<?php

declare(strict_types=1);

namespace Magdev\WpPrometheus\Tests\Unit\Metrics;

use Magdev\WpPrometheus\Metrics\CustomMetricBuilder;
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(CustomMetricBuilder::class)]
class CustomMetricBuilderTest extends TestCase
{
    private CustomMetricBuilder $builder;

    protected function setUp(): void
    {
        parent::setUp();
        $this->builder = new CustomMetricBuilder();
    }

    // ── validate_name() ──────────────────────────────────────────────

    #[Test]
    #[DataProvider('validMetricNamesProvider')]
    public function validate_name_accepts_valid_names(string $name): void
    {
        $this->assertTrue($this->builder->validate_name($name));
    }

    public static function validMetricNamesProvider(): array
    {
        return [
            'simple'                  => ['my_metric'],
            'with_colon'              => ['my:metric'],
            'starts_with_underscore'  => ['_private_metric'],
            'starts_with_colon'       => [':special_metric'],
            'uppercase'               => ['MY_METRIC'],
            'mixed_case'              => ['myMetric123'],
            'single_letter'           => ['m'],
        ];
    }

    #[Test]
    #[DataProvider('invalidMetricNamesProvider')]
    public function validate_name_rejects_invalid_names(string $name): void
    {
        $this->assertFalse($this->builder->validate_name($name));
    }

    public static function invalidMetricNamesProvider(): array
    {
        return [
            'starts_with_digit' => ['0metric'],
            'contains_dash'     => ['my-metric'],
            'contains_space'    => ['my metric'],
            'contains_dot'      => ['my.metric'],
            'empty_string'      => [''],
            'special_chars'     => ['metric@name'],
        ];
    }

    // ── validate_label_name() ────────────────────────────────────────

    #[Test]
    #[DataProvider('validLabelNamesProvider')]
    public function validate_label_name_accepts_valid_names(string $name): void
    {
        $this->assertTrue($this->builder->validate_label_name($name));
    }

    public static function validLabelNamesProvider(): array
    {
        return [
            'simple'                 => ['status'],
            'with_underscore'        => ['http_method'],
            'starts_with_underscore' => ['_internal'],
            'uppercase'              => ['METHOD'],
            'alphanumeric'           => ['label1'],
        ];
    }

    #[Test]
    #[DataProvider('invalidLabelNamesProvider')]
    public function validate_label_name_rejects_invalid_names(string $name): void
    {
        $this->assertFalse($this->builder->validate_label_name($name));
    }

    public static function invalidLabelNamesProvider(): array
    {
        return [
            'double_underscore_prefix' => ['__reserved'],
            'starts_with_digit'        => ['1label'],
            'contains_colon'           => ['label:name'],
            'contains_dash'            => ['label-name'],
            'empty_string'             => [''],
            'contains_space'           => ['label name'],
        ];
    }

    // ── validate() ───────────────────────────────────────────────────

    #[Test]
    public function validate_returns_empty_for_valid_metric(): void
    {
        $errors = $this->builder->validate($this->validMetric());
        $this->assertEmpty($errors);
    }

    #[Test]
    public function validate_requires_name(): void
    {
        $metric = $this->validMetric();
        $metric['name'] = '';

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('name is required', $errors[0]);
    }

    #[Test]
    public function validate_rejects_invalid_metric_name(): void
    {
        $metric = $this->validMetric();
        $metric['name'] = '0invalid';

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('must start with', $errors[0]);
    }

    #[Test]
    #[DataProvider('reservedPrefixProvider')]
    public function validate_rejects_reserved_prefix(string $prefix): void
    {
        $metric = $this->validMetric();
        $metric['name'] = $prefix . 'test';

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('reserved prefix', implode(' ', $errors));
    }

    public static function reservedPrefixProvider(): array
    {
        return [
            'wordpress_' => ['wordpress_'],
            'go_'        => ['go_'],
            'process_'   => ['process_'],
            'promhttp_'  => ['promhttp_'],
        ];
    }

    #[Test]
    public function validate_detects_duplicate_name(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [
            'existing-id' => [
                'id'   => 'existing-id',
                'name' => 'custom_existing',
                'help' => 'test',
            ],
        ];

