package virtualmachine

import (
	"context"
	"fmt"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/pkg/errors"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/log"

	proxmoxv1alpha1 "github.com/sankofa/crossplane-provider-proxmox/apis/v1alpha1"
	"github.com/sankofa/crossplane-provider-proxmox/pkg/proxmox"
	"github.com/sankofa/crossplane-provider-proxmox/pkg/quota"
	"github.com/sankofa/crossplane-provider-proxmox/pkg/utils"
)

// ProxmoxVMReconciler reconciles a ProxmoxVM object
type ProxmoxVMReconciler struct {
	client.Client
	Scheme *runtime.Scheme
}

//+kubebuilder:rbac:groups=proxmox.sankofa.nexus,resources=proxmoxvms,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=proxmox.sankofa.nexus,resources=proxmoxvms/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=proxmox.sankofa.nexus,resources=proxmoxvms/finalizers,verbs=update

// Reconcile is part of the main kubernetes reconciliation loop
func (r *ProxmoxVMReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	logger := log.FromContext(ctx)

	var vm proxmoxv1alpha1.ProxmoxVM
	if err := r.Get(ctx, req.NamespacedName, &vm); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	// Validate ProviderConfigReference
	if vm.Spec.ProviderConfigReference == nil {
		return ctrl.Result{}, errors.New("providerConfigRef is required")
	}
	if vm.Spec.ProviderConfigReference.Name == "" {
		return ctrl.Result{}, errors.New("providerConfigRef.name is required")
	}

	// Get ProviderConfig
	var providerConfig proxmoxv1alpha1.ProviderConfig
	providerConfigName := vm.Spec.ProviderConfigReference.Name
	if err := r.Get(ctx, client.ObjectKey{Name: providerConfigName}, &providerConfig); err != nil {
		return ctrl.Result{}, errors.Wrapf(err, "cannot get provider config %s", providerConfigName)
	}

	// Track retry attempts for exponential backoff
	attemptCount := 0
	if vm.Status.Conditions != nil {
		for _, condition := range vm.Status.Conditions {
			if condition.Type == "Failed" {
				attemptCount++
			}
		}
	}

	// Get credentials from secret
	creds, err := r.getCredentials(ctx, &providerConfig)
	if err != nil {
		logger.Error(err, "cannot get credentials")
		delay := GetRequeueDelay(err, attemptCount)
		return ctrl.Result{RequeueAfter: delay}, errors.Wrap(err, "cannot get credentials")
	}

	// Find the site configuration
	site, err := r.findSite(&providerConfig, vm.Spec.ForProvider.Site)
	if err != nil {
		logger.Error(err, "cannot find site", "site", vm.Spec.ForProvider.Site)
		delay := GetRequeueDelay(err, attemptCount)
		return ctrl.Result{RequeueAfter: delay}, errors.Wrapf(err, "cannot find site %s", vm.Spec.ForProvider.Site)
	}

	// Create Proxmox client
	proxmoxClient, err := proxmox.NewClient(
		site.Endpoint,
		creds.Username,
		creds.Password,
		site.InsecureSkipTLSVerify,
	)
	if err != nil {
		return ctrl.Result{}, errors.Wrap(err, "cannot create Proxmox client")
	}

		// Check node health before proceeding
		if err := proxmoxClient.CheckNodeHealth(ctx, vm.Spec.ForProvider.Node); err != nil {
			logger.Error(err, "node health check failed", "node", vm.Spec.ForProvider.Node)
			// Update status with error condition
			vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
				Type:               "NodeUnhealthy",
				Status:             "True",
				Reason:             "HealthCheckFailed",
				Message:            err.Error(),
				LastTransitionTime: metav1.Now(),
			})
			r.Status().Update(ctx, &vm)
			return ctrl.Result{RequeueAfter: 2 * time.Minute}, nil
		}

		// Validate network bridge exists on node
		if vm.Spec.ForProvider.Network != "" {
			networkExists, err := proxmoxClient.NetworkExists(ctx, vm.Spec.ForProvider.Node, vm.Spec.ForProvider.Network)
			if err != nil {
				logger.Error(err, "failed to check network bridge", "node", vm.Spec.ForProvider.Node, "network", vm.Spec.ForProvider.Network)
				// Don't fail on check error - network might exist but API call failed
			} else if !networkExists {
				err := fmt.Errorf("network bridge '%s' does not exist on node '%s'", vm.Spec.ForProvider.Network, vm.Spec.ForProvider.Node)
				logger.Error(err, "network bridge validation failed")
				vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
					Type:               "ValidationFailed",
					Status:             "True",
					Reason:             "NetworkNotFound",
					Message:            err.Error(),
					LastTransitionTime: metav1.Now(),
				})
				r.Status().Update(ctx, &vm)
				return ctrl.Result{}, errors.Wrap(err, "network bridge validation failed")
			}
		}

