#ifndef FUSEAPP_H
#define FUSEAPP_H

#define FUSE_USE_VERSION 26
#include <fuse.h>
#include <typeinfo>
#include <exception>
#include <stdio.h>
#include <errno.h>

class FuseAppBase {
	public:
		FuseAppBase();
		virtual ~FuseAppBase() = 0;
		virtual void * init (struct fuse_conn_info * info);
		virtual int opt_parse(void *, const char * arg, int key, struct fuse_args *);
		virtual int access(const char *, int);
		virtual int chmod(const char *, mode_t);
		virtual int chown(const char *, uid_t, gid_t);
		virtual int create(const char *, mode_t, struct fuse_file_info *);
		virtual int fgetattr(const char *, struct stat *, struct fuse_file_info *);
		virtual int flush(const char *, struct fuse_file_info *);
		virtual int fsync(const char *, int, struct fuse_file_info *);
		virtual int fsyncdir(const char *, int, struct fuse_file_info *);
		virtual int ftruncate(const char *, off_t, struct fuse_file_info *);
		virtual int getattr(const char *, struct stat *);
		virtual int getxattr(const char *, const char *, char *, size_t);
		virtual int link(const char *, const char *);
		virtual int listxattr(const char *, char *, size_t);
		virtual int mkdir(const char *, mode_t);
		virtual int mknod(const char *, mode_t, dev_t);
		virtual int open(const char *, struct fuse_file_info *);
		virtual int opendir(const char *, struct fuse_file_info *);
		virtual int read(const char *, char *, size_t, off_t, struct fuse_file_info *);
		virtual int readdir(const char *, void *, fuse_fill_dir_t, off_t, struct fuse_file_info *);
		virtual int readlink(const char *, char *, size_t);
		virtual int release(const char *, struct fuse_file_info *);
		virtual int releasedir(const char *, struct fuse_file_info *);
		virtual int removexattr(const char *, const char *);
		virtual int rename(const char *, const char *);
		virtual int rmdir(const char *);
		virtual int setxattr(const char *, const char *, const char *, size_t, int);
		virtual int statfs(const char *, struct statvfs *);
		virtual int symlink(const char *, const char *);
		virtual int truncate(const char *, off_t);
		virtual int unlink(const char *);
		virtual int write(const char *, const char *, size_t, off_t, struct fuse_file_info *);
		virtual int lock(const char *, struct fuse_file_info *, int cmd, struct flock *);
		virtual int utimens(const char *, const struct timespec tv[2]);
		virtual int bmap(const char *, size_t blocksize, uint64_t *idx);
		virtual int ioctl(const char *, int cmd, void *arg, struct fuse_file_info *, unsigned int flags, void * data);
		virtual int poll(const char *, struct fuse_file_info *, struct fuse_pollhandle *, unsigned *);
		virtual int write_buf(const char *, struct fuse_bufvec *buf, off_t off, struct fuse_file_info *);
		virtual int read_buf(const char *, struct fuse_bufvec **bufp, size_t size, off_t off, struct fuse_file_info *);
		virtual int flock(const char *, struct fuse_file_info *, int op);
		virtual int fallocate(const char *, int, off_t, off_t, struct fuse_file_info *);
		virtual int onError(const std::exception & err) throw();