        $metric = $this->validMetric();
        $metric['name'] = 'custom_existing';

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('already exists', implode(' ', $errors));
    }

    #[Test]
    public function validate_allows_same_name_when_editing(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [
            'my-id' => [
                'id'   => 'my-id',
                'name' => 'custom_existing',
                'help' => 'test',
            ],
        ];

        $metric = $this->validMetric();
        $metric['id'] = 'my-id';
        $metric['name'] = 'custom_existing';

        $errors = $this->builder->validate($metric);
        $this->assertEmpty($errors);
    }

    #[Test]
    public function validate_requires_help_text(): void
    {
        $metric = $this->validMetric();
        $metric['help'] = '';

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('Help text is required', $errors[0]);
    }

    #[Test]
    public function validate_requires_valid_type(): void
    {
        $metric = $this->validMetric();
        $metric['type'] = 'counter';

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('Invalid metric type', implode(' ', $errors));
    }

    #[Test]
    public function validate_rejects_too_many_labels(): void
    {
        $metric = $this->validMetric();
        $metric['labels'] = ['a', 'b', 'c', 'd', 'e', 'f'];

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('Maximum', implode(' ', $errors));
    }

    #[Test]
    public function validate_rejects_invalid_label_names_in_array(): void
    {
        $metric = $this->validMetric();
        $metric['labels'] = ['valid', '__reserved'];

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('Invalid label name', implode(' ', $errors));
    }

    #[Test]
    public function validate_rejects_non_array_labels(): void
    {
        $metric = $this->validMetric();
        $metric['labels'] = 'not_an_array';

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('Labels must be an array', implode(' ', $errors));
    }

    #[Test]
    public function validate_requires_valid_value_type(): void
    {
        $metric = $this->validMetric();
        $metric['value_type'] = 'invalid';

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('Invalid value type', implode(' ', $errors));
    }

    #[Test]
    public function validate_requires_option_name_for_option_type(): void
    {
        $metric = $this->validMetric();
        $metric['value_type'] = 'option';
        $metric['value_config'] = [];

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('Option name is required', implode(' ', $errors));
    }

    #[Test]
    public function validate_accepts_option_type_with_option_name(): void
    {
        $metric = $this->validMetric();
        $metric['value_type'] = 'option';
        $metric['value_config'] = ['option_name' => 'my_wp_option'];

        $errors = $this->builder->validate($metric);
        $this->assertEmpty($errors);
    }

    #[Test]
    public function validate_rejects_too_many_label_values(): void
    {
        $metric = $this->validMetric();
        $metric['labels'] = ['status'];
        $metric['label_values'] = array_fill(0, 51, ['active', 1.0]);

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('Maximum', implode(' ', $errors));
    }

    #[Test]
    public function validate_checks_label_value_row_count(): void
    {
        $metric = $this->validMetric();
        $metric['labels'] = ['status', 'type'];
        // Row has 2 items but needs 3 (2 labels + 1 value).
        $metric['label_values'] = [['active', 1.0]];

        $errors = $this->builder->validate($metric);
        $this->assertNotEmpty($errors);
        $this->assertStringContainsString('values for all labels', implode(' ', $errors));
    }

    // ── get_all() / get() ────────────────────────────────────────────

    #[Test]
    public function get_all_returns_empty_array_by_default(): void
    {
        $this->assertSame([], $this->builder->get_all());
    }

    #[Test]
    public function get_all_returns_stored_metrics(): void
    {
        $metrics = ['id1' => ['name' => 'test_metric']];
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = $metrics;

        $this->assertSame($metrics, $this->builder->get_all());
    }

    #[Test]
    public function get_all_returns_empty_when_option_is_not_array(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = 'not_an_array';
        $this->assertSame([], $this->builder->get_all());
    }

    #[Test]
    public function get_returns_metric_by_id(): void
    {
        $metric = ['id' => 'my-id', 'name' => 'test_metric', 'help' => 'Test'];
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = ['my-id' => $metric];

        $this->assertSame($metric, $this->builder->get('my-id'));
    }

    #[Test]
    public function get_returns_null_for_nonexistent_id(): void
    {
        $this->assertNull($this->builder->get('nonexistent'));
    }

