<?php

declare(strict_types=1);

namespace Magdev\WpPrometheus\Tests\Unit\Metrics;

use Magdev\WpPrometheus\Metrics\RuntimeCollector;
use Magdev\WpPrometheus\Tests\Helpers\GlobalFunctionState;
use Magdev\WpPrometheus\Tests\Unit\TestCase;
use PHPUnit\Framework\Attributes\CoversClass;
use PHPUnit\Framework\Attributes\DataProvider;
use PHPUnit\Framework\Attributes\Test;

#[CoversClass(RuntimeCollector::class)]
class RuntimeCollectorTest extends TestCase
{
    private RuntimeCollector $collector;
    private array $originalServer = [];

    protected function setUp(): void
    {
        parent::setUp();
        $this->originalServer = $_SERVER;
        $this->collector = $this->createInstance();
    }

    protected function tearDown(): void
    {
        $_SERVER = $this->originalServer;
        $this->resetSingleton();
        parent::tearDown();
    }

    // ── Singleton ────────────────────────────────────────────────────

    #[Test]
    public function get_instance_returns_singleton(): void
    {
        $instance1 = RuntimeCollector::get_instance();
        $instance2 = RuntimeCollector::get_instance();

        $this->assertSame($instance1, $instance2);
    }

    #[Test]
    public function get_instance_returns_runtime_collector(): void
    {
        $instance = RuntimeCollector::get_instance();
        $this->assertInstanceOf(RuntimeCollector::class, $instance);
    }

    // ── get_stored_metrics() ─────────────────────────────────────────

    #[Test]
    public function get_stored_metrics_returns_default_when_empty(): void
    {
        $metrics = $this->collector->get_stored_metrics();
        $this->assertSame([], $metrics);
    }

    #[Test]
    public function get_stored_metrics_returns_stored_data(): void
    {
        $stored = [
            'counters'   => ['key' => ['name' => 'test', 'value' => 5]],
            'histograms' => [],
            'last_reset' => 1000000,
        ];
        GlobalFunctionState::$options['wp_prometheus_runtime_metrics'] = $stored;

        $metrics = $this->collector->get_stored_metrics();
        $this->assertSame($stored, $metrics);
    }

    #[Test]
    public function get_stored_metrics_returns_default_for_non_array(): void
    {
        GlobalFunctionState::$options['wp_prometheus_runtime_metrics'] = 'invalid';

        $metrics = $this->collector->get_stored_metrics();
        $this->assertArrayHasKey('counters', $metrics);
        $this->assertArrayHasKey('histograms', $metrics);
        $this->assertArrayHasKey('last_reset', $metrics);
    }

    // ── reset_metrics() ──────────────────────────────────────────────

    #[Test]
    public function reset_metrics_deletes_option(): void
    {
        GlobalFunctionState::$options['wp_prometheus_runtime_metrics'] = ['data'];

        RuntimeCollector::reset_metrics();

        $this->assertSame(1, GlobalFunctionState::getCallCount('delete_option'));
        $this->assertArrayNotHasKey(
            'wp_prometheus_runtime_metrics',
            GlobalFunctionState::$options
        );
    }

    // ── get_duration_buckets() ───────────────────────────────────────

    #[Test]
    public function get_duration_buckets_returns_expected_values(): void
    {
        $buckets = RuntimeCollector::get_duration_buckets();

        $this->assertIsArray($buckets);
        $this->assertCount(11, $buckets);
        $this->assertSame(0.005, $buckets[0]);
        $this->assertEquals(10, end($buckets));
    }

    #[Test]
    public function duration_buckets_are_in_ascending_order(): void
    {
        $buckets = RuntimeCollector::get_duration_buckets();
        $sorted = $buckets;
        sort($sorted);

