package config

import (
	"strings"
	"testing"
)

func TestNormalizeLanguage(t *testing.T) {
	cases := map[string]string{
		"":                   "en",
		"en":                 "en",
		"EN":                 "en",
		"en-US":              "en",
		"english":            "en",
		"zh":                 "zh-CN",
		"zh-CN":              "zh-CN",
		"ZH-CN":              "zh-CN",
		"zh_cn":              "zh-CN",
		"zh-Hans":            "zh-CN",
		"Simplified Chinese": "zh-CN",
		"fr":                 "en", // unsupported falls back
	}
	for in, want := range cases {
		if got := NormalizeLanguage(in); got != want {
			t.Errorf("NormalizeLanguage(%q) = %q, want %q", in, got, want)
		}
	}
}

func TestOutputLanguageDirective(t *testing.T) {
	if d := OutputLanguageDirective("en"); d != "" {
		t.Errorf("English directive should be empty, got %q", d)
	}
	if d := OutputLanguageDirective(""); d != "" {
		t.Errorf("empty/default directive should be empty, got %q", d)
	}
	d := OutputLanguageDirective("zh-CN")
	if d == "" {
		t.Fatal("zh-CN directive should be non-empty")
	}
	if !strings.Contains(d, "简体中文") {
		t.Errorf("zh-CN directive should name the language, got %q", d)
	}
	// Unsupported codes fall back to English (no directive).
	if d := OutputLanguageDirective("fr"); d != "" {
		t.Errorf("unsupported language should produce no directive, got %q", d)
	}
}

func TestLanguageDisplayName(t *testing.T) {
	if got := LanguageDisplayName("en"); got != "English" {
		t.Errorf("LanguageDisplayName(en) = %q", got)
	}
	if got := LanguageDisplayName("zh-CN"); !strings.Contains(got, "Chinese") {
		t.Errorf("LanguageDisplayName(zh-CN) = %q", got)
	}
}