package rabbitmq

import (
	"context"
	"fmt"
	"sync"
	"time"

	"github.com/gogf/gf/v2/frame/g"
	amqp "github.com/rabbitmq/amqp091-go"
)

var (
	conn    *amqp.Connection
	channel *amqp.Channel
	once    sync.Once
	mu      sync.RWMutex
)

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

// Init 初始化 RabbitMQ 连接
func Init(ctx context.Context, cfg *Config) error {
	var err error
	once.Do(func() {
		// 构建连接字符串
		url := fmt.Sprintf("amqp://%s:%s@%s:%d/%s",
			cfg.Username,
			cfg.Password,
			cfg.Host,
			cfg.Port,
			cfg.VHost,
		)

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

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

		// 监听连接关闭
		go handleConnectionClose(ctx)

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

	return err
}

// InitFromConfig 从配置文件初始化
func InitFromConfig(ctx context.Context) error {
	cfg := &Config{
		Host:     g.Cfg().MustGet(ctx, "rabbitmq.host").String(),
		Port:     g.Cfg().MustGet(ctx, "rabbitmq.port").Int(),
		Username: g.Cfg().MustGet(ctx, "rabbitmq.username").String(),
		Password: g.Cfg().MustGet(ctx, "rabbitmq.password").String(),
		VHost:    g.Cfg().MustGet(ctx, "rabbitmq.vhost", "/").String(),
	}

	return Init(ctx, cfg)
}

// GetChannel 获取 Channel
func GetChannel() (*amqp.Channel, error) {
	mu.RLock()
	defer mu.RUnlock()

	if channel == nil || channel.IsClosed() {
		return nil, fmt.Errorf("RabbitMQ Channel 未初始化或已关闭")
	}

	return channel, nil
}

// GetConnection 获取连接
func GetConnection() (*amqp.Connection, error) {
	mu.RLock()
	defer mu.RUnlock()

	if conn == nil || conn.IsClosed() {
		return nil, fmt.Errorf("RabbitMQ 连接未初始化或已关闭")
	}

	return conn, nil
}

// handleConnectionClose 监听连接关闭并重连
func handleConnectionClose(ctx context.Context) {
	closeErr := make(chan *amqp.Error)
	conn.NotifyClose(closeErr)

	err := <-closeErr
	if err != nil {
		g.Log().Errorf(ctx, "RabbitMQ 连接关闭: %v，尝试重连...", err)
		reconnect(ctx)
	}
}

// reconnect 重新连接
func reconnect(ctx context.Context) {
	mu.Lock()
	defer mu.Unlock()

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

		cfg := &Config{
			Host:     g.Cfg().MustGet(ctx, "rabbitmq.host").String(),
			Port:     g.Cfg().MustGet(ctx, "rabbitmq.port").Int(),
			Username: g.Cfg().MustGet(ctx, "rabbitmq.username").String(),
			Password: g.Cfg().MustGet(ctx, "rabbitmq.password").String(),
			VHost:    g.Cfg().MustGet(ctx, "rabbitmq.vhost", "/").String(),
		}

		url := fmt.Sprintf("amqp://%s:%s@%s:%d/%s",
			cfg.Username,
			cfg.Password,
			cfg.Host,
			cfg.Port,
			cfg.VHost,
		)

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

		channel, err = conn.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")
		go handleConnectionClose(ctx)
		return
	}

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

// Close 关闭连接
func Close(ctx context.Context) error {
	mu.Lock()
	defer mu.Unlock()

	if channel != nil {
		if err := channel.Close(); err != nil {
			g.Log().Errorf(ctx, "关闭 RabbitMQ Channel 失败: %v", err)
		}
	}

	if conn != nil {
		if err := conn.Close(); err != nil {
			g.Log().Errorf(ctx, "关闭 RabbitMQ 连接失败: %v", err)
			return err
		}
	}

	g.Log().Info(ctx, "RabbitMQ 连接已关闭")
	return nil
}