package context

import (
	"regexp"
	"time"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/client-go/dynamic"
	clientset "k8s.io/client-go/kubernetes"
	"k8s.io/klog/v2"
	controllerruntime "sigs.k8s.io/controller-runtime"

	"github.com/karmada-io/karmada/pkg/controllers/federatedhpa/config"
	"github.com/karmada-io/karmada/pkg/resourceinterpreter"
	"github.com/karmada-io/karmada/pkg/sharedcli/ratelimiterflag"
	"github.com/karmada-io/karmada/pkg/util/fedinformer/genericmanager"
	"github.com/karmada-io/karmada/pkg/util/objectwatcher"
	"github.com/karmada-io/karmada/pkg/util/overridemanager"
)

// Options defines all the parameters required by our controllers.
type Options struct {
	// Controllers contains all controller names.
	Controllers []string
	// ClusterMonitorPeriod represents cluster-controller monitoring period, i.e. how often does
	// cluster-controller check cluster health signal posted from cluster-status-controller.
	// This value should be lower than ClusterMonitorGracePeriod.
	ClusterMonitorPeriod metav1.Duration
	// ClusterMonitorGracePeriod represents the grace period after last cluster health probe time.
	// If it doesn't receive update for this amount of time, it will start posting
	// "ClusterReady==ConditionUnknown".
	ClusterMonitorGracePeriod metav1.Duration
	// ClusterStartupGracePeriod specifies the grace period of allowing a cluster to be unresponsive during
	// startup before marking it unhealthy.
	ClusterStartupGracePeriod metav1.Duration
	// ClusterStatusUpdateFrequency is the frequency that controller computes and report cluster status.
	// It must work with ClusterMonitorGracePeriod.
	ClusterStatusUpdateFrequency metav1.Duration
	// FailoverEvictionTimeout is the grace period for deleting scheduling result on failed clusters.
	FailoverEvictionTimeout metav1.Duration
	// ClusterLeaseDuration is a duration that candidates for a lease need to wait to force acquire it.
	// This is measure against time of last observed lease RenewTime.
	ClusterLeaseDuration metav1.Duration
	// ClusterLeaseRenewIntervalFraction is a fraction coordinated with ClusterLeaseDuration that
	// how long the current holder of a lease has last updated the lease.
	ClusterLeaseRenewIntervalFraction float64
	// ClusterSuccessThreshold is the duration of successes for the cluster to be considered healthy after recovery.
	ClusterSuccessThreshold metav1.Duration
	// ClusterFailureThreshold is the duration of failure for the cluster to be considered unhealthy.
	ClusterFailureThreshold metav1.Duration
	// ClusterCacheSyncTimeout is the timeout period waiting for cluster cache to sync.
	ClusterCacheSyncTimeout metav1.Duration
	// ClusterAPIQPS is the QPS to use while talking with cluster kube-apiserver.
	ClusterAPIQPS float32
	// ClusterAPIBurst is the burst to allow while talking with cluster kube-apiserver.
	ClusterAPIBurst int
	// SkippedPropagatingNamespaces is a list of namespace regular expressions, matching namespaces will be skipped propagating.
	SkippedPropagatingNamespaces []*regexp.Regexp
	// ClusterName is the name of cluster.
	ClusterName string
	// ConcurrentWorkSyncs is the number of Works that are allowed to sync concurrently.
	ConcurrentWorkSyncs int
	// RateLimiterOptions contains the options for rate limiter.
	RateLimiterOptions ratelimiterflag.Options
	// If set to true enables NoExecute Taints and will evict all not-tolerating
	// objects propagating on Clusters tainted with this kind of Taints.
	EnableTaintManager bool
	// GracefulEvictionTimeout is the timeout period waiting for the grace-eviction-controller performs the final
	// removal since the workload(resource) has been moved to the graceful eviction tasks.
	GracefulEvictionTimeout metav1.Duration
	// EnableClusterResourceModeling indicates if enable cluster resource modeling.
	// The resource modeling might be used by the scheduler to make scheduling decisions
	// in scenario of dynamic replica assignment based on cluster free resources.
	// Disable if it does not fit your cases for better performance.
	EnableClusterResourceModeling bool
	// CertRotationCheckingInterval defines the interval of checking if the certificate need to be rotated.
	CertRotationCheckingInterval time.Duration
	// CertRotationRemainingTimeThreshold defines the threshold of remaining time of the valid certificate.
	// If the ratio of remaining time to total time is less than or equal to this threshold, the certificate rotation starts.
	CertRotationRemainingTimeThreshold float64
	// KarmadaKubeconfigNamespace is the namespace of the secret containing karmada-agent certificate.
	KarmadaKubeconfigNamespace string
	// HPAControllerConfiguration is the config of federatedHPA-controller.
	HPAControllerConfiguration config.HPAControllerConfiguration
}

// Context defines the context object for controller.
type Context struct {
	Mgr                         controllerruntime.Manager
	ObjectWatcher               objectwatcher.ObjectWatcher
	Opts                        Options
	StopChan                    <-chan struct{}
	DynamicClientSet            dynamic.Interface
	KubeClientSet               clientset.Interface
	OverrideManager             overridemanager.OverrideManager
	ControlPlaneInformerManager genericmanager.SingleClusterInformerManager
	ResourceInterpreter         resourceinterpreter.ResourceInterpreter
}

// IsControllerEnabled check if a specified controller enabled or not.
func (c Context) IsControllerEnabled(name string, disabledByDefaultControllers sets.Set[string]) bool {
	hasStar := false
	for _, ctrl := range c.Opts.Controllers {
		if ctrl == name {
			return true
		}
		if ctrl == "-"+name {
			return false
		}
		if ctrl == "*" {
			hasStar = true
		}
	}
	// if we get here, there was no explicit choice
	if !hasStar {
		// nothing on by default
		return false
	}

	return !disabledByDefaultControllers.Has(name)
}

// InitFunc is used to launch a particular controller.
// Any error returned will cause the controller process to `Fatal`
// The bool indicates whether the controller was enabled.
type InitFunc func(ctx Context) (enabled bool, err error)

// Initializers is a public map of named controller groups
type Initializers map[string]InitFunc

// ControllerNames returns all known controller names
func (i Initializers) ControllerNames() []string {
	return sets.StringKeySet(i).List()
}

// StartControllers starts a set of controllers with a specified ControllerContext
func (i Initializers) StartControllers(ctx Context, controllersDisabledByDefault sets.Set[string]) error {
	for controllerName, initFn := range i {
		if !ctx.IsControllerEnabled(controllerName, controllersDisabledByDefault) {
			klog.Warningf("%q is disabled", controllerName)
			continue
		}
		klog.V(1).Infof("Starting %q", controllerName)
		started, err := initFn(ctx)
		if err != nil {
			klog.Errorf("Error starting %q", controllerName)
			return err
		}
		if !started {
			klog.Warningf("Skipping %q", controllerName)
			continue
		}
		klog.Infof("Started %q", controllerName)
	}
	return nil
}