// Package event define real time data evnet operation functions
package event

import (
	"context"
	"encoding/json"

	"eventRT/database"
	"eventRT/logger"
	"eventRT/mq"

	"github.com/rabbitmq/amqp091-go"
	"go.mongodb.org/mongo-driver/bson"
)

const (
	queueName      = "event-up-down-queue"
	exchangeName   = "event-exchange"
	dbName         = "eventdb"
	collectionName = "alarms"
)

// ReceiptUpDownLimitAlarm define func to receipt up down limit alarm event from modelRT service and process the event alarm
func ReceiptUpDownLimitAlarm(ctx context.Context) {
	conn := mq.GetConn()
	if conn == nil {
		logger.Error(ctx, "get rabbitMQ connection for receiving alarms failed")
		return
	}

	channel, err := conn.Channel()
	if err != nil {
		logger.Error(ctx, "open rabbitMQ channel for consumer failed", "error", err)
		return
	}
	defer channel.Close()

	err = channel.QueueBind(
		queueName, // 队列名
		"event.#.updown.*",
		exchangeName, // 交换机名
		false,
		nil,
	)
	if err != nil {
		logger.Error(ctx, "channel bind queue and exchange failed", "error", err)
		return
	}

	err = channel.Qos(1, 0, false)
	if err != nil {
		logger.Error(ctx, "set rabbitMQ Qos config failed", "error", err)
	}

	// registered consumer
	msgs, err := channel.Consume(
		queueName, // queue
		"",        // consumer tag
		false,     // auto-ack
		false,     // exclusive
		false,     // no-local
		false,     // no-wait
		nil,       // args
	)
	if err != nil {
		logger.Error(ctx, "failed to register a consumer", "error", err)
		return
	}

	logger.Info(ctx, "started receiving up-down limit alarms from rabbitMQ")

	for {
		select {
		case <-ctx.Done():
			logger.Info(ctx, "receipt up-down limit alarm stopped by context cancel")
			return
		case msg, ok := <-msgs:
			if !ok {
				logger.Error(ctx, "message channel closed, exiting consumer loop")
				return
			}
			processAlarmEventMessage(ctx, msg)
		}
	}
}

func processAlarmEventMessage(ctx context.Context, msg amqp091.Delivery) {
	logger.Info(ctx, "received event alarm from modelRT up and down limit compute process")
	mongodbClient := database.GetMongoClient()

	var alarmEvent EventRecord
	err := json.Unmarshal(msg.Body, &alarmEvent)
	if err != nil {
		logger.Error(ctx, "unmarshal alarm event message failed", "error", err)
		return
	}

	// TODO 根据业务逻辑进行进一步处理，如写入数据库、推送前端等
	_, err = mongodbClient.Database("eventdb").Collection("alarms").InsertOne(ctx, alarmEvent)
	if err != nil {
		logger.Error(ctx, "failed to insert alarm event into database", "error", err)
		return
	}

	// TODO 尝试跳过中间结构体的方式插入到 mongoDB 中
	var doc bson.D
	err = bson.UnmarshalExtJSON(msg.Body, true, &doc)
	if err != nil {
		logger.Error(ctx, "unmarshal alarm event message failed", "error", err)
	}
	result, err := mongodbClient.Database(dbName).Collection(collectionName).InsertOne(ctx, doc)
	if err != nil {
		logger.Error(ctx, "failed to insert alarm event into database", "error", err)
		return
	}
	err = msg.Ack(false)
	if err != nil {
		logger.Error(ctx, "ack alarm event message failed", "error", err)
		return
	}
	logger.Info(ctx, "alarm event inserted into database", "result", result)
}