package session

import (
	"context"
	"time"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"repositories.action2quare.com/ayo/gocommon"
	"repositories.action2quare.com/ayo/gocommon/logger"
)

const (
	session_collection_name = gocommon.CollectionName("session")
)

type provider_mongo struct {
	mongoClient gocommon.MongoClient
}

type sessionMongo struct {
	Id   primitive.ObjectID `bson:"_id,omitempty"`
	Auth *Authorization     `bson:"auth"`
	Key  storagekey         `bson:"key"`
	Ts   primitive.DateTime `bson:"_ts"`
}

func newProviderWithMongo(ctx context.Context, mongoUrl string, ttl time.Duration) (Provider, error) {
	mc, err := gocommon.NewMongoClient(ctx, mongoUrl)
	if err != nil {
		return nil, err
	}

	if err = mc.MakeUniqueIndices(session_collection_name, map[string]bson.D{
		"key": {{Key: "key", Value: 1}},
	}); err != nil {
		return nil, err
	}

	if err := mc.MakeExpireIndex(session_collection_name, int32(ttl.Seconds())); err != nil {
		return nil, err
	}

	return &provider_mongo{
		mongoClient: mc,
	}, nil
}

func (p *provider_mongo) New(input *Authorization) (string, error) {
	sk := make_storagekey(input.Account)

	_, _, err := p.mongoClient.Update(session_collection_name, bson.M{
		"_id": input.Account,
	}, bson.M{
		"$set": sessionMongo{
			Auth: input,
			Key:  sk,
			Ts:   primitive.NewDateTimeFromTime(time.Now().UTC()),
		},
	}, options.Update().SetUpsert(true))

	return string(storagekey_to_publickey(sk)), err
}

func (p *provider_mongo) Delete(acc primitive.ObjectID) error {
	_, err := p.mongoClient.Delete(session_collection_name, bson.M{
		"_id": acc,
	})
	return err
}

func (p *provider_mongo) Query(pk string) (Authorization, error) {
	sk := publickey_to_storagekey(publickey(pk))
	var auth Authorization
	err := p.mongoClient.FindOneAs(session_collection_name, bson.M{
		"key": sk,
	}, &auth)

	return auth, err
}

func (p *provider_mongo) Touch(pk string) (bool, error) {
	sk := publickey_to_storagekey(publickey(pk))
	worked, _, err := p.mongoClient.Update(session_collection_name, bson.M{
		"key": sk,
	}, bson.M{
		"$currentDate": bson.M{
			"_ts": bson.M{"$type": "date"},
		},
	}, options.Update().SetUpsert(false))

	if err != nil {
		logger.Println("provider Touch :", err)
		return false, err
	}

	return worked, nil
}

type consumer_mongo struct {
	consumer_common[*sessionMongo]
	ids         map[primitive.ObjectID]storagekey
	mongoClient gocommon.MongoClient
	ttl         time.Duration
}

type sessionPipelineDocument struct {
	OperationType string `bson:"operationType"`
	DocumentKey   struct {
		Id primitive.ObjectID `bson:"_id"`
	} `bson:"documentKey"`
	Session *sessionMongo `bson:"fullDocument"`
}

func newConsumerWithMongo(ctx context.Context, mongoUrl string, ttl time.Duration) (Consumer, error) {
	mc, err := gocommon.NewMongoClient(ctx, mongoUrl)
	if err != nil {
		return nil, err
	}

	consumer := &consumer_mongo{
		consumer_common: consumer_common[*sessionMongo]{
			ttl:       ttl,
			ctx:       ctx,
			stages:    [2]*cache_stage[*sessionMongo]{make_cache_stage[*sessionMongo](), make_cache_stage[*sessionMongo]()},
			startTime: time.Now(),
		},
		ids:         make(map[primitive.ObjectID]storagekey),
		ttl:         ttl,
		mongoClient: mc,
	}

	go func() {
		matchStage := bson.D{
			{
				Key: "$match", Value: bson.D{
					{Key: "operationType", Value: bson.D{
						{Key: "$in", Value: bson.A{
							"delete",
							"insert",
							"update",
						}},
					}},
				},
			}}
		projectStage := bson.D{
			{
				Key: "$project", Value: bson.D{
					{Key: "documentKey", Value: 1},
					{Key: "operationType", Value: 1},
					{Key: "fullDocument", Value: 1},
				},
			},
		}

		var stream *mongo.ChangeStream
		nextswitch := time.Now().Add(ttl)
		for {
			if stream == nil {
				stream, err = mc.Watch(session_collection_name, mongo.Pipeline{matchStage, projectStage})
				if err != nil {
					logger.Error("watchAuthCollection watch failed :", err)
					time.Sleep(time.Minute)
					continue
				}
			}