	// Reconcile VM
	if vm.Status.VMID == 0 {
		// Validate VM specification before creation
		if err := utils.ValidateVMName(vm.Spec.ForProvider.Name); err != nil {
			logger.Error(err, "invalid VM name")
			vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
				Type:               "ValidationFailed",
				Status:             "True",
				Reason:             "InvalidVMName",
				Message:            err.Error(),
				LastTransitionTime: metav1.Now(),
			})
			r.Status().Update(ctx, &vm)
			return ctrl.Result{}, errors.Wrap(err, "invalid VM name")
		}

		if err := utils.ValidateMemory(vm.Spec.ForProvider.Memory); err != nil {
			logger.Error(err, "invalid memory specification")
			vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
				Type:               "ValidationFailed",
				Status:             "True",
				Reason:             "InvalidMemory",
				Message:            err.Error(),
				LastTransitionTime: metav1.Now(),
			})
			r.Status().Update(ctx, &vm)
			return ctrl.Result{}, errors.Wrap(err, "invalid memory specification")
		}

		if err := utils.ValidateDisk(vm.Spec.ForProvider.Disk); err != nil {
			logger.Error(err, "invalid disk specification")
			vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
				Type:               "ValidationFailed",
				Status:             "True",
				Reason:             "InvalidDisk",
				Message:            err.Error(),
				LastTransitionTime: metav1.Now(),
			})
			r.Status().Update(ctx, &vm)
			return ctrl.Result{}, errors.Wrap(err, "invalid disk specification")
		}

		if err := utils.ValidateCPU(vm.Spec.ForProvider.CPU); err != nil {
			logger.Error(err, "invalid CPU specification")
			vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
				Type:               "ValidationFailed",
				Status:             "True",
				Reason:             "InvalidCPU",
				Message:            err.Error(),
				LastTransitionTime: metav1.Now(),
			})
			r.Status().Update(ctx, &vm)
			return ctrl.Result{}, errors.Wrap(err, "invalid CPU specification")
		}

		if err := utils.ValidateNetworkBridge(vm.Spec.ForProvider.Network); err != nil {
			logger.Error(err, "invalid network bridge specification")
			vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
				Type:               "ValidationFailed",
				Status:             "True",
				Reason:             "InvalidNetwork",
				Message:            err.Error(),
				LastTransitionTime: metav1.Now(),
			})
			r.Status().Update(ctx, &vm)
			return ctrl.Result{}, errors.Wrap(err, "invalid network bridge specification")
		}

		if err := utils.ValidateImageSpec(vm.Spec.ForProvider.Image); err != nil {
			logger.Error(err, "invalid image specification")
			vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
				Type:               "ValidationFailed",
				Status:             "True",
				Reason:             "InvalidImage",
				Message:            err.Error(),
				LastTransitionTime: metav1.Now(),
			})
			r.Status().Update(ctx, &vm)
			return ctrl.Result{}, errors.Wrap(err, "invalid image specification")
		}

		// Create VM
		logger.Info("Creating VM", "name", vm.Name, "node", vm.Spec.ForProvider.Node)
		
		// Extract tenant_id from Kubernetes labels or annotations (for multi-tenancy)
		tenantID := ""
		if vm.Labels != nil {
			if tid, ok := vm.Labels["tenant.sankofa.nexus/id"]; ok {
				tenantID = tid
			} else if tid, ok := vm.Labels["tenant-id"]; ok {
				tenantID = tid
			}
		}
		if tenantID == "" && vm.Annotations != nil {
			if tid, ok := vm.Annotations["tenant.sankofa.nexus/id"]; ok {
				tenantID = tid
			} else if tid, ok := vm.Annotations["tenant-id"]; ok {
				tenantID = tid
			}
		}

		// Enforce quota if tenant ID is present
		if tenantID != "" {
			apiURL := os.Getenv("SANKOFA_API_URL")
			apiToken := os.Getenv("SANKOFA_API_TOKEN")
			if apiURL != "" && apiToken != "" {
				quotaClient := quota.NewQuotaClient(apiURL, apiToken)
				
