#include "Fuse.h"
#include <memory>
#include <cassert>

#include "FuseErrnoException.h"
#include "Filesystem.h"
#include <iostream>
#include <messmer/cpp-utils/assert/assert.h>
#include <messmer/cpp-utils/logging/logging.h>
#include <csignal>

using std::vector;
using std::string;

namespace bf = boost::filesystem;
using namespace cpputils::logging;
using namespace fspp::fuse;

#define FUSE_OBJ ((Fuse *) fuse_get_context()->private_data)

// Remove the following line, if you don't want to output each fuse operation on the console
//#define FSPP_LOG 1

namespace {
int fusepp_getattr(const char *path, struct stat *stbuf) {
  int rs = FUSE_OBJ->getattr(bf::path(path), stbuf);
  return rs;
}

int fusepp_fgetattr(const char *path, struct stat *stbuf, fuse_file_info *fileinfo) {
  return FUSE_OBJ->fgetattr(bf::path(path), stbuf, fileinfo);
}

int fusepp_readlink(const char *path, char *buf, size_t size) {
  return FUSE_OBJ->readlink(bf::path(path), buf, size);
}

int fusepp_mknod(const char *path, mode_t mode, dev_t rdev) {
  return FUSE_OBJ->mknod(bf::path(path), mode, rdev);
}

int fusepp_mkdir(const char *path, mode_t mode) {
  return FUSE_OBJ->mkdir(bf::path(path), mode);
}

int fusepp_unlink(const char *path) {
  return FUSE_OBJ->unlink(bf::path(path));
}

int fusepp_rmdir(const char *path) {
  return FUSE_OBJ->rmdir(bf::path(path));
}

int fusepp_symlink(const char *to, const char *from) {
  return FUSE_OBJ->symlink(bf::path(to), bf::path(from));
}

int fusepp_rename(const char *from, const char *to) {
  return FUSE_OBJ->rename(bf::path(from), bf::path(to));
}

int fusepp_link(const char *from, const char *to) {
  return FUSE_OBJ->link(bf::path(from), bf::path(to));
}

int fusepp_chmod(const char *path, mode_t mode) {
  return FUSE_OBJ->chmod(bf::path(path), mode);
}

int fusepp_chown(const char *path, uid_t uid, gid_t gid) {
  return FUSE_OBJ->chown(bf::path(path), uid, gid);
}

int fusepp_truncate(const char *path, off_t size) {
  return FUSE_OBJ->truncate(bf::path(path), size);
}

int fusepp_ftruncate(const char *path, off_t size, fuse_file_info *fileinfo) {
  return FUSE_OBJ->ftruncate(bf::path(path), size, fileinfo);
}

int fusepp_utimens(const char *path, const timespec times[2]) {
  return FUSE_OBJ->utimens(bf::path(path), times);
}

int fusepp_open(const char *path, fuse_file_info *fileinfo) {
  return FUSE_OBJ->open(bf::path(path), fileinfo);
}

int fusepp_release(const char *path, fuse_file_info *fileinfo) {
  return FUSE_OBJ->release(bf::path(path), fileinfo);
}

int fusepp_read(const char *path, char *buf, size_t size, off_t offset, fuse_file_info *fileinfo) {
  return FUSE_OBJ->read(bf::path(path), buf, size, offset, fileinfo);
}

int fusepp_write(const char *path, const char *buf, size_t size, off_t offset, fuse_file_info *fileinfo) {
  return FUSE_OBJ->write(bf::path(path), buf, size, offset, fileinfo);
}

int fusepp_statfs(const char *path, struct statvfs *fsstat) {
  return FUSE_OBJ->statfs(bf::path(path), fsstat);
}

int fusepp_flush(const char *path, fuse_file_info *fileinfo) {
  return FUSE_OBJ->flush(bf::path(path), fileinfo);
}

int fusepp_fsync(const char *path, int datasync, fuse_file_info *fileinfo) {
  return FUSE_OBJ->fsync(bf::path(path), datasync, fileinfo);
}

