//@ts-check
import * as fs from 'fs'
import { dlopen, FFIType } from 'bun:ffi'
import { filesystems } from './suportedFilesystems'

/* These are the fs-independent mount-flags: up to 16 flags are
   supported  */
export const flags = {
    MS_RDONLY: 1,		/* Mount read-only.  */
    MS_NOSUID: 2,		/* Ignore suid and sgid bits.  */
    MS_NODEV: 4,			/* Disallow access to device special files.  */
    MS_NOEXEC: 8,		/* Disallow program execution.  */
    MS_SYNCHRONOUS: 16,		/* Writes are synced at once.  */
    MS_REMOUNT: 32,		/* Alter flags of a mounted FS.  */
    MS_MANDLOCK: 64,		/* Allow mandatory locks on an FS.  */
    MS_DIRSYNC: 128,		/* Directory modifications are synchronous.  */
    MS_NOATIME: 1024,		/* Do not update access times.  */
    MS_NODIRATIME: 2048,		/* Do not update directory access times.  */
    MS_BIND: 4096,		/* Bind directory at different place.  */
    MS_MOVE: 8192,
    MS_REC: 16384,
    MS_SILENT: 32768,
    MS_POSIXACL: 1 << 16,	/* VFS does not apply the umask.  */
    MS_UNBINDABLE: 1 << 17,	/* Change to unbindable.  */
    MS_PRIVATE: 1 << 18,		/* Change to private.  */
    MS_SLAVE: 1 << 19,		/* Change to slave.  */
    MS_SHARED: 1 << 20,		/* Change to shared.  */
    MS_RELATIME: 1 << 21,	/* Update atime relative to mtime/ctime.  */
    MS_KERNMOUNT: 1 << 22,	/* This is a kern_mount call.  */
    MS_I_VERSION:  1 << 23,	/* Update inode I_version field.  */
    MS_STRICTATIME: 1 << 24,	/* Always perform atime updates.  */
    MS_LAZYTIME: 1 << 25,	/* Update the on-disk [acm]times lazily.  */
    MS_ACTIVE: 1 << 30,
    MS_NOUSER: 1 << 31
};

const {
	symbols: {
		mount,
	},
} = dlopen('/usr/lib/libc.so.6', {
	mount: {
		args: [ FFIType.cstring, FFIType.cstring, FFIType.cstring, FFIType.u64, FFIType.cstring ],
		returns: FFIType.int,
	},
});



/**
 * @param {string} devicePath
 * @param {string} mountPoint
 * @param {string} fstype
 * @param {number} flags
 * @param {string} fsparams
 * @returns {number}
 */
export function JSmount(devicePath, mountPoint, fstype, flags, fsparams) {
    const filesystem = filesystems.find( v => v.name === fstype)
    if(! filesystem) {
        throw "Invalid filesystem"
    }

    if(! fs.existsSync(devicePath) && filesystem.hasdev)
        throw "Device don't exist"
    return mount(Buffer.from(devicePath), Buffer.from(mountPoint), Buffer.from(fstype), flags, Buffer.from(fsparams))
}