package repositories

import (
	"errors"
	"testing"

	"nearle/models"
)

/*
Variants are a relationship between two products, and every test here is about
a shape that would break the ordering screen rather than merely store bad data.

The bug this replaces: `productvariants` had `productid` and `variantproductid`
all along, neither was mapped, so a variant could never be attached to a
product. The app fell back to `products.variants` — a group number that is 0 on
every product — and asked for "everything in group 0", which matched the
tenant's whole ungrouped catalogue. Six unrelated products came back as each
other's sizes and the order could not be placed.
*/

func TestAVariantWithoutAParentIsRefused(t *testing.T) {
	r := &productRepository{}
	_, err := r.AddProductVariant(models.Productvariant{Tenantid: 1, Variantproductid: 7})
	if !errors.Is(err, ErrVariantParentMissing) {
		t.Fatalf("expected a missing-parent refusal, got %v", err)
	}
}

func TestAVariantThatOrdersNothingIsRefused(t *testing.T) {
	// Without `variantproductid` there is no product to put in the basket, so
	// the size would be pickable and unbuyable.
	r := &productRepository{}
	_, err := r.AddProductVariant(models.Productvariant{Tenantid: 1, Productid: 7})
	if !errors.Is(err, ErrVariantProductMissing) {
		t.Fatalf("expected a missing-product refusal, got %v", err)
	}
}

func TestAProductCannotBeItsOwnVariant(t *testing.T) {
	// The picker would offer the thing already tapped, and choosing it loops.
	r := &productRepository{}
	_, err := r.AddProductVariant(models.Productvariant{Tenantid: 1, Productid: 7, Variantproductid: 7})
	if !errors.Is(err, ErrVariantSelfReference) {
		t.Fatalf("expected a self-reference refusal, got %v", err)
	}
}

func TestNoProductsMeansNoQueryAndNoVariants(t *testing.T) {
	// Guards the N+1: the batch loader must not run a query for an empty page.
	// `r.db` is nil here, so reaching the database at all would panic.
	r := &productRepository{}
	got, err := r.VariantsForProducts(1, 1, nil)
	if err != nil {
		t.Fatalf("VariantsForProducts: %v", err)
	}
	if len(got) != 0 {
		t.Errorf("expected no variants, got %d", len(got))
	}
}

func TestAnUnknownTenantAsksTheDatabaseNothing(t *testing.T) {
	r := &productRepository{}
	if _, err := r.VariantsForProducts(0, 1, []int{7, 8}); err != nil {
		t.Fatalf("VariantsForProducts: %v", err)
	}
}