package k3sconfig

import (
	"context"
	"fmt"
	"os"
	"time"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gcfg"
	"github.com/r3labs/diff/v2"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/tools/clientcmd"
)

type K8sConfig struct {
	ApiServer  string `json:"apiServer"`
	Token      string `json:"token"`
	Kubeconfig string `json:"kubeconfig"`
	Namespace  string `json:"namespace"`
}

func init() {
	ctx := context.Background()

	consulAddr := g.Cfg().MustGet(ctx, "consul.address").String()
	if consulAddr != "" {
		g.Log().Debug(ctx, "📄 [K3sConfig] 检测到 consul.address 配置，使用 Consul，跳过 K3s 加载")
		return
	}

	loadFromK3sCluster(ctx)
}

func loadFromK3sCluster(ctx context.Context) {
	serviceName := g.Cfg().MustGet(ctx, "server.name", "").String()

	if serviceName == "" {
		panic("❌ [K3sConfig] 配置文件中未设置 server.name")
	}

	k8sConfig := getK8sConfig(ctx)
	namespace := k8sConfig.Namespace
	if namespace == "" {
		namespace = "default"
	}

	configMapName := fmt.Sprintf("%s-config", serviceName)
	g.Log().Info(ctx, "🔗 [K3sConfig] 从 K3s 集群加载配置:", configMapName)

	var config *rest.Config
	var err error

	if k8sConfig.ApiServer != "" && k8sConfig.Token != "" {
		g.Log().Infof(ctx, "📍 [K3sConfig] 使用远程 K8s API Server: %s", k8sConfig.ApiServer)
		config = &rest.Config{
			Host:        k8sConfig.ApiServer,
			BearerToken: k8sConfig.Token,
			TLSClientConfig: rest.TLSClientConfig{
				Insecure: true,
			},
		}
	} else if k8sConfig.Kubeconfig != "" {
		g.Log().Infof(ctx, "📍 [K3sConfig] 使用 Kubeconfig 文件: %s", k8sConfig.Kubeconfig)
		config, err = clientcmd.BuildConfigFromFlags("", k8sConfig.Kubeconfig)
		if err != nil {
			panic(fmt.Sprintf("❌ [K3sConfig] 构建 K8s 配置失败: %v", err))
		}
	} else {
		kubeconfigEnv := os.Getenv("KUBECONFIG")
		if kubeconfigEnv != "" {
			g.Log().Infof(ctx, "📍 [K3sConfig] 使用环境变量 KUBECONFIG: %s", kubeconfigEnv)
			config, err = clientcmd.BuildConfigFromFlags("", kubeconfigEnv)
			if err != nil {
				panic(fmt.Sprintf("❌ [K3sConfig] 构建 K8s 配置失败: %v", err))
			}
		} else {
			home, _ := os.UserHomeDir()
			defaultKubeconfig := fmt.Sprintf("%s/.kube/config", home)
			g.Log().Infof(ctx, "📍 [K3sConfig] 使用默认 Kubeconfig: %s", defaultKubeconfig)
			config, err = clientcmd.BuildConfigFromFlags("", defaultKubeconfig)
			if err != nil {
				panic(fmt.Sprintf("❌ [K3sConfig] 构建 K8s 配置失败: %v", err))
			}
		}
	}

	g.Log().Infof(ctx, "🔌 [K3sConfig] K8s API Server: %s", config.Host)

	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(fmt.Sprintf("❌ [K3sConfig] 创建 K8s 客户端失败: %v", err))
	}

	cm, err := clientset.CoreV1().ConfigMaps(namespace).Get(ctx, configMapName, metav1.GetOptions{})
	if err != nil {
		panic(fmt.Sprintf("❌ [K3sConfig] 获取 ConfigMap 失败: %v", err))
	}

	g.Log().Infof(ctx, "📦 [K3sConfig] ConfigMap 信息 - Name: %s, Namespace: %s, ResourceVersion: %s",
		cm.Name, cm.Namespace, cm.ResourceVersion)

	configData, ok := cm.Data["config.yml"]
	if !ok {
		g.Log().Debugf(ctx, "📋 [K3sConfig] ConfigMap 可用键: %v", getMapKeys(cm.Data))
		panic("❌ [K3sConfig] ConfigMap 中未找到 config.yml 键")
	}

