package apikey

import (
	"crypto/sha256"
	"encoding/base64"
	"fmt"
	"time"

	"github.com/pkg/errors"

	portainer "github.com/portainer/portainer/api"
	"github.com/portainer/portainer/api/dataservices"
)

const portainerAPIKeyPrefix = "ptr_"

var ErrInvalidAPIKey = errors.New("Invalid API key")

type apiKeyService struct {
	apiKeyRepository dataservices.APIKeyRepository
	userRepository   dataservices.UserService
	cache            *apiKeyCache
}

func NewAPIKeyService(apiKeyRepository dataservices.APIKeyRepository, userRepository dataservices.UserService) *apiKeyService {
	return &apiKeyService{
		apiKeyRepository: apiKeyRepository,
		userRepository:   userRepository,
		cache:            NewAPIKeyCache(defaultAPIKeyCacheSize),
	}
}

// HashRaw computes a hash digest of provided raw API key.
func (a *apiKeyService) HashRaw(rawKey string) []byte {
	hashDigest := sha256.Sum256([]byte(rawKey))
	return hashDigest[:]
}

// GenerateApiKey generates a raw API key for a user (for one-time display).
// The generated API key is stored in the cache and database.
func (a *apiKeyService) GenerateApiKey(user portainer.User, description string) (string, *portainer.APIKey, error) {
	randKey := generateRandomKey(32)
	encodedRawAPIKey := base64.StdEncoding.EncodeToString(randKey)
	prefixedAPIKey := portainerAPIKeyPrefix + encodedRawAPIKey

	hashDigest := a.HashRaw(prefixedAPIKey)

	apiKey := &portainer.APIKey{
		UserID:      user.ID,
		Description: description,
		Prefix:      prefixedAPIKey[:7],
		DateCreated: time.Now().Unix(),
		Digest:      hashDigest,
	}

	err := a.apiKeyRepository.CreateAPIKey(apiKey)
	if err != nil {
		return "", nil, errors.Wrap(err, "Unable to create API key")
	}

	// persist api-key to cache
	a.cache.Set(apiKey.Digest, user, *apiKey)

	return prefixedAPIKey, apiKey, nil
}

// GetAPIKey returns an API key by its ID.
func (a *apiKeyService) GetAPIKey(apiKeyID portainer.APIKeyID) (*portainer.APIKey, error) {
	return a.apiKeyRepository.GetAPIKey(apiKeyID)
}

// GetAPIKeys returns all the API keys associated to a user.
func (a *apiKeyService) GetAPIKeys(userID portainer.UserID) ([]portainer.APIKey, error) {
	return a.apiKeyRepository.GetAPIKeysByUserID(userID)
}

// GetDigestUserAndKey returns the user and api-key associated to a specified hash digest.
// A cache lookup is performed first; if the user/api-key is not found in the cache, respective database lookups are performed.
func (a *apiKeyService) GetDigestUserAndKey(digest []byte) (portainer.User, portainer.APIKey, error) {
	// get api key from cache if possible
	cachedUser, cachedKey, ok := a.cache.Get(digest)
	if ok {
		return cachedUser, cachedKey, nil
	}

	apiKey, err := a.apiKeyRepository.GetAPIKeyByDigest(digest)
	if err != nil {
		return portainer.User{}, portainer.APIKey{}, errors.Wrap(err, "Unable to retrieve API key")
	}

	user, err := a.userRepository.User(apiKey.UserID)
	if err != nil {
		return portainer.User{}, portainer.APIKey{}, errors.Wrap(err, "Unable to retrieve digest user")
	}

	// persist api-key to cache - for quicker future lookups
	a.cache.Set(apiKey.Digest, *user, *apiKey)

	return *user, *apiKey, nil
}

// UpdateAPIKey updates an API key and in cache and database.
func (a *apiKeyService) UpdateAPIKey(apiKey *portainer.APIKey) error {
	user, _, err := a.GetDigestUserAndKey(apiKey.Digest)
	if err != nil {
		return errors.Wrap(err, "Unable to retrieve API key")
	}
	a.cache.Set(apiKey.Digest, user, *apiKey)
	return a.apiKeyRepository.UpdateAPIKey(apiKey)
}

// DeleteAPIKey deletes an API key and removes the digest/api-key entry from the cache.
func (a *apiKeyService) DeleteAPIKey(apiKeyID portainer.APIKeyID) error {
	// get api-key digest to remove from cache
	apiKey, err := a.apiKeyRepository.GetAPIKey(apiKeyID)
	if err != nil {
		return errors.Wrap(err, fmt.Sprintf("Unable to retrieve API key: %d", apiKeyID))
	}

	// delete the user/api-key from cache
	a.cache.Delete(apiKey.Digest)
	return a.apiKeyRepository.DeleteAPIKey(apiKeyID)
}

func (a *apiKeyService) InvalidateUserKeyCache(userId portainer.UserID) bool {
	return a.cache.InvalidateUserKeyCache(userId)
}