package controller

import (
	"context"
	"fmt"
	"net"

	"k8s.io/apimachinery/pkg/runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"

	v1alpha1 "git.unkin.net/unkin/kea-operator/api/v1alpha1"
)

// KeaSubnetReconciler validates KeaSubnet CRs and maintains their status. The
// actual kea config is rendered by the KeaCluster controller, which watches
// subnets and re-renders on change.
type KeaSubnetReconciler struct {
	client.Client
	Scheme *runtime.Scheme
}

// +kubebuilder:rbac:groups=kea.unkin.net,resources=keasubnets,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=kea.unkin.net,resources=keasubnets/status,verbs=get;update;patch

func (r *KeaSubnetReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	var subnet v1alpha1.KeaSubnet
	if err := r.Get(ctx, req.NamespacedName, &subnet); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	if _, _, err := net.ParseCIDR(subnet.Spec.Subnet); err != nil {
		subnet.Status.Phase = "Invalid"
		setReady(&subnet.Status.Conditions, subnet.Generation, false, "InvalidCIDR", err.Error())
		_ = r.Status().Update(ctx, &subnet)
		return ctrl.Result{}, nil
	}
	for _, p := range subnet.Spec.Pools {
		if err := validatePool(p); err != nil {
			subnet.Status.Phase = "Invalid"
			setReady(&subnet.Status.Conditions, subnet.Generation, false, "InvalidPool", err.Error())
			_ = r.Status().Update(ctx, &subnet)
			return ctrl.Result{}, nil
		}
	}

	subnet.Status.Phase = "Ready"
	subnet.Status.AssignedID = subnet.Spec.ID
	subnet.Status.ObservedGeneration = subnet.Generation
	setReady(&subnet.Status.Conditions, subnet.Generation, true, "Validated", "subnet accepted")
	if err := r.Status().Update(ctx, &subnet); err != nil {
		return ctrl.Result{}, err
	}
	return ctrl.Result{}, nil
}

func validatePool(p string) error {
	// Accept "start - end" (with or without spaces) or a single address.
	fields := splitPool(p)
	for _, f := range fields {
		if net.ParseIP(f) == nil {
			return fmt.Errorf("invalid pool address %q in %q", f, p)
		}
	}
	return nil
}

func (r *KeaSubnetReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&v1alpha1.KeaSubnet{}).
		Complete(r)
}