package service

import (
	"context"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/google/uuid"
	"github.com/ocdp/cluster-service/internal/domain/entity"
	"github.com/ocdp/cluster-service/internal/domain/repository"
)

// InstanceService Helm 实例管理领域服务
type InstanceService struct {
	instanceRepo repository.InstanceRepository
	clusterRepo  repository.ClusterRepository
	registryRepo repository.RegistryRepository
	helmClient   repository.HelmClient
	ociClient    repository.OCIClient
	entryClient  repository.InstanceEntryClient
}

// NewInstanceService 创建实例服务
func NewInstanceService(
	instanceRepo repository.InstanceRepository,
	clusterRepo repository.ClusterRepository,
	registryRepo repository.RegistryRepository,
	helmClient repository.HelmClient,
	ociClient repository.OCIClient,
	entryClient repository.InstanceEntryClient,
) *InstanceService {
	return &InstanceService{
		instanceRepo: instanceRepo,
		clusterRepo:  clusterRepo,
		registryRepo: registryRepo,
		helmClient:   helmClient,
		ociClient:    ociClient,
		entryClient:  entryClient,
	}
}

const chartCacheDir = "/tmp/charts"

func (s *InstanceService) chartArchivePath(instance *entity.Instance) string {
	filename := fmt.Sprintf("%s-%s.tgz", instance.Chart, instance.Version)
	return filepath.Join(chartCacheDir, filename)
}

func (s *InstanceService) downloadChart(ctx context.Context, registry *entity.Registry, instance *entity.Instance) error {
	if err := os.MkdirAll(chartCacheDir, 0755); err != nil {
		return fmt.Errorf("failed to ensure chart cache dir: %w", err)
	}
	chartPath := s.chartArchivePath(instance)
	if err := s.ociClient.PullArtifact(ctx, registry, instance.Repository, instance.Version, chartPath); err != nil {
		return fmt.Errorf("failed to download chart artifact: %w", err)
	}
	return nil
}

// CreateInstance 创建（安装）新实例
func (s *InstanceService) CreateInstance(ctx context.Context, instance *entity.Instance) error {
	// 生成 ID
	instance.ID = uuid.New().String()

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

	// 检查集群是否存在
	cluster, err := s.clusterRepo.GetByID(ctx, instance.ClusterID)
	if err != nil {
		return entity.ErrClusterNotFound
	}

	// 检查 Registry 是否存在
	registry, err := s.registryRepo.GetByID(ctx, instance.RegistryID)
	if err != nil {
		return entity.ErrRegistryNotFound
	}

	// 检查实例是否已存在
	existingInstance, _ := s.instanceRepo.GetByClusterAndName(ctx, instance.ClusterID, instance.Name)
	if existingInstance != nil {
		return entity.ErrInstanceExists
	}

	instance.BeginOperation(entity.OperationInstall, "Preparing installation")

	// 先写入数据库，记录 pending 状态
	if err := s.instanceRepo.Create(ctx, instance); err != nil {
		return err
	}

	// 下载 chart artifact 供 Helm 使用
	if err := s.downloadChart(ctx, registry, instance); err != nil {
		instance.MarkFailure("Failed to download chart", err)
		_ = s.instanceRepo.Update(ctx, instance)
		return err
	}

	// 异步执行 Helm 安装并监控状态
	go s.executeAndSyncInstall(context.Background(), instance.ID, cluster, registry, instance)

	// 立即返回，状态同步由后台任务处理
	return nil
}

// GetInstance 获取实例
func (s *InstanceService) GetInstance(ctx context.Context, id string) (*entity.Instance, error) {
	return s.instanceRepo.GetByID(ctx, id)
}

// GetInstanceStatus 获取实例实时状态
func (s *InstanceService) GetInstanceStatus(ctx context.Context, id string) (*entity.Instance, error) {
	// 从数据库获取基本信息
	instance, err := s.instanceRepo.GetByID(ctx, id)
	if err != nil {
		return nil, entity.ErrInstanceNotFound
	}

	// 获取集群信息
	cluster, err := s.clusterRepo.GetByID(ctx, instance.ClusterID)
	if err != nil {
		return nil, entity.ErrClusterNotFound
	}

	// 从 Helm 获取实时状态
	liveStatus, err := s.helmClient.GetStatus(ctx, cluster, instance.Name, instance.Namespace)
	if err != nil {
		return instance, err // 返回数据库中的信息，但标记错误
	}