//int fusepp_setxattr(const char*, const char*, const char*, size_t, int)
//int fusepp_getxattr(const char*, const char*, char*, size_t)
//int fusepp_listxattr(const char*, char*, size_t)
//int fusepp_removexattr(const char*, const char*)

int fusepp_opendir(const char *path, fuse_file_info *fileinfo) {
  return FUSE_OBJ->opendir(bf::path(path), fileinfo);
}

int fusepp_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, fuse_file_info *fileinfo) {
  return FUSE_OBJ->readdir(bf::path(path), buf, filler, offset, fileinfo);
}

int fusepp_releasedir(const char *path, fuse_file_info *fileinfo) {
  return FUSE_OBJ->releasedir(bf::path(path), fileinfo);
}

int fusepp_fsyncdir(const char *path, int datasync, fuse_file_info *fileinfo) {
  return FUSE_OBJ->fsyncdir(bf::path(path), datasync, fileinfo);
}

void* fusepp_init(fuse_conn_info *conn) {
  auto f = FUSE_OBJ;
  f->init(conn);
  return f;
}

void fusepp_destroy(void *userdata) {
  auto f = FUSE_OBJ;
  ASSERT(userdata == f, "Wrong userdata set");
  UNUSED(userdata); //In case the assert is disabled
  f->destroy();
}

int fusepp_access(const char *path, int mask) {
  return FUSE_OBJ->access(bf::path(path), mask);
}

int fusepp_create(const char *path, mode_t mode, fuse_file_info *fileinfo) {
  return FUSE_OBJ->create(bf::path(path), mode, fileinfo);
}

/*int fusepp_lock(const char*, fuse_file_info*, int cmd, flock*)
int fusepp_bmap(const char*, size_t blocksize, uint64_t *idx)
int fusepp_ioctl(const char*, int cmd, void *arg, fuse_file_info*, unsigned int flags, void *data)
int fusepp_poll(const char*, fuse_file_info*, fuse_pollhandle *ph, unsigned *reventsp)
int fusepp_write_buf(const char*, fuse_bufvec *buf, off_t off, fuse_file_info*)
int fusepp_read_buf(const chas*, struct fuse_bufvec **bufp, size_t size, off_T off, fuse_file_info*)
int fusepp_flock(const char*, fuse_file_info*, int op)
int fusepp_fallocate(const char*, int, off_t, off_t, fuse_file_info*)*/

fuse_operations *operations() {
  static std::unique_ptr<fuse_operations> singleton(nullptr);

  if (!singleton) {
    singleton = std::make_unique<fuse_operations>();
    singleton->getattr = &fusepp_getattr;
    singleton->fgetattr = &fusepp_fgetattr;
    singleton->readlink = &fusepp_readlink;
    singleton->mknod = &fusepp_mknod;
    singleton->mkdir = &fusepp_mkdir;
    singleton->unlink = &fusepp_unlink;
    singleton->rmdir = &fusepp_rmdir;
    singleton->symlink = &fusepp_symlink;
    singleton->rename = &fusepp_rename;
    singleton->link = &fusepp_link;
    singleton->chmod = &fusepp_chmod;
    singleton->chown = &fusepp_chown;
    singleton->truncate = &fusepp_truncate;
    singleton->utimens = &fusepp_utimens;
    singleton->open = &fusepp_open;
    singleton->read = &fusepp_read;
    singleton->write = &fusepp_write;
    singleton->statfs = &fusepp_statfs;
    singleton->flush = &fusepp_flush;
    singleton->release = &fusepp_release;
    singleton->fsync = &fusepp_fsync;
  /*#ifdef HAVE_SYS_XATTR_H
    singleton->setxattr = &fusepp_setxattr;
    singleton->getxattr = &fusepp_getxattr;
    singleton->listxattr = &fusepp_listxattr;
    singleton->removexattr = &fusepp_removexattr;
  #endif*/
    singleton->opendir = &fusepp_opendir;
    singleton->readdir = &fusepp_readdir;
    singleton->releasedir = &fusepp_releasedir;
    singleton->fsyncdir = &fusepp_fsyncdir;
    singleton->init = &fusepp_init;
    singleton->destroy = &fusepp_destroy;
    singleton->access = &fusepp_access;
    singleton->create = &fusepp_create;
    singleton->ftruncate = &fusepp_ftruncate;
  }

  return singleton.get();
}
}

Fuse::~Fuse() {
}

Fuse::Fuse(Filesystem *fs)
  :_fs(fs), _mountdir(), _running(false) {
}

void Fuse::run(int argc, char **argv) {
  vector<char*> _argv(argv, argv + argc);
  _mountdir = argv[1];
  fuse_main(_argv.size(), _argv.data(), operations(), (void*)this);
}

bool Fuse::running() const {
  return _running;
}

void Fuse::stop() {
  //TODO Find better way to unmount (i.e. don't use external fusermount). Unmounting by kill(getpid(), SIGINT) worked, but left the mount directory transport endpoint as not connected.
  int ret = system(("fusermount -z -u " + _mountdir.native()).c_str()); // "-z" takes care that if the filesystem can't be unmounted right now because something is opened, it will be unmounted as soon as it can be.
  if (ret != 0) {
    LOG(ERROR) << "Could not unmount filesystem";
  }
}

int Fuse::getattr(const bf::path &path, struct stat *stbuf) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "getattr(" << path << ", _, _)";
#endif
  try {
    _fs->lstat(path, stbuf);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::getattr: " << e.what();
    return -EIO;
  } catch(fspp::fuse::FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::fgetattr(const bf::path &path, struct stat *stbuf, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "fgetattr(" << path << ", _, _)\n";
#endif

