package ai

import (
	"errors"
	"golang.org/x/text/language"
)

const (
	TTSProtocolDashScopeHTTP = "dashscope_tts_http"
	TTSProtocolDashScopeTask = "dashscope_task_websocket"
)

// Task language labels/locales express the language; DashScope task parameters
// use ISO language hints. Do not infer an unspecified language from a region.
func bailianLanguageHint(value string) (string, error) {
	names := map[string]string{"Chinese": "zh", "English": "en", "Japanese": "ja", "Korean": "ko", "German": "de", "French": "fr", "Russian": "ru", "Italian": "it", "Spanish": "es", "Portuguese": "pt"}
	if code, ok := names[value]; ok {
		return code, nil
	}
	tag, err := language.Parse(value)
	if err != nil {
		return "", errors.New("language cannot be expressed by the selected task protocol")
	}
	base, _, _ := tag.Raw()
	if base.String() == "und" {
		return "", errors.New("task language must be explicit")
	}
	return base.String(), nil
}

func bailianTTSLanguageHints(value string) ([]string, error) {
	if value == "Auto" {
		return nil, nil
	} // Explicit user selection, not a missing-value default.
	hint, err := bailianLanguageHint(value)
	if err != nil {
		return nil, err
	}
	return []string{hint}, nil
}