	g.Log().Infof(ctx, "📄 [K3sConfig] 获取到的配置内容长度: %d 字节", len(configData))
	adapter, err := gcfg.NewAdapterContent()
	if err != nil {
		panic(fmt.Sprintf("❌ [K3sConfig] 创建配置适配器失败: %v", err))
	}

	adapter.SetContent(configData)
	g.Cfg().SetAdapter(adapter)
	g.Log().Infof(ctx, "✅ [K3sConfig] 成功从 K3s 加载配置: %s/%s", namespace, configMapName)

	go watchK3sConfig(ctx, clientset, namespace, configMapName, cm.ResourceVersion)
}

func getK8sConfig(ctx context.Context) K8sConfig {
	return K8sConfig{
		ApiServer:  g.Cfg().MustGet(ctx, "k8s.apiServer", "").String(),
		Token:      g.Cfg().MustGet(ctx, "k8s.token", "").String(),
		Kubeconfig: g.Cfg().MustGet(ctx, "k8s.kubeconfig", "").String(),
		Namespace:  g.Cfg().MustGet(ctx, "k8s.namespace", "default").String(),
	}
}

func watchK3sConfig(ctx context.Context, clientset *kubernetes.Clientset, namespace, configMapName string, lastResourceVersion string) {
	g.Log().Info(ctx, "👀 [K3sConfig] 开始监听 ConfigMap 变更...")

	for {
		time.Sleep(10 * time.Second)

		cm, err := clientset.CoreV1().ConfigMaps(namespace).Get(ctx, configMapName, metav1.GetOptions{
			ResourceVersion: "0",
		})
		if err != nil {
			g.Log().Errorf(ctx, "❌ [K3sConfig] 监听 ConfigMap 失败: %v", err)
			continue
		}

		if cm.ResourceVersion == lastResourceVersion {
			continue
		}

		g.Log().Infof(ctx, "🔔 [K3sConfig] 检测到 ConfigMap 变更, Old Version: %s, New Version: %s",
			lastResourceVersion, cm.ResourceVersion)

		configData, ok := cm.Data["config.yml"]
		if !ok {
			g.Log().Error(ctx, "❌ [K3sConfig] ConfigMap 中未找到 config.yml 键")
			continue
		}

		updateK3sConfig(configData)
		lastResourceVersion = cm.ResourceVersion
	}
}

func updateK3sConfig(content string) {
	ctx := context.Background()

	oldConfig, _ := g.Cfg().Data(ctx)

	adapter, err := gcfg.NewAdapterContent()
	if err != nil {
		g.Log().Errorf(ctx, "❌ [K3sConfig] 创建配置适配器失败: %v", err)
		return
	}
	adapter.SetContent(content)
	g.Cfg().SetAdapter(adapter)

	newConfig, _ := g.Cfg().Data(ctx)

	changelog, err := diff.Diff(oldConfig, newConfig)
	if err != nil {
		g.Log().Errorf(ctx, "❌ [K3sConfig] 配置对比失败: %v", err)
		return
	}

	if len(changelog) == 0 {
		g.Log().Info(ctx, "✅ [K3sConfig] 配置已热更新成功（内容无实质变化）")
		return
	}

	g.Log().Infof(ctx, "=== [K3sConfig] 检测到配置变更 (%d 项) ===", len(changelog))
	for _, change := range changelog {
		switch change.Type {
		case "create":
			g.Log().Infof(ctx, "[+] 新增: %s = %v", change.Path, change.To)
		case "update":
			g.Log().Infof(ctx, "[~] 修改: %s: %v -> %v", change.Path, change.From, change.To)
		case "delete":
			g.Log().Infof(ctx, "[-] 删除: %s (原值: %v)", change.Path, change.From)
		}
	}
	g.Log().Info(ctx, "=================================")
}

func getMapKeys(m map[string]string) []string {
	keys := make([]string, 0, len(m))
	for k := range m {
		keys = append(keys, k)
	}
	return keys
}

func loadConfigFromFile(ctx context.Context, configPath string) {
	adapter, err := gcfg.NewAdapterFile(configPath)
	if err != nil {
		g.Log().Errorf(ctx, "❌ [K3sConfig] 创建文件适配器失败: %v", err)
		return
	}

	g.Cfg().SetAdapter(adapter)
	g.Log().Info(ctx, "✅ [K3sConfig] 已成功加载配置:", configPath)
}