package writecache

import (
	"math"
	"sync/atomic"

	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/fstree"
)

func (c *cache) estimateCacheSize() (uint64, uint64) {
	fsCount := c.objCounters.FS()
	fsSize := fsCount * c.maxObjectSize
	c.metrics.SetEstimateSize(0, fsSize)
	c.metrics.SetActualCounters(0, fsCount)
	return fsCount, fsSize
}

func (c *cache) hasEnoughSpaceFS() bool {
	return c.hasEnoughSpace(c.maxObjectSize)
}

func (c *cache) hasEnoughSpace(objectSize uint64) bool {
	count, size := c.estimateCacheSize()
	if c.maxCacheCount > 0 && count+1 > c.maxCacheCount {
		return false
	}
	return c.maxCacheSize >= size+objectSize
}

var _ fstree.FileCounter = &counters{}

type counters struct {
	cFS atomic.Uint64
}

func (x *counters) FS() uint64 {
	return x.cFS.Load()
}

// Set implements fstree.ObjectCounter.
func (x *counters) Set(v uint64) {
	x.cFS.Store(v)
}

// Inc implements fstree.ObjectCounter.
func (x *counters) Inc() {
	x.cFS.Add(1)
}

// Dec implements fstree.ObjectCounter.
func (x *counters) Dec() {
	x.cFS.Add(math.MaxUint64)
}

func (c *cache) initCounters() error {
	c.estimateCacheSize()
	return nil
}