/*
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 keepersecurity

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"maps"
	"regexp"
	"strings"

	ksm "github.com/keeper-security/secrets-manager-go/core"
	corev1 "k8s.io/api/core/v1"

	esv1beta1 "github.com/external-secrets/external-secrets/apis/externalsecrets/v1beta1"
)

const (
	errKeeperSecuritySecretsNotFound            = "unable to find secrets. %w"
	errKeeperSecuritySecretNotFound             = "unable to find secret %s. Error: %w"
	errKeeperSecuritySecretNotUnique            = "more than 1 secret %s found"
	errKeeperSecurityNoSecretsFound             = "no secrets found"
	errKeeperSecurityInvalidSecretInvalidFormat = "invalid secret. Invalid format: %w"
	errKeeperSecurityInvalidSecretDuplicatedKey = "invalid Secret. Following keys are duplicated %s"
	errKeeperSecurityInvalidProperty            = "invalid Property. Secret %s does not have any key matching %s"
	errKeeperSecurityInvalidField               = "invalid Field. Key %s does not exists"
	errKeeperSecurityNoFields                   = "invalid Secret. Secret %s does not contain any valid field/file"
	keeperSecurityFileRef                       = "fileRef"
	keeperSecurityMfa                           = "oneTimeCode"
	errTagsNotImplemented                       = "'find.tags' is not implemented in the KeeperSecurity provider"
	errPathNotImplemented                       = "'find.path' is not implemented in the KeeperSecurity provider"
	errInvalidJSONSecret                        = "invalid Secret. Secret %s can not be converted to JSON. %w"
	errInvalidRegex                             = "find.name.regex. Invalid Regular expresion %s. %w"
	errInvalidRemoteRefKey                      = "match.remoteRef.remoteKey. Invalid format. Format should match secretName/key got %s"
	errInvalidSecretType                        = "ESO can only push/delete records of type %s. Secret %s is type %s"
	errFieldNotFound                            = "secret %s does not contain any custom field with label %s"

	externalSecretType = "externalSecrets"
	secretType         = "secret"
	LoginType          = "login"
	LoginTypeExpr      = "login|username"
	PasswordType       = "password"
	URLTypeExpr        = "url|baseurl"
	URLType            = "url"
)

type Client struct {
	ksmClient SecurityClient
	folderID  string
}

type SecurityClient interface {
	GetSecrets(filter []string) ([]*ksm.Record, error)
	GetSecretByTitle(recordTitle string) (*ksm.Record, error)
	GetSecretsByTitle(recordTitle string) (records []*ksm.Record, err error)
	CreateSecretWithRecordData(recUID, folderUID string, recordData *ksm.RecordCreate) (string, error)
	DeleteSecrets(recrecordUids []string) (map[string]string, error)
	Save(record *ksm.Record) error
}

type Field struct {
	Type  string `json:"type"`
	Value []any  `json:"value"`
}

type CustomField struct {
	Type  string `json:"type"`
	Label string `json:"label"`
	Value []any  `json:"value"`
}

type File struct {
	Title   string `json:"type"`
	Content string `json:"content"`
}

type Secret struct {
	Title  string        `json:"title"`
	Type   string        `json:"type"`
	Fields []Field       `json:"fields"`
	Custom []CustomField `json:"custom"`
	Files  []File        `json:"files"`
}

func (c *Client) Validate() (esv1beta1.ValidationResult, error) {
	return esv1beta1.ValidationResultReady, nil
}

func (c *Client) GetSecret(_ context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) ([]byte, error) {
	record, err := c.findSecretByID(ref.Key)
	if err != nil {
		return nil, err
	}
	secret, err := c.getValidKeeperSecret(record)
	if err != nil {
		return nil, err
	}

	return secret.getItem(ref)
}

func (c *Client) GetSecretMap(_ context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) (map[string][]byte, error) {
	record, err := c.findSecretByID(ref.Key)
	if err != nil {
		return nil, err
	}
	secret, err := c.getValidKeeperSecret(record)
	if err != nil {
		return nil, err
	}

