package core

import (
	"context"
	"encoding/hex"
	"os"
	"path"
	"sync/atomic"
	"time"
	"unsafe"

	"repositories.action2quare.com/ayo/gocommon"
	"repositories.action2quare.com/ayo/gocommon/logger"

	"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"
)

type servicePipelineDocument struct {
	OperationType string `bson:"operationType"`
	DocumentKey   struct {
		Id primitive.ObjectID `bson:"_id"`
	} `bson:"documentKey"`
	Service *serviceDescription `bson:"fullDocument"`
}

type filePipelineDocument struct {
	OperationType string `bson:"operationType"`
	DocumentKey   struct {
		Id primitive.ObjectID `bson:"_id"`
	} `bson:"documentKey"`
	File *FileDocumentDesc `bson:"fullDocument"`
}

func (mg *Maingate) watchFileCollection(parentctx context.Context, serveMux gocommon.ServerMuxInterface, prefix string) {
	defer func() {
		s := recover()
		if s != nil {
			logger.Error(s)
		}
	}()

	matchStage := bson.D{
		{
			Key: "$match", Value: bson.D{
				{Key: "operationType", Value: bson.D{
					{Key: "$in", Value: bson.A{
						"delete",
						"insert",
					}},
				}},
			},
		}}
	projectStage := bson.D{
		{
			Key: "$project", Value: bson.D{
				{Key: "operationType", Value: 1},
				{Key: "documentKey", Value: 1},
				{Key: "fullDocument", Value: 1},
			},
		},
	}
	var stream *mongo.ChangeStream
	var err error
	var ctx context.Context

	for {
		if stream == nil {
			stream, err = mg.mongoClient.Watch(CollectionFile, mongo.Pipeline{matchStage, projectStage}, options.ChangeStream().SetFullDocument(options.UpdateLookup))
			if err != nil {
				logger.Error("watchFileCollection watch failed :", err)
				time.Sleep(time.Second)
				continue
			}
			ctx = context.TODO()
		}

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

		if !changed {
			if stream.Err() != nil || stream.ID() == 0 {
				select {
				case <-ctx.Done():
					logger.Println("watchServiceCollection is done")
					stream.Close(ctx)
					return

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

		var data filePipelineDocument
		if err := stream.Decode(&data); err == nil {
			switch data.OperationType {
			case "insert":
				data.File.Save()

			case "delete":
				subfolder := hex.EncodeToString(data.DocumentKey.Id[:4])
				rf := hex.EncodeToString(data.DocumentKey.Id[4:8])

				subpath := path.Join("static", subfolder, rf)
				os.RemoveAll(subpath)
			}
		}
	}
}

func (mg *Maingate) watchServiceCollection(parentctx context.Context, serveMux gocommon.ServerMuxInterface, prefix string) {
	defer func() {
		s := recover()
		if s != nil {
			logger.Error(s)
		}
	}()

	matchStage := bson.D{
		{
			Key: "$match", Value: bson.D{
				{Key: "operationType", Value: bson.D{
					{Key: "$in", Value: bson.A{
						"insert",
						"update",
						"replace",
					}},
				}},
			},
		}}
	projectStage := bson.D{
		{
			Key: "$project", Value: bson.D{
				{Key: "operationType", Value: 1},
				{Key: "fullDocument", Value: 1},
			},
		},
	}

	var stream *mongo.ChangeStream
	var err error
	var ctx context.Context

	for {
		if stream == nil {
			stream, err = mg.mongoClient.Watch(CollectionService, mongo.Pipeline{matchStage, projectStage}, options.ChangeStream().SetFullDocument(options.UpdateLookup))
			if err != nil {
				logger.Error("watchServiceCollection watch failed :", err)
				time.Sleep(time.Minute)
				continue
			}
			ctx = context.TODO()
		}

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

		if changed {
			var data servicePipelineDocument
			if err := stream.Decode(&data); err == nil {
				ot := data.OperationType
				switch ot {
				case "insert":
					// 새 서비스 추가됨
					if err := data.Service.prepare(mg); err != nil {
						logger.Error("service cannot be prepared :", data.Service, err)
					} else {
						// 내가 임시로 가지고 있던 서비스일 수 있다.
						if mg.service().Id == data.Service.Id {
							logger.Println("service is on the board! :", data.Service)
							atomic.StorePointer(&mg.serviceptr, unsafe.Pointer(data.Service))
						}
					}

				case "replace":
					fallthrough

				case "update":
					data.Service.prepare(mg)
					atomic.StorePointer(&mg.serviceptr, unsafe.Pointer(data.Service))
				}
			} else {
				logger.Error("watchServiceCollection stream.Decode failed :", err)
			}
		} else if stream.Err() != nil || stream.ID() == 0 {
			select {
			case <-ctx.Done():
				logger.Println("watchServiceCollection is done")
				stream.Close(ctx)
				return

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