    // ── save() ───────────────────────────────────────────────────────

    #[Test]
    public function save_creates_new_metric_and_returns_id(): void
    {
        $metric = $this->validMetric();
        $id = $this->builder->save($metric);

        $this->assertNotEmpty($id);
        $this->assertGreaterThanOrEqual(1, GlobalFunctionState::getCallCount('update_option'));

        $saved = GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME];
        $this->assertArrayHasKey($id, $saved);
        $this->assertSame('custom_test_metric', $saved[$id]['name']);
    }

    #[Test]
    public function save_throws_on_validation_failure(): void
    {
        $metric = [
            'name'       => '',
            'help'       => '',
            'type'       => 'gauge',
            'value_type' => 'static',
        ];

        $this->expectException(\InvalidArgumentException::class);
        $this->builder->save($metric);
    }

    #[Test]
    public function save_updates_existing_metric(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [
            'existing-id' => [
                'id'         => 'existing-id',
                'name'       => 'custom_test_metric',
                'help'       => 'Original help',
                'type'       => 'gauge',
                'value_type' => 'static',
                'labels'     => [],
                'created_at' => 1000000,
            ],
        ];

        $metric = $this->validMetric();
        $metric['id'] = 'existing-id';
        $metric['help'] = 'Updated help';

        $id = $this->builder->save($metric);

        $this->assertSame('existing-id', $id);
        $saved = GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME];
        $this->assertSame('Updated help', $saved['existing-id']['help']);
    }

    #[Test]
    public function save_sanitizes_metric_data(): void
    {
        $metric = $this->validMetric();
        $metric['labels'] = ['valid_label'];
        $metric['label_values'] = [['active', 42.5]];

        $id = $this->builder->save($metric);
        $saved = GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME][$id];

        $this->assertSame(['valid_label'], $saved['labels']);
        $this->assertSame([['active', 42.5]], $saved['label_values']);
        $this->assertIsBool($saved['enabled']);
    }

    // ── delete() ─────────────────────────────────────────────────────

    #[Test]
    public function delete_removes_metric(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [
            'my-id' => ['id' => 'my-id', 'name' => 'custom_metric'],
        ];

        $this->assertTrue($this->builder->delete('my-id'));
        $this->assertArrayNotHasKey(
            'my-id',
            GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME]
        );
    }

    #[Test]
    public function delete_returns_false_for_nonexistent(): void
    {
        $this->assertFalse($this->builder->delete('nonexistent'));
    }

    // ── export() ─────────────────────────────────────────────────────

    #[Test]
    public function export_returns_valid_json_with_metadata(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [
            'id1' => ['name' => 'metric1', 'help' => 'Test 1'],
        ];

        $json = $this->builder->export();
        $data = json_decode($json, true);

        $this->assertIsArray($data);
        $this->assertSame(CustomMetricBuilder::EXPORT_VERSION, $data['version']);
        $this->assertSame(WP_PROMETHEUS_VERSION, $data['plugin_version']);
        $this->assertArrayHasKey('exported_at', $data);
        $this->assertCount(1, $data['metrics']);
    }

    #[Test]
    public function export_does_not_include_site_url(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [];

        $json = $this->builder->export();
        $data = json_decode($json, true);

        $this->assertArrayNotHasKey('site_url', $data);
    }

    // ── import() ─────────────────────────────────────────────────────

    #[Test]
    public function import_rejects_oversized_json(): void
    {
        $json = str_repeat('x', CustomMetricBuilder::MAX_IMPORT_SIZE + 1);

        $this->expectException(\InvalidArgumentException::class);
        $this->expectExceptionMessage('exceeds maximum size');
        $this->builder->import($json);
    }

    #[Test]
    public function import_rejects_invalid_json(): void
    {
        $this->expectException(\InvalidArgumentException::class);
        $this->expectExceptionMessage('Invalid JSON');
        $this->builder->import('{invalid json');
    }

    #[Test]
    public function import_rejects_missing_metrics_key(): void
    {
        $this->expectException(\InvalidArgumentException::class);
        $this->expectExceptionMessage('No metrics found');
        $this->builder->import('{"version":"1.0.0"}');
    }