	return secret.getItems(ref)
}

func (c *Client) GetAllSecrets(_ context.Context, ref esv1beta1.ExternalSecretFind) (map[string][]byte, error) {
	if ref.Tags != nil {
		return nil, errors.New(errTagsNotImplemented)
	}
	if ref.Path != nil {
		return nil, errors.New(errPathNotImplemented)
	}
	secretData := make(map[string][]byte)
	records, err := c.findSecrets()
	if err != nil {
		return nil, err
	}
	for _, record := range records {
		secret, err := c.getValidKeeperSecret(record)
		if err != nil {
			return nil, err
		}
		match, err := regexp.MatchString(ref.Name.RegExp, secret.Title)
		if err != nil {
			return nil, fmt.Errorf(errInvalidRegex, ref.Name.RegExp, err)
		}
		if !match {
			continue
		}
		secretData[secret.Title], err = secret.getItem(esv1beta1.ExternalSecretDataRemoteRef{})
		if err != nil {
			return nil, err
		}
	}

	return secretData, nil
}

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

func (c *Client) PushSecret(_ context.Context, secret *corev1.Secret, data esv1beta1.PushSecretData) error {
	if data.GetSecretKey() == "" {
		return errors.New("pushing the whole secret is not yet implemented")
	}

	value := secret.Data[data.GetSecretKey()]
	parts, err := c.buildSecretNameAndKey(data)
	if err != nil {
		return err
	}

	record, err := c.findSecretByName(parts[0])
	if err != nil {
		return err
	}

	if record != nil {
		if record.Type() == externalSecretType {
			return c.updateSecret(record, parts[1], value)
		} else {
			return fmt.Errorf(errInvalidSecretType, externalSecretType, record.Title(), record.Type())
		}
	} else {
		_, err = c.createSecret(parts[0], parts[1], value)
		return err
	}
}

func (c *Client) DeleteSecret(_ context.Context, remoteRef esv1beta1.PushSecretRemoteRef) error {
	parts, err := c.buildSecretNameAndKey(remoteRef)
	if err != nil {
		return err
	}
	secret, err := c.findSecretByName(parts[0])
	if err != nil {
		return err
	} else if secret == nil {
		return nil // not found == already deleted (success)
	}

	if secret.Type() != externalSecretType {
		return fmt.Errorf(errInvalidSecretType, externalSecretType, secret.Title(), secret.Type())
	}
	_, err = c.ksmClient.DeleteSecrets([]string{secret.Uid})
	return err
}

func (c *Client) SecretExists(_ context.Context, _ esv1beta1.PushSecretRemoteRef) (bool, error) {
	return false, errors.New("not implemented")
}

func (c *Client) buildSecretNameAndKey(remoteRef esv1beta1.PushSecretRemoteRef) ([]string, error) {
	parts := strings.Split(remoteRef.GetRemoteKey(), "/")
	if len(parts) != 2 {
		return nil, fmt.Errorf(errInvalidRemoteRefKey, remoteRef.GetRemoteKey())
	}

	return parts, nil
}

func (c *Client) createSecret(name, key string, value []byte) (string, error) {
	normalizedKey := strings.ToLower(key)
	externalSecretRecord := ksm.NewRecordCreate(externalSecretType, name)
	login := regexp.MustCompile(LoginTypeExpr)
	pass := regexp.MustCompile(PasswordType)
	url := regexp.MustCompile(URLTypeExpr)

	switch {
	case login.MatchString(normalizedKey):
		externalSecretRecord.Fields = append(externalSecretRecord.Fields,
			ksm.NewLogin(string(value)),
		)
	case pass.MatchString(normalizedKey):
		externalSecretRecord.Fields = append(externalSecretRecord.Fields,
			ksm.NewPassword(string(value)),
		)
	case url.MatchString(normalizedKey):
		externalSecretRecord.Fields = append(externalSecretRecord.Fields,
			ksm.NewUrl(string(value)),
		)
	default:
		field := ksm.KeeperRecordField{Type: secretType, Label: key}
		externalSecretRecord.Custom = append(externalSecretRecord.Custom,
			ksm.Secret{KeeperRecordField: field, Value: []string{string(value)}},
		)
	}

