/*
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"
	"maps"

	batchv1 "k8s.io/api/batch/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/controller/controllerutil"
	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"
	llamacpp "github.com/LocoStack/loco-operator/pkg/templates/llama_cpp"
)

// ManagedModelReconciler reconciles a ManagedModel object
type ManagedModelReconciler struct {
	client.Client
	Scheme *runtime.Scheme
}

// +kubebuilder:rbac:groups=locostack.com,resources=managedmodels,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=locostack.com,resources=managedmodels/status,verbs=get;update;patch
// +kubebuilder:rbac:groups=locostack.com,resources=managedmodels/finalizers,verbs=update
// +kubebuilder:rbac:groups=locostack.com,resources=components,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=locostack.com,resources=stacks,verbs=get;list;watch
// +kubebuilder:rbac:groups=batch,resources=jobs,verbs=get;list;watch;create;update;patch;delete

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

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

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

	stack := &v1alpha1.Stack{}
	if err := r.Get(ctx, client.ObjectKey{Namespace: mm.Namespace, Name: mm.Spec.StackRef.Name}, stack); err != nil {
		if apierrors.IsNotFound(err) {
			return ctrl.Result{}, nil
		}
		log.Error(err, "Failed to get Stack for ManagedModel", "namespace", mm.Namespace, "name", mm.Name, "stack", mm.Spec.StackRef.Name)
		return ctrl.Result{}, err
	}

	chatTemplateConfigMapName, err := r.reconcileChatTemplate(ctx, stack, mm)
	if err != nil {
		return ctrl.Result{}, err
	}

	pvcName, weightsReady, weightsFailed, err := r.reconcileWeights(ctx, stack, mm)
	if err != nil {
		return ctrl.Result{}, err
	}

	if weightsFailed {
		apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
			Type:               "Available",
			Status:             metav1.ConditionFalse,
			Reason:             "WeightsFailed",
			Message:            "ManagedModel weights are not available",
			ObservedGeneration: mm.Generation,
		})
	} else if !weightsReady {
		apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
			Type:               "Available",
			Status:             metav1.ConditionFalse,
			Reason:             "WeightsNotReady",
			Message:            "ManagedModel weights are not ready",
			ObservedGeneration: mm.Generation,
		})
	} else {
		componentAvailable, err := r.reconcileComponent(ctx, mm, pvcName, chatTemplateConfigMapName)
		if err != nil {
			return ctrl.Result{}, err
		}
		gatewayBound, err := r.reconcileGatewayStatus(ctx, mm)
		if err != nil {
			log.Error(err, "Failed to reconcile gateway status for ManagedModel", "namespace", req.NamespacedName.Namespace, "name", req.NamespacedName.Name)
			return ctrl.Result{}, err
		}
		if !componentAvailable {
			apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
				Type:               "Available",
				Status:             metav1.ConditionFalse,
				Reason:             "ModelUnavailable",
				Message:            "ManagedModel is not available",
				ObservedGeneration: mm.Generation,
			})
		} else if !gatewayBound {
			apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
				Type:               "Available",
				Status:             metav1.ConditionFalse,
				Reason:             "GatewayUnbound",
				Message:            "ManagedModel is not bound to a gateway",
				ObservedGeneration: mm.Generation,
			})
		} else {
			apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
				Type:               "Available",
				Status:             metav1.ConditionTrue,
				Reason:             "ModelAvailable",
				Message:            "ManagedModel is available",
				ObservedGeneration: mm.Generation,
			})
		}
	}

	mm.Status.ObservedGeneration = mm.Generation
	if err := r.Status().Patch(ctx, mm, patch); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	log.Info("Reconciled ManagedModel", "namespace", req.NamespacedName.Namespace, "name", req.NamespacedName.Name)
	return ctrl.Result{}, nil
}

func (r *ManagedModelReconciler) reconcileChatTemplate(ctx context.Context, stack *v1alpha1.Stack, mm *v1alpha1.ManagedModel) (string, error) {
	if mm.Spec.Category != "language" {
		return "undefined", nil
	}
	cmName := fmt.Sprintf("%s-chat-template", mm.Name)
	if mm.Spec.RuntimeInferenceParams == nil || mm.Spec.RuntimeInferenceParams.ChatTemplate == "" {
		return cmName, nil
	}
	cm := &corev1.ConfigMap{
		ObjectMeta: metav1.ObjectMeta{
			Name:      cmName,
			Namespace: mm.Namespace,
		},
	}
	err := r.Get(ctx, client.ObjectKey{Namespace: mm.Namespace, Name: cm.Name}, cm)
	if err != nil && !apierrors.IsNotFound(err) {
		return "", err
	}

