From 8ac9001df2007ad2c50a525ace2b7ee695747f52 Mon Sep 17 00:00:00 2001
From: tsmethurst <tobi.smethurst@protonmail.com>
Date: Thu, 2 Jun 2022 17:07:59 +0200
Subject: [PATCH] simplify GetParseMentionFunc

---
 internal/processing/util.go | 93 ++++++++-----------------------------
 1 file changed, 19 insertions(+), 74 deletions(-)

diff --git a/internal/processing/util.go b/internal/processing/util.go
index 1cd9e6aea..76d1187f9 100644
--- a/internal/processing/util.go
+++ b/internal/processing/util.go
@@ -21,13 +21,14 @@
 import (
 	"context"
 	"fmt"
-	"strings"
 
+	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/federation"
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/id"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
 
 func GetParseMentionFunc(dbConn db.DB, federator federation.Federator) gtsmodel.ParseMentionFunc {
@@ -38,91 +39,35 @@ func GetParseMentionFunc(dbConn db.DB, federator federation.Federator) gtsmodel.
 			return nil, fmt.Errorf("couldn't get mention origin account with id %s", originAccountID)
 		}
 
-		// A mentioned account looks like "@test@example.org" or just "@test" for a local account
-		// -- we can guarantee this from the regex that targetAccounts should have been derived from.
-		// But we still need to do a bit of fiddling to get what we need here -- the username and domain (if given).
-
-		// 1.  trim off the first @
-		trimmed := strings.TrimPrefix(targetAccount, "@")
-
-		// 2. split the username and domain
-		split := strings.Split(trimmed, "@")
-
-		// 3. if it's length 1 it's a local account, length 2 means remote, anything else means something is wrong
-
-		var local bool
-		switch len(split) {
-		case 1:
-			local = true
-		case 2:
-			local = false
-		default:
-			return nil, fmt.Errorf("mentioned account format '%s' was not valid", targetAccount)
-		}
-
-		var username, domain string
-		username = split[0]
-		if !local {
-			domain = split[1]
-		}
-
-		// 4. check we now have a proper username and domain
-		if username == "" || (!local && domain == "") {
-			return nil, fmt.Errorf("username or domain for '%s' was nil", targetAccount)
+		username, domain, err := util.ExtractNamestringParts(targetAccount)
+		if err != nil {
+			return nil, fmt.Errorf("couldn't extract namestring parts from %s: %s", targetAccount, err)
 		}
 
 		var mentionedAccount *gtsmodel.Account
-
-		if local {
+		if domain == "" || domain == config.GetHost() || domain == config.GetAccountDomain() {
 			localAccount, err := dbConn.GetLocalAccountByUsername(ctx, username)
 			if err != nil {
 				return nil, err
 			}
 			mentionedAccount = localAccount
 		} else {
-			remoteAccount := &gtsmodel.Account{}
-
-			where := []db.Where{
-				{
-					Key:             "username",
-					Value:           username,
-					CaseInsensitive: true,
-				},
-				{
-					Key:             "domain",
-					Value:           domain,
-					CaseInsensitive: true,
-				},
+			var requestingUsername string
+			if originAccount.Domain == "" {
+				requestingUsername = originAccount.Username
+			}
+			remoteAccount, err := federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+				RequestingUsername:    requestingUsername,
+				RemoteAccountUsername: username,
+				RemoteAccountHost:     domain,
+			})
+			if err != nil {
+				return nil, fmt.Errorf("error dereferencing account: %s", err)
 			}
 
-			err := dbConn.GetWhere(ctx, where, remoteAccount)
-			if err == nil {
-				// the account was already in the database
-				mentionedAccount = remoteAccount
-			} else {
-				// we couldn't get it from the database
-				if err != db.ErrNoEntries {
-					// a serious error has happened so bail
-					return nil, fmt.Errorf("error getting account with username '%s' and domain '%s': %s", username, domain, err)
-				}
+			// we were able to resolve it!
+			mentionedAccount = remoteAccount
 
-				// We just don't have the account, so try getting it.
-				var requestingUsername string
-				if originAccount.Domain == "" {
-					requestingUsername = originAccount.Username
-				}
-				resolvedAccount, err := federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
-					RequestingUsername:    requestingUsername,
-					RemoteAccountUsername: username,
-					RemoteAccountHost:     domain,
-				})
-				if err != nil {
-					return nil, fmt.Errorf("error dereferencing account: %s", err)
-				}
-
-				// we were able to resolve it!
-				mentionedAccount = resolvedAccount
-			}
 		}
 
 		mentionID, err := id.NewRandomULID()