/*
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 kubernetes

import (
	"bytes"
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"reflect"
	"strings"

	"github.com/tidwall/gjson"
	v1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"

	esv1beta1 "github.com/external-secrets/external-secrets/apis/externalsecrets/v1beta1"
	"github.com/external-secrets/external-secrets/pkg/constants"
	"github.com/external-secrets/external-secrets/pkg/find"
	"github.com/external-secrets/external-secrets/pkg/metrics"
	"github.com/external-secrets/external-secrets/pkg/utils"
)

const (
	metaLabels      = "labels"
	metaAnnotations = "annotations"
)

func (c *Client) GetSecret(ctx context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) ([]byte, error) {
	secret, err := c.userSecretClient.Get(ctx, ref.Key, metav1.GetOptions{})
	if err != nil {
		return nil, err
	}

	// if property is not defined, we will return the json-serialized secret
	if ref.Property == "" {
		if ref.MetadataPolicy == esv1beta1.ExternalSecretMetadataPolicyFetch {
			m := map[string]map[string]string{}
			m[metaLabels] = secret.Labels
			m[metaAnnotations] = secret.Annotations

			j, err := utils.JSONMarshal(m)
			if err != nil {
				return nil, err
			}
			return j, nil
		}

		m := map[string]string{}
		for key, val := range secret.Data {
			m[key] = string(val)
		}
		j, err := utils.JSONMarshal(m)
		if err != nil {
			return nil, err
		}
		return j, nil
	}

	return getSecret(secret, ref)
}

func (c *Client) DeleteSecret(ctx context.Context, remoteRef esv1beta1.PushSecretRemoteRef) error {
	if remoteRef.GetProperty() == "" {
		return fmt.Errorf("requires property in RemoteRef to delete secret value")
	}

	extSecret, getErr := c.userSecretClient.Get(ctx, remoteRef.GetRemoteKey(), metav1.GetOptions{})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesGetSecret, getErr)
	if getErr != nil {
		if apierrors.IsNotFound(getErr) {
			// return gracefully if no secret exists
			return nil
		}
		return getErr
	}
	if _, ok := extSecret.Data[remoteRef.GetProperty()]; !ok {
		// return gracefully if specified secret does not contain the given property
		return nil
	}

	if len(extSecret.Data) > 1 {
		return c.removeProperty(ctx, extSecret, remoteRef)
	}
	return c.fullDelete(ctx, remoteRef.GetRemoteKey())
}

func (c *Client) PushSecret(ctx context.Context, secret *v1.Secret, data esv1beta1.PushSecretData) error {
	if data.GetProperty() == "" && data.GetSecretKey() != "" {
		return fmt.Errorf("requires property in RemoteRef to push secret value if secret key is defined")
	}

	extSecret, getErr := c.userSecretClient.Get(ctx, data.GetRemoteKey(), metav1.GetOptions{})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesGetSecret, getErr)
	if getErr != nil {
		// create if it not exists
		if apierrors.IsNotFound(getErr) {
			typ := v1.SecretTypeOpaque
			if secret.Type != "" {
				typ = secret.Type
			}

			return c.createSecret(ctx, secret, typ, data)
		}
		return getErr
	}

	// the whole secret was pushed to the provider
	if data.GetSecretKey() == "" {
		if data.GetProperty() != "" {
			value, err := c.marshalData(secret)
			if err != nil {
				return err
			}

			if v, ok := extSecret.Data[data.GetProperty()]; ok && bytes.Equal(v, value) {
				return nil
			}

			return c.updateProperty(ctx, extSecret, data, value)
		}

		if reflect.DeepEqual(extSecret.Data, secret.Data) {
			return nil
		}

		return c.updateMap(ctx, extSecret, secret.Data)
	}

	// only a single property was pushed
	if v, ok := extSecret.Data[data.GetProperty()]; ok && bytes.Equal(v, secret.Data[data.GetSecretKey()]) {
		return nil
	}

	return c.updateProperty(ctx, extSecret, data, secret.Data[data.GetSecretKey()])
}

func (c *Client) marshalData(secret *v1.Secret) ([]byte, error) {
	values := make(map[string]string)
	for k, v := range secret.Data {
		values[k] = string(v)
	}

