package auth

import (
	"context"
	"fmt"
	"github.com/go-redis/redis/v8"
	"github.com/google/uuid"
	jsonIterator "github.com/json-iterator/go"
	"github.com/tidwall/buntdb"
	"time"
)

var (
	jsonMarshal   = jsonIterator.Marshal
	jsonUnmarshal = jsonIterator.Unmarshal
)

type TokenStore interface {
	Create(info TokenInfo) error
	RemoveByAccess(access string) error
	RemoveByRefresh(refresh string) error
	GetByAccess(access string) (TokenInfo, error)
	GetByRefresh(refresh string) (TokenInfo, error)
}

// NewMemoryTokenStore create a token buntStore instance based on memory
func NewMemoryTokenStore() (TokenStore, error) {
	return NewFileTokenStore(":memory:")
}

// NewFileTokenStore create a token buntStore instance based on file
func NewFileTokenStore(filename string) (TokenStore, error) {
	db, err := buntdb.Open(filename)
	if err != nil {
		return nil, err
	}
	return &buntStore{db: db}, nil
}

// buntStore token storage based on buntdb(https://github.com/tidwall/buntdb)
type buntStore struct {
	db *buntdb.DB
}

func (ts *buntStore) remove(key string) error {
	err := ts.db.Update(func(tx *buntdb.Tx) error {
		_, err := tx.Delete(key)
		return err
	})
	if err == buntdb.ErrNotFound {
		return nil
	}
	return err
}

func (ts *buntStore) getData(key string) (TokenInfo, error) {
	var ti TokenInfo
	err := ts.db.View(func(tx *buntdb.Tx) error {
		jv, err := tx.Get(key)
		if err != nil {
			return err
		}

		var tm Token
		err = jsonUnmarshal([]byte(jv), &tm)
		if err != nil {
			return err
		}
		ti = &tm
		return nil
	})
	if err != nil {
		if err == buntdb.ErrNotFound {
			return nil, nil
		}
		return nil, err
	}
	return ti, nil
}

func (ts *buntStore) getBasicID(key string) (string, error) {
	var basicID string
	err := ts.db.View(func(tx *buntdb.Tx) error {
		v, err := tx.Get(key)
		if err != nil {
			return err
		}
		basicID = v
		return nil
	})
	if err != nil {
		if err == buntdb.ErrNotFound {
			return "", nil
		}
		return "", err
	}
	return basicID, nil
}

// Create and buntStore the new token information
func (ts *buntStore) Create(info TokenInfo) error {
	ct := time.Now()
	jv, err := jsonMarshal(info)
	if err != nil {
		return err
	}

	return ts.db.Update(func(tx *buntdb.Tx) error {
		basicID := uuid.Must(uuid.NewRandom()).String()
		aexp := info.GetAccessExpiresIn()
		rexp := aexp
		expires := true
		if refresh := info.GetRefresh(); refresh != "" {
			rexp = info.GetRefreshCreateAt().Add(info.GetRefreshExpiresIn()).Sub(ct)
			if aexp.Seconds() > rexp.Seconds() {
				aexp = rexp
			}
			expires = info.GetRefreshExpiresIn() != 0
			_, _, err = tx.Set(refresh, basicID, &buntdb.SetOptions{Expires: expires, TTL: rexp})
			if err != nil {
				return err
			}
		}

		_, _, err = tx.Set(basicID, string(jv), &buntdb.SetOptions{Expires: expires, TTL: rexp})
		if err != nil {
			return err
		}

		_, _, err = tx.Set(info.GetAccess(), basicID, &buntdb.SetOptions{Expires: expires, TTL: aexp})
		return err
	})
}

// RemoveByAccess use the access token to delete the token information
func (ts *buntStore) RemoveByAccess(access string) error {
	return ts.remove(access)
}

// RemoveByRefresh use the refresh token to delete the token information
func (ts *buntStore) RemoveByRefresh(refresh string) error {
	return ts.remove(refresh)
}

// GetByAccess use the access token for token information data
func (ts *buntStore) GetByAccess(access string) (TokenInfo, error) {
	basicID, err := ts.getBasicID(access)
	if err != nil {
		return nil, err
	}
	return ts.getData(basicID)
}

// GetByRefresh use the refresh token for token information data
func (ts *buntStore) GetByRefresh(refresh string) (TokenInfo, error) {
	basicID, err := ts.getBasicID(refresh)
	if err != nil {
		return nil, err
	}
	return ts.getData(basicID)
}

/*------------------------------------------------------------------------------------*/

