package linguistics

import (
    "strings"
    lingua "github.com/pemistahl/lingua-go"
)

// LinguaLanguageDetector implements LanguageDetector using lingua-go
type LinguaLanguageDetector struct {
    detector lingua.LanguageDetector
}

// NewLinguaLanguageDetector builds a detector for all supported languages
func NewLinguaLanguageDetector() *LinguaLanguageDetector {
    det := lingua.NewLanguageDetectorBuilder().FromAllLanguages().Build()
    return &LinguaLanguageDetector{detector: det}
}

// DetectLanguage returns a lowercase ISO 639-1 code if possible
func (l *LinguaLanguageDetector) DetectLanguage(text string) (string, bool) {
    lang, ok := l.detector.DetectLanguageOf(text)
    if !ok {
        return "", false
    }
    // Prefer ISO 639-1 when available else fallback to ISO 639-3
    if s := lang.IsoCode639_1().String(); s != "" {
        return s, true
    }
    if s := lang.IsoCode639_3().String(); s != "" {
        return s, true
    }
    // fallback to language name
    return strings.ToLower(lang.String()), true
}