	// marshal
	value, err := utils.JSONMarshal(values)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal secrets into a single property: %w", err)
	}

	return value, nil
}

func (c *Client) GetSecretMap(ctx context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) (map[string][]byte, error) {
	secret, err := c.userSecretClient.Get(ctx, ref.Key, metav1.GetOptions{})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesGetSecret, err)
	if apierrors.IsNotFound(err) {
		return nil, esv1beta1.NoSecretError{}
	}
	if err != nil {
		return nil, err
	}
	var tmpMap map[string][]byte
	if ref.MetadataPolicy == esv1beta1.ExternalSecretMetadataPolicyFetch {
		tmpMap, err = getSecretMetadata(secret)
		if err != nil {
			return nil, err
		}
	} else {
		tmpMap = secret.Data
	}

	if ref.Property != "" {
		retMap, err := getPropertyMap(ref.Key, ref.Property, tmpMap)
		if err != nil {
			return nil, err
		}
		return retMap, nil
	}

	return tmpMap, nil
}

func getPropertyMap(key, property string, tmpMap map[string][]byte) (map[string][]byte, error) {
	byteArr, err := utils.JSONMarshal(tmpMap)
	if err != nil {
		return nil, err
	}
	var retMap map[string][]byte
	jsonStr := string(byteArr)
	// We need to search if a given key with a . exists before using gjson operations.
	idx := strings.Index(property, ".")
	if idx > -1 {
		refProperty := strings.ReplaceAll(property, ".", "\\.")
		retMap, err = getMapFromValues(refProperty, jsonStr)
		if err != nil {
			return nil, err
		}
		if retMap != nil {
			return retMap, nil
		}
	}
	retMap, err = getMapFromValues(property, jsonStr)
	if err != nil {
		return nil, err
	}
	if retMap == nil {
		return nil, fmt.Errorf("property %s does not exist in key %s", property, key)
	}
	return retMap, nil
}

func getMapFromValues(property, jsonStr string) (map[string][]byte, error) {
	val := gjson.Get(jsonStr, property)
	if val.Exists() {
		retMap := make(map[string][]byte)
		var tmpMap map[string]interface{}
		decoded, err := base64.StdEncoding.DecodeString(val.String())
		if err != nil {
			return nil, err
		}
		err = json.Unmarshal(decoded, &tmpMap)
		if err != nil {
			return nil, err
		}
		for k, v := range tmpMap {
			b, err := utils.JSONMarshal(v)
			if err != nil {
				return nil, err
			}
			retMap[k] = b
		}
		return retMap, nil
	}
	return nil, nil
}

func getSecretMetadata(secret *v1.Secret) (map[string][]byte, error) {
	var err error
	tmpMap := make(map[string][]byte)
	tmpMap[metaLabels], err = utils.JSONMarshal(secret.ObjectMeta.Labels)
	if err != nil {
		return nil, err
	}
	tmpMap[metaAnnotations], err = utils.JSONMarshal(secret.ObjectMeta.Annotations)
	if err != nil {
		return nil, err
	}

	return tmpMap, nil
}

func (c *Client) GetAllSecrets(ctx context.Context, ref esv1beta1.ExternalSecretFind) (map[string][]byte, error) {
	if ref.Tags != nil {
		return c.findByTags(ctx, ref)
	}
	if ref.Name != nil {
		return c.findByName(ctx, ref)
	}
	return nil, fmt.Errorf("unexpected find operator: %#v", ref)
}

func (c *Client) findByTags(ctx context.Context, ref esv1beta1.ExternalSecretFind) (map[string][]byte, error) {
	// empty/nil tags = everything
	sel, err := labels.ValidatedSelectorFromSet(ref.Tags)
	if err != nil {
		return nil, fmt.Errorf("unable to validate selector tags: %w", err)
	}
	secrets, err := c.userSecretClient.List(ctx, metav1.ListOptions{LabelSelector: sel.String()})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesListSecrets, err)
	if err != nil {
		return nil, fmt.Errorf("unable to list secrets: %w", err)
	}
	data := make(map[string][]byte)
	for _, secret := range secrets.Items {
		jsonStr, err := utils.JSONMarshal(convertMap(secret.Data))
		if err != nil {
			return nil, err
		}
		data[secret.Name] = jsonStr
	}
	return utils.ConvertKeys(ref.ConversionStrategy, data)
}

func (c *Client) findByName(ctx context.Context, ref esv1beta1.ExternalSecretFind) (map[string][]byte, error) {
	secrets, err := c.userSecretClient.List(ctx, metav1.ListOptions{})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesListSecrets, err)
	if err != nil {
		return nil, fmt.Errorf("unable to list secrets: %w", err)
	}
	matcher, err := find.New(*ref.Name)
	if err != nil {
		return nil, err
	}
	data := make(map[string][]byte)
	for _, secret := range secrets.Items {
		if !matcher.MatchName(secret.Name) {
			continue
		}
		jsonStr, err := utils.JSONMarshal(convertMap(secret.Data))
		if err != nil {
			return nil, err
		}
		data[secret.Name] = jsonStr
	}
	return utils.ConvertKeys(ref.ConversionStrategy, data)
}

func (c *Client) Close(_ context.Context) error {
	return nil
}

func convertMap(in map[string][]byte) map[string]string {
	out := make(map[string]string)
	for k, v := range in {
		out[k] = string(v)
	}
	return out
}

func (c *Client) createSecret(ctx context.Context, secret *v1.Secret, typed v1.SecretType, remoteRef esv1beta1.PushSecretData) error {
	data := make(map[string][]byte)

	if remoteRef.GetProperty() != "" {
		// set a specific remote key
		if remoteRef.GetSecretKey() == "" {
			value, err := c.marshalData(secret)
			if err != nil {
				return err
			}

			data[remoteRef.GetProperty()] = value
		} else {
			// push a specific secret key into a specific remote property
			data[remoteRef.GetProperty()] = secret.Data[remoteRef.GetSecretKey()]
		}
	} else {
		// push the whole secret as is using each key of the secret as a property in the created secret
		data = secret.Data
	}

	s := v1.Secret{
		ObjectMeta: metav1.ObjectMeta{
			Name:      remoteRef.GetRemoteKey(),
			Namespace: c.store.RemoteNamespace,
		},
		Data: data,
		Type: typed,
	}