    #[Test]
    public function import_skip_mode_skips_duplicates(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [
            'existing' => [
                'id'   => 'existing',
                'name' => 'custom_existing_metric',
                'help' => 'Test',
            ],
        ];

        $json = json_encode([
            'version' => '1.0.0',
            'metrics' => [
                [
                    'name'       => 'custom_existing_metric',
                    'help'       => 'Test',
                    'type'       => 'gauge',
                    'value_type' => 'static',
                ],
            ],
        ]);

        $result = $this->builder->import($json, 'skip');
        $this->assertSame(1, $result['skipped']);
        $this->assertSame(0, $result['imported']);
    }

    #[Test]
    public function import_rename_mode_renames_duplicates(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [
            'existing' => [
                'id'         => 'existing',
                'name'       => 'custom_existing_metric',
                'help'       => 'Existing',
                'type'       => 'gauge',
                'value_type' => 'static',
                'labels'     => [],
            ],
        ];

        $json = json_encode([
            'version' => '1.0.0',
            'metrics' => [
                [
                    'name'       => 'custom_existing_metric',
                    'help'       => 'Imported',
                    'type'       => 'gauge',
                    'value_type' => 'static',
                    'labels'     => [],
                ],
            ],
        ]);

        $result = $this->builder->import($json, 'rename');
        $this->assertSame(1, $result['imported']);

        $all = $this->builder->get_all();
        $names = array_column($all, 'name');
        $this->assertContains('custom_existing_metric', $names);
        $this->assertContains('custom_existing_metric_imported_1', $names);
    }

    #[Test]
    public function import_invalid_mode_defaults_to_skip(): void
    {
        GlobalFunctionState::$options[CustomMetricBuilder::OPTION_NAME] = [
            'existing' => [
                'id'   => 'existing',
                'name' => 'custom_existing_metric',
                'help' => 'Test',
            ],
        ];

        $json = json_encode([
            'version' => '1.0.0',
            'metrics' => [
                [
                    'name'       => 'custom_existing_metric',
                    'help'       => 'Test',
                    'type'       => 'gauge',
                    'value_type' => 'static',
                ],
            ],
        ]);

        $result = $this->builder->import($json, 'invalid_mode');
        $this->assertSame(1, $result['skipped']);
    }

    #[Test]
    public function import_counts_metrics_without_name_as_errors(): void
    {
        $json = json_encode([
            'version' => '1.0.0',
            'metrics' => [['help' => 'No name']],
        ]);

        $result = $this->builder->import($json);
        $this->assertSame(1, $result['errors']);
        $this->assertSame(0, $result['imported']);
    }

    #[Test]
    public function import_successfully_imports_new_metric(): void
    {
        $json = json_encode([
            'version' => '1.0.0',
            'metrics' => [
                [
                    'name'       => 'custom_new_metric',
                    'help'       => 'A new metric',
                    'type'       => 'gauge',
                    'value_type' => 'static',
                    'labels'     => [],
                ],
            ],
        ]);

        $result = $this->builder->import($json);
        $this->assertSame(1, $result['imported']);
        $this->assertSame(0, $result['skipped']);
        $this->assertSame(0, $result['errors']);

        $all = $this->builder->get_all();
        $names = array_column($all, 'name');
        $this->assertContains('custom_new_metric', $names);
    }

    // ── Constants ────────────────────────────────────────────────────

    #[Test]
    public function constants_are_defined(): void
    {
        $this->assertSame('wp_prometheus_custom_metrics', CustomMetricBuilder::OPTION_NAME);
        $this->assertSame(5, CustomMetricBuilder::MAX_LABELS);
        $this->assertSame(50, CustomMetricBuilder::MAX_LABEL_VALUES);
        $this->assertSame(1048576, CustomMetricBuilder::MAX_IMPORT_SIZE);
    }

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

    private function validMetric(): array
    {
        return [
            'name'         => 'custom_test_metric',
            'help'         => 'A test metric',
            'type'         => 'gauge',
            'value_type'   => 'static',
            'labels'       => [],
            'label_values' => [],
            'enabled'      => true,
        ];
    }
}