// Copyright © 2023 OpenIM. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package redis

import (
	"context"
	"errors"
	"github.com/gogo/protobuf/jsonpb"
	"github.com/openimsdk/open-im-server/v3/pkg/common/storage/cache"
	"github.com/openimsdk/open-im-server/v3/pkg/common/storage/cache/cachekey"
	"github.com/openimsdk/open-im-server/v3/pkg/msgprocessor"
	"github.com/openimsdk/protocol/constant"
	"github.com/openimsdk/protocol/sdkws"
	"github.com/openimsdk/tools/errs"
	"github.com/openimsdk/tools/log"
	"github.com/openimsdk/tools/utils/stringutil"
	"github.com/redis/go-redis/v9"
	"golang.org/x/sync/errgroup"
	"time"
)

const msgCacheTimeout = 86400 * time.Second

var concurrentLimit = 3

func NewMsgCache(client redis.UniversalClient, redisEnablePipeline bool) cache.MsgCache {
	return &msgCache{rdb: client, msgCacheTimeout: msgCacheTimeout, redisEnablePipeline: redisEnablePipeline}
}

type msgCache struct {
	rdb                 redis.UniversalClient
	msgCacheTimeout     time.Duration
	redisEnablePipeline bool
}

func (c *msgCache) getAllMessageCacheKey(conversationID string) string {
	return cachekey.GetAllMessageCacheKey(conversationID)
}

func (c *msgCache) getMessageCacheKey(conversationID string, seq int64) string {
	return cachekey.GetMessageCacheKey(conversationID, seq)
}
func (c *msgCache) getMessageDelUserListKey(conversationID string, seq int64) string {
	return cachekey.GetMessageDelUserListKey(conversationID, seq)
}

func (c *msgCache) getUserDelList(conversationID, userID string) string {
	return cachekey.GetUserDelListKey(conversationID, userID)
}

func (c *msgCache) getSendMsgKey(id string) string {
	return cachekey.GetSendMsgKey(id)
}

func (c *msgCache) getLockMessageTypeKey(clientMsgID string, TypeKey string) string {
	return cachekey.GetLockMessageTypeKey(clientMsgID, TypeKey)
}

func (c *msgCache) getMessageReactionExPrefix(clientMsgID string, sessionType int32) string {
	return cachekey.GetMessageReactionExKey(clientMsgID, sessionType)
}

func (c *msgCache) SetMessageToCache(ctx context.Context, conversationID string, msgs []*sdkws.MsgData) (int, error) {
	if c.redisEnablePipeline {
		return c.PipeSetMessageToCache(ctx, conversationID, msgs)
	}
	return c.ParallelSetMessageToCache(ctx, conversationID, msgs)
}

func (c *msgCache) PipeSetMessageToCache(ctx context.Context, conversationID string, msgs []*sdkws.MsgData) (int, error) {
	pipe := c.rdb.Pipeline()
	for _, msg := range msgs {
		s, err := msgprocessor.Pb2String(msg)
		if err != nil {
			return 0, err
		}

		key := c.getMessageCacheKey(conversationID, msg.Seq)
		_ = pipe.Set(ctx, key, s, c.msgCacheTimeout)
	}

	results, err := pipe.Exec(ctx)
	if err != nil {
		return 0, errs.Wrap(err)
	}

	for _, res := range results {
		if res.Err() != nil {
			return 0, errs.Wrap(err)
		}
	}

	return len(msgs), nil
}

func (c *msgCache) ParallelSetMessageToCache(ctx context.Context, conversationID string, msgs []*sdkws.MsgData) (int, error) {
	wg := errgroup.Group{}
	wg.SetLimit(concurrentLimit)

	for _, msg := range msgs {
		msg := msg // closure safe var
		wg.Go(func() error {
			s, err := msgprocessor.Pb2String(msg)
			if err != nil {
				return errs.Wrap(err)
			}

