package cache

import (
	"strings"
	"sync"

	"github.com/container-storage-interface/spec/lib/go/csi"
)

type SnapshotCache interface {
	Add(snapshot Snapshot)

	Delete(i int)

	List(ready bool) []csi.Snapshot

	FindSnapshot(k, v string) (int, Snapshot)
}

type Snapshot struct {
	Name        string
	Parameters  map[string]string
	SnapshotCSI csi.Snapshot
}

type snapshotCache struct {
	snapshotsRWL sync.RWMutex
	snapshots    []Snapshot
}

func NewSnapshotCache() SnapshotCache {
	return &snapshotCache{
		snapshots: make([]Snapshot, 0),
	}
}

func (snap *snapshotCache) Add(snapshot Snapshot) {
	snap.snapshotsRWL.Lock()
	defer snap.snapshotsRWL.Unlock()

	snap.snapshots = append(snap.snapshots, snapshot)
}

func (snap *snapshotCache) Delete(i int) {
	snap.snapshotsRWL.Lock()
	defer snap.snapshotsRWL.Unlock()

	copy(snap.snapshots[i:], snap.snapshots[i+1:])
	snap.snapshots = snap.snapshots[:len(snap.snapshots)-1]
}

func (snap *snapshotCache) List(ready bool) []csi.Snapshot {
	snap.snapshotsRWL.RLock()
	defer snap.snapshotsRWL.RUnlock()

	snapshots := make([]csi.Snapshot, 0)
	for _, v := range snap.snapshots {
		if v.SnapshotCSI.GetReadyToUse() {
			snapshots = append(snapshots, v.SnapshotCSI)
		}
	}

	return snapshots
}

func (snap *snapshotCache) FindSnapshot(k, v string) (int, Snapshot) {
	snap.snapshotsRWL.RLock()
	defer snap.snapshotsRWL.RUnlock()

	snapshotIdx := -1
	for i, vi := range snap.snapshots {
		switch k {
		case "id":
			if strings.EqualFold(v, vi.SnapshotCSI.GetSnapshotId()) {
				return i, vi
			}
		case "sourceVolumeId":
			if strings.EqualFold(v, vi.SnapshotCSI.SourceVolumeId) {
				return i, vi
			}
		case "name":
			if vi.Name == v {
				return i, vi
			}
		}
	}

	return snapshotIdx, Snapshot{}
}