refactor: make Language, TTSLock and EngineName to struct in Translator

GetSrcLang, GetDstLang, SetSrcLang, SetDstLang, SwapLang are reusable
functions from translator to translator. So make Language struct.

GetEngineName is also a reusable function. So make EngineName struct.

Finally, let Translator to inherit those functions in these three
(Language, TTSLock, EngineName) structs. No need to write the duplicated
functions for each Translator.

internal/translate/apertiumtranslate/translator.go

@@ -8,55 +8,38 @@ import (
 	"net/http"
 	"net/url"
 
-	"github.com/eeeXun/gtt/internal/lock"
+	"github.com/eeeXun/gtt/internal/translate/core"
 )
 
 const (
 	textURL = "https://www.apertium.org/apy/translate?langpair=%s|%s&q=%s"
 )
 
 type ApertiumTranslate struct {
-	srcLang    string
-	dstLang    string
-	EngineName string
-	SoundLock  *lock.Lock
+	*core.Language
+	*core.TTSLock
+	core.EngineName
 }
 
-func (t *ApertiumTranslate) GetEngineName() string {
-	return t.EngineName
+func NewApertiumTranslate() *ApertiumTranslate {
+	return &ApertiumTranslate{
+		Language:   core.NewLanguage(),
+		TTSLock:    core.NewTTSLock(),
+		EngineName: core.NewEngineName("ApertiumTranslate"),
+	}
 }
 
 func (t *ApertiumTranslate) GetAllLang() []string {
 	return lang
 }
 
-func (t *ApertiumTranslate) GetSrcLang() string {
-	return t.srcLang
-}
-
-func (t *ApertiumTranslate) GetDstLang() string {
-	return t.dstLang
-}
-
-func (t *ApertiumTranslate) SetSrcLang(srcLang string) {
-	t.srcLang = srcLang
-}
-
-func (t *ApertiumTranslate) SetDstLang(dstLang string) {
-	t.dstLang = dstLang
-}
-
-func (t *ApertiumTranslate) SwapLang() {
-	t.srcLang, t.dstLang = t.dstLang, t.srcLang
-}
-
 func (t *ApertiumTranslate) Translate(message string) (translation, definition, partOfSpeech string, err error) {
 	var data map[string]interface{}
 
 	urlStr := fmt.Sprintf(
 		textURL,
-		langCode[t.srcLang],
-		langCode[t.dstLang],
+		langCode[t.GetSrcLang()],
+		langCode[t.GetDstLang()],
 		url.QueryEscape(message),
 	)
 	res, err := http.Get(urlStr)
@@ -82,12 +65,18 @@ func (t *ApertiumTranslate) Translate(message string) (translation, definition,
 	default:
 		return "", "", "", errors.New(
 			fmt.Sprintf("%s does not support translate from %s to %s.\nSee available pair on %s",
-				t.EngineName,
-				t.srcLang,
-				t.dstLang,
+				t.GetEngineName(),
+				t.GetSrcLang(),
+				t.GetDstLang(),
 				"https://www.apertium.org/",
 			))
 	}
 
 	return translation, definition, partOfSpeech, nil
 }
+
+func (t *ApertiumTranslate) PlayTTS(lang, message string) error {
+	defer t.ReleaseLock()
+
+	return errors.New(t.GetEngineName() + " does not support text to speech")
+}

internal/translate/argostranslate/translator.go

@@ -8,56 +8,39 @@ import (
 	"net/http"
 	"net/url"
 
-	"github.com/eeeXun/gtt/internal/lock"
+	"github.com/eeeXun/gtt/internal/translate/core"
 )
 
 const (
 	textURL = "https://translate.argosopentech.com/translate"
 )
 
 type ArgosTranslate struct {
-	srcLang    string
-	dstLang    string
-	EngineName string
-	SoundLock  *lock.Lock
+	*core.Language
+	*core.TTSLock
+	core.EngineName
 }
 
-func (t *ArgosTranslate) GetEngineName() string {
-	return t.EngineName
+func NewArgosTranslate() *ArgosTranslate {
+	return &ArgosTranslate{
+		Language:   core.NewLanguage(),
+		TTSLock:    core.NewTTSLock(),
+		EngineName: core.NewEngineName("ArgosTranslate"),
+	}
 }
 
 func (t *ArgosTranslate) GetAllLang() []string {
 	return lang
 }
 
-func (t *ArgosTranslate) GetSrcLang() string {
-	return t.srcLang
-}
-
-func (t *ArgosTranslate) GetDstLang() string {
-	return t.dstLang
-}
-
-func (t *ArgosTranslate) SetSrcLang(srcLang string) {
-	t.srcLang = srcLang
-}
-
-func (t *ArgosTranslate) SetDstLang(dstLang string) {
-	t.dstLang = dstLang
-}
-
-func (t *ArgosTranslate) SwapLang() {
-	t.srcLang, t.dstLang = t.dstLang, t.srcLang
-}
-
 func (t *ArgosTranslate) Translate(message string) (translation, definition, partOfSpeech string, err error) {
 	var data map[string]interface{}
 
 	res, err := http.PostForm(textURL,
 		url.Values{
 			"q":      {message},
-			"source": {langCode[t.srcLang]},
-			"target": {langCode[t.dstLang]},
+			"source": {langCode[t.GetSrcLang()]},
+			"target": {langCode[t.GetDstLang()]},
 		})
 	if err != nil {
 		return "", "", "", err
@@ -78,3 +61,9 @@ func (t *ArgosTranslate) Translate(message string) (translation, definition, par
 
 	return translation, definition, partOfSpeech, nil
 }
+
+func (t *ArgosTranslate) PlayTTS(lang, message string) error {
+	defer t.ReleaseLock()
+
+	return errors.New(t.GetEngineName() + " does not support text to speech")
+}

internal/translate/core/language.go

@@ -0,0 +1,30 @@
+package core
+
+type Language struct {
+	srcLang string
+	dstLang string
+}
+
+func NewLanguage() *Language {
+	return &Language{}
+}
+
+func (l *Language) GetSrcLang() string {
+	return l.srcLang
+}
+
+func (l *Language) GetDstLang() string {
+	return l.dstLang
+}
+
+func (l *Language) SetSrcLang(lang string) {
+	l.srcLang = lang
+}
+
+func (l *Language) SetDstLang(lang string) {
+	l.dstLang = lang
+}
+
+func (l *Language) SwapLang() {
+	l.srcLang, l.dstLang = l.dstLang, l.srcLang
+}

internal/translate/core/lock.go

@@ -0,0 +1,35 @@
+package core
+
+type TTSLock struct {
+	stop        bool
+	threadCount int8
+}
+
+func NewTTSLock() *TTSLock {
+	return &TTSLock{
+		stop:        true,
+		threadCount: 0,
+	}
+}
+
+func (l *TTSLock) LockAvailable() bool {
+	return l.stop && l.threadCount == 0
+}
+
+func (l *TTSLock) AcquireLock() {
+	l.stop = false
+	l.threadCount++
+}
+
+func (l *TTSLock) IsStopped() bool {
+	return l.stop
+}
+
+func (l *TTSLock) StopTTS() {
+	l.stop = true
+}
+
+func (l *TTSLock) ReleaseLock() {
+	l.stop = true
+	l.threadCount--
+}

internal/translate/core/name.go

@@ -0,0 +1,15 @@
+package core
+
+type EngineName struct {
+	name string
+}
+
+func NewEngineName(name string) EngineName {
+	return EngineName{
+		name: name,
+	}
+}
+
+func (e EngineName) GetEngineName() string {
+	return e.name
+}