<?php

use App\Models\Cart;
use App\Models\Product;
use App\Models\User;
use Illuminate\Foundation\Testing\RefreshDatabase;

uses(RefreshDatabase::class);

test('guests can add to cart without being authenticated', function () {
    $product = Product::factory()->create();

    $this->postJson('/api/cart', ['product_id' => $product->id])
        ->assertSuccessful()
        ->assertJsonFragment(['product_id' => $product->id, 'quantity' => 1]);
});

test('adding a product creates a cart and returns cart items', function () {
    $product = Product::factory()->create();

    $response = $this->postJson('/api/cart', ['product_id' => $product->id]);

    $response->assertSuccessful()
        ->assertJsonFragment(['product_id' => $product->id, 'quantity' => 1]);

    expect(Cart::count())->toBe(1);
});

test('adding the same product increments quantity', function () {
    $product = Product::factory()->create();

    $this->postJson('/api/cart', ['product_id' => $product->id]);
    $response = $this->postJson('/api/cart', ['product_id' => $product->id]);

    $response->assertSuccessful()
        ->assertJsonFragment(['product_id' => $product->id, 'quantity' => 2]);
});

test('adding a non-existent product fails validation', function () {
    $this->postJson('/api/cart', ['product_id' => 9999])
        ->assertUnprocessable();
});

test('updating a cart item changes its quantity', function () {
    $product = Product::factory()->create();
    $cart = Cart::factory()->create(['user_id' => null]);
    $cart->products()->attach($product->id, ['quantity' => 1]);

    $response = $this->withSession(['cart_id' => $cart->id])
        ->patchJson("/api/cart/{$product->id}", ['quantity' => 5]);

    $response->assertSuccessful()
        ->assertJsonFragment(['product_id' => $product->id, 'quantity' => 5]);
});

test('removing a product detaches it from the cart', function () {
    $product = Product::factory()->create();
    $cart = Cart::factory()->create(['user_id' => null]);
    $cart->products()->attach($product->id, ['quantity' => 2]);

    $response = $this->withSession(['cart_id' => $cart->id])
        ->deleteJson("/api/cart/{$product->id}");

    $response->assertSuccessful()
        ->assertJsonMissing(['product_id' => $product->id]);

    expect($cart->fresh()->products)->toHaveCount(0);
});

test('a cart can optionally belong to a user', function () {
    $user = User::factory()->create();
    $cartWithUser = Cart::factory()->create(['user_id' => $user->id]);
    $cartGuest = Cart::factory()->create(['user_id' => null]);

    expect($cartWithUser->user)->toBeInstanceOf(User::class);
    expect($cartGuest->user)->toBeNull();
});