<?php

namespace Tests\Unit\Post\UseCases;

use App\Exceptions\BadRequestException;
use App\Exceptions\ForbiddenException;
use App\Post\CreatePostDto;
use App\Post\Post;
use App\Post\UseCases\SetFeaturedPost\SetFeaturedPost;
use App\Post\UseCases\SetFeaturedPost\SetFeaturedPostRequest;
use DateTimeImmutable;
use DateTimeZone;
use DomainException;
use Tests\Fakes\FakePostRepository;
use Tests\TestCase;

class SetFeaturedPostTest extends TestCase
{
    private FakePostRepository $postRepo;

    private SetFeaturedPost $useCase;

    private DateTimeImmutable $now;

    protected function setUp(): void
    {
        $this->now = new DateTimeImmutable(
            '2026-05-06T12:00:00',
            new DateTimeZone('UTC'),
        );
        $this->postRepo = new FakePostRepository;
        $this->useCase = new SetFeaturedPost($this->postRepo);
    }

    private function seedPost(): Post
    {
        return $this->postRepo->create(new CreatePostDto(
            userId: 1,
            title: 'A',
            body: 'B',
            createdAt: $this->now,
        ));
    }

    public function test_non_admin_throws_forbidden(): void
    {
        $post = $this->seedPost();
        $this->expectException(ForbiddenException::class);
        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $post->getId(),
            slot: 1,
            requesterIsAdmin: false,
        ));
    }

    public function test_invalid_slot_throws_bad_request(): void
    {
        $post = $this->seedPost();
        $this->expectException(BadRequestException::class);
        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $post->getId(),
            slot: 3,
            requesterIsAdmin: true,
        ));
    }

    public function test_zero_post_id_throws_bad_request(): void
    {
        $this->expectException(BadRequestException::class);
        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: 0,
            slot: 1,
            requesterIsAdmin: true,
        ));
    }

    public function test_unknown_post_throws_domain_exception(): void
    {
        $this->expectException(DomainException::class);
        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: 999,
            slot: 1,
            requesterIsAdmin: true,
        ));
    }

    public function test_admin_assigns_slot(): void
    {
        $post = $this->seedPost();

        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $post->getId(),
            slot: 1,
            requesterIsAdmin: true,
        ));

        $reloaded = $this->postRepo->find($post->getId());
        $this->assertSame(1, $reloaded->getFeatureSlot());
    }

    public function test_assigning_same_slot_evicts_previous_post(): void
    {
        $first = $this->seedPost();
        $second = $this->seedPost();

        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $first->getId(),
            slot: 1,
            requesterIsAdmin: true,
        ));
        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $second->getId(),
            slot: 1,
            requesterIsAdmin: true,
        ));

        $this->assertNull(
            $this->postRepo->find($first->getId())->getFeatureSlot(),
        );
        $this->assertSame(
            1,
            $this->postRepo->find($second->getId())->getFeatureSlot(),
        );
    }

    public function test_two_posts_can_occupy_separate_slots(): void
    {
        $first = $this->seedPost();
        $second = $this->seedPost();

        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $first->getId(),
            slot: 1,
            requesterIsAdmin: true,
        ));
        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $second->getId(),
            slot: 2,
            requesterIsAdmin: true,
        ));

        $featured = $this->postRepo->findFeatured();
        $this->assertCount(2, $featured);
        $this->assertSame(1, $featured[0]->getFeatureSlot());
        $this->assertSame(2, $featured[1]->getFeatureSlot());
    }

    public function test_moving_post_to_other_slot_clears_old_slot(): void
    {
        $post = $this->seedPost();

        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $post->getId(),
            slot: 1,
            requesterIsAdmin: true,
        ));
        $this->useCase->execute(new SetFeaturedPostRequest(
            postId: $post->getId(),
            slot: 2,
            requesterIsAdmin: true,
        ));

        $this->assertNull(
            $this->postRepo->findByFeatureSlot(1),
        );
        $this->assertSame(
            $post->getId(),
            $this->postRepo->findByFeatureSlot(2)->getId(),
        );
    }
}