/*
Copyright © The ESO Authors

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

    https://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 secretmanager implements the External Secrets provider for CloudRu Secret Manager.
package secretmanager

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strconv"
	"strings"

	smsv2 "github.com/cloudru-tech/secret-manager-sdk/api/v2"
	"github.com/google/uuid"
	"github.com/tidwall/gjson"
	corev1 "k8s.io/api/core/v1"

	esv1 "github.com/external-secrets/external-secrets/apis/externalsecrets/v1"
	"github.com/external-secrets/external-secrets/providers/v1/cloudru/secretmanager/adapter"
	"github.com/external-secrets/external-secrets/runtime/esutils"
)

var (
	// ErrInvalidSecretVersion represents the error, when trying to access the secret with non-numeric version.
	ErrInvalidSecretVersion = errors.New("invalid secret version: should be a valid int32 value or 'latest' keyword")
)

// SecretProvider is an API client for the Cloud.ru Secret Manager.
type SecretProvider interface {
	// ListSecrets lists secrets by the given request.
	ListSecrets(ctx context.Context, req *adapter.ListSecretsRequest) ([]*smsv2.Secret, error)
	// AccessSecretVersionByPath gets the secret by the given path.
	AccessSecretVersionByPath(ctx context.Context, projectID, path string, version *int32) ([]byte, error)
	// AccessSecretVersion gets the secret by the given request.
	AccessSecretVersion(ctx context.Context, id, version string) ([]byte, error)
}

// Client is a provider for CloudRu Secret Manager.
type Client struct {
	apiClient SecretProvider

	projectID string
}

// GetSecret gets the secret by the remote reference.
func (c *Client) GetSecret(ctx context.Context, ref esv1.ExternalSecretDataRemoteRef) ([]byte, error) {
	secret, err := c.accessSecret(ctx, ref.Key, ref.Version)
	if err != nil {
		return nil, err
	}

	prop := strings.TrimSpace(ref.Property)
	if prop == "" {
		return secret, nil
	}

	// For more obvious behavior, we return an error if we are dealing with invalid JSON
	// this is needed, because the gjson library works fine with value for `key`, for example:
	//
	// {"key": "value", another: "value"}
	//
	// but it will return "" when accessing to a property `another` (no quotes)
	if err = json.Unmarshal(secret, &map[string]any{}); err != nil {
		return nil, fmt.Errorf("expecting the secret %q in JSON format, could not access property %q", ref.Key, ref.Property)
	}

	result := gjson.Parse(string(secret)).Get(prop)
	if !result.Exists() {
		return nil, fmt.Errorf("the requested property %q does not exist in secret %q", prop, ref.Key)
	}

	return []byte(result.Str), nil
}

// GetSecretMap retrieves a secret from CloudRu SecretManager and returns it as a map of key/value pairs.
func (c *Client) GetSecretMap(ctx context.Context, ref esv1.ExternalSecretDataRemoteRef) (map[string][]byte, error) {
	secret, err := c.accessSecret(ctx, ref.Key, ref.Version)
	if err != nil {
		return nil, err
	}

	secretMap := make(map[string]json.RawMessage)
	if err = json.Unmarshal(secret, &secretMap); err != nil {
		return nil, fmt.Errorf("expecting the secret %q in JSON format", ref.Key)
	}

	out := make(map[string][]byte)
	for k, v := range secretMap {
		out[k] = []byte(strings.Trim(string(v), "\""))
	}

	return out, nil
}

// GetAllSecrets returns all secrets matching the find criteria (path, name, tags).
func (c *Client) GetAllSecrets(ctx context.Context, ref esv1.ExternalSecretFind) (map[string][]byte, error) {
	if len(ref.Tags) == 0 && ref.Name == nil && ref.Path == nil {
		return nil, fmt.Errorf("at least one of the following fields must be set: tags, name, path")
	}

	var nameFilter string
	if ref.Name != nil {
		nameFilter = ref.Name.RegExp
	}

	searchReq := &adapter.ListSecretsRequest{
		ProjectID: c.projectID,
		Labels:    ref.Tags,
		NameRegex: nameFilter,
	}
	if ref.Path != nil {
		searchReq.Path = *ref.Path
	}
	secrets, err := c.apiClient.ListSecrets(ctx, searchReq)
	if err != nil {
		return nil, fmt.Errorf("failed to list secrets: %w", err)
	}

	out := make(map[string][]byte)
	for _, s := range secrets {
		secret, accessErr := c.accessSecret(ctx, s.GetId(), "latest")
		if accessErr != nil {
			return nil, accessErr
		}

		out[s.GetPath()] = secret
	}

	return esutils.ConvertKeys(ref.ConversionStrategy, out)
}

func (c *Client) accessSecret(ctx context.Context, key, version string) ([]byte, error) {
	// check if the secret key is UUID
	// The uuid value means that the provided `key` is a secret identifier.
	// if not, then it is a secret name, and we need to get the secret by
	// name before accessing the version.
	if _, err := uuid.Parse(key); err != nil {
		var versionNum *int32
		if version != "" && version != "latest" {
			num, parseErr := strconv.ParseInt(version, 10, 32)
			if parseErr != nil {
				return nil, ErrInvalidSecretVersion
			}

			versionNum = &[]int32{int32(num)}[0]
		}

		return c.apiClient.AccessSecretVersionByPath(ctx, c.projectID, key, versionNum)
	}

	return c.apiClient.AccessSecretVersion(ctx, key, version)
}

// PushSecret pushes a secret to CloudRu Secret Manager.
func (c *Client) PushSecret(context.Context, *corev1.Secret, esv1.PushSecretData) error {
	return fmt.Errorf("push secret is not supported")
}

// DeleteSecret deletes a secret from CloudRu Secret Manager.
func (c *Client) DeleteSecret(context.Context, esv1.PushSecretRemoteRef) error {
	return fmt.Errorf("not implemented")
}

// SecretExists checks if a secret exists in CloudRu Secret Manager.
func (c *Client) SecretExists(context.Context, esv1.PushSecretRemoteRef) (bool, error) {
	return false, fmt.Errorf("secret exists is not supported")
}

// Validate validates the client.
func (c *Client) Validate() (esv1.ValidationResult, error) {
	return esv1.ValidationResultUnknown, nil
}

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