				// Parse memory from string (e.g., "8Gi" -> 8)
				memoryGB := utils.ParseMemoryToGB(vm.Spec.ForProvider.Memory)
				diskGB := utils.ParseDiskToGB(vm.Spec.ForProvider.Disk)
				
				resourceRequest := quota.ResourceRequest{
					Compute: &quota.ComputeRequest{
						VCPU:     &vm.Spec.ForProvider.CPU,
						Memory:   &memoryGB,
						Instances: intPtr(1),
					},
					Storage: &quota.StorageRequest{
						Size: &diskGB,
					},
				}
				
				if err := quotaClient.EnforceQuota(ctx, tenantID, resourceRequest); err != nil {
					logger.Error(err, "Quota check failed", "tenantID", tenantID)
					return ctrl.Result{RequeueAfter: 60 * time.Second}, errors.Wrap(err, "quota exceeded")
				}
				logger.Info("Quota check passed", "tenantID", tenantID)
			} else {
				logger.Info("Skipping quota check - API URL or token not configured")
			}
		}

		vmSpec := proxmox.VMSpec{
			Node:    vm.Spec.ForProvider.Node,
			Name:    vm.Spec.ForProvider.Name,
			CPU:     vm.Spec.ForProvider.CPU,
			Memory:  vm.Spec.ForProvider.Memory,
			Disk:    vm.Spec.ForProvider.Disk,
			Storage: vm.Spec.ForProvider.Storage,
			Network: vm.Spec.ForProvider.Network,
			Image:   vm.Spec.ForProvider.Image,
			UserData: vm.Spec.ForProvider.UserData,
			SSHKeys: vm.Spec.ForProvider.SSHKeys,
			TenantID: tenantID, // Pass tenant_id to Proxmox client
		}

		createdVM, err := proxmoxClient.CreateVM(ctx, vmSpec)
		if err != nil {
			// CRITICAL: Check if VM was partially created (VMID assigned but creation failed)
			// This happens when importdisk fails after VM is created
			errorStr := err.Error()
			if strings.Contains(errorStr, "VM") && strings.Contains(errorStr, "has been cleaned up") {
				// VM was created but cleaned up due to error (e.g., importdisk not supported)
				// Categorize error and update status to prevent infinite retry loop
				errorCategory := categorizeError(errorStr)
				vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
					Type:               errorCategory.Type,
					Status:             "True",
					Reason:             errorCategory.Reason,
					Message:            errorStr,
					LastTransitionTime: metav1.Now(),
				})
				if updateErr := r.Status().Update(ctx, &vm); updateErr != nil {
					logger.Error(updateErr, "failed to update status after creation failure")
				}
			// Use exponential backoff based on attempt count
			delay := GetRequeueDelay(err, attemptCount)
			return ctrl.Result{RequeueAfter: delay}, errors.Wrap(err, "cannot create VM - VM was cleaned up")
			}
			
			// For other errors, check if a VM was created but not returned
			// Try to find orphaned VMs by name
			vms, listErr := proxmoxClient.ListVMs(ctx, vm.Spec.ForProvider.Node)
			if listErr == nil {
				for _, existingVM := range vms {
					if existingVM.Name == vm.Spec.ForProvider.Name {
						// Found orphaned VM - attempt cleanup
						logger.Info("Found orphaned VM, attempting cleanup", "vmID", existingVM.ID, "name", existingVM.Name)
						cleanupErr := proxmoxClient.DeleteVM(ctx, existingVM.ID)
						if cleanupErr != nil {
							logger.Error(cleanupErr, "Failed to cleanup orphaned VM", "vmID", existingVM.ID)
						} else {
							logger.Info("Successfully cleaned up orphaned VM", "vmID", existingVM.ID)
						}
					}
				}
			}
			
			// Categorize error and update status with appropriate condition
			errorCategory := categorizeError(errorStr)
			vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
				Type:               errorCategory.Type,
				Status:             "True",
				Reason:             errorCategory.Reason,
				Message:            errorStr,
				LastTransitionTime: metav1.Now(),
			})
			if updateErr := r.Status().Update(ctx, &vm); updateErr != nil {
				logger.Error(updateErr, "failed to update status after creation failure")
			}
			
			// Use exponential backoff based on attempt count
			delay := GetRequeueDelay(err, attemptCount)
			return ctrl.Result{RequeueAfter: delay}, errors.Wrap(err, "cannot create VM")
		}

		vm.Status.VMID = createdVM.ID
		// Set initial status conservatively - VM is created but may not be running yet
		vm.Status.State = "created" // Use "created" instead of actual status until verified
		// IP address may not be available immediately - will be updated in next reconcile
		vm.Status.IPAddress = ""
		