	return c.ksmClient.CreateSecretWithRecordData("", c.folderID, externalSecretRecord)
}

func (c *Client) updateSecret(secret *ksm.Record, key string, value []byte) error {
	normalizedKey := strings.ToLower(key)
	login := regexp.MustCompile(LoginTypeExpr)
	pass := regexp.MustCompile(PasswordType)
	url := regexp.MustCompile(URLTypeExpr)
	custom := false

	switch {
	case login.MatchString(normalizedKey):
		secret.SetFieldValueSingle(LoginType, string(value))
	case pass.MatchString(normalizedKey):
		secret.SetPassword(string(value))
	case url.MatchString(normalizedKey):
		secret.SetFieldValueSingle(URLType, string(value))
	default:
		custom = true
	}
	if custom {
		field := secret.GetCustomFieldValueByLabel(key)
		if field != "" {
			secret.SetCustomFieldValueSingle(key, string(value))
		} else {
			return fmt.Errorf(errFieldNotFound, secret.Title(), key)
		}
	}

	return c.ksmClient.Save(secret)
}

func (c *Client) getValidKeeperSecret(secret *ksm.Record) (*Secret, error) {
	keeperSecret := Secret{}
	err := json.Unmarshal([]byte(secret.RawJson), &keeperSecret)
	if err != nil {
		return nil, fmt.Errorf(errKeeperSecurityInvalidSecretInvalidFormat, err)
	}
	keeperSecret.addFiles(secret.Files)
	err = keeperSecret.validate()
	if err != nil {
		return nil, err
	}

	return &keeperSecret, nil
}

func (c *Client) findSecrets() ([]*ksm.Record, error) {
	records, err := c.ksmClient.GetSecrets([]string{})
	if err != nil {
		return nil, fmt.Errorf(errKeeperSecuritySecretsNotFound, err)
	}

	return records, nil
}

func (c *Client) findSecretByID(id string) (*ksm.Record, error) {
	records, err := c.ksmClient.GetSecrets([]string{id})
	if err != nil {
		return nil, fmt.Errorf(errKeeperSecuritySecretNotFound, id, err)
	}

	if len(records) == 0 {
		return nil, errors.New(errKeeperSecurityNoSecretsFound)
	}
	if len(records) > 1 {
		return nil, fmt.Errorf(errKeeperSecuritySecretNotUnique, id)
	}

	return records[0], nil
}

func (c *Client) findSecretByName(name string) (*ksm.Record, error) {
	records, err := c.ksmClient.GetSecretsByTitle(name)
	if err != nil {
		return nil, err
	}

	// filter in-place, preserve only records of type externalSecretType
	n := 0
	for _, record := range records {
		if record.Type() == externalSecretType {
			records[n] = record
			n++
		}
	}
	records = records[:n]

	// record not found is not an error - handled differently:
	// PushSecret will create new record instead
	// DeleteSecret will consider record already deleted (no error)
	if len(records) == 0 {
		return nil, nil
	} else if len(records) == 1 {
		return records[0], nil
	}

	// len(records) > 1
	return nil, fmt.Errorf(errKeeperSecuritySecretNotUnique, name)
}

func (s *Secret) validate() error {
	fields := make(map[string]int)
	for _, field := range s.Fields {
		fields[field.Type]++
	}

	for _, customField := range s.Custom {
		fields[customField.Label]++
	}

	for _, file := range s.Files {
		fields[file.Title]++
	}
	var duplicates []string
	for key, ocurrences := range fields {
		if ocurrences > 1 {
			duplicates = append(duplicates, key)
		}
	}
	if len(duplicates) != 0 {
		return fmt.Errorf(errKeeperSecurityInvalidSecretDuplicatedKey, strings.Join(duplicates, ", "))
	}