	// 合并实时状态
	instance.Status = liveStatus.Status
	instance.Revision = liveStatus.Revision

	return instance, nil
}

// UpdateInstance 更新（升级）实例
func (s *InstanceService) UpdateInstance(ctx context.Context, instance *entity.Instance) error {
	// 检查实例是否存在
	existingInstance, err := s.instanceRepo.GetByID(ctx, instance.ID)
	if err != nil {
		return entity.ErrInstanceNotFound
	}

	// 获取集群信息
	cluster, err := s.clusterRepo.GetByID(ctx, existingInstance.ClusterID)
	if err != nil {
		return entity.ErrClusterNotFound
	}

	// 获取 Registry 信息
	registry, err := s.registryRepo.GetByID(ctx, instance.RegistryID)
	if err != nil {
		return entity.ErrRegistryNotFound
	}

	instance.BeginOperation(entity.OperationUpgrade, "Pending upgrade")
	if err := s.instanceRepo.Update(ctx, instance); err != nil {
		return err
	}

	// 下载所需 Chart
	if err := s.downloadChart(ctx, registry, instance); err != nil {
		instance.MarkFailure("Failed to download chart", err)
		_ = s.instanceRepo.Update(ctx, instance)
		return err
	}

	// 异步执行 Helm 升级并监控状态
	go s.executeAndSyncUpgrade(context.Background(), instance.ID, cluster, registry, instance)

	// 立即返回，状态同步由后台任务处理
	return nil
}

// DeleteInstance 删除（卸载）实例
func (s *InstanceService) DeleteInstance(ctx context.Context, id string) error {
	// 检查实例是否存在
	instance, err := s.instanceRepo.GetByID(ctx, id)
	if err != nil {
		return entity.ErrInstanceNotFound
	}

	// 获取集群信息
	cluster, err := s.clusterRepo.GetByID(ctx, instance.ClusterID)
	if err != nil {
		return entity.ErrClusterNotFound
	}

	instance.BeginOperation(entity.OperationDelete, "Pending uninstall")
	if err := s.instanceRepo.Update(ctx, instance); err != nil {
		return err
	}

	// 异步执行 Helm 卸载并监控状态
	go s.executeAndSyncUninstall(context.Background(), instance.ID, cluster, instance.Name, instance.Namespace)

	// 立即返回，状态同步由后台任务处理
	return nil
}

// RollbackInstance 回滚实例
func (s *InstanceService) RollbackInstance(ctx context.Context, id string, revision int) error {
	// 检查实例是否存在
	instance, err := s.instanceRepo.GetByID(ctx, id)
	if err != nil {
		return entity.ErrInstanceNotFound
	}

	// 获取集群信息
	cluster, err := s.clusterRepo.GetByID(ctx, instance.ClusterID)
	if err != nil {
		return entity.ErrClusterNotFound
	}

	instance.BeginOperation(entity.OperationRollback, fmt.Sprintf("Rolling back to revision %d", revision))
	if err := s.instanceRepo.Update(ctx, instance); err != nil {
		return err
	}

	// 异步执行 Helm 回滚并监控状态
	go s.executeAndSyncRollback(context.Background(), instance.ID, cluster, instance.Name, instance.Namespace, revision)

	// 立即返回，状态同步由后台任务处理
	return nil
}

// GetInstanceHistory 获取实例历史
func (s *InstanceService) GetInstanceHistory(ctx context.Context, id string) ([]*entity.ReleaseHistory, error) {
	// 检查实例是否存在
	instance, err := s.instanceRepo.GetByID(ctx, id)
	if err != nil {
		return nil, entity.ErrInstanceNotFound
	}

	// 获取集群信息
	cluster, err := s.clusterRepo.GetByID(ctx, instance.ClusterID)
	if err != nil {
		return nil, entity.ErrClusterNotFound
	}

	// 从 Helm 获取历史
	return s.helmClient.GetHistory(ctx, cluster, instance.Name, instance.Namespace)
}

// ListInstancesByCluster 列出集群的所有实例
func (s *InstanceService) ListInstancesByCluster(ctx context.Context, clusterID string) ([]*entity.Instance, error) {
	// 检查集群是否存在
	_, err := s.clusterRepo.GetByID(ctx, clusterID)
	if err != nil {
		return nil, entity.ErrClusterNotFound
	}

	return s.instanceRepo.ListByCluster(ctx, clusterID)
}

// ListInstanceEntries 列出实例关联的入口信息（Service / Ingress）
func (s *InstanceService) ListInstanceEntries(ctx context.Context, clusterID, instanceID string) ([]*entity.InstanceEntry, error) {
	instance, err := s.instanceRepo.GetByID(ctx, instanceID)
	if err != nil {
		return nil, entity.ErrInstanceNotFound
	}
	if instance.ClusterID != clusterID {
		return nil, entity.ErrInstanceNotFound
	}

