package locale_test

import (
	"context"
	"net/http"
	"os"
	"testing"

	"github.com/food-ai/backend/internal/infra/locale"
)

func TestMain(m *testing.M) {
	// Populate Supported map with all known languages before running tests.
	// In production this is done by locale.LoadFromDB at startup.
	for _, code := range []string{"en", "ru", "es", "de", "fr", "it", "pt", "zh", "ja", "ko", "ar", "hi"} {
		locale.Supported[code] = true
	}
	os.Exit(m.Run())
}

func TestParse(t *testing.T) {
	tests := []struct {
		name       string
		acceptLang string
		want       string
	}{
		{
			name:       "empty header returns default",
			acceptLang: "",
			want:       locale.Default,
		},
		{
			name:       "exact match",
			acceptLang: "ru",
			want:       "ru",
		},
		{
			name:       "region subtag stripped",
			acceptLang: "ru-RU",
			want:       "ru",
		},
		{
			name:       "full browser header picks first supported",
			acceptLang: "ru-RU,ru;q=0.9,en-US;q=0.8,en;q=0.7",
			want:       "ru",
		},
		{
			name:       "unsupported first falls through to supported",
			acceptLang: "xx-XX,ru;q=0.8",
			want:       "ru",
		},
		{
			name:       "completely unsupported returns default",
			acceptLang: "xx-XX,yy-YY",
			want:       locale.Default,
		},
		{
			name:       "chinese region subtag",
			acceptLang: "zh-CN,zh;q=0.9",
			want:       "zh",
		},
		{
			name:       "case insensitive",
			acceptLang: "RU-RU",
			want:       "ru",
		},
		{
			name:       "whitespace around tag",
			acceptLang: "  ru  ",
			want:       "ru",
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			got := locale.Parse(tc.acceptLang)
			if got != tc.want {
				t.Errorf("Parse(%q) = %q, want %q", tc.acceptLang, got, tc.want)
			}
		})
	}
}

func TestWithLangAndFromContext(t *testing.T) {
	ctx := context.Background()

	if got := locale.FromContext(ctx); got != locale.Default {
		t.Errorf("FromContext on empty ctx = %q, want %q", got, locale.Default)
	}

	ctx = locale.WithLang(ctx, "ru")
	if got := locale.FromContext(ctx); got != "ru" {
		t.Errorf("FromContext after WithLang(ru) = %q, want %q", got, "ru")
	}
}

func TestFromRequest(t *testing.T) {
	req, _ := http.NewRequest(http.MethodGet, "/", nil)
	req.Header.Set("Accept-Language", "es-ES,es;q=0.9")

	if got := locale.FromRequest(req); got != "es" {
		t.Errorf("FromRequest = %q, want %q", got, "es")
	}
}