		// Clear any previous failure conditions
		for i := len(vm.Status.Conditions) - 1; i >= 0; i-- {
			if vm.Status.Conditions[i].Type == "Failed" {
				vm.Status.Conditions = append(vm.Status.Conditions[:i], vm.Status.Conditions[i+1:]...)
			}
		}
		
		// Add success condition
		vm.Status.Conditions = append(vm.Status.Conditions, metav1.Condition{
			Type:               "Ready",
			Status:             "True",
			Reason:             "Created",
			Message:            fmt.Sprintf("VM %d created successfully", createdVM.ID),
			LastTransitionTime: metav1.Now(),
		})

		if err := r.Status().Update(ctx, &vm); err != nil {
			return ctrl.Result{}, errors.Wrap(err, "cannot update VM status")
		}

		return ctrl.Result{RequeueAfter: 10 * time.Second}, nil
	}

	// Update VM status
	vmStatus, err := proxmoxClient.GetVMStatus(ctx, vm.Status.VMID)
	if err != nil {
		// If VM status can't be retrieved, try to get from ListVMs
		vms, listErr := proxmoxClient.ListVMs(ctx, vm.Spec.ForProvider.Node)
		if listErr != nil {
			return ctrl.Result{}, errors.Wrap(err, "cannot get VM status")
		}
		for _, v := range vms {
			if v.ID == vm.Status.VMID {
				vm.Status.State = v.Status
				vm.Status.IPAddress = v.IP
				break
			}
		}
	} else {
		vm.Status.State = vmStatus.State
		vm.Status.IPAddress = vmStatus.IPAddress
	}

	if err := r.Status().Update(ctx, &vm); err != nil {
		return ctrl.Result{}, errors.Wrap(err, "cannot update VM status")
	}

	// Check if VM needs to be updated
	needsUpdate := false
	if vmStatus != nil {
		// Compare with current status - for now, always check if spec differs
		// In a real implementation, you'd compare current VM config with spec
		needsUpdate = vm.Spec.ForProvider.CPU > 0 || vm.Spec.ForProvider.Memory != ""
	}

	if needsUpdate {
		logger.Info("Updating VM", "name", vm.Name, "vmId", vm.Status.VMID)
		
		vmSpec := proxmox.VMSpec{
			Node:   vm.Spec.ForProvider.Node,
			Name:   vm.Spec.ForProvider.Name,
			CPU:    vm.Spec.ForProvider.CPU,
			Memory: vm.Spec.ForProvider.Memory,
		}

		_, err := proxmoxClient.UpdateVM(ctx, vm.Status.VMID, vmSpec)
		if err != nil {
			return ctrl.Result{}, errors.Wrap(err, "cannot update VM")
		}

		return ctrl.Result{RequeueAfter: 10 * time.Second}, nil
	}

	return ctrl.Result{RequeueAfter: 30 * time.Second}, nil
}

// CleanupOrphanedVMs scans for and cleans up orphaned VMs on controller startup
// Orphaned VMs are VMs in Proxmox that don't have corresponding Kubernetes resources
func (r *ProxmoxVMReconciler) CleanupOrphanedVMs(ctx context.Context) error {
	logger := log.FromContext(ctx)
	logger.Info("Starting orphaned VM cleanup on controller startup")

	// List all ProxmoxVM resources
	var vmList proxmoxv1alpha1.ProxmoxVMList
	if err := r.List(ctx, &vmList, &client.ListOptions{}); err != nil {
		logger.Error(err, "failed to list ProxmoxVM resources")
		return err
	}

	// Build map of expected VMIDs
	expectedVMIDs := make(map[int]bool)
	for _, vm := range vmList.Items {
		if vm.Status.VMID > 0 {
			expectedVMIDs[vm.Status.VMID] = true
		}
	}

	// Get all ProviderConfigs to check VMs on all sites
	var configList proxmoxv1alpha1.ProviderConfigList
	if err := r.List(ctx, &configList, &client.ListOptions{}); err != nil {
		logger.Error(err, "failed to list ProviderConfig resources")
		return err
	}

	cleanedCount := 0
	for _, config := range configList.Items {
		// Get credentials
		creds, err := r.getCredentials(ctx, &config)
		if err != nil {
			logger.Error(err, "failed to get credentials for cleanup", "config", config.Name)
			continue
		}

