login: wrap and propagate errors

pkg/connector/login.go

@@ -46,7 +46,7 @@ func (rc *RedditConnector) GetLoginFlows() []bridgev2.LoginFlow {
 
 func (rc *RedditConnector) CreateLogin(ctx context.Context, user *bridgev2.User, flowID string) (bridgev2.LoginProcess, error) {
 	if flowID != FlowIDPassword {
-		return nil, fmt.Errorf("unknown login flow ID: %s", flowID)
+		return nil, bridgev2.ErrInvalidLoginFlowID
 	}
 	return &PasswordLogin{main: rc, user: user}, nil
 }
@@ -142,7 +142,11 @@ func (p *PasswordLogin) SubmitUserInput(ctx context.Context, input map[string]st
 		username := strings.TrimSpace(input[FieldUsername])
 		password := input[FieldPassword]
 		if username == "" || password == "" {
-			return nil, errors.New("username and password are required")
+			return nil, bridgev2.RespError{
+				ErrCode:    "COM.BEEPER.REDDIT.MISSING_CREDENTIALS",
+				Err:        "Username and password are required.",
+				StatusCode: http.StatusBadRequest,
+			}
 		}
 		p.username = username
 		p.password = password
@@ -160,7 +164,11 @@ func (p *PasswordLogin) SubmitUserInput(ctx context.Context, input map[string]st
 	// Second call: OTP code from the user.
 	otp := strings.TrimSpace(input[FieldOTPCode])
 	if otp == "" {
-		return nil, errors.New("OTP code is required")
+		return nil, bridgev2.RespError{
+			ErrCode:    "COM.BEEPER.REDDIT.MISSING_OTP",
+			Err:        "A two-factor code is required.",
+			StatusCode: http.StatusBadRequest,
+		}
 	}
 	// The redditchat library reads the OTP from RedditLoginOptions.TOTPCode,
 	// not via a callback. So we restart the login flow with the OTP populated;
@@ -172,7 +180,7 @@ func (p *PasswordLogin) SubmitUserInput(ctx context.Context, input map[string]st
 func (p *PasswordLogin) SubmitCookies(ctx context.Context, cookies map[string]string) (*bridgev2.LoginStep, error) {
 	token := strings.TrimSpace(cookies[FieldRecaptchaToken])
 	if token == "" {
-		return nil, errors.New("missing reCAPTCHA token")
+		return nil, ErrLoginCaptchaFailed
 	}
 	clientVersion := strings.TrimSpace(cookies[FieldClientVersion])
 	// Send the token to the waiting login goroutine.
@@ -197,7 +205,7 @@ func (p *PasswordLogin) awaitNextStep(ctx context.Context) (*bridgev2.LoginStep,
 			if errors.Is(p.loginErr, errLoginNeedsOTP) {
 				return p.buildOTPStep(), nil
 			}
-			return nil, p.loginErr
+			return nil, wrapRedditLoginError(p.loginErr)
 		}
 		return p.completeStep(ctx)
 	case <-ctx.Done():
@@ -299,7 +307,7 @@ func (p *PasswordLogin) runLogin(ctx context.Context) {
 	// captcha token and tries to read the OTP. With TOTPCode unset, it fails
 	// with "otp required". We surface that as errLoginNeedsOTP so the caller
 	// restarts with the OTP filled in.
-	if err != nil && strings.Contains(err.Error(), "otp required") {
+	if errors.Is(err, redditchat.ErrOTPRequired) {
 		err = errLoginNeedsOTP
 	}
 

