/*
Copyright 2024.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package jobmanager

import (
	"context"
	"fmt"
	"time"

	batchv1 "k8s.io/api/batch/v1"
	corev1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/resource"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/utils/ptr"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	"sigs.k8s.io/controller-runtime/pkg/log"

	nucleiv1alpha1 "github.com/mortenolsen/nuclei-operator/api/v1alpha1"
)

const (
	// DefaultScannerImage is the default image used for scanner pods
	DefaultScannerImage = "ghcr.io/morten-olsen/nuclei-operator:latest"

	// DefaultTimeout is the default scan timeout
	DefaultTimeout = 30 * time.Minute

	// DefaultTTLAfterFinished is the default TTL for completed jobs
	DefaultTTLAfterFinished = 3600 // 1 hour

	// DefaultBackoffLimit is the default number of retries for failed jobs
	DefaultBackoffLimit = 2

	// LabelManagedBy is the label key for identifying managed resources
	LabelManagedBy = "app.kubernetes.io/managed-by"

	// LabelComponent is the label key for component identification
	LabelComponent = "app.kubernetes.io/component"

	// LabelScanName is the label key for the scan name
	LabelScanName = "nuclei.homelab.mortenolsen.pro/scan-name"

	// LabelScanNamespace is the label key for the scan namespace
	LabelScanNamespace = "nuclei.homelab.mortenolsen.pro/scan-namespace"
)

// Config holds the configuration for the JobManager
type Config struct {
	// ScannerImage is the default image to use for scanner pods
	ScannerImage string

	// DefaultTimeout is the default scan timeout
	DefaultTimeout time.Duration

	// TTLAfterFinished is the TTL for completed jobs in seconds
	TTLAfterFinished int32

	// BackoffLimit is the number of retries for failed jobs
	BackoffLimit int32

	// MaxConcurrent is the maximum number of concurrent scan jobs
	MaxConcurrent int

	// ServiceAccountName is the service account to use for scanner pods
	ServiceAccountName string

	// DefaultResources are the default resource requirements for scanner pods
	DefaultResources corev1.ResourceRequirements

	// DefaultTemplates are the default templates to use for scans
	DefaultTemplates []string

	// DefaultSeverity is the default severity filter
	DefaultSeverity []string
}

// DefaultConfig returns a Config with default values
func DefaultConfig() Config {
	return Config{
		ScannerImage:       DefaultScannerImage,
		DefaultTimeout:     DefaultTimeout,
		TTLAfterFinished:   DefaultTTLAfterFinished,
		BackoffLimit:       DefaultBackoffLimit,
		MaxConcurrent:      5,
		ServiceAccountName: "nuclei-scanner",
		DefaultResources: corev1.ResourceRequirements{
			Requests: corev1.ResourceList{
				corev1.ResourceCPU:    resource.MustParse("100m"),
				corev1.ResourceMemory: resource.MustParse("256Mi"),
			},
			Limits: corev1.ResourceList{
				corev1.ResourceCPU:    resource.MustParse("1"),
				corev1.ResourceMemory: resource.MustParse("1Gi"),
			},
		},
	}
}

// JobManager manages scanner jobs for NucleiScan resources
type JobManager struct {
	client.Client
	Scheme *runtime.Scheme
	Config Config
}

// NewJobManager creates a new JobManager with the given configuration
func NewJobManager(c client.Client, scheme *runtime.Scheme, config Config) *JobManager {
	return &JobManager{
		Client: c,
		Scheme: scheme,
		Config: config,
	}
}

// CreateScanJob creates a new scanner job for the given NucleiScan
func (m *JobManager) CreateScanJob(ctx context.Context, scan *nucleiv1alpha1.NucleiScan) (*batchv1.Job, error) {
	logger := log.FromContext(ctx)

	job := m.buildJob(scan)

	// Set owner reference so the job is garbage collected when the scan is deleted
	if err := controllerutil.SetControllerReference(scan, job, m.Scheme); err != nil {
		return nil, fmt.Errorf("failed to set controller reference: %w", err)
	}

	logger.Info("Creating scanner job",
		"job", job.Name,
		"namespace", job.Namespace,
		"image", job.Spec.Template.Spec.Containers[0].Image,
		"targets", len(scan.Spec.Targets))

	if err := m.Create(ctx, job); err != nil {
		return nil, fmt.Errorf("failed to create job: %w", err)
	}

	return job, nil
}

// GetJob retrieves a job by name and namespace
func (m *JobManager) GetJob(ctx context.Context, name, namespace string) (*batchv1.Job, error) {
	job := &batchv1.Job{}
	err := m.Get(ctx, types.NamespacedName{Name: name, Namespace: namespace}, job)
	if err != nil {
		return nil, err
	}
	return job, nil
}