  // On FreeBSD, trying to do anything with the mountpoint ends up
  // opening it, and then using the FD for an fgetattr.  So in the
  // special case of a path of "/", I need to do a getattr on the
  // underlying root directory instead of doing the fgetattr().
  // TODO Check if necessary
  if (path.native() == "/") {
    return getattr(path, stbuf);
  }

  try {
    _fs->fstat(fileinfo->fh, stbuf);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::fgetattr: " << e.what();
    return -EIO;
  } catch(fspp::fuse::FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::readlink(const bf::path &path, char *buf, size_t size) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "readlink(" << path << ", _, " << size << ")";
#endif
  try {
    _fs->readSymlink(path, buf, size);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::readlink: " << e.what();
    return -EIO;
  } catch (fspp::fuse::FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::mknod(const bf::path &path, mode_t mode, dev_t rdev) {
  UNUSED(rdev);
  UNUSED(mode);
  UNUSED(path);
  LOG(WARN) << "Called non-implemented mknod(" << path << ", " << mode << ", _)";
  return ENOSYS;
}

int Fuse::mkdir(const bf::path &path, mode_t mode) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "mkdir(" << path << ", " << mode << ")";
#endif
  try {
    auto context = fuse_get_context();
    _fs->mkdir(path, mode, context->uid, context->gid);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::mkdir: " << e.what();
    return -EIO;
  } catch(fspp::fuse::FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::unlink(const bf::path &path) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "unlink(" << path << ")";
#endif
  try {
    _fs->unlink(path);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::unlink: " << e.what();
    return -EIO;
  } catch(fspp::fuse::FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::rmdir(const bf::path &path) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "rmdir(" << path << ")";
#endif
  try {
    _fs->rmdir(path);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::rmdir: " << e.what();
    return -EIO;
  } catch(fspp::fuse::FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::symlink(const bf::path &from, const bf::path &to) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "symlink(" << from << ", " << to << ")";
#endif
  try {
	auto context = fuse_get_context();
    _fs->createSymlink(from, to, context->uid, context->gid);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::symlink: " << e.what();
    return -EIO;
  } catch(fspp::fuse::FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::rename(const bf::path &from, const bf::path &to) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "rename(" << from << ", " << to << ")";
#endif
  try {
    _fs->rename(from, to);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::rename: " << e.what();
    return -EIO;
  } catch(fspp::fuse::FuseErrnoException &e) {
    return -e.getErrno();
  }
}

//TODO
int Fuse::link(const bf::path &from, const bf::path &to) {
  LOG(WARN) << "NOT IMPLEMENTED: link(" << from << ", " << to << ")";
  //auto real_from = _impl->RootDir() / from;
  //auto real_to = _impl->RootDir() / to;
  //int retstat = ::link(real_from.c_str(), real_to.c_str());
  //return errcode_map(retstat);
  return ENOSYS;
}

int Fuse::chmod(const bf::path &path, mode_t mode) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "chmod(" << path << ", " << mode << ")";
#endif
  try {
	_fs->chmod(path, mode);
	return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::chmod: " << e.what();
    return -EIO;
  } catch (fspp::fuse::FuseErrnoException &e) {
	return -e.getErrno();
  }
}

int Fuse::chown(const bf::path &path, uid_t uid, gid_t gid) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "chown(" << path << ", " << uid << ", " << gid << ")";
#endif
  try {
	_fs->chown(path, uid, gid);
	return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::chown: " << e.what();
    return -EIO;
  } catch (fspp::fuse::FuseErrnoException &e) {
	return -e.getErrno();
  }
}

int Fuse::truncate(const bf::path &path, off_t size) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "truncate(" << path << ", " << size << ")";
#endif
  try {
    _fs->truncate(path, size);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::truncate: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::ftruncate(const bf::path &path, off_t size, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "ftruncate(" << path << ", " << size << ")";
#endif
  UNUSED(path);
  try {
    _fs->ftruncate(fileinfo->fh, size);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::ftruncate: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

