package menu_test

import (
	"testing"

	"github.com/food-ai/backend/internal/domain/menu"
)

func TestResolveWeekStart_ValidFormat(t *testing.T) {
	// ISO week 1 of 2026 starts on Monday 2025-12-29
	result, resolveError := menu.ResolveWeekStart("2026-W01")
	if resolveError != nil {
		t.Fatalf("unexpected error: %v", resolveError)
	}
	if result != "2025-12-29" {
		t.Errorf("ResolveWeekStart(2026-W01) = %q, want %q", result, "2025-12-29")
	}
}

func TestResolveWeekStart_Week10(t *testing.T) {
	// Week 10 of 2026 starts on Monday 2026-03-02
	result, resolveError := menu.ResolveWeekStart("2026-W10")
	if resolveError != nil {
		t.Fatalf("unexpected error: %v", resolveError)
	}
	if result != "2026-03-02" {
		t.Errorf("ResolveWeekStart(2026-W10) = %q, want %q", result, "2026-03-02")
	}
}

func TestResolveWeekStart_InvalidFormat(t *testing.T) {
	_, resolveError := menu.ResolveWeekStart("2026-01-05")
	if resolveError == nil {
		t.Fatal("expected error for date format input, got nil")
	}
}

func TestResolveWeekStart_InvalidWeekNum(t *testing.T) {
	_, resolveError := menu.ResolveWeekStart("2026-W99")
	if resolveError == nil {
		t.Fatal("expected error for week 99, got nil")
	}
}

func TestResolveWeekStart_WeekZero(t *testing.T) {
	_, resolveError := menu.ResolveWeekStart("2026-W00")
	if resolveError == nil {
		t.Fatal("expected error for week 0, got nil")
	}
}

func TestResolveWeekStart_EmptyReturnsCurrentMonday(t *testing.T) {
	// Empty string should return current week's Monday without error.
	result, resolveError := menu.ResolveWeekStart("")
	if resolveError != nil {
		t.Fatalf("unexpected error: %v", resolveError)
	}
	if len(result) != 10 {
		t.Errorf("expected date in YYYY-MM-DD format, got %q", result)
	}
}