	cluster, err := s.clusterRepo.GetByID(ctx, clusterID)
	if err != nil {
		return nil, entity.ErrClusterNotFound
	}

	if s.entryClient == nil {
		return nil, fmt.Errorf("instance entry client is not configured")
	}

	return s.entryClient.ListEntries(ctx, cluster, instance)
}

// executeAndSyncInstall 异步执行安装并监控状态
func (s *InstanceService) executeAndSyncInstall(ctx context.Context, instanceID string, cluster *entity.Cluster, registry *entity.Registry, instance *entity.Instance) {
	// 执行 Helm 安装
	if err := s.helmClient.Install(ctx, cluster, instance); err != nil {
		// 更新实例状态为失败
		instance, updateErr := s.instanceRepo.GetByID(ctx, instanceID)
		if updateErr == nil && instance != nil {
			instance.MarkFailure("Helm install failed", err)
			_ = s.instanceRepo.Update(ctx, instance)
		}
		return
	}

	// 安装成功后，同步状态
	s.syncInstanceStatus(ctx, instanceID, cluster, instance.Name, instance.Namespace, entity.OperationInstall)
}

// executeAndSyncUpgrade 异步执行升级并监控状态
func (s *InstanceService) executeAndSyncUpgrade(ctx context.Context, instanceID string, cluster *entity.Cluster, registry *entity.Registry, instance *entity.Instance) {
	// 执行 Helm 升级
	if err := s.helmClient.Upgrade(ctx, cluster, instance); err != nil {
		// 更新实例状态为失败
		instance, updateErr := s.instanceRepo.GetByID(ctx, instanceID)
		if updateErr == nil && instance != nil {
			instance.MarkFailure("Helm upgrade failed", err)
			_ = s.instanceRepo.Update(ctx, instance)
		}
		return
	}

	// 升级成功后，同步状态
	s.syncInstanceStatus(ctx, instanceID, cluster, instance.Name, instance.Namespace, entity.OperationUpgrade)
}

// executeAndSyncRollback 异步执行回滚并监控状态
func (s *InstanceService) executeAndSyncRollback(ctx context.Context, instanceID string, cluster *entity.Cluster, releaseName, namespace string, revision int) {
	// 执行 Helm 回滚
	if err := s.helmClient.Rollback(ctx, cluster, releaseName, namespace, revision); err != nil {
		// 更新实例状态为失败
		instance, updateErr := s.instanceRepo.GetByID(ctx, instanceID)
		if updateErr == nil && instance != nil {
			instance.MarkFailure("Helm rollback failed", err)
			_ = s.instanceRepo.Update(ctx, instance)
		}
		return
	}

	// 回滚成功后，同步状态
	s.syncInstanceStatus(ctx, instanceID, cluster, releaseName, namespace, entity.OperationRollback)
}

// executeAndSyncUninstall 异步执行卸载并监控状态
func (s *InstanceService) executeAndSyncUninstall(ctx context.Context, instanceID string, cluster *entity.Cluster, releaseName, namespace string) {
	// 先验证 release 名称是否有效
	// 如果名称无效，说明这个 release 根本不可能存在于 Helm 中，直接删除数据库记录
	if err := entity.ValidateReleaseName(releaseName); err != nil {
		// Release 名称无效，直接删除数据库记录
		_ = s.instanceRepo.Delete(ctx, instanceID)
		return
	}

	// 执行 Helm 卸载
	err := s.helmClient.Uninstall(ctx, cluster, releaseName, namespace)

	// 获取实例
	instance, getErr := s.instanceRepo.GetByID(ctx, instanceID)
	if getErr != nil {
		return
	}

	if err != nil {
		// 检查错误类型
		if errors.Is(err, entity.ErrInstanceNotFound) {
			// 未找到，说明已经卸载，直接删除数据库记录
			_ = s.instanceRepo.Delete(ctx, instanceID)
		} else {
			// 检查是否是 release 名称无效的错误（可能在某些情况下 Helm 会返回这个错误）
			errMsg := strings.ToLower(err.Error())
			if strings.Contains(errMsg, "release name is invalid") ||
			   (strings.Contains(errMsg, "invalid") && strings.Contains(errMsg, "release")) {
				// Release 名称无效，直接删除数据库记录
				_ = s.instanceRepo.Delete(ctx, instanceID)
			} else {
				// 其他错误，标记为失败
				instance.MarkFailure("Helm uninstall failed", err)
				_ = s.instanceRepo.Update(ctx, instance)
			}
		}
		return
	}