//TODO
int Fuse::utimens(const bf::path &path, const timespec times[2]) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "utimens(" << path << ", _)";
#endif
  try {
    _fs->utimens(path, times);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::utimens: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::open(const bf::path &path, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "open(" << path << ", _)";
#endif
  try {
    fileinfo->fh = _fs->openFile(path, fileinfo->flags);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::open: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::release(const bf::path &path, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "release(" << path << ", _)";
#endif
  UNUSED(path);
  try {
    _fs->closeFile(fileinfo->fh);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::release: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::read(const bf::path &path, char *buf, size_t size, off_t offset, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "read(" << path << ", _, " << size << ", " << offset << ", _ )";
#endif
  UNUSED(path);
  try {
    return _fs->read(fileinfo->fh, buf, size, offset);
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::read: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::write(const bf::path &path, const char *buf, size_t size, off_t offset, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "write(" << path << ", _, " << size << ", " << offset << ", _)";
#endif
  UNUSED(path);
  try {
    _fs->write(fileinfo->fh, buf, size, offset);
    return size;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::write: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

//TODO
int Fuse::statfs(const bf::path &path, struct statvfs *fsstat) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "statfs(" << path << ", _)";
#endif
  try {
    _fs->statfs(path, fsstat);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::statfs: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

//TODO
int Fuse::flush(const bf::path &path, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  //TODO Implement it
  LOG(WARN) << "Called non-implemented flush(" << path << ", _)";
#endif
  UNUSED(path);
  try {
    _fs->flush(fileinfo->fh);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::flush: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::fsync(const bf::path &path, int datasync, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "fsync(" << path << ", " << datasync << ", _)";
#endif
  UNUSED(path);
  try {
    if (datasync) {
      _fs->fdatasync(fileinfo->fh);
    } else {
      _fs->fsync(fileinfo->fh);
    }
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::fsync: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::opendir(const bf::path &path, fuse_file_info *fileinfo) {
  UNUSED(path);
  UNUSED(fileinfo);
  //LOG(DEBUG) << "opendir(" << path << ", _)";
  //We don't need opendir, because readdir works directly on the path
  return 0;
}

int Fuse::readdir(const bf::path &path, void *buf, fuse_fill_dir_t filler, off_t offset, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "readdir(" << path << ", _, _, " << offset << ", _)";
#endif
  UNUSED(fileinfo);
  UNUSED(offset);
  try {
    auto entries = _fs->readDir(path);
    struct stat stbuf;
    for (const auto &entry : *entries) {
      //We could pass more file metadata to filler() in its third parameter,
      //but it doesn't help performance since fuse ignores everything in stbuf
      //except for file-type bits in st_mode and (if used) st_ino.
      //It does getattr() calls on all entries nevertheless.
      if (entry.type == Dir::EntryType::DIR) {
        stbuf.st_mode = S_IFDIR;
      } else if (entry.type == Dir::EntryType::FILE) {
        stbuf.st_mode = S_IFREG;
      } else if (entry.type == Dir::EntryType::SYMLINK) {
        stbuf.st_mode = S_IFLNK;
      } else {
        ASSERT(false, "Unknown entry type");
      }
      if (filler(buf, entry.name.c_str(), &stbuf, 0) != 0) {
        return -ENOMEM;
      }
    }
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::readdir: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::releasedir(const bf::path &path, fuse_file_info *fileinfo) {
  UNUSED(path);
  UNUSED(fileinfo);
  //LOG(DEBUG) << "releasedir(" << path << ", _)";
  //We don't need releasedir, because readdir works directly on the path
  return 0;
}

//TODO
int Fuse::fsyncdir(const bf::path &path, int datasync, fuse_file_info *fileinfo) {
  UNUSED(fileinfo);
  UNUSED(datasync);
  UNUSED(path);
  //LOG(WARN) << "Called non-implemented fsyncdir(" << path << ", " << datasync << ", _)";
  return 0;
}

void Fuse::init(fuse_conn_info *conn) {
  UNUSED(conn);
  _running = true;

#ifdef FSPP_LOG
  cpputils::logging::setLevel(DEBUG);
#endif

  LOG(INFO) << "Filesystem started.";
}

void Fuse::destroy() {
  _running = false;
  LOG(INFO) << "Filesystem stopped.";
}

int Fuse::access(const bf::path &path, int mask) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "access(" << path << ", " << mask << ")";
#endif
  try {
    _fs->access(path, mask);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::access: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}

int Fuse::create(const bf::path &path, mode_t mode, fuse_file_info *fileinfo) {
#ifdef FSPP_LOG
  LOG(DEBUG) << "create(" << path << ", " << mode << ", _)";
#endif
  try {
    auto context = fuse_get_context();
    fileinfo->fh = _fs->createAndOpenFile(path, mode, context->uid, context->gid);
    return 0;
  } catch(const cpputils::AssertFailed &e) {
    LOG(ERROR) << "AssertFailed in Fuse::create: " << e.what();
    return -EIO;
  } catch (FuseErrnoException &e) {
    return -e.getErrno();
  }
}