			key := c.getMessageCacheKey(conversationID, msg.Seq)
			if err := c.rdb.Set(ctx, key, s, c.msgCacheTimeout).Err(); err != nil {
				return errs.Wrap(err)
			}
			return nil
		})
	}

	err := wg.Wait()
	if err != nil {
		return 0, errs.WrapMsg(err, "wg.Wait failed")
	}

	return len(msgs), nil
}

func (c *msgCache) UserDeleteMsgs(ctx context.Context, conversationID string, seqs []int64, userID string) error {
	for _, seq := range seqs {
		delUserListKey := c.getMessageDelUserListKey(conversationID, seq)
		userDelListKey := c.getUserDelList(conversationID, userID)
		err := c.rdb.SAdd(ctx, delUserListKey, userID).Err()
		if err != nil {
			return errs.Wrap(err)
		}
		err = c.rdb.SAdd(ctx, userDelListKey, seq).Err()
		if err != nil {
			return errs.Wrap(err)
		}
		if err := c.rdb.Expire(ctx, delUserListKey, c.msgCacheTimeout).Err(); err != nil {
			return errs.Wrap(err)
		}
		if err := c.rdb.Expire(ctx, userDelListKey, c.msgCacheTimeout).Err(); err != nil {
			return errs.Wrap(err)
		}
	}

	return nil
}

func (c *msgCache) GetUserDelList(ctx context.Context, userID, conversationID string) (seqs []int64, err error) {
	result, err := c.rdb.SMembers(ctx, c.getUserDelList(conversationID, userID)).Result()
	if err != nil {
		return nil, errs.Wrap(err)
	}
	seqs = make([]int64, len(result))
	for i, v := range result {
		seqs[i] = stringutil.StringToInt64(v)
	}

	return seqs, nil
}

func (c *msgCache) DelUserDeleteMsgsList(ctx context.Context, conversationID string, seqs []int64) {
	for _, seq := range seqs {
		delUsers, err := c.rdb.SMembers(ctx, c.getMessageDelUserListKey(conversationID, seq)).Result()
		if err != nil {
			log.ZWarn(ctx, "DelUserDeleteMsgsList failed", err, "conversationID", conversationID, "seq", seq)

			continue
		}
		if len(delUsers) > 0 {
			var failedFlag bool
			for _, userID := range delUsers {
				err = c.rdb.SRem(ctx, c.getUserDelList(conversationID, userID), seq).Err()
				if err != nil {
					failedFlag = true
					log.ZWarn(ctx, "DelUserDeleteMsgsList failed", err, "conversationID", conversationID, "seq", seq, "userID", userID)
				}
			}
			if !failedFlag {
				if err := c.rdb.Del(ctx, c.getMessageDelUserListKey(conversationID, seq)).Err(); err != nil {
					log.ZWarn(ctx, "DelUserDeleteMsgsList failed", err, "conversationID", conversationID, "seq", seq)
				}
			}
		}
	}
}

func (c *msgCache) DeleteMessages(ctx context.Context, conversationID string, seqs []int64) error {
	if c.redisEnablePipeline {
		return c.PipeDeleteMessages(ctx, conversationID, seqs)
	}

	return c.ParallelDeleteMessages(ctx, conversationID, seqs)
}

func (c *msgCache) ParallelDeleteMessages(ctx context.Context, conversationID string, seqs []int64) error {
	wg := errgroup.Group{}
	wg.SetLimit(concurrentLimit)

	for _, seq := range seqs {
		seq := seq
		wg.Go(func() error {
			err := c.rdb.Del(ctx, c.getMessageCacheKey(conversationID, seq)).Err()
			if err != nil {
				return errs.Wrap(err)
			}
			return nil
		})
	}

	return wg.Wait()
}

func (c *msgCache) PipeDeleteMessages(ctx context.Context, conversationID string, seqs []int64) error {
	pipe := c.rdb.Pipeline()
	for _, seq := range seqs {
		_ = pipe.Del(ctx, c.getMessageCacheKey(conversationID, seq))
	}

