package main

import (
	"strings"
	"testing"
)

func TestAllKeysExistInBothLocales(t *testing.T) {
	enMessages := messages["en"]
	esMessages := messages["es"]

	for key := range enMessages {
		if _, ok := esMessages[key]; !ok {
			t.Errorf("key %q exists in 'en' but not in 'es'", key)
		}
	}
	for key := range esMessages {
		if _, ok := enMessages[key]; !ok {
			t.Errorf("key %q exists in 'es' but not in 'en'", key)
		}
	}
}

func TestFormatStringParity(t *testing.T) {
	enMessages := messages["en"]
	esMessages := messages["es"]

	for key, enFmt := range enMessages {
		esFmt, ok := esMessages[key]
		if !ok {
			continue
		}
		enCount := strings.Count(enFmt, "%s") + strings.Count(enFmt, "%d")
		esCount := strings.Count(esFmt, "%s") + strings.Count(esFmt, "%d")
		if enCount != esCount {
			t.Errorf("key %q: 'en' has %d format verbs, 'es' has %d", key, enCount, esCount)
		}
	}
}

func TestFallbackToEnglish(t *testing.T) {
	result := T("fr", MsgCommandEmpty)
	expected := messages["en"][MsgCommandEmpty]
	if result != expected {
		t.Errorf("expected fallback to English %q, got %q", expected, result)
	}
}

func TestLocaleNormalization(t *testing.T) {
	tests := []struct {
		locale   string
		expected string
	}{
		{"es-ES", "es"},
		{"es-MX", "es"},
		{"EN-US", "en"},
		{"en", "en"},
		{"", "en"},
	}

	for _, tt := range tests {
		got := normalizeLocale(tt.locale)
		if got != tt.expected {
			t.Errorf("normalizeLocale(%q) = %q, want %q", tt.locale, got, tt.expected)
		}
	}
}

func TestTWithArgs(t *testing.T) {
	result := T("en", MsgNoBooksFound, "test query")
	expected := `No books found for "test query".`
	if result != expected {
		t.Errorf("expected %q, got %q", expected, result)
	}
}

func TestTWithSpanish(t *testing.T) {
	result := T("es", MsgNoBooksFound, "test query")
	expected := `No se encontraron libros para "test query".`
	if result != expected {
		t.Errorf("expected %q, got %q", expected, result)
	}
}

func TestTUnknownKeyReturnsKey(t *testing.T) {
	result := T("en", "nonexistent.key")
	if result != "nonexistent.key" {
		t.Errorf("expected key returned as-is, got %q", result)
	}
}

func TestTNoArgs(t *testing.T) {
	result := T("en", MsgCommandEmpty)
	expected := "Empty command received."
	if result != expected {
		t.Errorf("expected %q, got %q", expected, result)
	}
}