base models.Address on the mail.Address type

This allows us to hook into the std libs implementation of parsing related stuff.
For this, we need to get rid of the distinction between a mailbox and a host
to just a single "address" field.

However this is already the common case. All but one users immediately
concatenated the mbox/domain to a single address.

So this in effects makes it simpler for most cases and we simply do the
transformation in the special case.

lib/format/format.go

@@ -2,22 +2,46 @@ package format
 
 import (
 	"errors"
-	"fmt"
+	"mime"
 	gomail "net/mail"
 	"strings"
 	"time"
 	"unicode"
 
 	"git.sr.ht/~sircmpwn/aerc/models"
+	"github.com/emersion/go-message"
 )
 
-func parseAddress(address string) *gomail.Address {
+func ParseAddress(address string) (*models.Address, error) {
 	addrs, err := gomail.ParseAddress(address)
 	if err != nil {
-		return nil
+		return nil, err
+	}
+	return (*models.Address)(addrs), nil
+}
+
+func ParseAddressList(s string) ([]*models.Address, error) {
+	parser := gomail.AddressParser{
+		&mime.WordDecoder{message.CharsetReader},
+	}
+	list, err := parser.ParseList(s)
+	if err != nil {
+		return nil, err
 	}
 
-	return addrs
+	addrs := make([]*models.Address, len(list))
+	for i, a := range list {
+		addrs[i] = (*models.Address)(a)
+	}
+	return addrs, nil
+}
+
+func FormatAddresses(l []*models.Address) string {
+	formatted := make([]string, len(l))
+	for i, a := range l {
+		formatted[i] = a.Format()
+	}
+	return strings.Join(formatted, ", ")
 }
 
 func ParseMessageFormat(
@@ -29,7 +53,10 @@ func ParseMessageFormat(
 	retval := make([]byte, 0, len(format))
 	var args []interface{}
 
-	accountFromAddress := parseAddress(fromAddress)
+	accountFromAddress, err := ParseAddress(fromAddress)
+	if err != nil {
+		return "", nil, err
+	}
 
 	var c rune
 	for i, ni := 0, 0; i < len(format); {
@@ -87,8 +114,7 @@ func ParseMessageFormat(
 			}
 			addr := msg.Envelope.From[0]
 			retval = append(retval, 's')
-			args = append(args,
-				fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host))
+			args = append(args, addr.Address)
 		case 'A':
 			if msg.Envelope == nil {
 				return "", nil,
@@ -106,8 +132,7 @@ func ParseMessageFormat(
 				addr = msg.Envelope.ReplyTo[0]
 			}
 			retval = append(retval, 's')
-			args = append(args,
-				fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host))
+			args = append(args, addr.Address)
 		case 'C':
 			retval = append(retval, 'd')
 			args = append(args, number)
@@ -158,7 +183,7 @@ func ParseMessageFormat(
 			if addr.Name != "" {
 				val = addr.Name
 			} else {
-				val = fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host)
+				val = addr.Address
 			}
 			retval = append(retval, 's')
 			args = append(args, val)
@@ -188,7 +213,7 @@ func ParseMessageFormat(
 			if addr.Name != "" {
 				val = addr.Name
 			} else {
-				val = fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host)
+				val = addr.Address
 			}
 			retval = append(retval, 's')
 			args = append(args, val)
@@ -197,7 +222,7 @@ func ParseMessageFormat(
 				return "", nil,
 					errors.New("no envelope available for this message")
 			}
-			addrs := models.FormatAddresses(msg.Envelope.To)
+			addrs := FormatAddresses(msg.Envelope.To)
 			retval = append(retval, 's')
 			args = append(args, addrs)
 		case 'R':
@@ -205,7 +230,7 @@ func ParseMessageFormat(
 				return "", nil,
 					errors.New("no envelope available for this message")
 			}
-			addrs := models.FormatAddresses(msg.Envelope.Cc)
+			addrs := FormatAddresses(msg.Envelope.Cc)
 			retval = append(retval, 's')
 			args = append(args, addrs)
 		case 's':
@@ -226,8 +251,7 @@ func ParseMessageFormat(
 			}
 			addr := msg.Envelope.To[0]
 			retval = append(retval, 's')
-			args = append(args,
-				fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host))
+			args = append(args, addr.Address)
 		case 'T':
 			retval = append(retval, 's')
 			args = append(args, accountName)
@@ -241,8 +265,12 @@ func ParseMessageFormat(
 					errors.New("found no address for sender")
 			}
 			addr := msg.Envelope.From[0]
+			mailbox := addr.Address // fallback if there's no @ sign
+			if split := strings.SplitN(addr.Address, "@", 2); len(split) == 2 {
+				mailbox = split[1]
+			}
 			retval = append(retval, 's')
-			args = append(args, addr.Mailbox)
+			args = append(args, mailbox)
 		case 'v':
 			if msg.Envelope == nil {
 				return "", nil,