#ifndef FUSEAPP_H
#define FUSEAPP_H

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

class DLL_PUBLIC 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();
		virtual void beforeOperation();
		void log(int level, const char * message) const throw();
		void logf(int level, const char * fmt, ...) const throw() __attribute__ ((__format__ (__printf__, 3, 4)));
		virtual void vlogf(int level, const char * fmt, va_list) const throw() __attribute__ ((__format__ (__printf__, 3, 0))) = 0;

		virtual int fuse_opt_parse(struct fuse_args *args, void *data, const struct fuse_opt opts[], fuse_opt_proc_t proc) = 0;
		virtual int main(int, char **, const struct fuse_operations *) = 0;

#define GetHelper(func) getHelper<decltype(&FuseAppBase::func), decltype(&FuseApp::func), &FuseAppBase::func>(&FuseAppBase::func)
		template <typename FuseApp>
		static int run(int argc, char ** argv, FuseApp * fa)
		{
			auto args = fa->runint(argc, argv);
			struct fuse_operations operations = {
				GetHelper(getattr),
				GetHelper(readlink),
				NULL, // getdir deprecated
				GetHelper(mknod),
				GetHelper(mkdir),
				GetHelper(unlink),
				GetHelper(rmdir),
				GetHelper(symlink),
				GetHelper(rename),
				GetHelper(link),
				GetHelper(chmod),
				GetHelper(chown),
				GetHelper(truncate),
				NULL, // utime deprecated
				GetHelper(open),
				GetHelper(read),
				GetHelper(write),
				GetHelper(statfs),
				GetHelper(flush),
				GetHelper(release),
				GetHelper(fsync),
				GetHelper(setxattr),
				GetHelper(getxattr),
				GetHelper(listxattr),
				GetHelper(removexattr),
				GetHelper(opendir),
				GetHelper(readdir),
				GetHelper(releasedir),
				GetHelper(fsyncdir),
				fuseInit,
				fuseDestroy,
				GetHelper(access),
				GetHelper(create),
				GetHelper(ftruncate),
				GetHelper(fgetattr),
#if (FUSE_MINOR_VERSION >= 6)
				GetHelper(lock),
				GetHelper(utimens),
				GetHelper(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
				GetHelper(ioctl),
				GetHelper(poll),
#if (FUSE_MINOR_VERSION >= 9)
				GetHelper(write_buf),
				GetHelper(read_buf),
				GetHelper(flock),
				GetHelper(fallocate),
#endif
#endif
#endif
			};
			return fa->main(args.argc, args.argv, &operations);
		}
		struct fuse_args runint(int, char **);

	private:
		static void * fuseInit(struct fuse_conn_info *conn);
		static void fuseDestroy(void *);

		template <typename BFunc, typename IFunc, BFunc bfunc, typename ... Args>
		static typename std::enable_if<!std::is_same<BFunc, IFunc>::value, int(*)(Args...)>::type getHelper(int(FuseAppBase::*)(Args...))
		{
			return &helper<BFunc, bfunc, Args...>;
		}
		template <typename BFunc, typename IFunc, BFunc bfunc, typename ... Args>
		static typename std::enable_if<std::is_same<BFunc, IFunc>::value, int(*)(Args...)>::type getHelper(int(FuseAppBase::*)(Args...))
		{
			return nullptr;
		}
		template <typename Func, Func f, typename ... Args>
		static int helper(Args ... a)
		{
			for (int t = 0; ; ++t) {
				try {
					fuseApp->beforeOperation();
					return (fuseApp->*f)(a...);
				}
				catch (const std::exception & ex) {
					if (t < 10) {
						if (int rtn = fuseApp->onError(ex)) {
							return rtn;
						}
					}
					else {
						fuseApp->logf(LOG_ERR, "Retries expired with %s calling %s", ex.what(), typeid(f).name());
						return -EIO;
					}
				}
				catch (...) {
					fuseApp->logf(LOG_ERR, "Unknown exception calling %s", typeid(f).name());
					return -EIO;
				}
			}
		}
		template <typename Func, Func f, typename ... Args>
		static int internalHelper(Args ... a)
		{
			return (fuseApp->*f)(a...);
		}

		static FuseAppBase * fuseApp;
};

#endif