package message

import (
	"context"
	"sync"
	"time"

	"github.com/gogf/gf/v2/encoding/gjson"
	"github.com/gogf/gf/v2/errors/gerror"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/util/gconv"
	amqp "github.com/rabbitmq/amqp091-go"
)

var (
	rabbitConn           *amqp.Connection
	rabbitChannel        *amqp.Channel
	rabbitOnce           sync.Once
	rabbitMu             sync.RWMutex
	rabbitCloseWatcher   chan struct{}
	rabbitWatcherStarted bool
)

// Config RabbitMQ 配置
type RabbitMQConfig1 struct {
	Host     string
	Port     int
	Username string
	Password string
	VHost    string
}

// rabbitMQConfig 默认配置
func getRabbitMQConfig() *RabbitMQConfig1 {
	return &RabbitMQConfig1{
		Host:     g.Cfg().MustGet(context.Background(), "rabbitmq.host").String(),
		Port:     g.Cfg().MustGet(context.Background(), "rabbitmq.port").Int(),
		Username: g.Cfg().MustGet(context.Background(), "rabbitmq.username").String(),
		Password: g.Cfg().MustGet(context.Background(), "rabbitmq.password").String(),
		VHost:    g.Cfg().MustGet(context.Background(), "rabbitmq.vhost", "/").String(),
	}
}

// initRabbitMQ 初始化 RabbitMQ 连接
func initRabbitMQ(ctx context.Context) error {
	var err error
	rabbitOnce.Do(func() {
		cfg := getRabbitMQConfig()
		url := "amqp://" + cfg.Username + ":" + cfg.Password + "@" + cfg.Host + ":" + gconv.String(cfg.Port) + "/" + cfg.VHost

		rabbitConn, err = amqp.Dial(url)
		if err != nil {
			g.Log().Errorf(ctx, "RabbitMQ 连接失败: %v", err)
			return
		}

		rabbitChannel, err = rabbitConn.Channel()
		if err != nil {
			g.Log().Errorf(ctx, "创建 RabbitMQ Channel 失败: %v", err)
			return
		}

		rabbitCloseWatcher = make(chan struct{})

		if !rabbitWatcherStarted {
			go handleRabbitMQConnectionClose(ctx)
			rabbitWatcherStarted = true
		}

		g.Log().Info(ctx, "RabbitMQ 连接成功")
	})

	return err
}

// getRabbitMQChannel 获取 RabbitMQ Channel
func getRabbitMQChannel() (*amqp.Channel, error) {
	rabbitMu.RLock()
	defer rabbitMu.RUnlock()

	if rabbitChannel == nil || rabbitChannel.IsClosed() {
		return nil, gerror.New("RabbitMQ Channel 未初始化或已关闭")
	}

	return rabbitChannel, nil
}

// getRabbitMQConnection 获取 RabbitMQ 连接
func getRabbitMQConnection() (*amqp.Connection, error) {
	rabbitMu.RLock()
	defer rabbitMu.RUnlock()

	if rabbitConn == nil || rabbitConn.IsClosed() {
		return nil, gerror.New("RabbitMQ 连接未初始化或已关闭")
	}

	return rabbitConn, nil
}

// handleRabbitMQConnectionClose 监听连接关闭并重连
func handleRabbitMQConnectionClose(ctx context.Context) {
	for {
		select {
		case <-rabbitCloseWatcher:
			g.Log().Info(ctx, "停止监听 RabbitMQ 连接状态")
			return
		default:
		}

		rabbitMu.RLock()
		currentConn := rabbitConn
		rabbitMu.RUnlock()

		if currentConn == nil {
			return
		}

		closeErr := make(chan *amqp.Error, 1)
		currentConn.NotifyClose(closeErr)

		select {
		case err := <-closeErr:
			if err != nil {
				g.Log().Errorf(ctx, "RabbitMQ 连接关闭: %v，尝试重连...", err)
				reconnectRabbitMQ(ctx)
			}
		case <-rabbitCloseWatcher:
			g.Log().Info(ctx, "停止监听 RabbitMQ 连接状态")
			return
		}
	}
}

// reconnectRabbitMQ 重新连接
func reconnectRabbitMQ(ctx context.Context) {
	rabbitMu.Lock()
	defer rabbitMu.Unlock()

	for i := 0; i < 10; i++ {
		time.Sleep(time.Duration(i+1) * time.Second)

		cfg := getRabbitMQConfig()
		url := "amqp://" + cfg.Username + ":" + cfg.Password + "@" + cfg.Host + ":" + gconv.String(cfg.Port) + "/" + cfg.VHost

		var err error
		rabbitConn, err = amqp.Dial(url)
		if err != nil {
			g.Log().Errorf(ctx, "重连失败 (尝试 %d/10): %v", i+1, err)
			continue
		}

		rabbitChannel, err = rabbitConn.Channel()
		if err != nil {
			g.Log().Errorf(ctx, "创建 Channel 失败 (尝试 %d/10): %v", i+1, err)
			continue
		}

		g.Log().Info(ctx, "RabbitMQ 重连成功")
		return
	}

	g.Log().Fatal(ctx, "RabbitMQ 重连失败，已达到最大重试次数")
}

// startRabbitMQConsumer 启动 RabbitMQ 消费者
func startRabbitMQConsumer(ctx context.Context, msg QueueMessage) error {
	// 初始化连接
	if err := initRabbitMQ(ctx); err != nil {
		return gerror.Wrap(err, "初始化 RabbitMQ 连接失败")
	}