		// Check each site
		for _, site := range config.Spec.Sites {
			client, err := proxmox.NewClient(
				site.Endpoint,
				creds.Username,
				creds.Password,
				site.InsecureSkipTLSVerify,
			)
			if err != nil {
				logger.Error(err, "failed to create Proxmox client for cleanup", "site", site.Name)
				continue
			}

			// List VMs on this node
			vms, err := client.ListVMs(ctx, site.Node)
			if err != nil {
				logger.Error(err, "failed to list VMs for cleanup", "site", site.Name, "node", site.Node)
				continue
			}

			// Check for orphaned VMs (VMs not in expected list)
			for _, vm := range vms {
				if !expectedVMIDs[vm.ID] {
					// Check if VM has a name that suggests it might be orphaned
					// (e.g., matches pattern of our VMs but no Kubernetes resource)
					logger.Info("Found potential orphaned VM", "vmID", vm.ID, "name", vm.Name, "node", site.Node)
					
					// Only clean up if VM is stopped (safer)
					if vm.Status == "stopped" {
						logger.Info("Cleaning up orphaned stopped VM", "vmID", vm.ID)
						if err := client.DeleteVM(ctx, vm.ID); err != nil {
							logger.Error(err, "failed to cleanup orphaned VM", "vmID", vm.ID)
						} else {
							cleanedCount++
							logger.Info("Successfully cleaned up orphaned VM", "vmID", vm.ID)
						}
					} else {
						logger.Info("Skipping orphaned VM cleanup - VM is not stopped", "vmID", vm.ID, "status", vm.Status)
					}
				}
			}
		}
	}

	if cleanedCount > 0 {
		logger.Info("Orphaned VM cleanup completed", "cleanedCount", cleanedCount)
	} else {
		logger.Info("Orphaned VM cleanup completed - no orphaned VMs found")
	}

	return nil
}

// SetupWithManager sets up the controller with the Manager
func (r *ProxmoxVMReconciler) SetupWithManager(mgr ctrl.Manager) error {
	// Run cleanup on startup (non-blocking, in background)
	go func() {
		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
		defer cancel()
		logger := log.FromContext(ctx)
		if err := r.CleanupOrphanedVMs(ctx); err != nil {
			logger.Error(err, "orphaned VM cleanup failed on startup")
		}
	}()

	return ctrl.NewControllerManagedBy(mgr).
		For(&proxmoxv1alpha1.ProxmoxVM{}).
		Complete(r)
}

// Helper functions
type credentials struct {
	Username string
	Password string
}

func (r *ProxmoxVMReconciler) getCredentials(ctx context.Context, config *proxmoxv1alpha1.ProviderConfig) (*credentials, error) {
	if config.Spec.Credentials.SecretRef == nil {
		return nil, fmt.Errorf("no secret reference in provider config")
	}

	secretRef := config.Spec.Credentials.SecretRef
	
	// Get secret from Kubernetes
	secret := &corev1.Secret{}
	secretKey := client.ObjectKey{
		Namespace: secretRef.Namespace,
		Name:      secretRef.Name,
	}
	
	if err := r.Get(ctx, secretKey, secret); err != nil {
		return nil, errors.Wrap(err, "cannot get secret")
	}
	
	// Parse credentials from secret
	// Support both username/password and JSON token formats
	var username, password string
	
	// Try username/password format first
	if userData, ok := secret.Data["username"]; ok {
		username = string(userData)
	}
	if passData, ok := secret.Data["password"]; ok {
		password = string(passData)
	}
	
	// Try token format (for Proxmox API tokens)
	if tokenData, ok := secret.Data["token"]; ok {
		// For token-based auth, username is in format "user@realm!tokenid"
		// and password is the token secret
		if userData, ok := secret.Data["tokenid"]; ok {
			username = string(userData)
		}
		password = string(tokenData)
	}
	
	if username == "" || password == "" {
		return nil, fmt.Errorf("username/password or token missing in secret")
	}
	
	return &credentials{
		Username: username,
		Password: password,
	}, nil
}

func (r *ProxmoxVMReconciler) findSite(config *proxmoxv1alpha1.ProviderConfig, siteName string) (*proxmoxv1alpha1.ProxmoxSite, error) {
	for _, site := range config.Spec.Sites {
		if site.Name == siteName {
			return &site, nil
		}
	}
	return nil, fmt.Errorf("site %s not found", siteName)
}

// Helper functions for quota enforcement (use shared utils)

func intPtr(i int) *int {
	return &i
}