	_, err = controllerutil.CreateOrUpdate(ctx, r.Client, cm, func() error {
		if cm.CreationTimestamp.IsZero() {
			cm.Labels = reconciler.ResourceLabels(stack.Name, "Artifact", cmName, "")
			chatTemplate := ""
			if mm.Spec.RuntimeInferenceParams != nil {
				chatTemplate = mm.Spec.RuntimeInferenceParams.ChatTemplate
			}
			cm.Data = map[string]string{
				"template": chatTemplate,
			}
		}
		return controllerutil.SetControllerReference(mm, cm, r.Scheme)
	})
	if err != nil {
		return "", fmt.Errorf("Failed to create or update chat template: %w", err)
	}
	return cmName, nil
}

func (r *ManagedModelReconciler) reconcileWeights(ctx context.Context, stack *v1alpha1.Stack, mm *v1alpha1.ManagedModel) (string, bool, bool, error) {
	artifactsReconciler := reconciler.NewArtifactReconciler(r.Client, r.Scheme, stack, "model", mm, &mm.Spec.Weights)
	pvc, completed, failed, err := artifactsReconciler.ReconcileArtifact(ctx)
	pvcName := ""
	if pvc != nil {
		pvcName = pvc.Name
	}
	return pvcName, completed, failed, err
}

func (r *ManagedModelReconciler) reconcileComponent(ctx context.Context, mm *v1alpha1.ManagedModel, pvcName string, chatTemplateConfigMapName string) (bool, error) {
	compName := fmt.Sprintf("model-%s", mm.Name)
	comp := &v1alpha1.Component{
		ObjectMeta: metav1.ObjectMeta{
			Name:      compName,
			Namespace: mm.Namespace,
		},
	}
	err := r.Get(ctx, client.ObjectKey{Namespace: mm.Namespace, Name: compName}, comp)

	tmpl, err := templates.Manager.ResolveTemplate(mm.Spec.Template, "")
	if err != nil {
		apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
			Type:               "ModelRuntimeResolved",
			Status:             metav1.ConditionFalse,
			Reason:             "TemplateNotResolved",
			Message:            fmt.Sprintf("Failed to reconcile template for ManagedModel: %v", err),
			ObservedGeneration: mm.Generation,
		})
		return false, nil
	}
	apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
		Type:               "ModelRuntimeResolved",
		Status:             metav1.ConditionTrue,
		Reason:             "TemplateResolved",
		Message:            fmt.Sprintf("Successfully resolved template for ManagedModel: %v", tmpl.Name),
		ObservedGeneration: mm.Generation,
	})

	_, err = controllerutil.CreateOrUpdate(ctx, r.Client, comp, func() error {
		if comp.Labels == nil {
			comp.Labels = make(map[string]string)
		}
		stackName := ""
		if mm.Spec.StackRef != nil {
			stackName = mm.Spec.StackRef.Name
		}
		maps.Copy(comp.Labels, reconciler.ResourceLabels(stackName, "Model", mm.Name, ""))
		comp.Spec.Category = "Model"
		comp.Spec.Template = &tmpl
		variables := map[string]string{
			"spec.chatTemplateConfigMapName": chatTemplateConfigMapName,
		}
		params := mm.Spec.RuntimeInferenceParams
		if params != nil {
			if params.ChatTemplate != "" {
				variables["spec.runtimeInferenceParameters.chatTemplateFilePath"] = fmt.Sprintf("%s/template", llamacpp.LLAMA_CPP_TEMPLATE_PATH)
			}
			if params.ContextWindow != nil {
				variables["spec.runtimeInferenceParameters.contextWindow"] = fmt.Sprintf("%d", *params.ContextWindow)
			}
			if params.Temperature != "" {
				variables["spec.runtimeInferenceParameters.temperature"] = params.Temperature
			}
			if params.TopK != nil {
				variables["spec.runtimeInferenceParameters.topK"] = fmt.Sprintf("%d", *params.TopK)
			}
			if params.TopP != "" {
				variables["spec.runtimeInferenceParameters.topP"] = params.TopP
			}
		}
		if mm.Spec.Weights.HuggingFace != nil {
			variables["spec.modelName"] = mm.Spec.Weights.HuggingFace.FileName
			variables["spec.pvcName"] = pvcName
		}
		comp.Spec.Variables = variables
		if mm.Spec.StackRef != nil {
			comp.Spec.StackRef = &corev1.LocalObjectReference{Name: mm.Spec.StackRef.Name}
		}
		return controllerutil.SetControllerReference(mm, comp, r.Scheme)
	})

	available := apimeta.IsStatusConditionTrue(comp.Status.Conditions, "Available")
	if available {
		mm.Status.Endpoint = comp.Status.Endpoint
		apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
			Type:               "Ready",
			Status:             metav1.ConditionTrue,
			Reason:             "ComponentAvailable",
			Message:            "Component is available",
			ObservedGeneration: mm.Generation,
		})
	} else {
		apimeta.SetStatusCondition(&mm.Status.Conditions, metav1.Condition{
			Type:               "Ready",
			Status:             metav1.ConditionFalse,
			Reason:             "ComponentUnavailable",
			Message:            "Component is not available",
			ObservedGeneration: mm.Generation,
		})
	}
	return available, err
}

func (r *ManagedModelReconciler) reconcileGatewayStatus(ctx context.Context, mm *v1alpha1.ManagedModel) (bool, error) {
	condition, err := reconciler.ReconcileGatewayStatus(ctx, r.Client, r.Scheme, mm.Spec.StackRef.Name, mm)
	if err != nil {
		return false, err
	}
	apimeta.SetStatusCondition(&mm.Status.Conditions, *condition)
	return condition.Status == metav1.ConditionTrue, nil
}

// SetupWithManager sets up the controller with the Manager.
func (r *ManagedModelReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&v1alpha1.ManagedModel{}).
		Owns(&batchv1.Job{}).
		Owns(&corev1.PersistentVolumeClaim{}).
		Owns(&v1alpha1.Component{}).
		Watches(&v1alpha1.Component{}, ComponentEventHandler("ManagedModel")).
		Named("managedmodel").
		Complete(r)
}