/*
Copyright 2026 LocoStack.

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 controller

import (
	"context"
	"fmt"

	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	apimeta "k8s.io/apimachinery/pkg/api/meta"
	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/client/apiutil"
	logf "sigs.k8s.io/controller-runtime/pkg/log"

	"github.com/LocoStack/loco-operator/api/v1alpha1"
	"github.com/LocoStack/loco-operator/internal/reconciler"
	"github.com/LocoStack/loco-operator/pkg/templates"
)

// ComponentReconciler reconciles a Component object
type ComponentReconciler struct {
	client.Client
	Scheme *runtime.Scheme
}

// +kubebuilder:rbac:groups=locostack.com,resources=components,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=locostack.com,resources=components/status,verbs=get;update;patch
// +kubebuilder:rbac:groups=locostack.com,resources=components/finalizers,verbs=update
// +kubebuilder:rbac:groups="",resources=configmaps,verbs=get;list;watch;create;update;patch
// +kubebuilder:rbac:groups="",resources=persistentvolumes,verbs=get;list;watch;create;update;patch
// +kubebuilder:rbac:groups="",resources=persistentvolumeclaims,verbs=get;list;watch;create;update;patch
// +kubebuilder:rbac:groups="",resources=secrets,verbs=get;list;watch;create;update;patch
// +kubebuilder:rbac:groups="",resources=services,verbs=get;list;watch;create;update;patch
// +kubebuilder:rbac:groups="apps",resources=deployments,verbs=get;list;watch;create;update;patch

func (r *ComponentReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	log := logf.FromContext(ctx)

	comp := &v1alpha1.Component{}
	if err := r.Get(ctx, req.NamespacedName, comp); err != nil {
		if apierrors.IsNotFound(err) {
			return ctrl.Result{}, nil
		}
		log.Error(err, "Failed to get Component", "namespace", req.NamespacedName.Namespace, "name", req.NamespacedName.Name)
		return ctrl.Result{}, err
	}

	patch := client.MergeFrom(comp.DeepCopy())

	tmpl, err := templates.Manager.ResolveTemplate(comp.Spec.Template, "")
	if err != nil {
		apimeta.SetStatusCondition(&comp.Status.Conditions, metav1.Condition{
			Type:               "Reconciled",
			Status:             metav1.ConditionFalse,
			Reason:             "TemplateResolutionFailed",
			Message:            fmt.Sprintf("Could not resolve template: %v", err),
			ObservedGeneration: comp.Generation,
		})
		log.Error(err, "Failed to resolve template for Component", "namespace", req.NamespacedName.Namespace, "name", req.NamespacedName.Name)
		_ = r.Status().Patch(ctx, comp, patch)
		return ctrl.Result{}, nil
	}

	stack := &v1alpha1.Stack{}
	if comp.Spec.StackRef == nil || comp.Spec.StackRef.Name == "" {
		stack = nil
	} else if err := r.Get(ctx, client.ObjectKey{Namespace: comp.Namespace, Name: comp.Spec.StackRef.Name}, stack); err != nil {
		stack = nil
	}

	componentReconciler := r.getComponentReconciler(comp, stack)
	dependencies, err := componentReconciler.ReconcileComponent(ctx, &tmpl, make(map[string]string))
	if err != nil {
		apimeta.SetStatusCondition(&comp.Status.Conditions, metav1.Condition{
			Type:               "Reconciled",
			Status:             metav1.ConditionFalse,
			Reason:             "ReconcileFailed",
			Message:            fmt.Sprintf("Could not reconcile component: %v", err),
			ObservedGeneration: comp.Generation,
		})
		log.Error(err, "Failed to reconcile Component", "namespace", req.NamespacedName.Namespace, "name", req.NamespacedName.Name)
		_ = r.Status().Patch(ctx, comp, patch)
		return ctrl.Result{}, nil
	}

	comp.Status.Endpoint = fmt.Sprintf("http://%s.%s.svc.cluster.local:%d", componentReconciler.ResourceName(""), comp.Namespace, tmpl.Spec.Runtime.Port)
	comp.Status.ObservedGeneration = comp.Generation
	if len(dependencies) > 0 {
		comp.Status.Dependencies = make(map[string]map[string]int64)
		for _, dep := range dependencies {
			gvk, err := apiutil.GVKForObject(dep, r.Scheme)
			if err != nil {
				log.Error(err, "Failed to get GVK for dependency", "dependency", dep)
				continue
			}
			if gvk.Group != v1alpha1.GroupVersion.Group {
				continue
			}
			kind := gvk.Kind
			name := dep.GetName()
			generation := dep.GetGeneration()

			if _, exists := comp.Status.Dependencies[kind]; !exists {
				comp.Status.Dependencies[kind] = make(map[string]int64)
			}
			comp.Status.Dependencies[kind][name] = generation
		}
	}
	apimeta.SetStatusCondition(&comp.Status.Conditions, metav1.Condition{
		Type:               "Reconciled",
		Status:             metav1.ConditionTrue,
		Reason:             "ReconcileSucceeded",
		Message:            "Component reconciled",
		ObservedGeneration: comp.Generation,
	})
	if available := componentReconciler.ComponentAvailable(ctx); !available {
		apimeta.SetStatusCondition(&comp.Status.Conditions, metav1.Condition{
			Type:               "Available",
			Status:             metav1.ConditionFalse,
			Reason:             "ServiceUnavailable",
			Message:            "Component is not available",
			ObservedGeneration: comp.Generation,
		})
	} else {
		apimeta.SetStatusCondition(&comp.Status.Conditions, metav1.Condition{
			Type:               "Available",
			Status:             metav1.ConditionTrue,
			Reason:             "ComponentReady",
			Message:            "Component is available",
			ObservedGeneration: comp.Generation,
		})
	}
	if err := r.Status().Patch(ctx, comp, patch); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	log.Info("Reconciled Component", "namespace", comp.Namespace, "name", comp.Name)
	return ctrl.Result{}, nil
}

func (r *ComponentReconciler) getComponentReconciler(comp *v1alpha1.Component, stack *v1alpha1.Stack) reconciler.ComponentReconciler {
	switch comp.Spec.Template.Name {
	case "litellm":
		return reconciler.NewLiteLLMReconciler(r.Client, r.Scheme, stack, comp)
	case "qdrant":
		return reconciler.NewQdrantReconciler(r.Client, r.Scheme, stack, comp)
	case "neo4j":
		return reconciler.NewNeo4jReconciler(r.Client, r.Scheme, stack, comp)
	case "postgresql":
		return reconciler.NewPostgreSQLReconciler(r.Client, r.Scheme, stack, comp)
	default:
		return reconciler.NewDefaultComponentReconciler(r.Client, r.Scheme, stack, comp)
	}
}

// SetupWithManager sets up the controller with the Manager.
func (r *ComponentReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&v1alpha1.Component{}).
		Owns(&corev1.ConfigMap{}).
		Owns(&corev1.Secret{}).
		Owns(&corev1.PersistentVolumeClaim{}).
		Owns(&corev1.Service{}).
		Owns(&appsv1.Deployment{}).
		Named("component").
		Complete(r)
}