aerc: use aerc as an mbox viewer

Use Aerc as an mbox viewer. Open an mbox file from the command line in a
new tab with the mbox backend. Provide a convenient and quick way to
display emails from an mbox.

Usage: aerc mbox://<path>

where the path can either be a directory or an mbox file. If it is a
directory, every file with an .mbox suffix will be loaded as a folder.

The account config will be copied from the selected account. This allows
the answer emails in the mbox account.

Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>

aerc.go

@@ -200,6 +200,7 @@ func main() {
 	} else {
 		defer as.Close()
 		as.OnMailto = aerc.Mailto
+		as.OnMbox = aerc.Mbox
 	}
 
 	// set the aerc version so that we can use it in the template funcs

lib/socket.go

@@ -21,6 +21,7 @@ type AercServer struct {
 	logger   *log.Logger
 	listener net.Listener
 	OnMailto func(addr *url.URL) error
+	OnMbox   func(source string) error
 }
 
 func StartServer(logger *log.Logger) (*AercServer, error) {
@@ -92,6 +93,16 @@ func (as *AercServer) handleClient(conn net.Conn) {
 			} else {
 				conn.Write([]byte("result: success\n"))
 			}
+		case "mbox":
+			var err error
+			if as.OnMbox != nil {
+				err = as.OnMbox(msg)
+			}
+			if err != nil {
+				conn.Write([]byte(fmt.Sprintf("result: %v\n", err)))
+			} else {
+				conn.Write([]byte("result: success\n"))
+			}
 		}
 	}
 	as.logger.Printf("Closed Unix connection %d", clientId)

widgets/aerc.go

@@ -618,6 +618,33 @@ func (aerc *Aerc) Mailto(addr *url.URL) error {
 	return nil
 }
 
+func (aerc *Aerc) Mbox(source string) error {
+	acctConf := config.AccountConfig{}
+	if selectedAcct := aerc.SelectedAccount(); selectedAcct != nil {
+		acctConf = *selectedAcct.acct
+		info := fmt.Sprintf("Loading outgoing mbox mail settings from account [%s]", selectedAcct.Name())
+		aerc.PushStatus(info, 10*time.Second)
+		aerc.Logger().Println(info)
+	} else {
+		acctConf.From = "<user@localhost>"
+	}
+	acctConf.Name = "mbox"
+	acctConf.Source = source
+	acctConf.Default = "INBOX"
+	acctConf.Archive = "Archive"
+	acctConf.Postpone = "Drafts"
+	acctConf.CopyTo = "Sent"
+
+	mboxView, err := NewAccountView(aerc, aerc.conf, &acctConf, aerc.logger, aerc, nil)
+	if err != nil {
+		aerc.NewTab(errorScreen(err.Error(), aerc.conf.Ui), acctConf.Name)
+	} else {
+		aerc.accounts[acctConf.Name] = mboxView
+		aerc.NewTab(mboxView, acctConf.Name)
+	}
+	return nil
+}
+
 func (aerc *Aerc) CloseBackends() error {
 	var returnErr error
 	for _, acct := range aerc.accounts {