Refactor application structure and initialize core components

I decided to rewrite the program taking into account the experience gained.

internal/application/setting/ffmpeg.go

@@ -0,0 +1,25 @@
+package setting
+
+func (s *setting) GetFFmpegPath() string {
+	return s.fyneApp.Preferences().String("ffmpegPath")
+}
+
+func (s *setting) SetFFmpegPath(path string) {
+	s.fyneApp.Preferences().SetString("ffmpegPath", path)
+}
+
+func (s *setting) GetFFprobePath() string {
+	return s.fyneApp.Preferences().String("ffprobePath")
+}
+
+func (s *setting) SetFFprobePath(path string) {
+	s.fyneApp.Preferences().SetString("ffprobePath", path)
+}
+
+func (s *setting) GetFFplayPath() string {
+	return s.fyneApp.Preferences().String("ffplayPath")
+}
+
+func (s *setting) SetFFplayPath(path string) {
+	s.fyneApp.Preferences().SetString("ffplayPath", path)
+}

internal/application/setting/lang.go

@@ -0,0 +1,66 @@
+package setting
+
+import (
+	"encoding/json"
+	"fyne.io/fyne/v2"
+	fyneLang "fyne.io/fyne/v2/lang"
+	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/internal/resources"
+)
+
+var supportedLanguages = map[string]Lang{
+	"ru": {Code: "ru", Title: "Русский"},
+	"kk": {Code: "kk", Title: "Қазақ Тілі"},
+	"en": {Code: "en", Title: "English"},
+}
+
+type Lang struct {
+	Code  string
+	Title string
+}
+
+func ChangeLang(lang Lang) error {
+	translationsData, err := getTranslations(lang)
+	if err != nil {
+		return err
+	}
+
+	name := fyneLang.SystemLocale().LanguageString()
+	return fyneLang.AddTranslations(fyne.NewStaticResource(name+".json", translationsData))
+}
+
+func defaultLang() Lang {
+	return supportedLanguages["ru"]
+}
+
+func getTranslations(language Lang) ([]byte, error) {
+	translations := resources.GetTranslations()
+
+	baseJson, err := translations.ReadFile("translations/base." + language.Code + ".json")
+	if err != nil {
+		return nil, err
+	}
+	appJson, err := translations.ReadFile("translations/app." + language.Code + ".json")
+	if err != nil {
+		return nil, err
+	}
+
+	return mergeTranslations(baseJson, appJson)
+}
+
+func mergeTranslations(baseJson []byte, appJson []byte) ([]byte, error) {
+	base := map[string]interface{}{}
+	custom := map[string]interface{}{}
+	err := json.Unmarshal(baseJson, &base)
+	if err != nil {
+		return nil, err
+	}
+	err = json.Unmarshal(appJson, &custom)
+	if err != nil {
+		return nil, err
+	}
+
+	for k, v := range custom {
+		base[k] = v
+	}
+	return json.Marshal(base)
+}

internal/application/setting/setting.go

@@ -0,0 +1,65 @@
+package setting
+
+import (
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/lang"
+	"golang.org/x/text/language"
+)
+
+type SettingContract interface {
+	GetLanguages() []Lang
+	GetCurrentLangOrDefaultLang() (currentLang Lang, isDefault bool)
+	SetLang(language Lang) error
+	GetFFmpegPath() string
+	SetFFmpegPath(path string)
+	GetFFprobePath() string
+	SetFFprobePath(path string)
+	GetFFplayPath() string
+	SetFFplayPath(path string)
+}
+
+type setting struct {
+	fyneApp fyne.App
+}
+
+func NewSetting(fyneApp fyne.App) SettingContract {
+	return &setting{
+		fyneApp: fyneApp,
+	}
+}
+
+func (s *setting) GetLanguages() []Lang {
+	items := []Lang{}
+	for _, item := range supportedLanguages {
+		items = append(items, item)
+	}
+	return items
+}
+
+func (s *setting) GetCurrentLangOrDefaultLang() (currentLang Lang, isDefault bool) {
+	languageCode := s.fyneApp.Preferences().String("language")
+
+	if languageCode == "" {
+		languageTag, err := language.Parse(lang.SystemLocale().LanguageString())
+		if err != nil {
+			return currentLang, true
+		}
+		base, _ := languageTag.Base()
+		languageCode = base.String()
+	}
+
+	if currentLang, ok := supportedLanguages[languageCode]; ok {
+		return currentLang, false
+	}
+
+	return defaultLang(), true
+}
+
+func (s *setting) SetLang(language Lang) error {
+	err := ChangeLang(language)
+	if err != nil {
+		return err
+	}
+	s.fyneApp.Preferences().SetString("language", language.Code)
+	return nil
+}