// DeleteJob deletes a job by name and namespace
func (m *JobManager) DeleteJob(ctx context.Context, name, namespace string) error {
	job := &batchv1.Job{
		ObjectMeta: metav1.ObjectMeta{
			Name:      name,
			Namespace: namespace,
		},
	}
	return m.Delete(ctx, job, client.PropagationPolicy(metav1.DeletePropagationBackground))
}

// GetJobPodName returns the name of the pod created by the job
func (m *JobManager) GetJobPodName(ctx context.Context, job *batchv1.Job) (string, error) {
	podList := &corev1.PodList{}
	err := m.List(ctx, podList,
		client.InNamespace(job.Namespace),
		client.MatchingLabels{"job-name": job.Name})
	if err != nil {
		return "", err
	}

	if len(podList.Items) == 0 {
		return "", nil
	}

	// Return the first pod (there should only be one for our jobs)
	return podList.Items[0].Name, nil
}

// IsJobComplete returns true if the job has completed (successfully or failed)
func (m *JobManager) IsJobComplete(job *batchv1.Job) bool {
	for _, condition := range job.Status.Conditions {
		if (condition.Type == batchv1.JobComplete || condition.Type == batchv1.JobFailed) &&
			condition.Status == corev1.ConditionTrue {
			return true
		}
	}
	return false
}

// IsJobSuccessful returns true if the job completed successfully
func (m *JobManager) IsJobSuccessful(job *batchv1.Job) bool {
	for _, condition := range job.Status.Conditions {
		if condition.Type == batchv1.JobComplete && condition.Status == corev1.ConditionTrue {
			return true
		}
	}
	return false
}

// IsJobFailed returns true if the job failed
func (m *JobManager) IsJobFailed(job *batchv1.Job) bool {
	for _, condition := range job.Status.Conditions {
		if condition.Type == batchv1.JobFailed && condition.Status == corev1.ConditionTrue {
			return true
		}
	}
	return false
}

// GetJobFailureReason returns the reason for job failure
func (m *JobManager) GetJobFailureReason(job *batchv1.Job) string {
	for _, condition := range job.Status.Conditions {
		if condition.Type == batchv1.JobFailed && condition.Status == corev1.ConditionTrue {
			return condition.Message
		}
	}
	return "Unknown failure reason"
}

// CountActiveJobs returns the number of currently active scan jobs
func (m *JobManager) CountActiveJobs(ctx context.Context) (int, error) {
	jobList := &batchv1.JobList{}
	err := m.List(ctx, jobList, client.MatchingLabels{
		LabelManagedBy: "nuclei-operator",
		LabelComponent: "scanner",
	})
	if err != nil {
		return 0, err
	}

	count := 0
	for _, job := range jobList.Items {
		if job.Status.Active > 0 {
			count++
		}
	}
	return count, nil
}

// AtCapacity returns true if the maximum number of concurrent jobs has been reached
func (m *JobManager) AtCapacity(ctx context.Context) (bool, error) {
	count, err := m.CountActiveJobs(ctx)
	if err != nil {
		return false, err
	}
	return count >= m.Config.MaxConcurrent, nil
}

// CleanupOrphanedJobs removes jobs that no longer have an associated NucleiScan
func (m *JobManager) CleanupOrphanedJobs(ctx context.Context) error {
	logger := log.FromContext(ctx)

	jobList := &batchv1.JobList{}
	err := m.List(ctx, jobList, client.MatchingLabels{
		LabelManagedBy: "nuclei-operator",
		LabelComponent: "scanner",
	})
	if err != nil {
		return err
	}

	for _, job := range jobList.Items {
		// Check if owner reference exists and the owner still exists
		ownerRef := metav1.GetControllerOf(&job)
		if ownerRef == nil {
			logger.Info("Deleting orphaned job without owner", "job", job.Name, "namespace", job.Namespace)
			if err := m.DeleteJob(ctx, job.Name, job.Namespace); err != nil && !apierrors.IsNotFound(err) {
				logger.Error(err, "Failed to delete orphaned job", "job", job.Name)
			}
			continue
		}