// NewRedisStoreWithCli create an instance of a redis store
func NewRedisStoreWithCli(cli *redis.Client, keyNamespace string) TokenStore {
	store := &redisStore{
		cli: cli,
		ctx: context.TODO(),
		ns:  keyNamespace,
	}
	return store
}

// TokenStore redis token store
type redisStore struct {
	cli *redis.Client
	ctx context.Context
	ns  string
}

func (s *redisStore) wrapperKey(key string) string {
	return fmt.Sprintf("%s%s", s.ns, key)
}

func (s *redisStore) checkError(result redis.Cmder) (bool, error) {
	if err := result.Err(); err != nil {
		if err == redis.Nil {
			return true, nil
		}
		return false, err
	}
	return false, nil
}

func (s *redisStore) remove(key string) error {
	result := s.cli.Del(s.ctx, s.wrapperKey(key))
	_, err := s.checkError(result)
	return err
}

func (s *redisStore) removeToken(tokenString string, isRefresh bool) error {
	basicID, err := s.getBasicID(tokenString)
	if err != nil {
		return err
	} else if basicID == "" {
		return nil
	}

	err = s.remove(tokenString)
	if err != nil {
		return err
	}

	token, err := s.getToken(basicID)
	if err != nil {
		return err
	} else if token == nil {
		return nil
	}

	checkToken := token.GetRefresh()
	if isRefresh {
		checkToken = token.GetAccess()
	}
	result := s.cli.Exists(s.ctx, s.wrapperKey(checkToken))
	if err = result.Err(); err != nil && err != redis.Nil {
		return err
	} else if result.Val() == 0 {
		return s.remove(basicID)
	}

	return nil
}

func (s *redisStore) parseToken(result *redis.StringCmd) (TokenInfo, error) {
	if ok, err := s.checkError(result); err != nil {
		return nil, err
	} else if ok {
		return nil, nil
	}

	buf, err := result.Bytes()
	if err != nil {
		if err == redis.Nil {
			return nil, nil
		}
		return nil, err
	}

	var token Token
	if err = jsonUnmarshal(buf, &token); err != nil {
		return nil, err
	}
	return &token, nil
}

func (s *redisStore) getToken(key string) (TokenInfo, error) {
	result := s.cli.Get(s.ctx, s.wrapperKey(key))
	return s.parseToken(result)
}

func (s *redisStore) parseBasicID(result *redis.StringCmd) (string, error) {
	if ok, err := s.checkError(result); err != nil {
		return "", err
	} else if ok {
		return "", nil
	}
	return result.Val(), nil
}

func (s *redisStore) getBasicID(token string) (string, error) {
	result := s.cli.Get(s.ctx, s.wrapperKey(token))
	return s.parseBasicID(result)
}

// Create and store the new token information
func (s *redisStore) Create(info TokenInfo) error {
	ct := time.Now()
	jv, err := jsonMarshal(info)
	if err != nil {
		return err
	}

	pipe := s.cli.TxPipeline()
	basicID := uuid.Must(uuid.NewRandom()).String()
	aexp := info.GetAccessExpiresIn()
	rexp := aexp

	if refresh := info.GetRefresh(); refresh != "" {
		rexp = info.GetRefreshCreateAt().Add(info.GetRefreshExpiresIn()).Sub(ct)
		if aexp.Seconds() > rexp.Seconds() {
			aexp = rexp
		}
		pipe.Set(s.ctx, s.wrapperKey(refresh), basicID, rexp)
	}

	pipe.Set(s.ctx, s.wrapperKey(info.GetAccess()), basicID, aexp)
	pipe.Set(s.ctx, s.wrapperKey(basicID), jv, rexp)

	if _, err = pipe.Exec(s.ctx); err != nil {
		return err
	}
	return nil
}

// RemoveByAccess Use the access token to delete the token information
func (s *redisStore) RemoveByAccess(access string) error {
	return s.removeToken(access, false)
}

// RemoveByRefresh Use the refresh token to delete the token information
func (s *redisStore) RemoveByRefresh(refresh string) error {
	return s.removeToken(refresh, true)
}

// GetByAccess Use the access token for token information data
func (s *redisStore) GetByAccess(access string) (TokenInfo, error) {
	basicID, err := s.getBasicID(access)
	if err != nil || basicID == "" {
		return nil, err
	}
	return s.getToken(basicID)
}

// GetByRefresh Use the refresh token for token information data
func (s *redisStore) GetByRefresh(refresh string) (TokenInfo, error) {
	basicID, err := s.getBasicID(refresh)
	if err != nil || basicID == "" {
		return nil, err
	}
	return s.getToken(basicID)
}