package service

import (
	"context"
	"encoding/base64"
	"fmt"
	"os"

	"github.com/google/uuid"
	"github.com/ocdp/cluster-service/internal/domain/entity"
	"github.com/ocdp/cluster-service/internal/domain/repository"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/tools/clientcmd"
)

// ClusterService 集群管理领域服务
type ClusterService struct {
	clusterRepo repository.ClusterRepository
}

// NewClusterService 创建集群服务
func NewClusterService(clusterRepo repository.ClusterRepository) *ClusterService {
	return &ClusterService{
		clusterRepo: clusterRepo,
	}
}

// CreateCluster 创建新集群
func (s *ClusterService) CreateCluster(ctx context.Context, cluster *entity.Cluster) error {
	// 生成 ID
	cluster.ID = uuid.New().String()

	// 验证
	if err := cluster.Validate(); err != nil {
		return err
	}

	// 检查是否已存在
	existingCluster, _ := s.clusterRepo.GetByName(ctx, cluster.Name)
	if existingCluster != nil {
		return entity.ErrClusterExists
	}

	return s.clusterRepo.Create(ctx, cluster)
}

// GetCluster 获取集群
func (s *ClusterService) GetCluster(ctx context.Context, id string) (*entity.Cluster, error) {
	return s.clusterRepo.GetByID(ctx, id)
}

// UpdateCluster 更新集群
func (s *ClusterService) UpdateCluster(ctx context.Context, cluster *entity.Cluster) error {
	// 检查是否存在
	_, err := s.clusterRepo.GetByID(ctx, cluster.ID)
	if err != nil {
		return entity.ErrClusterNotFound
	}

	// 验证
	if err := cluster.Validate(); err != nil {
		return err
	}

	return s.clusterRepo.Update(ctx, cluster)
}

// DeleteCluster 删除集群
func (s *ClusterService) DeleteCluster(ctx context.Context, id string) error {
	// 检查是否存在
	_, err := s.clusterRepo.GetByID(ctx, id)
	if err != nil {
		return entity.ErrClusterNotFound
	}

	return s.clusterRepo.Delete(ctx, id)
}

// ListClusters 列出所有集群
func (s *ClusterService) ListClusters(ctx context.Context) ([]*entity.Cluster, error) {
	return s.clusterRepo.List(ctx)
}

// ListByWorkspace 列出指定 workspace 的集群（包括共享集群）
func (s *ClusterService) ListByWorkspace(ctx context.Context, workspaceID string) ([]*entity.Cluster, error) {
	return s.clusterRepo.GetByWorkspace(ctx, workspaceID)
}

// GetSharedClusters 获取所有共享集群
func (s *ClusterService) GetSharedClusters(ctx context.Context) ([]*entity.Cluster, error) {
	return s.clusterRepo.GetShared(ctx)
}

// TestConnection 测试集群连接是否可用
func (s *ClusterService) TestConnection(ctx context.Context, cluster *entity.Cluster) error {
	// Mock 模式直接返回成功
	if os.Getenv("ADAPTER_MODE") == "mock" {
		return nil
	}

	// 尝试创建 k8s client
	config, err := s.createRestConfig(cluster)
	if err != nil {
		return fmt.Errorf("failed to create k8s config: %w", err)
	}

	// 设置超时
	config.Timeout = 30 * 1000000000 // 30秒 (nanoseconds)

	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		return fmt.Errorf("failed to create k8s client: %w", err)
	}

	// 测试连接 - 获取 version 信息
	version, err := clientset.ServerVersion()
	if err != nil {
		return fmt.Errorf("failed to connect to cluster: %w", err)
	}

	if version == nil {
		return fmt.Errorf("cluster returned nil version")
	}

	return nil
}

// createRestConfig 从 cluster 实体创建 k8s REST 配置
func (s *ClusterService) createRestConfig(cluster *entity.Cluster) (*rest.Config, error) {
	// 优先使用 kubeconfig 格式（如果 CAData 包含完整的 kubeconfig 内容）
	if len(cluster.CAData) > 100 && (cluster.CAData[:11] == "apiVersion:" || cluster.CAData[:5] == "kind:") {
		return clientcmd.RESTConfigFromKubeConfig([]byte(cluster.CAData))
	}

	// 使用证书或 token 认证
	config := &rest.Config{
		Host: cluster.Host,
	}

	if cluster.CertData != "" && cluster.KeyData != "" {
		// 尝试解码 base64 编码的证书，如果失败则尝试原始 PEM
		var caData, certData, keyData []byte
		var decodeErr error

		// 先尝试 base64 解码
		caData, decodeErr = base64.StdEncoding.DecodeString(cluster.CAData)
		if decodeErr != nil {
			// base64 解码失败，可能是原始 PEM
			caData = []byte(cluster.CAData)
		}

		certData, decodeErr = base64.StdEncoding.DecodeString(cluster.CertData)
		if decodeErr != nil {
			certData = []byte(cluster.CertData)
		}

		keyData, decodeErr = base64.StdEncoding.DecodeString(cluster.KeyData)
		if decodeErr != nil {
			keyData = []byte(cluster.KeyData)
		}

		config.TLSClientConfig = rest.TLSClientConfig{
			CAData:   caData,
			CertData: certData,
			KeyData:  keyData,
			Insecure: false,
		}
	} else if cluster.Token != "" {
		config.BearerToken = cluster.Token
	} else {
		// 尝试使用本地 kubeconfig
		kubeconfig := os.Getenv("KUBECONFIG")
		if kubeconfig == "" {
			kubeconfig = ".kube/config"
		}
		// 尝试从文件加载 kubeconfig
		if _, err := os.Stat(kubeconfig); err != nil {
			return nil, fmt.Errorf("no valid credentials found for cluster %s (no cert/key/token, and kubeconfig file not found: %s)", cluster.Name, kubeconfig)
		}
		return clientcmd.BuildConfigFromFlags("", kubeconfig)
	}

	return config, nil
}