Shared GUI for Bridge and Import/Export

internal/transfer/mailbox.go

@@ -21,6 +21,8 @@ import (
 	"crypto/sha256"
 	"fmt"
 	"strings"
+
+	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
 )
 
 // Mailbox is universal data holder of mailbox details for every provider.
@@ -36,6 +38,19 @@ func (m Mailbox) Hash() string {
 	return fmt.Sprintf("%x", sha256.Sum256([]byte(m.Name)))
 }
 
+// LeastUsedColor is intended to return color for creating a new inbox or label
+func LeastUsedColor(mailboxes []Mailbox) string {
+	usedColors := []string{}
+
+	if mailboxes != nil {
+		for _, m := range mailboxes {
+			usedColors = append(usedColors, m.Color)
+		}
+	}
+
+	return pmapi.LeastUsedColor(usedColors)
+}
+
 // findMatchingMailboxes returns all matching mailboxes from `mailboxes`.
 // Only one exclusive mailbox is returned.
 func (m Mailbox) findMatchingMailboxes(mailboxes []Mailbox) []Mailbox {

internal/transfer/mailbox_test.go

@@ -23,6 +23,49 @@ import (
 	r "github.com/stretchr/testify/require"
 )
 
+func TestLeastUsedColor(t *testing.T) {
+	var mailboxes []Mailbox
+	// Unset mailboxes, should use first available color
+	mailboxes = nil
+	r.Equal(t, "#7272a7", LeastUsedColor(mailboxes))
+
+	// No mailboxes at all, should use first available color
+	mailboxes = []Mailbox{}
+	r.Equal(t, "#7272a7", LeastUsedColor(mailboxes))
+
+	// All colors have same frequency, should use first available color
+	mailboxes = []Mailbox{
+		{Name: "Mbox1", Color: "#7272a7"},
+		{Name: "Mbox2", Color: "#cf5858"},
+		{Name: "Mbox3", Color: "#c26cc7"},
+		{Name: "Mbox4", Color: "#7569d1"},
+		{Name: "Mbox5", Color: "#69a9d1"},
+		{Name: "Mbox6", Color: "#5ec7b7"},
+		{Name: "Mbox7", Color: "#72bb75"},
+		{Name: "Mbox8", Color: "#c3d261"},
+		{Name: "Mbox9", Color: "#e6c04c"},
+		{Name: "Mbox10", Color: "#e6984c"},
+		{Name: "Mbox11", Color: "#8989ac"},
+		{Name: "Mbox12", Color: "#cf7e7e"},
+		{Name: "Mbox13", Color: "#c793ca"},
+		{Name: "Mbox14", Color: "#9b94d1"},
+		{Name: "Mbox15", Color: "#a8c4d5"},
+		{Name: "Mbox16", Color: "#97c9c1"},
+		{Name: "Mbox17", Color: "#9db99f"},
+		{Name: "Mbox18", Color: "#c6cd97"},
+		{Name: "Mbox19", Color: "#e7d292"},
+		{Name: "Mbox20", Color: "#dfb286"},
+	}
+	r.Equal(t, "#7272a7", LeastUsedColor(mailboxes))
+
+	// First three colors already used, but others wasn't. Should use first non-used one.
+	mailboxes = []Mailbox{
+		{Name: "Mbox1", Color: "#7272a7"},
+		{Name: "Mbox2", Color: "#cf5858"},
+		{Name: "Mbox3", Color: "#c26cc7"},
+	}
+	r.Equal(t, "#7569d1", LeastUsedColor(mailboxes))
+}
 func TestFindMatchingMailboxes(t *testing.T) {
 	mailboxes := []Mailbox{
 		{Name: "Inbox", IsExclusive: true},

internal/transfer/transfer.go

@@ -141,8 +141,8 @@ func (t *Transfer) CreateTargetMailbox(mailbox Mailbox) (Mailbox, error) {
 	return t.target.CreateMailbox(mailbox)
 }
 
-// ChangeTarget allows to change target. Ideally should not be used.
-// Useful for situration after user changes mind where to export files and similar.
+// ChangeTarget changes the target. It is safe to change target for export,
+// must not be changed for import. Do not set after you started transfer.
 func (t *Transfer) ChangeTarget(target TargetProvider) {
 	t.target = target
 }