pkg/connector/loginerrors.go

@@ -0,0 +1,67 @@
+package connector
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"maunium.net/go/mautrix/bridgev2"
+
+	"github.com/beeper/reddit/pkg/redditchat"
+)
+
+var (
+	ErrLoginInvalidCredentials = bridgev2.RespError{
+		ErrCode:    "COM.BEEPER.REDDIT.INVALID_CREDENTIALS",
+		Err:        "Reddit rejected that username or password. Please check them and try again.",
+		StatusCode: http.StatusUnauthorized,
+	}
+	ErrLoginInvalidOTP = bridgev2.RespError{
+		ErrCode:    "COM.BEEPER.REDDIT.INVALID_OTP",
+		Err:        "That two-factor code wasn't accepted. Please try again.",
+		StatusCode: http.StatusUnauthorized,
+	}
+	ErrLoginSSORequired = bridgev2.RespError{
+		ErrCode:    "COM.BEEPER.REDDIT.SSO_REQUIRED",
+		Err:        "This Reddit account signs in with Google or Apple, which this bridge can't use. Set a Reddit password on reddit.com, then try again.",
+		StatusCode: http.StatusBadRequest,
+	}
+	ErrLoginVerificationBlocked = bridgev2.RespError{
+		ErrCode:    "COM.BEEPER.REDDIT.VERIFICATION_BLOCKED",
+		Err:        "Reddit blocked the sign-in with a verification check. Please wait a few minutes and try again.",
+		StatusCode: http.StatusForbidden,
+	}
+	ErrLoginCaptchaFailed = bridgev2.RespError{
+		ErrCode:    "COM.BEEPER.REDDIT.CAPTCHA_FAILED",
+		Err:        "The CAPTCHA couldn't be completed. Please try again.",
+		StatusCode: http.StatusBadRequest,
+	}
+	ErrLoginUnknown = bridgev2.RespError{
+		ErrCode:    "M_UNKNOWN",
+		Err:        "Internal error logging in to Reddit",
+		StatusCode: http.StatusInternalServerError,
+	}
+)
+
+// wrapRedditLoginError translates a redditchat error into one the client can act on.
+// The original error is kept in the chain with %w — importantly, redditchat's status
+// errors embed the raw response body, which must never be shown to a user.
+func wrapRedditLoginError(err error) error {
+	if err == nil {
+		return nil
+	}
+	mapped := ErrLoginUnknown
+	switch {
+	case errors.Is(err, redditchat.ErrInvalidCredentials):
+		mapped = ErrLoginInvalidCredentials
+	case errors.Is(err, redditchat.ErrInvalidOTP):
+		mapped = ErrLoginInvalidOTP
+	case errors.Is(err, redditchat.ErrSSORequired):
+		mapped = ErrLoginSSORequired
+	case errors.Is(err, redditchat.ErrBrowserVerificationBlocked):
+		mapped = ErrLoginVerificationBlocked
+	case errors.Is(err, redditchat.ErrCaptchaRequired):
+		mapped = ErrLoginCaptchaFailed
+	}
+	return fmt.Errorf("%w: %w", mapped, err)
+}

pkg/redditchat/login.go

@@ -45,6 +45,10 @@ const (
 var (
 	ErrCaptchaRequired            = errors.New("reddit login: captcha token provider required")
 	ErrBrowserVerificationBlocked = errors.New("reddit login: browser verification blocked")
+	ErrOTPRequired                = errors.New("reddit login: otp required; provide TOTPCode or TOTPSecret")
+	ErrInvalidOTP                 = errors.New("reddit login: otp code rejected")
+	ErrInvalidCredentials         = errors.New("reddit login: username or password rejected")
+	ErrSSORequired                = errors.New("reddit login: account requires SSO login")
 )
 
 type CaptchaRequest struct {
@@ -399,7 +403,7 @@ func (s *RedditSession) checkOIDCRequired(ctx context.Context, username, loginPa
 		return err
 	}
 	if resp.IsSSO {
-		return errors.New("reddit login: account requires SSO login")
+		return ErrSSORequired
 	}
 	return nil
 }
@@ -453,9 +457,11 @@ func (s *RedditSession) submitPassword(ctx context.Context, opts RedditLoginOpti
 			return err
 		}
 		if resp.StatusCode != http.StatusOK {
-			return redditStatusError(resp, body)
+			return fmt.Errorf("%w: %w", ErrInvalidOTP, redditStatusError(resp, body))
 		}
 		return nil
+	case http.StatusBadRequest, http.StatusUnauthorized, http.StatusForbidden:
+		return fmt.Errorf("%w: %w", ErrInvalidCredentials, redditStatusError(resp, body))
 	default:
 		return redditStatusError(resp, body)
 	}
@@ -575,7 +581,7 @@ func (opts RedditLoginOptions) otpCode(now time.Time) (string, error) {
 		return opts.TOTPCode, nil
 	}
 	if opts.TOTPSecret == "" {
-		return "", errors.New("reddit login: otp required; provide TOTPCode or TOTPSecret")
+		return "", ErrOTPRequired
 	}
 	return GenerateTOTP(opts.TOTPSecret, now)
 }
@@ -725,7 +731,7 @@ func checkLoginResponseBody(ctx context.Context, body []byte) error {
 		if len(msg) > 500 {
 			msg = msg[:500]
 		}
-		return fmt.Errorf("reddit login: password step rejected: %s", msg)
+		return fmt.Errorf("%w: %s", ErrInvalidCredentials, msg)
 	}
 	return nil
 }