	return nil
}

func (s *Secret) addFiles(keeperFiles []*ksm.KeeperFile) {
	for _, f := range keeperFiles {
		s.Files = append(
			s.Files,
			File{
				Title:   f.Title,
				Content: string(f.GetFileData()),
			},
		)
	}
}

func (s *Secret) getItem(ref esv1beta1.ExternalSecretDataRemoteRef) ([]byte, error) {
	if ref.Property != "" {
		return s.getProperty(ref.Property)
	}
	secret, err := s.toString()

	return []byte(secret), err
}

func (s *Secret) getItems(ref esv1beta1.ExternalSecretDataRemoteRef) (map[string][]byte, error) {
	secretData := make(map[string][]byte)
	if ref.Property != "" {
		value, err := s.getProperty(ref.Property)
		if err != nil {
			return nil, err
		}
		secretData[ref.Property] = value

		return secretData, nil
	}

	fields := s.getFields()
	maps.Copy(secretData, fields)
	customFields := s.getCustomFields()
	maps.Copy(secretData, customFields)
	files := s.getFiles()
	maps.Copy(secretData, files)

	if len(secretData) == 0 {
		return nil, fmt.Errorf(errKeeperSecurityNoFields, s.Title)
	}

	return secretData, nil
}

func getFieldValue(value []any) []byte {
	if len(value) < 1 {
		return []byte{}
	} else if len(value) == 1 {
		res, _ := json.Marshal(value[0])
		if str, ok := value[0].(string); ok {
			res = []byte(str)
		}
		return res
	} else {
		res, _ := json.Marshal(value)
		return res
	}
}

func (s *Secret) getField(key string) ([]byte, error) {
	for _, field := range s.Fields {
		if field.Type == key && field.Type != keeperSecurityFileRef && field.Type != keeperSecurityMfa && len(field.Value) > 0 {
			return getFieldValue(field.Value), nil
		}
	}

	return nil, fmt.Errorf(errKeeperSecurityInvalidField, key)
}

func (s *Secret) getFields() map[string][]byte {
	secretData := make(map[string][]byte)
	for _, field := range s.Fields {
		if len(field.Value) > 0 {
			secretData[field.Type] = getFieldValue(field.Value)
		}
	}

	return secretData
}

func (s *Secret) getCustomField(key string) ([]byte, error) {
	for _, field := range s.Custom {
		if field.Label == key && len(field.Value) > 0 {
			return getFieldValue(field.Value), nil
		}
	}

	return nil, fmt.Errorf(errKeeperSecurityInvalidField, key)
}

func (s *Secret) getCustomFields() map[string][]byte {
	secretData := make(map[string][]byte)
	for _, field := range s.Custom {
		if len(field.Value) > 0 {
			secretData[field.Label] = getFieldValue(field.Value)
		}
	}

	return secretData
}

func (s *Secret) getFile(key string) ([]byte, error) {
	for _, file := range s.Files {
		if file.Title == key {
			return []byte(file.Content), nil
		}
	}

	return nil, fmt.Errorf(errKeeperSecurityInvalidField, key)
}

func (s *Secret) getProperty(key string) ([]byte, error) {
	field, _ := s.getField(key)
	if field != nil {
		return field, nil
	}
	customField, _ := s.getCustomField(key)
	if customField != nil {
		return customField, nil
	}
	file, _ := s.getFile(key)
	if file != nil {
		return file, nil
	}

	return nil, fmt.Errorf(errKeeperSecurityInvalidProperty, s.Title, key)
}

func (s *Secret) getFiles() map[string][]byte {
	secretData := make(map[string][]byte)
	for _, file := range s.Files {
		secretData[file.Title] = []byte(file.Content)
	}

	return secretData
}

func (s *Secret) toString() (string, error) {
	secretJSON, err := json.Marshal(s)
	if err != nil {
		return "", fmt.Errorf(errInvalidJSONSecret, s.Title, err)
	}

	return string(secretJSON), nil
}