	_, err := c.userSecretClient.Create(ctx, &s, metav1.CreateOptions{})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesCreateSecret, err)
	return err
}

// fullDelete removes remote secret completely.
func (c *Client) fullDelete(ctx context.Context, secretName string) error {
	err := c.userSecretClient.Delete(ctx, secretName, metav1.DeleteOptions{})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesDeleteSecret, err)

	// gracefully return on not found
	if apierrors.IsNotFound(err) {
		return nil
	}
	return err
}

// removeProperty removes single data property from remote secret.
func (c *Client) removeProperty(ctx context.Context, extSecret *v1.Secret, remoteRef esv1beta1.PushSecretRemoteRef) error {
	delete(extSecret.Data, remoteRef.GetProperty())
	_, err := c.userSecretClient.Update(ctx, extSecret, metav1.UpdateOptions{})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesUpdateSecret, err)
	return err
}

func (c *Client) updateMap(ctx context.Context, extSecret *v1.Secret, values map[string][]byte) error {
	// update the existing map with values from the pushed secret but keep existing values in tack.
	for k, v := range values {
		extSecret.Data[k] = v
	}

	return c.updateSecret(ctx, extSecret)
}

func (c *Client) updateProperty(ctx context.Context, extSecret *v1.Secret, remoteRef esv1beta1.PushSecretRemoteRef, value []byte) error {
	if extSecret.Data == nil {
		extSecret.Data = make(map[string][]byte)
	}

	// otherwise update remote secret
	extSecret.Data[remoteRef.GetProperty()] = value

	return c.updateSecret(ctx, extSecret)
}

func (c *Client) updateSecret(ctx context.Context, extSecret *v1.Secret) error {
	_, err := c.userSecretClient.Update(ctx, extSecret, metav1.UpdateOptions{})
	metrics.ObserveAPICall(constants.ProviderKubernetes, constants.CallKubernetesUpdateSecret, err)

	return err
}

func getSecret(secret *v1.Secret, ref esv1beta1.ExternalSecretDataRemoteRef) ([]byte, error) {
	if ref.MetadataPolicy == esv1beta1.ExternalSecretMetadataPolicyFetch {
		s, found, err := getFromSecretMetadata(secret, ref)
		if err != nil {
			return nil, err
		}

		if !found {
			return nil, fmt.Errorf("property %s does not exist in metadata of secret %q", ref.Property, ref.Key)
		}

		return s, nil
	}

	s, found := getFromSecretData(secret, ref)
	if !found {
		return nil, fmt.Errorf("property %s does not exist in data of secret %q", ref.Property, ref.Key)
	}

	return s, nil
}

func getFromSecretData(secret *v1.Secret, ref esv1beta1.ExternalSecretDataRemoteRef) ([]byte, bool) {
	// Check if a property with "." exists first such as file.png
	v, ok := secret.Data[ref.Property]
	if ok {
		return v, true
	}

	idx := strings.Index(ref.Property, ".")
	if idx == -1 || idx == 0 || idx == len(ref.Property)-1 {
		return nil, false
	}

	v, ok = secret.Data[ref.Property[:idx]]
	if !ok {
		return nil, false
	}

	val := gjson.Get(string(v), ref.Property[idx+1:])
	if !val.Exists() {
		return nil, false
	}

	return []byte(val.String()), true
}

func getFromSecretMetadata(secret *v1.Secret, ref esv1beta1.ExternalSecretDataRemoteRef) ([]byte, bool, error) {
	path := strings.Split(ref.Property, ".")

	var metadata map[string]string
	switch path[0] {
	case metaLabels:
		metadata = secret.Labels
	case metaAnnotations:
		metadata = secret.Annotations
	default:
		return nil, false, nil
	}

	if len(path) == 1 {
		j, err := utils.JSONMarshal(metadata)
		if err != nil {
			return nil, false, err
		}
		return j, true, nil
	}

	v, ok := metadata[path[1]]
	if !ok {
		return nil, false, nil
	}
	if len(path) == 2 {
		return []byte(v), true, nil
	}

	val := gjson.Get(v, strings.Join(path[2:], ""))
	if !val.Exists() {
		return nil, false, nil
	}

	return []byte(val.String()), true, nil
}