	results, err := pipe.Exec(ctx)
	if err != nil {
		return errs.WrapMsg(err, "pipe.del")
	}

	for _, res := range results {
		if res.Err() != nil {
			return errs.Wrap(err)
		}
	}

	return nil
}

func (c *msgCache) CleanUpOneConversationAllMsg(ctx context.Context, conversationID string) error {
	vals, err := c.rdb.Keys(ctx, c.getAllMessageCacheKey(conversationID)).Result()
	if errors.Is(err, redis.Nil) {
		return nil
	}
	if err != nil {
		return errs.Wrap(err)
	}
	for _, v := range vals {
		if err := c.rdb.Del(ctx, v).Err(); err != nil {
			return errs.Wrap(err)
		}
	}
	return nil
}

func (c *msgCache) DelMsgFromCache(ctx context.Context, userID string, seqs []int64) error {
	for _, seq := range seqs {
		key := c.getMessageCacheKey(userID, seq)
		result, err := c.rdb.Get(ctx, key).Result()
		if err != nil {
			if errors.Is(err, redis.Nil) {
				continue
			}

			return errs.Wrap(err)
		}
		var msg sdkws.MsgData
		err = jsonpb.UnmarshalString(result, &msg)
		if err != nil {
			return err
		}
		msg.Status = constant.MsgDeleted
		s, err := msgprocessor.Pb2String(&msg)
		if err != nil {
			return errs.Wrap(err)
		}
		if err := c.rdb.Set(ctx, key, s, c.msgCacheTimeout).Err(); err != nil {
			return errs.Wrap(err)
		}
	}

	return nil
}

func (c *msgCache) SetSendMsgStatus(ctx context.Context, id string, status int32) error {
	return errs.Wrap(c.rdb.Set(ctx, c.getSendMsgKey(id), status, time.Hour*24).Err())
}

func (c *msgCache) GetSendMsgStatus(ctx context.Context, id string) (int32, error) {
	result, err := c.rdb.Get(ctx, c.getSendMsgKey(id)).Int()
	return int32(result), errs.Wrap(err)
}

func (c *msgCache) LockMessageTypeKey(ctx context.Context, clientMsgID string, TypeKey string) error {
	key := c.getLockMessageTypeKey(clientMsgID, TypeKey)
	return errs.Wrap(c.rdb.SetNX(ctx, key, 1, time.Minute).Err())
}

func (c *msgCache) UnLockMessageTypeKey(ctx context.Context, clientMsgID string, TypeKey string) error {
	key := c.getLockMessageTypeKey(clientMsgID, TypeKey)
	return errs.Wrap(c.rdb.Del(ctx, key).Err())
}

func (c *msgCache) JudgeMessageReactionExist(ctx context.Context, clientMsgID string, sessionType int32) (bool, error) {
	n, err := c.rdb.Exists(ctx, c.getMessageReactionExPrefix(clientMsgID, sessionType)).Result()
	if err != nil {
		return false, errs.Wrap(err)
	}

	return n > 0, nil
}

func (c *msgCache) SetMessageTypeKeyValue(ctx context.Context, clientMsgID string, sessionType int32, typeKey, value string) error {
	return errs.Wrap(c.rdb.HSet(ctx, c.getMessageReactionExPrefix(clientMsgID, sessionType), typeKey, value).Err())
}

func (c *msgCache) SetMessageReactionExpire(ctx context.Context, clientMsgID string, sessionType int32, expiration time.Duration) (bool, error) {
	val, err := c.rdb.Expire(ctx, c.getMessageReactionExPrefix(clientMsgID, sessionType), expiration).Result()
	return val, errs.Wrap(err)
}

func (c *msgCache) GetMessageTypeKeyValue(ctx context.Context, clientMsgID string, sessionType int32, typeKey string) (string, error) {
	val, err := c.rdb.HGet(ctx, c.getMessageReactionExPrefix(clientMsgID, sessionType), typeKey).Result()
	return val, errs.Wrap(err)
}

