package utils

import (
	"context"

	"github.com/go-logr/logr"
	"github.com/kyverno/kyverno/api/kyverno"
	kyvernov1 "github.com/kyverno/kyverno/api/kyverno/v1"
	"github.com/kyverno/kyverno/pkg/admissionpolicy"
	"github.com/kyverno/kyverno/pkg/clients/dclient"
	"github.com/kyverno/kyverno/pkg/config"
	"github.com/kyverno/kyverno/pkg/engine"
	engineapi "github.com/kyverno/kyverno/pkg/engine/api"
	"github.com/kyverno/kyverno/pkg/engine/jmespath"
	reportutils "github.com/kyverno/kyverno/pkg/utils/report"
	"go.uber.org/multierr"
	admissionregistrationv1beta1 "k8s.io/api/admissionregistration/v1beta1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
)

type scanner struct {
	logger          logr.Logger
	engine          engineapi.Engine
	config          config.Configuration
	jp              jmespath.Interface
	client          dclient.Interface
	reportingConfig reportutils.ReportingConfiguration
}

type ScanResult struct {
	EngineResponse *engineapi.EngineResponse
	Error          error
}

type Scanner interface {
	ScanResource(context.Context, unstructured.Unstructured, map[string]string, []admissionregistrationv1beta1.ValidatingAdmissionPolicyBinding, ...engineapi.GenericPolicy) map[*engineapi.GenericPolicy]ScanResult
}

func NewScanner(
	logger logr.Logger,
	engine engineapi.Engine,
	config config.Configuration,
	jp jmespath.Interface,
	client dclient.Interface,
	reportingConfig reportutils.ReportingConfiguration,
) Scanner {
	return &scanner{
		logger:          logger,
		engine:          engine,
		config:          config,
		jp:              jp,
		client:          client,
		reportingConfig: reportingConfig,
	}
}

func (s *scanner) ScanResource(ctx context.Context, resource unstructured.Unstructured, nsLabels map[string]string, bindings []admissionregistrationv1beta1.ValidatingAdmissionPolicyBinding, policies ...engineapi.GenericPolicy) map[*engineapi.GenericPolicy]ScanResult {
	results := map[*engineapi.GenericPolicy]ScanResult{}
	for i, policy := range policies {
		var errors []error
		logger := s.logger.WithValues("kind", resource.GetKind(), "namespace", resource.GetNamespace(), "name", resource.GetName())
		var response *engineapi.EngineResponse
		if policy.GetType() == engineapi.KyvernoPolicyType {
			var err error
			pol := policy.AsKyvernoPolicy()
			if s.reportingConfig.ValidateReportsEnabled() {
				response, err = s.validateResource(ctx, resource, nsLabels, pol)
				if err != nil {
					logger.Error(err, "failed to scan resource")
					errors = append(errors, err)
				}
			}
			spec := pol.GetSpec()
			if spec.HasVerifyImages() && len(errors) == 0 && s.reportingConfig.ImageVerificationReportsEnabled() {
				if response != nil {
					// remove responses of verify image rules
					ruleResponses := make([]engineapi.RuleResponse, 0, len(response.PolicyResponse.Rules))
					for _, v := range response.PolicyResponse.Rules {
						if v.RuleType() != engineapi.ImageVerify {
							ruleResponses = append(ruleResponses, v)
						}
					}
					response.PolicyResponse.Rules = ruleResponses
				}

				ivResponse, err := s.validateImages(ctx, resource, nsLabels, pol)
				if err != nil {
					logger.Error(err, "failed to scan images")
					errors = append(errors, err)
				}
				if response == nil {
					response = ivResponse
				} else if ivResponse != nil {
					response.PolicyResponse.Rules = append(response.PolicyResponse.Rules, ivResponse.PolicyResponse.Rules...)
				}
			}
		} else {
			pol := policy.AsValidatingAdmissionPolicy()
			policyData := admissionpolicy.NewPolicyData(*pol)
			for _, binding := range bindings {
				if binding.Spec.PolicyName == pol.Name {
					policyData.AddBinding(binding)
				}
			}
			res, err := admissionpolicy.Validate(policyData, resource, map[string]map[string]string{}, s.client)
			if err != nil {
				errors = append(errors, err)
			}
			response = &res
		}
		results[&policies[i]] = ScanResult{response, multierr.Combine(errors...)}
	}
	return results
}

func (s *scanner) validateResource(ctx context.Context, resource unstructured.Unstructured, nsLabels map[string]string, policy kyvernov1.PolicyInterface) (*engineapi.EngineResponse, error) {
	policyCtx, err := engine.NewPolicyContext(s.jp, resource, kyvernov1.Create, nil, s.config)
	if err != nil {
		return nil, err
	}
	policyCtx = policyCtx.
		WithNewResource(resource).
		WithPolicy(policy).
		WithNamespaceLabels(nsLabels)
	response := s.engine.Validate(ctx, policyCtx)
	if len(response.PolicyResponse.Rules) > 0 {
		s.logger.V(6).Info("validateResource", "policy", policy, "response", response)
	}
	return &response, nil
}

func (s *scanner) validateImages(ctx context.Context, resource unstructured.Unstructured, nsLabels map[string]string, policy kyvernov1.PolicyInterface) (*engineapi.EngineResponse, error) {
	annotations := resource.GetAnnotations()
	if annotations != nil {
		resource = *resource.DeepCopy()
		delete(annotations, kyverno.AnnotationImageVerify)
		resource.SetAnnotations(annotations)
	}
	policyCtx, err := engine.NewPolicyContext(s.jp, resource, kyvernov1.Create, nil, s.config)
	if err != nil {
		return nil, err
	}
	policyCtx = policyCtx.
		WithNewResource(resource).
		WithPolicy(policy).
		WithNamespaceLabels(nsLabels)
	response, _ := s.engine.VerifyAndPatchImages(ctx, policyCtx)
	if len(response.PolicyResponse.Rules) > 0 {
		s.logger.V(6).Info("validateImages", "policy", policy, "response", response)
	}
	return &response, nil
}