        $this->assertSame($sorted, $buckets);
    }

    // ── get_normalized_endpoint() (private, via reflection) ──────────

    #[Test]
    public function normalized_endpoint_returns_admin_when_is_admin(): void
    {
        $_SERVER['REQUEST_URI'] = '/wp-admin/options-general.php';
        GlobalFunctionState::$options['__is_admin'] = true;

        $result = $this->callPrivateMethod('get_normalized_endpoint');
        $this->assertSame('admin', $result);
    }

    #[Test]
    public function normalized_endpoint_returns_ajax_when_doing_ajax(): void
    {
        $_SERVER['REQUEST_URI'] = '/wp-admin/admin-ajax.php';
        GlobalFunctionState::$options['__wp_doing_ajax'] = true;

        $result = $this->callPrivateMethod('get_normalized_endpoint');
        $this->assertSame('ajax', $result);
    }

    #[Test]
    public function normalized_endpoint_returns_cron_when_doing_cron(): void
    {
        // Use a generic URI (not /wp-cron.php) to ensure function is checked, not URL pattern.
        $_SERVER['REQUEST_URI'] = '/some-page';
        GlobalFunctionState::$options['__wp_doing_cron'] = true;

        $result = $this->callPrivateMethod('get_normalized_endpoint');
        $this->assertSame('cron', $result);
    }

    #[Test]
    #[DataProvider('urlEndpointProvider')]
    public function normalized_endpoint_from_url_pattern(string $uri, string $expected): void
    {
        $_SERVER['REQUEST_URI'] = $uri;

        $result = $this->callPrivateMethod('get_normalized_endpoint');
        $this->assertSame($expected, $result);
    }

    public static function urlEndpointProvider(): array
    {
        return [
            'rest api'         => ['/wp-json/wp/v2/posts', 'rest-api'],
            'login page'       => ['/wp-login.php', 'login'],
            'login with query' => ['/wp-login.php?action=login', 'login'],
            'wp-cron'          => ['/wp-cron.php', 'cron'],
            'feed root'        => ['/feed/', 'feed'],
            'feed trailing'    => ['/category/news/feed', 'feed'],
            'feed with slash'  => ['/feed', 'feed'],
            'homepage'         => ['/', 'frontend'],
            'page'             => ['/about-us', 'frontend'],
            'post'             => ['/2024/01/hello-world', 'frontend'],
        ];
    }

    // ── is_metrics_request() (private, via reflection) ───────────────

    #[Test]
    public function is_metrics_request_true_for_metrics_uri(): void
    {
        $_SERVER['REQUEST_URI'] = '/metrics';
        $this->assertTrue($this->callPrivateMethod('is_metrics_request'));
    }

    #[Test]
    public function is_metrics_request_true_with_trailing_slash(): void
    {
        $_SERVER['REQUEST_URI'] = '/metrics/';
        $this->assertTrue($this->callPrivateMethod('is_metrics_request'));
    }

    #[Test]
    public function is_metrics_request_false_for_other_uri(): void
    {
        $_SERVER['REQUEST_URI'] = '/some-page';
        $this->assertFalse($this->callPrivateMethod('is_metrics_request'));
    }

    #[Test]
    public function is_metrics_request_false_when_no_uri(): void
    {
        unset($_SERVER['REQUEST_URI']);
        $this->assertFalse($this->callPrivateMethod('is_metrics_request'));
    }

    // ── Helpers ──────────────────────────────────────────────────────

    private function createInstance(): RuntimeCollector
    {
        $reflection = new \ReflectionClass(RuntimeCollector::class);
        return $reflection->newInstanceWithoutConstructor();
    }

    private function resetSingleton(): void
    {
        $reflection = new \ReflectionClass(RuntimeCollector::class);
        $property = $reflection->getProperty('instance');
        $property->setValue(null, null);
    }

    private function callPrivateMethod(string $method, array $args = []): mixed
    {
        $reflection = new \ReflectionMethod($this->collector, $method);
        return $reflection->invoke($this->collector, ...$args);
    }
}