/*
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 reconciler

import (
	"context"
	"fmt"
	"strings"

	"github.com/LocoStack/loco-operator/api/v1alpha1"
	corev1 "k8s.io/api/core/v1"
	"sigs.k8s.io/controller-runtime/pkg/client"
)

type ComponentReconciler interface {
	// create all resources for the component, and return the list of dependencies
	ReconcileComponent(ctx context.Context, tmpl *v1alpha1.Template, variables map[string]string) ([]client.Object, error)
	ComponentAvailable(ctx context.Context) bool
	ResourceName(name string) string
}

func ResourceLabels(stack, component, name, namespace string) map[string]string {
	labels := map[string]string{
		"app.kubernetes.io/managed-by": "loco-operator",
		"locostack.com/stack":          stack,
		"locostack.com/component":      component,
		"locostack.com/name":           name,
	}
	if namespace != "" {
		labels["locostack.com/namespace"] = namespace
	}
	return labels
}

// substituteVariables replaces placeholders in the input string with actual values from the variables map.
// Placeholders are in the format $(placeholder).
func substituteVariables(variables map[string]string, input string) (bool, string) {
	for placeholder, value := range variables {
		if !strings.Contains(input, "$(") {
			return true, input
		}
		if strings.Contains(input, fmt.Sprintf("$(%s)", placeholder)) {
			input = strings.ReplaceAll(input, fmt.Sprintf("$(%s)", placeholder), value)
		}
	}
	return false, input
}

func mustSubstituteVariables(variables map[string]string, input string) string {
	_, substituted := substituteVariables(variables, input)
	return substituted
}

func buildVolumes(variables map[string]string, tmpl *v1alpha1.Template) []corev1.Volume {
	volumes := make([]corev1.Volume, len(tmpl.Spec.Volumes))
	if len(volumes) == 0 {
		volumes = nil
	} else {
		for i, vol := range tmpl.Spec.Volumes {
			volumes[i] = vol
			if vol.VolumeSource.ConfigMap != nil {
				volumes[i].VolumeSource.ConfigMap.LocalObjectReference.Name = mustSubstituteVariables(variables, vol.VolumeSource.ConfigMap.LocalObjectReference.Name)
			}
			if vol.VolumeSource.Secret != nil {
				volumes[i].VolumeSource.Secret.SecretName = mustSubstituteVariables(variables, vol.VolumeSource.Secret.SecretName)
			}
			if vol.VolumeSource.PersistentVolumeClaim != nil {
				volumes[i].VolumeSource.PersistentVolumeClaim.ClaimName = mustSubstituteVariables(variables, vol.VolumeSource.PersistentVolumeClaim.ClaimName)
			}
		}
	}
	return volumes
}

func buildContainerSpec(variables map[string]string, tmpl *v1alpha1.Template) corev1.Container {
	command := make([]string, len(tmpl.Spec.Runtime.Command))
	if len(command) == 0 {
		command = nil
	} else {
		for i, cmd := range tmpl.Spec.Runtime.Command {
			command[i] = mustSubstituteVariables(variables, cmd)
		}
	}
	args := make([]string, len(tmpl.Spec.Runtime.Args))
	if len(args) == 0 {
		args = nil
	} else {
		for i, arg := range tmpl.Spec.Runtime.Args {
			args[i] = mustSubstituteVariables(variables, arg)
		}
		for _, arg := range tmpl.Spec.Runtime.ExtraArgs {
			args = append(args, mustSubstituteVariables(variables, arg))
		}
		for _, arg := range tmpl.Spec.Runtime.ConditionalArgs {
			complete, substituted := substituteVariables(variables, arg.When)
			if complete && substituted != "" {
				for _, a := range arg.Args {
					args = append(args, mustSubstituteVariables(variables, a))
				}
			}
		}
	}
	env := make([]corev1.EnvVar, len(tmpl.Spec.Runtime.Env))
	if len(env) == 0 {
		env = nil
	} else {
		for i, envVar := range tmpl.Spec.Runtime.Env {
			env[i] = envVar
			env[i].Value = mustSubstituteVariables(variables, envVar.Value)
			if envVar.ValueFrom != nil && envVar.ValueFrom.SecretKeyRef != nil {
				env[i].ValueFrom.SecretKeyRef.LocalObjectReference.Name = mustSubstituteVariables(variables, envVar.ValueFrom.SecretKeyRef.LocalObjectReference.Name)
				env[i].ValueFrom.SecretKeyRef.Key = mustSubstituteVariables(variables, envVar.ValueFrom.SecretKeyRef.Key)
			}
		}
	}
	envFrom := make([]corev1.EnvFromSource, len(tmpl.Spec.Runtime.EnvFrom))
	if len(envFrom) == 0 {
		envFrom = nil
	} else {
		for i, envFromSource := range tmpl.Spec.Runtime.EnvFrom {
			envFrom[i] = envFromSource
			if envFromSource.ConfigMapRef != nil {
				envFrom[i].ConfigMapRef.LocalObjectReference.Name = mustSubstituteVariables(variables, envFromSource.ConfigMapRef.LocalObjectReference.Name)
			}
			if envFromSource.SecretRef != nil {
				envFrom[i].SecretRef.LocalObjectReference.Name = mustSubstituteVariables(variables, envFromSource.SecretRef.LocalObjectReference.Name)
			}
		}
	}
	ports := make([]corev1.ContainerPort, 0)
	if tmpl.Spec.Runtime.Port != 0 {
		ports = append(ports, corev1.ContainerPort{
			ContainerPort: tmpl.Spec.Runtime.Port,
			Protocol:      corev1.ProtocolTCP,
		})
	}
	return corev1.Container{
		Name:            "main",
		Image:           tmpl.Spec.Runtime.Image,
		ImagePullPolicy: corev1.PullIfNotPresent,
		Command:         command,
		Args:            args,
		Env:             env,
		EnvFrom:         envFrom,
		VolumeMounts:    tmpl.Spec.Runtime.VolumeMounts,
		Ports:           ports,
		Resources:       tmpl.Spec.Resources,
	}
}

func buildPodSpec(variables map[string]string, tmpl *v1alpha1.Template) (corev1.PodSpec, error) {
	return corev1.PodSpec{
		NodeSelector:              tmpl.Spec.NodeSelector,
		Affinity:                  tmpl.Spec.Affinity,
		Tolerations:               tmpl.Spec.Tolerations,
		TopologySpreadConstraints: tmpl.Spec.TopologySpreadConstraints,
		Containers:                []corev1.Container{buildContainerSpec(variables, tmpl)},
		SecurityContext:           tmpl.Spec.SecurityContext,
		Volumes:                   buildVolumes(variables, tmpl),
	}, nil
}