package configobject

import (
	"bytes"
	"errors"
	"io/fs"
	"path/filepath"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime"

	"edge-infra.dev/pkg/sds/lib/os/file"
	"edge-infra.dev/pkg/sds/lib/os/passthrough"
)

var (
	fileMode = fs.FileMode(0644)

	errCouldNotCastToSecretType = errors.New("could not cast object to Secret type")
)

type ConfigObject interface {
	metav1.Object
	runtime.Object

	ObjectType() string
	GetFiles() map[string][]byte
	GetLabelsSet() labels.Set
	GetFieldsSet() (fields.Set, error)
	Update(directory string, service string, fileHandler file.File, passthrough passthrough.Exec) error
	UpdateFiles(directory string, fileHandler file.File) (bool, error)
}

func getFieldsSetFromConfigObject(configObject ConfigObject) (fields.Set, error) {
	objectFields := fields.Set{"metadata.name": configObject.GetName(), "metadata.namespace": configObject.GetNamespace()}
	if configObject.ObjectType() == secretObjectType {
		secret, ok := configObject.(*Secret)
		if !ok {
			return nil, errCouldNotCastToSecretType
		}
		objectFields["type"] = secret.SecretType()
	}
	return objectFields, nil
}

func updateConfigObject(configObject ConfigObject, directory string, service string, fileHandler file.File, passthrough passthrough.Exec) error {
	updated, err := configObject.UpdateFiles(directory, fileHandler)
	if err != nil {
		return err
	}
	if updated && service != "" { // only restart services if files have changed
		_, err := passthrough.CombinedOutput("/usr/bin/systemctl", "restart", service)
		return err
	}
	return nil
}

func updateConfigObjectFiles(configObject ConfigObject, directory string, fileHandler file.File) (bool, error) {
	directory = filepath.Clean(directory)
	updated := false
	for filename, updatedData := range configObject.GetFiles() {
		path := filepath.Join(directory, filename)
		needsUpdating, err := fileNeedsUpdating(path, updatedData, fileHandler)
		if err != nil {
			return false, err
		}
		if needsUpdating {
			if err := fileHandler.Write(path, updatedData, fileMode); err != nil {
				return false, err
			}
			updated = true
		}
	}
	return updated, nil
}

func fileNeedsUpdating(path string, updatedData []byte, fileHandler file.File) (bool, error) {
	if !fileHandler.Exists(path) {
		return true, nil
	}
	currentData, err := fileHandler.Read(path)
	if err != nil {
		return false, err
	}
	return !bytes.Equal(currentData, updatedData), nil
}