	// 卸载成功，标记为已卸载
	instance.MarkSuccess(entity.StatusUninstalled, instance.Revision, "Instance uninstalled successfully")
	_ = s.instanceRepo.Update(ctx, instance)

	// 验证卸载是否完成：尝试获取状态，如果获取不到说明已卸载
	time.Sleep(3 * time.Second)
	_, statusErr := s.helmClient.GetStatus(ctx, cluster, releaseName, namespace)
	if statusErr != nil {
		// 无法获取状态，说明已卸载，删除数据库记录
		_ = s.instanceRepo.Delete(ctx, instanceID)
	} else {
		// 仍然可以获取状态，可能还在卸载中，继续等待
		// 设置状态为 uninstalled，但不删除记录，让用户手动删除或等待自动清理
		instance.MarkSuccess(entity.StatusUninstalled, instance.Revision, "Uninstall in progress")
		_ = s.instanceRepo.Update(ctx, instance)
	}
}

// syncInstanceStatus 同步实例状态（定期检查 Helm 状态并更新数据库）
func (s *InstanceService) syncInstanceStatus(ctx context.Context, instanceID string, cluster *entity.Cluster, releaseName, namespace string, operation entity.InstanceOperation) {
	maxAttempts := 30 // 最多尝试30次（约5分钟）
	interval := 10 * time.Second // 每10秒检查一次

	for i := 0; i < maxAttempts; i++ {
		time.Sleep(interval)

		// 获取数据库中的实例
		instance, err := s.instanceRepo.GetByID(ctx, instanceID)
		if err != nil {
			// 实例不存在，停止同步
			return
		}

		// 从 Helm 获取实时状态
		liveStatus, err := s.helmClient.GetStatus(ctx, cluster, releaseName, namespace)
		if err != nil {
			// 如果获取状态失败，可能是还在部署中，继续等待
			if i < maxAttempts-1 {
				continue
			}
			// 最后一次尝试失败，标记为失败
			instance.MarkFailure("Failed to get status from Helm", err)
			_ = s.instanceRepo.Update(ctx, instance)
			return
		}

		// 根据操作类型和 Helm 状态更新实例状态
		shouldUpdate := false
		switch operation {
		case entity.OperationInstall:
			// 安装操作：如果 Helm 状态是 deployed，则更新为 deployed
			if liveStatus.Status == entity.StatusDeployed {
				instance.MarkSuccess(entity.StatusDeployed, liveStatus.Revision, "Instance deployed successfully")
				shouldUpdate = true
			} else if liveStatus.Status == entity.StatusFailed {
				instance.MarkFailure("Installation failed", fmt.Errorf("Helm status: %s", liveStatus.Status))
				shouldUpdate = true
			}
		case entity.OperationUpgrade:
			// 升级操作：如果 Helm 状态是 deployed，则更新为 deployed
			if liveStatus.Status == entity.StatusDeployed {
				instance.MarkSuccess(entity.StatusDeployed, liveStatus.Revision, "Instance upgraded successfully")
				shouldUpdate = true
			} else if liveStatus.Status == entity.StatusFailed {
				instance.MarkFailure("Upgrade failed", fmt.Errorf("Helm status: %s", liveStatus.Status))
				shouldUpdate = true
			}
		case entity.OperationRollback:
			// 回滚操作：如果 Helm 状态是 deployed，则更新为 deployed
			if liveStatus.Status == entity.StatusDeployed {
				instance.MarkSuccess(entity.StatusDeployed, liveStatus.Revision, "Instance rolled back successfully")
				shouldUpdate = true
			} else if liveStatus.Status == entity.StatusFailed {
				instance.MarkFailure("Rollback failed", fmt.Errorf("Helm status: %s", liveStatus.Status))
				shouldUpdate = true
			}
		}

		// 如果状态已更新为最终状态，停止同步
		if shouldUpdate {
			_ = s.instanceRepo.Update(ctx, instance)
			return
		}

		// 如果状态已经是最终状态（deployed 或 failed），停止同步
		if instance.Status == entity.StatusDeployed || instance.Status == entity.StatusFailed {
			return
		}
	}

	// 超时，标记为失败
	instance, err := s.instanceRepo.GetByID(ctx, instanceID)
	if err == nil && instance != nil {
		instance.MarkFailure("Operation timeout", fmt.Errorf("Status sync timeout after %d attempts", maxAttempts))
		_ = s.instanceRepo.Update(ctx, instance)
	}
}