package tokens

import (
	"context"
	"crypto/rand"
	"encoding/base64"
	"io"
	"net/http"
	"time"

	"git.sendico.io/tech/sxchnge/bff/edge/shared/http/ipguard"
	"git.sendico.io/tech/sxchnge/bff/edge/shared/storage/refreshtokens"
	"git.sendico.io/tech/sxchnge/bff/pkg/merrors"
	"git.sendico.io/tech/sxchnge/bff/pkg/mlogger"
	"git.sendico.io/tech/sxchnge/bff/pkg/model"
	"git.sendico.io/tech/sxchnge/bff/pkg/mutil/mzap"
	"go.uber.org/zap"
)

func generateRefreshTokenData(length int) (string, error) {
	randomBytes := make([]byte, length)
	if _, err := io.ReadFull(rand.Reader, randomBytes); err != nil {
		return "", merrors.InternalWrap(err, "failed to generate secure random bytes")
	}

	return base64.URLEncoding.EncodeToString(randomBytes), nil
}

func PrepareRefreshToken(
	ctx context.Context,
	r *http.Request,
	rtdb refreshtokens.DB,
	length int,
	refreshExpiration int,
	session *model.SessionIdentifier,
	account *model.Account,
	logger mlogger.Logger,
) (*model.RefreshToken, error) {
	refreshToken, err := generateRefreshTokenData(length)
	if err != nil {
		logger.Warn("Failed to generate refresh token", zap.Error(err), mzap.StorableRef(account))
		return nil, err
	}
	sessionVersion, err := generateRefreshTokenData(16)
	if err != nil {
		logger.Warn("Failed to generate session version", zap.Error(err), mzap.StorableRef(account))
		return nil, err
	}
	versionedSession := *session
	versionedSession.SessionVersion = sessionVersion

	clientIP := ipguard.ClientIP(r)
	ipAddress := ""
	if clientIP != nil {
		ipAddress = clientIP.String()
	}

	token := &model.RefreshToken{
		AccountRef: account.GetID(),
		ClientRefreshToken: model.ClientRefreshToken{
			SessionIdentifier: versionedSession,
			RefreshToken:      refreshToken,
		},
		ExpiresAt: time.Now().Add(time.Duration(refreshExpiration) * time.Hour),
		IsRevoked: false,
		UserAgent: r.UserAgent(),
		IPAddress: ipAddress,
	}

	if err = rtdb.Create(ctx, token); err != nil {
		logger.Warn("Failed to store a refresh token", zap.Error(err), mzap.StorableRef(account),
			zap.String("client_id", token.ClientID), zap.String("device_id", token.DeviceID))
		return nil, err
	}

	return token, nil
}