statx *st_,
            fuse_timeouts_t   *timeout_)
{
  if(Config::is_ctrl_file(fusepath_))
    return ::_statx_controlfile(st_);

  return ::_statx(fusepath_,
                  flags_|AT_STATX_DONT_SYNC,
                  mask_,
                  st_,
                  timeout_);
}

int
FUSE::statx_fh(const uint64_t     fh_,
               const uint32_t     flags_,
               const uint32_t     mask_,
               struct fuse_statx *st_,
               fuse_timeouts_t   *timeout_)
{
  FileInfo *fi = reinterpret_cast<FileInfo*>(fh_);

  return ::_statx(fi->fusepath.c_str(),
                  flags_|AT_STATX_DONT_SYNC,
                  mask_,
                  st_,
                  timeout_);
}