	// 创建独立 Channel（避免并发冲突）
	conn, err := getRabbitMQConnection()
	if err != nil {
		return gerror.Wrap(err, "获取RabbitMQ连接失败")
	}

	ch, err := conn.Channel()
	if err != nil {
		return gerror.Wrap(err, "创建独立Channel失败")
	}

	// 声明队列
	_, err = ch.QueueDeclare(
		msg.Queue, // name
		true,      // durable
		false,     // autoDelete
		false,     // exclusive
		false,     // noWait
		nil,       // arguments
	)
	if err != nil {
		return gerror.Newf("声明队列失败: %v", err)
	}

	// 设置 QoS（并发控制）
	prefetchCount := msg.PrefetchCount
	if prefetchCount == 0 {
		prefetchCount = 1
	}
	err = ch.Qos(
		prefetchCount, // prefetchCount
		0,             // prefetchSize
		false,         // global
	)
	if err != nil {
		return gerror.Newf("设置 QoS 失败: %v", err)
	}

	// 开始消费
	msgs, err := ch.Consume(
		msg.Queue,       // queue
		msg.ConsumerTag, // consumer tag
		msg.AutoAck,     // auto-ack
		false,           // exclusive
		false,           // no-local
		false,           // no-wait
		nil,             // args
	)
	if err != nil {
		return gerror.Newf("开始消费失败: %v", err)
	}

	workerCount := msg.WorkerCount
	if workerCount == 0 {
		workerCount = 1
	}

	g.Log().Infof(ctx, "RabbitMQ 消费者已启动: queue=%s, prefetch=%d, workers=%d",
		msg.Queue, prefetchCount, workerCount)

	// 启动多个 worker
	for i := 0; i < workerCount; i++ {
		go rabbitMQWorker(ctx, i, msgs, msg)
	}

	return nil
}

// rabbitMQWorker RabbitMQ 工作协程
func rabbitMQWorker(ctx context.Context, workerID int, msgs <-chan amqp.Delivery, msg QueueMessage) {
	g.Log().Debugf(ctx, "RabbitMQ Worker %d 已启动", workerID)

	for {
		select {
		case <-ctx.Done():
			g.Log().Infof(ctx, "RabbitMQ Worker %d 收到停止信号，正在退出", workerID)
			return
		case delivery, ok := <-msgs:
			if !ok {
				g.Log().Infof(ctx, "RabbitMQ Worker %d 消息通道已关闭，退出", workerID)
				return
			}

			// 反序列化消息
			var message map[string]interface{}
			if err := gjson.DecodeTo(delivery.Body, &message); err != nil {
				g.Log().Errorf(ctx, "RabbitMQ Worker %d 反序列化消息失败: %v", workerID, err)
				if !msg.AutoAck {
					delivery.Nack(false, false)
				}
				continue
			}

			// 处理消息
			err := msg.HandleFunc(ctx, message)
			if err != nil {
				g.Log().Errorf(ctx, "RabbitMQ Worker %d 处理消息失败: %v", workerID, err)
				if !msg.AutoAck {
					delivery.Nack(false, false)
				}
			} else {
				if !msg.AutoAck {
					delivery.Ack(false)
				}
				g.Log().Debugf(ctx, "RabbitMQ Worker %d 处理消息成功", workerID)
			}
		}
	}
}

// publishToRabbitMQ 发布消息到 RabbitMQ
func publishToRabbitMQ(ctx context.Context, exchange, routingKey string, message interface{}) (messageID string, err error) {
	ch, err := getRabbitMQChannel()
	if err != nil {
		return
	}

	body, err := gjson.Encode(message)
	if err != nil {
		return "", gerror.Newf("消息序列化失败: %v", err)
	}

	err = ch.PublishWithContext(
		ctx,
		exchange,   // exchange
		routingKey, // routing key
		false,      // mandatory
		false,      // immediate
		amqp.Publishing{
			DeliveryMode: amqp.Persistent,
			ContentType:  "application/json",
			Body:         body,
		},
	)

	if err != nil {
		g.Log().Errorf(ctx, "发布消息失败: exchange=%s, routingKey=%s, err=%v", exchange, routingKey, err)
		return
	}

	g.Log().Debugf(ctx, "消息发布成功: exchange=%s, routingKey=%s", exchange, routingKey)
	return messageID, nil
}

// publishDelayedToRabbitMQ 发布延时消息到 RabbitMQ
func publishDelayedToRabbitMQ(ctx context.Context, exchange, routingKey string, message interface{}, delaySeconds int) (messageID string, err error) {
	ch, err := getRabbitMQChannel()
	if err != nil {
		return
	}

	body, err := gjson.Encode(message)
	if err != nil {
		return "", gerror.Newf("消息序列化失败: %v", err)
	}

	err = ch.PublishWithContext(
		ctx,
		exchange,   // exchange（必须是 x-delayed-message 类型）
		routingKey, // routing key
		false,      // mandatory
		false,      // immediate
		amqp.Publishing{
			DeliveryMode: amqp.Persistent,
			ContentType:  "application/json",
			Body:         body,
			Headers: amqp.Table{
				"x-delay": delaySeconds * 1000, // 延时（毫秒）
			},
		},
	)

	if err != nil {
		g.Log().Errorf(ctx, "发布延时消息失败: exchange=%s, routingKey=%s, delay=%ds, err=%v", exchange, routingKey, delaySeconds, err)
		return
	}

	g.Log().Debugf(ctx, "延时消息发布成功: exchange=%s, routingKey=%s, delay=%ds", exchange, routingKey, delaySeconds)
	return messageID, nil
}