<?php

declare(strict_types=1);

namespace Weerscherm\Tests;

use PHPUnit\Framework\TestCase;
use Weerscherm\BuienradarClient;
use Weerscherm\RadarService;
use Weerscherm\UpstreamException;

final class RadarServiceTest extends TestCase
{
    private const NOW = 1_800_000_000;
    private const GIF = "GIF89a\x01\x00\x01\x00vers";
    private const OLD_GIF = "GIF89a\x01\x00\x01\x00oud";

    private string $dir;
    private string $file;

    protected function setUp(): void
    {
        $this->dir = sys_get_temp_dir() . '/weerscherm-radar-' . uniqid();
        $this->file = $this->dir . '/radar.gif';
    }

    protected function tearDown(): void
    {
        array_map('unlink', glob($this->dir . '/*') ?: []);
        @rmdir($this->dir);
    }

    private function service(FakeHttp $http, int $ttl = 240): RadarService
    {
        return new RadarService(
            new BuienradarClient($http),
            $this->file,
            $ttl,
            static fn(): int => self::NOW,
        );
    }

    /** Legt een cachebestand neer met een gegeven leeftijd in seconden. */
    private function seedCache(string $bytes, int $ageSeconds): void
    {
        mkdir($this->dir, 0700, true);
        file_put_contents($this->file, $bytes);
        touch($this->file, self::NOW - $ageSeconds);
    }

    public function testFetchesAndCachesWhenNothingIsStored(): void
    {
        $http = (new FakeHttp())->queue(200, self::GIF);

        $result = $this->service($http)->image();

        self::assertSame(['bytes' => self::GIF, 'stale' => false, 'age' => 0], $result);
        self::assertStringEqualsFile($this->file, self::GIF);
        self::assertSame([], glob($this->dir . '/*.tmp.*') ?: [], 'geen tijdelijke bestanden achtergelaten');
    }

    public function testFreshCacheIsServedWithoutFetching(): void
    {
        $this->seedCache(self::OLD_GIF, 100);
        $http = new FakeHttp(); // geen response gepland: een fetch zou de test laten falen

        $result = $this->service($http)->image();

        self::assertSame(self::OLD_GIF, $result['bytes']);
        self::assertFalse($result['stale']);
        self::assertSame(100, $result['age']);
        self::assertSame([], $http->requests);
    }

    public function testExpiredCacheIsRefetched(): void
    {
        $this->seedCache(self::OLD_GIF, 300);
        $http = (new FakeHttp())->queue(200, self::GIF);

        $result = $this->service($http)->image();

        self::assertSame(self::GIF, $result['bytes']);
        self::assertFalse($result['stale']);
        self::assertCount(1, $http->requests);
        self::assertStringEqualsFile($this->file, self::GIF);
    }

    public function testUpstreamFailureFallsBackToTheCachedImageMarkedStale(): void
    {
        $this->seedCache(self::OLD_GIF, 3600);
        $http = (new FakeHttp())->queue(500, '');

        $result = $this->service($http)->image();

        self::assertSame(self::OLD_GIF, $result['bytes'], 'ongeacht de leeftijd: liever een oud beeld dan niets');
        self::assertTrue($result['stale']);
        self::assertSame(3600, $result['age']);
    }

    public function testUpstreamFailureWithoutCacheThrows(): void
    {
        $http = (new FakeHttp())->queue(500, '');

        $this->expectException(UpstreamException::class);
        $this->service($http)->image();
    }

    public function testEmptyCacheFileIsIgnored(): void
    {
        $this->seedCache('', 10);
        $http = (new FakeHttp())->queue(200, self::GIF);

        $result = $this->service($http)->image();

        self::assertSame(self::GIF, $result['bytes']);
        self::assertCount(1, $http->requests, 'een leeg cachebestand telt niet als geldige cache');
    }
}