package language

import (
	"os"
	"strings"

	"voicesnap/internal/model"
)

type SystemLocaleDetector interface {
	Detect() string
}

type SystemDetector struct{}

func NewSystemDetector() SystemDetector {
	return SystemDetector{}
}

func (SystemDetector) Detect() string {
	if locale := platformLocale(); strings.TrimSpace(locale) != "" {
		return locale
	}
	for _, key := range []string{"LC_ALL", "LC_MESSAGES", "LANG"} {
		if locale := os.Getenv(key); strings.TrimSpace(locale) != "" {
			return locale
		}
	}
	return ""
}

func NormalizeLocale(locale string) string {
	normalized := strings.ToLower(strings.TrimSpace(locale))
	normalized = strings.ReplaceAll(normalized, "_", "-")
	if idx := strings.Index(normalized, "."); idx >= 0 {
		normalized = normalized[:idx]
	}

	for _, profile := range model.ListLanguageProfiles() {
		for _, matcher := range profile.SystemMatchers {
			m := strings.ToLower(strings.ReplaceAll(strings.TrimSpace(matcher), "_", "-"))
			if normalized == m || strings.HasPrefix(normalized, m+"-") {
				return profile.ID
			}
		}
	}

	return model.EnglishLanguageID
}