package cache

import (
	"fmt"
	"time"

	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/data"
	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/internal/logs"
	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
	"github.com/bluele/gcache"
	"go.uber.org/zap"
)

type (
	// ListMultipartSessionCache contains cache for list multiparts session (during pagination).
	ListMultipartSessionCache struct {
		cache  gcache.Cache
		logger *zap.Logger
	}

	// ListMultipartSessionKey is a key to find a ListMultipartSessionCache's entry.
	ListMultipartSessionKey struct {
		cid      cid.ID
		prefix   string
		marker   string
		uploadID string
	}
)

const (
	// DefaultListMultipartSessionCacheLifetime is a default lifetime of entries in cache of ListMultipartUploads.
	DefaultListMultipartSessionCacheLifetime = time.Minute
	// DefaultListMultipartSessionCacheSize is a default size of cache of ListMultipartUploads.
	DefaultListMultipartSessionCacheSize = 100
)

// DefaultListMultipartSessionConfig returns new default cache expiration values.
func DefaultListMultipartSessionConfig(logger *zap.Logger) *Config {
	return &Config{
		Size:     DefaultListMultipartSessionCacheSize,
		Lifetime: DefaultListMultipartSessionCacheLifetime,
		Logger:   logger,
	}
}

func (k *ListMultipartSessionKey) String() string {
	return k.cid.EncodeToString() + k.prefix + k.marker + k.uploadID
}

// NewListMultipartSessionCache is a constructor which creates an object of ListObjectsCache with the given lifetime of entries.
func NewListMultipartSessionCache(config *Config) *ListMultipartSessionCache {
	gc := gcache.New(config.Size).LRU().Expiration(config.Lifetime).EvictedFunc(func(_ interface{}, val interface{}) {
		session, ok := val.(*data.ListMultipartSession)
		if !ok {
			config.Logger.Warn(logs.InvalidCacheEntryType, zap.String("actual", fmt.Sprintf("%T", val)),
				zap.String("expected", fmt.Sprintf("%T", session)))
		}

		if !session.Acquired.Load() {
			session.Cancel()
		}
	}).Build()
	return &ListMultipartSessionCache{cache: gc, logger: config.Logger}
}

// GetListMultipartSession returns a session of ListMultipartUploads request.
func (l *ListMultipartSessionCache) GetListMultipartSession(key ListMultipartSessionKey) *data.ListMultipartSession {
	entry, err := l.cache.Get(key)
	if err != nil {
		return nil
	}

	result, ok := entry.(*data.ListMultipartSession)
	if !ok {
		l.logger.Warn(logs.InvalidCacheEntryType, zap.String("actual", fmt.Sprintf("%T", entry)),
			zap.String("expected", fmt.Sprintf("%T", result)))
		return nil
	}

	return result
}

// PutListMultipartSession puts a ListMultipartUploads session info to cache.
func (l *ListMultipartSessionCache) PutListMultipartSession(key ListMultipartSessionKey, session *data.ListMultipartSession) error {
	s := l.GetListMultipartSession(key)
	if s != nil && s != session {
		if !s.Acquired.Load() {
			s.Cancel()
		}
	}
	return l.cache.Set(key, session)
}

// DeleteListMultipartSession removes key from cache.
func (l *ListMultipartSessionCache) DeleteListMultipartSession(key ListMultipartSessionKey) {
	l.cache.Remove(key)
}

// CreateListMultipartSessionCacheKey returns ListMultipartSessionKey with the given CID, prefix, marker and uploadID.
func CreateListMultipartSessionCacheKey(cnr cid.ID, prefix, marker, uploadID string) ListMultipartSessionKey {
	p := ListMultipartSessionKey{
		cid:      cnr,
		prefix:   prefix,
		marker:   marker,
		uploadID: uploadID,
	}

	return p
}