package rados

// #cgo LDFLAGS: -lrados
// #include <stdlib.h>
// #include <rados/librados.h>
import "C"

import (
	"time"
	"unsafe"

	"github.com/ceph/go-ceph/internal/retry"
)

// CreateSnap creates a pool-wide snapshot.
//
// Implements:
// int rados_ioctx_snap_create(rados_ioctx_t io, const char *snapname)
func (ioctx *IOContext) CreateSnap(snapName string) error {
	if err := ioctx.validate(); err != nil {
		return err
	}

	cSnapName := C.CString(snapName)
	defer C.free(unsafe.Pointer(cSnapName))

	ret := C.rados_ioctx_snap_create(ioctx.ioctx, cSnapName)
	return getError(ret)
}

// RemoveSnap deletes the pool snapshot.
//
// Implements:
//  int rados_ioctx_snap_remove(rados_ioctx_t io, const char *snapname)
func (ioctx *IOContext) RemoveSnap(snapName string) error {
	if err := ioctx.validate(); err != nil {
		return err
	}

	cSnapName := C.CString(snapName)
	defer C.free(unsafe.Pointer(cSnapName))

	ret := C.rados_ioctx_snap_remove(ioctx.ioctx, cSnapName)
	return getError(ret)
}

// SnapID represents the ID of a rados snapshot.
type SnapID C.rados_snap_t

// LookupSnap returns the ID of a pool snapshot.
//
// Implements:
//  int rados_ioctx_snap_lookup(rados_ioctx_t io, const char *name, rados_snap_t *id)
func (ioctx *IOContext) LookupSnap(snapName string) (SnapID, error) {
	var snapID SnapID

	if err := ioctx.validate(); err != nil {
		return snapID, err
	}

	cSnapName := C.CString(snapName)
	defer C.free(unsafe.Pointer(cSnapName))

	ret := C.rados_ioctx_snap_lookup(
		ioctx.ioctx,
		cSnapName,
		(*C.rados_snap_t)(&snapID))
	return snapID, getError(ret)
}

// GetSnapName returns the name of a pool snapshot with the given snapshot ID.
//
// Implements:
//  int rados_ioctx_snap_get_name(rados_ioctx_t io, rados_snap_t id, char *name, int maxlen)
func (ioctx *IOContext) GetSnapName(snapID SnapID) (string, error) {
	if err := ioctx.validate(); err != nil {
		return "", err
	}

	var (
		buf []byte
		err error
	)
	// range from 1k to 64KiB
	retry.WithSizes(1024, 1<<16, func(len int) retry.Hint {
		cLen := C.int(len)
		buf = make([]byte, cLen)
		ret := C.rados_ioctx_snap_get_name(
			ioctx.ioctx,
			(C.rados_snap_t)(snapID),
			(*C.char)(unsafe.Pointer(&buf[0])),
			cLen)
		err = getError(ret)
		return retry.Size(int(cLen)).If(err == errRange)
	})

	if err != nil {
		return "", err
	}
	return C.GoString((*C.char)(unsafe.Pointer(&buf[0]))), nil
}

// GetSnapStamp returns the time of the pool snapshot creation.
//
// Implements:
//  int rados_ioctx_snap_get_stamp(rados_ioctx_t io, rados_snap_t id, time_t *t)
func (ioctx *IOContext) GetSnapStamp(snapID SnapID) (time.Time, error) {
	var cTime C.time_t

	if err := ioctx.validate(); err != nil {
		return time.Unix(int64(cTime), 0), err
	}

	ret := C.rados_ioctx_snap_get_stamp(
		ioctx.ioctx,
		(C.rados_snap_t)(snapID),
		&cTime)
	return time.Unix(int64(cTime), 0), getError(ret)
}