GODT-22: Frontend-backend

- GODT-1246 Implement settings view.
- GODT-1257 GODT-1246: Account and Help view
- GODT-1298: Minimal working build (panics)
- GODT-1298: loading QML (needs Popup window)
- GODT-1298: WARN: Adding PopupWindow not possible!
    In therecipe qt the `quickwidgets` classes are within `quick` module, but
    forgot to add library and include paths into cgo flags. Therefore
    compilation fails and it would be hard to patch therecipe in order to
    fix it.

    I am not sure if rewrite PopupWindow into go would make any difference,
    therefore I decided to use normal QML Window without borders.
- GODT-1298: Rework status window, add backend props, slots and signals.
- GODT-1298: Users
- GODT-1298: Login
- GODT-1298: WIP Help and bug report
- GODT-1178: MacOS dock icon control
- GODT-1298: Help, bug report, update and events
- GODT-1298: Apple Mail config and Settings (without cache on disk)

internal/frontend/qt/helpers.go

@@ -0,0 +1,70 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+// +build build_qt
+
+package qt
+
+import (
+	"regexp"
+	"strings"
+
+	"github.com/therecipe/qt/core"
+	"github.com/therecipe/qt/gui"
+)
+
+// getCursorPos returns current mouse position to be able to use in QML
+func getCursorPos() *core.QPoint {
+	return gui.QCursor_Pos()
+}
+
+// newQByteArrayFromString is a wrapper for new QByteArray from string.
+func newQByteArrayFromString(name string) *core.QByteArray {
+	return core.NewQByteArray2(name, len(name))
+}
+
+var (
+	reMultiSpaces     = regexp.MustCompile(`\s{2,}`)
+	reStartWithSymbol = regexp.MustCompile(`^[.,/#!$@%^&*;:{}=\-_` + "`" + `~()]`)
+)
+
+// getInitials based on webapp implementation:
+// https://github.com/ProtonMail/WebClients/blob/55d96a8b4afaaa4372fc5f1ef34953f2070fd7ec/packages/shared/lib/helpers/string.ts#L145
+func getInitials(fullName string) string {
+	words := strings.Split(
+		reMultiSpaces.ReplaceAllString(fullName, " "),
+		" ",
+	)
+
+	n := 0
+	for _, word := range words {
+		if !reStartWithSymbol.MatchString(word) {
+			words[n] = word
+			n++
+		}
+	}
+
+	if n == 0 {
+		return "?"
+	}
+
+	initials := words[0][0:1]
+	if n != 1 {
+		initials += words[n-1][0:1]
+	}
+	return strings.ToUpper(initials)
+}