package auth

import (
	"encoding/json"
	"time"

	"github.com/google/uuid"
	"github.com/tidwall/buntdb"
)

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 Store instance based on memory
func NewMemoryTokenStore() (TokenStore, error) {
	return NewFileTokenStore(":memory:")
}

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

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

func (ts *Store) 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 *Store) 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 = json.Unmarshal([]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 *Store) 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 Store the new token information
func (ts *Store) Create(info TokenInfo) error {
	ct := time.Now()
	jv, err := json.Marshal(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 *Store) RemoveByAccess(access string) error {
	return ts.remove(access)
}

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

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