			changed := stream.TryNext(ctx)
			if ctx.Err() != nil {
				logger.Error("watchAuthCollection stream.TryNext failed. process should be restarted! :", ctx.Err().Error())
				break
			}

			if changed {
				var data sessionPipelineDocument
				if err := stream.Decode(&data); err == nil {
					ot := data.OperationType
					switch ot {
					case "insert":
						consumer.add(data.Session.Key, data.DocumentKey.Id, data.Session)
					case "update":
						if data.Session == nil {
							consumer.deleteById(data.DocumentKey.Id)
						} else {
							consumer.add(data.Session.Key, data.DocumentKey.Id, data.Session)
						}
					case "delete":
						consumer.deleteById(data.DocumentKey.Id)
					}
				} else {
					logger.Error("watchAuthCollection stream.Decode failed :", err)
				}
			} else if stream.Err() != nil || stream.ID() == 0 {
				select {
				case <-ctx.Done():
					logger.Println("watchAuthCollection is done")
					stream.Close(ctx)
					return

				case <-time.After(time.Second):
					logger.Error("watchAuthCollection stream error :", stream.Err())
					stream.Close(ctx)
					stream = nil
				}
			} else {
				time.Sleep(time.Second)
			}

			now := time.Now()
			for now.After(nextswitch) {
				consumer.changeStage()
				nextswitch = nextswitch.Add(ttl)
			}
		}
	}()

	return consumer, nil
}

func (c *consumer_mongo) query_internal(sk storagekey) (*sessionMongo, bool, error) {
	if _, deleted := c.stages[0].deleted[sk]; deleted {
		return nil, false, nil
	}

	if _, deleted := c.stages[1].deleted[sk]; deleted {
		return nil, false, nil
	}

	found, ok := c.stages[0].cache[sk]
	if !ok {
		found, ok = c.stages[1].cache[sk]
	}

	if ok {
		return found, false, nil
	}

	var si sessionMongo
	err := c.mongoClient.FindOneAs(session_collection_name, bson.M{
		"key": sk,
	}, &si)

	if err != nil {
		logger.Println("consumer Query :", err)
		return nil, false, err
	}

	if len(si.Key) > 0 {
		siptr := &si
		c.add_internal(sk, siptr)
		return siptr, true, nil
	}
	return nil, false, nil
}

func (c *consumer_mongo) Query(pk string) (Authorization, error) {
	c.lock.Lock()
	defer c.lock.Unlock()

	sk := publickey_to_storagekey(publickey(pk))
	si, _, err := c.query_internal(sk)
	if err != nil {
		return Authorization{}, err
	}

	if si == nil {
		return Authorization{}, nil
	}

	if time.Now().After(si.Ts.Time().Add(c.ttl)) {
		return Authorization{}, nil
	}

	return *si.Auth, nil
}

func (c *consumer_mongo) Touch(pk string) (Authorization, error) {
	c.lock.Lock()
	defer c.lock.Unlock()

	sk := publickey_to_storagekey(publickey(pk))
	worked, _, err := c.mongoClient.Update(session_collection_name, bson.M{
		"key": sk,
	}, bson.M{
		"$currentDate": bson.M{
			"_ts": bson.M{"$type": "date"},
		},
	}, options.Update().SetUpsert(false))

	if err != nil {
		logger.Println("consumer Touch :", err)
		return Authorization{}, err
	}

	if !worked {
		// 이미 만료되서 사라짐
		return Authorization{}, nil
	}

	si, added, err := c.query_internal(sk)
	if err != nil {
		return Authorization{}, err
	}

	if si == nil {
		return Authorization{}, nil
	}

	if !added {
		var doc sessionMongo
		err := c.mongoClient.FindOneAs(session_collection_name, bson.M{
			"key": sk,
		}, &doc)

		if err != nil {
			logger.Println("consumer Query :", err)
			return Authorization{}, err
		}

		if len(si.Key) > 0 {
			c.add_internal(sk, &doc)
			c.ids[doc.Id] = sk

			return *doc.Auth, nil
		}
	}

	return *si.Auth, nil
}

func (c *consumer_mongo) add(sk storagekey, id primitive.ObjectID, si *sessionMongo) {
	c.lock.Lock()
	defer c.lock.Unlock()

	c.consumer_common.add_internal(sk, si)
	c.ids[id] = sk
}

func (c *consumer_mongo) deleteById(id primitive.ObjectID) {
	c.lock.Lock()
	defer c.lock.Unlock()

	if sk, ok := c.ids[id]; ok {
		c.consumer_common.delete_internal(sk)
		delete(c.ids, id)
	}
}