UX of link account (Step 1) (#5006)

* Show either sign up OR sign in

* disambiguate fresh start from adding recovery options

* use tabs to switch between account link flows

* add active to tab body as well

* changes as per discussion

* handle specific error; fix missing err typo

1 files changed, 24 insertions, 2 deletions

diff --git a/routers/user/auth.go b/routers/user/auth.go
index a4a0ee3e6a..25aa437efd 100644
--- a/routers/user/auth.go
+++ b/routers/user/auth.go
@@ -664,8 +664,30 @@ func LinkAccount(ctx *context.Context) {
 		return
 	}
 
-	ctx.Data["user_name"] = gothUser.(goth.User).NickName
-	ctx.Data["email"] = gothUser.(goth.User).Email
+	uname := gothUser.(goth.User).NickName
+	email := gothUser.(goth.User).Email
+	ctx.Data["user_name"] = uname
+	ctx.Data["email"] = email
+
+	if len(email) != 0 {
+		u, err := models.GetUserByEmail(email)
+		if err != nil && !models.IsErrUserNotExist(err) {
+			ctx.ServerError("UserSignIn", err)
+			return
+		}
+		if u != nil {
+			ctx.Data["user_exists"] = true
+		}
+	} else if len(uname) != 0 {
+		u, err := models.GetUserByName(uname)
+		if err != nil && !models.IsErrUserNotExist(err) {
+			ctx.ServerError("UserSignIn", err)
+			return
+		}
+		if u != nil {
+			ctx.Data["user_exists"] = true
+		}
+	}
 
 	ctx.HTML(200, tplLinkAccount)
 }