#define IFIMPL(func) typeid(&FuseAppBase::func) == typeid(&FuseApp::func) ? NULL :
		template <typename FuseApp>
		static int run(int & argc, char** & argv, FuseApp * fa)
		{
			auto args = runint(argc, argv, fa);
			struct fuse_operations operations = {
				IFIMPL(getattr) fuseCall<const char *, struct stat *>::helper<&FuseAppBase::getattr>,
				IFIMPL(readlink) fuseCall<const char *, char *, size_t>::helper<&FuseAppBase::readlink>,
				NULL, // getdir deprecated
				IFIMPL(mknod) fuseCall<const char *, mode_t, dev_t>::helper<&FuseAppBase::mknod>,
				IFIMPL(mkdir) fuseCall<const char *, mode_t>::helper<&FuseAppBase::mkdir>,
				IFIMPL(unlink) fuseCall<const char *>::helper<&FuseAppBase::unlink>,
				IFIMPL(rmdir) fuseCall<const char *>::helper<&FuseAppBase::rmdir>,
				IFIMPL(symlink) fuseCall<const char *, const char *>::helper<&FuseAppBase::symlink>,
				IFIMPL(rename) fuseCall<const char *, const char *>::helper<&FuseAppBase::rename>,
				IFIMPL(link) fuseCall<const char *, const char *>::helper<&FuseAppBase::link>,
				IFIMPL(chmod) fuseCall<const char *, mode_t>::helper<&FuseAppBase::chmod>,
				IFIMPL(chown) fuseCall<const char *, uid_t, gid_t>::helper<&FuseAppBase::chown>,
				IFIMPL(truncate) fuseCall<const char *, off_t>::helper<&FuseAppBase::truncate>,
				NULL, // utime deprecated
				IFIMPL(open) fuseCall<const char *, struct fuse_file_info *>::helper<&FuseAppBase::open>,
				IFIMPL(read) fuseCall<const char *, char *, size_t, off_t, struct fuse_file_info *>::helper<&FuseAppBase::read>,
				IFIMPL(write) fuseCall<const char *, const char *, size_t, off_t, struct fuse_file_info *>::helper<&FuseAppBase::write>,
				IFIMPL(statfs) fuseCall<const char *, struct statvfs *>::helper<&FuseAppBase::statfs>,
				IFIMPL(flush) fuseCall<const char *, struct fuse_file_info *>::helper<&FuseAppBase::flush>,
				IFIMPL(release) fuseCall<const char *, struct fuse_file_info *>::helper<&FuseAppBase::release>,
				IFIMPL(fsync) fuseCall<const char *, int, struct fuse_file_info *>::helper<&FuseAppBase::fsync>,
				IFIMPL(setxattr) fuseCall<const char *, const char *, const char *, size_t, int>::helper<&FuseAppBase::setxattr>,
				IFIMPL(getxattr) fuseCall<const char *, const char *, char *, size_t>::helper<&FuseAppBase::getxattr>,
				IFIMPL(listxattr) fuseCall<const char *, char *, size_t>::helper<&FuseAppBase::listxattr>,
				IFIMPL(removexattr) fuseCall<const char *, const char *>::helper<&FuseAppBase::removexattr>,
				IFIMPL(opendir) fuseCall<const char *, struct fuse_file_info *>::helper<&FuseAppBase::opendir>,
				IFIMPL(readdir) fuseCall<const char *, void *, fuse_fill_dir_t, off_t, struct fuse_file_info *>::helper<&FuseAppBase::readdir>,
				IFIMPL(releasedir) fuseCall<const char *, struct fuse_file_info *>::helper<&FuseAppBase::releasedir>,
				IFIMPL(fsyncdir) fuseCall<const char *, int, struct fuse_file_info *>::helper<&FuseAppBase::fsyncdir>,
				fuseInit,
				fuseDestroy,
				IFIMPL(access) fuseCall<const char *, int>::helper<&FuseAppBase::access>,
				IFIMPL(create) fuseCall<const char *, mode_t, struct fuse_file_info *>::helper<&FuseAppBase::create>,
				IFIMPL(fgetattr) fuseCall<const char *, off_t, struct fuse_file_info *>::helper<&FuseAppBase::ftruncate>,
				IFIMPL(fgetattr) fuseCall<const char *, struct stat *, struct fuse_file_info *>::helper<&FuseAppBase::fgetattr>,
#if (FUSE_MINOR_VERSION >= 6)
				IFIMPL(lock) fuseCall<const char *, struct fuse_file_info *, int, struct flock *>::helper<&FuseAppBase::lock>,
				IFIMPL(utimens) fuseCall<const char *, const struct timespec [2]>::helper<&FuseAppBase::utimens>,
				IFIMPL(bmap) fuseCall<const char *, size_t, uint64_t *>::helper<&FuseAppBase::bmap>,
#if (FUSE_MINOR_VERSION >= 8)
				0, // flag_nullpath_ok
#if (FUSE_MINOR_VERSION >= 9)
				0, // flag_nopath
				0, // flag_utime_omit_ok
#endif
				0, // flag_reserved
				IFIMPL(ioctl) fuseCall<const char *, int, void *, struct fuse_file_info *, unsigned int, void *>::helper<&FuseAppBase::ioctl>,
				IFIMPL(poll) fuseCall<const char *, struct fuse_file_info *, struct fuse_pollhandle *, unsigned *>::helper<&FuseAppBase::poll>,
#if (FUSE_MINOR_VERSION >= 9)
				IFIMPL(write_buf) fuseCall<const char *, struct fuse_bufvec *, off_t, struct fuse_file_info *>::helper<&FuseAppBase::write_buf>,
				IFIMPL(read_buf) fuseCall<const char *, struct fuse_bufvec **, size_t, off_t, struct fuse_file_info *>::helper<&FuseAppBase::read_buf>,
				IFIMPL(flock) fuseCall<const char *, struct fuse_file_info *, int>::helper<&FuseAppBase::flock>,
				IFIMPL(fallocate) fuseCall<const char *, int, off_t, off_t, struct fuse_file_info *>::helper<&FuseAppBase::fallocate>,
#endif
#endif
#endif
			};
			return fuse_main(args.argc, args.argv, &operations, fa);
		}
	private:
		static struct fuse_args runint(int &, char ** &, FuseAppBase *);
		static void * fuseInit(struct fuse_conn_info *conn);
		static void fuseDestroy(void *);

		template <typename... Args>
		class fuseCall {
			public:
				template <int (FuseAppBase::*f)(Args...)>
				static int helper(Args ... a)
				{
					try {
						return (fuseApp->*f)(a...);
					}
					catch (const std::exception & ex) {
						if (int rtn = fuseApp->onError(ex)) {
							return rtn;
						}
						return helper<f>(a...);
					}
					catch (...) {
						fprintf(stderr, "Unknown exception calling %s\n", typeid(f).name());
						return -ENOSYS;
					}
				}
		};

		static FuseAppBase * fuseApp;
};

#endif