		// Check if the job is stuck (running longer than 2x the timeout)
		if job.Status.StartTime != nil {
			maxDuration := 2 * m.Config.DefaultTimeout
			if time.Since(job.Status.StartTime.Time) > maxDuration && job.Status.Active > 0 {
				logger.Info("Deleting stuck job", "job", job.Name, "namespace", job.Namespace,
					"age", time.Since(job.Status.StartTime.Time))
				if err := m.DeleteJob(ctx, job.Name, job.Namespace); err != nil && !apierrors.IsNotFound(err) {
					logger.Error(err, "Failed to delete stuck job", "job", job.Name)
				}
			}
		}
	}

	return nil
}

// buildJob creates a Job specification for the given NucleiScan
func (m *JobManager) buildJob(scan *nucleiv1alpha1.NucleiScan) *batchv1.Job {
	// Generate a unique job name
	jobName := fmt.Sprintf("nucleiscan-%s-%d", scan.Name, time.Now().Unix())
	if len(jobName) > 63 {
		jobName = jobName[:63]
	}

	// Determine the scanner image
	image := m.Config.ScannerImage
	if scan.Spec.ScannerConfig != nil && scan.Spec.ScannerConfig.Image != "" {
		image = scan.Spec.ScannerConfig.Image
	}

	// Determine timeout
	timeout := m.Config.DefaultTimeout
	if scan.Spec.ScannerConfig != nil && scan.Spec.ScannerConfig.Timeout != nil {
		timeout = scan.Spec.ScannerConfig.Timeout.Duration
	}
	activeDeadlineSeconds := int64(timeout.Seconds())

	// Determine resources
	resources := m.Config.DefaultResources
	if scan.Spec.ScannerConfig != nil && scan.Spec.ScannerConfig.Resources != nil {
		resources = *scan.Spec.ScannerConfig.Resources
	}

	// Build command arguments for scanner mode
	args := []string{
		"--mode=scanner",
		fmt.Sprintf("--scan-name=%s", scan.Name),
		fmt.Sprintf("--scan-namespace=%s", scan.Namespace),
	}

	// Build labels
	labels := map[string]string{
		LabelManagedBy:     "nuclei-operator",
		LabelComponent:     "scanner",
		LabelScanName:      scan.Name,
		LabelScanNamespace: scan.Namespace,
	}

	// Build node selector
	var nodeSelector map[string]string
	if scan.Spec.ScannerConfig != nil && scan.Spec.ScannerConfig.NodeSelector != nil {
		nodeSelector = scan.Spec.ScannerConfig.NodeSelector
	}

	// Build tolerations
	var tolerations []corev1.Toleration
	if scan.Spec.ScannerConfig != nil && scan.Spec.ScannerConfig.Tolerations != nil {
		tolerations = scan.Spec.ScannerConfig.Tolerations
	}

	job := &batchv1.Job{
		ObjectMeta: metav1.ObjectMeta{
			Name:      jobName,
			Namespace: scan.Namespace,
			Labels:    labels,
		},
		Spec: batchv1.JobSpec{
			TTLSecondsAfterFinished: ptr.To(m.Config.TTLAfterFinished),
			BackoffLimit:            ptr.To(m.Config.BackoffLimit),
			ActiveDeadlineSeconds:   &activeDeadlineSeconds,
			Template: corev1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{
					Labels: labels,
				},
				Spec: corev1.PodSpec{
					RestartPolicy:      corev1.RestartPolicyNever,
					ServiceAccountName: m.Config.ServiceAccountName,
					NodeSelector:       nodeSelector,
					Tolerations:        tolerations,
					SecurityContext: &corev1.PodSecurityContext{
						RunAsNonRoot: ptr.To(true),
						RunAsUser:    ptr.To(int64(65532)),
						RunAsGroup:   ptr.To(int64(65532)),
						FSGroup:      ptr.To(int64(65532)),
						SeccompProfile: &corev1.SeccompProfile{
							Type: corev1.SeccompProfileTypeRuntimeDefault,
						},
					},
					Containers: []corev1.Container{
						{
							Name:      "scanner",
							Image:     image,
							Args:      args,
							Resources: resources,
							SecurityContext: &corev1.SecurityContext{
								AllowPrivilegeEscalation: ptr.To(false),
								ReadOnlyRootFilesystem:   ptr.To(false), // Nuclei needs temp files
								Capabilities: &corev1.Capabilities{
									Drop: []corev1.Capability{"ALL"},
								},
							},
							Env: []corev1.EnvVar{
								{
									Name: "POD_NAME",
									ValueFrom: &corev1.EnvVarSource{
										FieldRef: &corev1.ObjectFieldSelector{
											FieldPath: "metadata.name",
										},
									},
								},
								{
									Name: "POD_NAMESPACE",
									ValueFrom: &corev1.EnvVarSource{
										FieldRef: &corev1.ObjectFieldSelector{
											FieldPath: "metadata.namespace",
										},
									},
								},
							},
						},
					},
				},
			},
		},
	}

	return job
}