func (c *msgCache) GetOneMessageAllReactionList(ctx context.Context, clientMsgID string, sessionType int32) (map[string]string, error) {
	val, err := c.rdb.HGetAll(ctx, c.getMessageReactionExPrefix(clientMsgID, sessionType)).Result()
	return val, errs.Wrap(err)
}

func (c *msgCache) DeleteOneMessageKey(ctx context.Context, clientMsgID string, sessionType int32, subKey string) error {
	return errs.Wrap(c.rdb.HDel(ctx, c.getMessageReactionExPrefix(clientMsgID, sessionType), subKey).Err())
}

func (c *msgCache) GetMessagesBySeq(ctx context.Context, conversationID string, seqs []int64) (seqMsgs []*sdkws.MsgData, failedSeqs []int64, err error) {
	if c.redisEnablePipeline {
		return c.PipeGetMessagesBySeq(ctx, conversationID, seqs)
	}

	return c.ParallelGetMessagesBySeq(ctx, conversationID, seqs)
}

func (c *msgCache) PipeGetMessagesBySeq(ctx context.Context, conversationID string, seqs []int64) (seqMsgs []*sdkws.MsgData, failedSeqs []int64, err error) {
	pipe := c.rdb.Pipeline()

	results := []*redis.StringCmd{}
	for _, seq := range seqs {
		results = append(results, pipe.Get(ctx, c.getMessageCacheKey(conversationID, seq)))
	}

	_, err = pipe.Exec(ctx)
	if err != nil && err != redis.Nil {
		return seqMsgs, failedSeqs, errs.WrapMsg(err, "pipe.get")
	}

	for idx, res := range results {
		seq := seqs[idx]
		if res.Err() != nil {
			log.ZError(ctx, "GetMessagesBySeq failed", err, "conversationID", conversationID, "seq", seq, "err", res.Err())
			failedSeqs = append(failedSeqs, seq)
			continue
		}

		msg := sdkws.MsgData{}
		if err = msgprocessor.String2Pb(res.Val(), &msg); err != nil {
			log.ZError(ctx, "GetMessagesBySeq Unmarshal failed", err, "res", res, "conversationID", conversationID, "seq", seq)
			failedSeqs = append(failedSeqs, seq)
			continue
		}

		if msg.Status == constant.MsgDeleted {
			failedSeqs = append(failedSeqs, seq)
			continue
		}

		seqMsgs = append(seqMsgs, &msg)
	}

	return
}

func (c *msgCache) ParallelGetMessagesBySeq(ctx context.Context, conversationID string, seqs []int64) (seqMsgs []*sdkws.MsgData, failedSeqs []int64, err error) {
	type entry struct {
		err error
		msg *sdkws.MsgData
	}

	wg := errgroup.Group{}
	wg.SetLimit(concurrentLimit)

	results := make([]entry, len(seqs)) // set slice len/cap to length of seqs.
	for idx, seq := range seqs {
		// closure safe var
		idx := idx
		seq := seq

		wg.Go(func() error {
			res, err := c.rdb.Get(ctx, c.getMessageCacheKey(conversationID, seq)).Result()
			if err != nil {
				log.ZError(ctx, "GetMessagesBySeq failed", err, "conversationID", conversationID, "seq", seq)
				results[idx] = entry{err: err}
				return nil
			}

			msg := sdkws.MsgData{}
			if err = msgprocessor.String2Pb(res, &msg); err != nil {
				log.ZError(ctx, "GetMessagesBySeq Unmarshal failed", err, "res", res, "conversationID", conversationID, "seq", seq)
				results[idx] = entry{err: err}
				return nil
			}

			if msg.Status == constant.MsgDeleted {
				results[idx] = entry{err: err}
				return nil
			}

			results[idx] = entry{msg: &msg}
			return nil
		})
	}

	_ = wg.Wait()

	for idx, res := range results {
		if res.err != nil {
			failedSeqs = append(failedSeqs, seqs[idx])
			continue
		}

		seqMsgs = append(seqMsgs, res.msg)
	}

	return
}