<?php

declare(strict_types=1);

namespace Tests\Feature\FormBuilder\ConditionalLogic;

use App\Exceptions\FormBuilder\CyclicDependencyException;
use App\Models\FormBuilder\FormField;
use App\Models\FormBuilder\FormSchema;
use App\Models\Organisation;
use App\Services\FormBuilder\FormFieldConditionalLogicService;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Tests\TestCase;

/**
 * Cycle detection (ARCH §8). Migrated from
 * FormFieldService::assertNoConditionalCycle (pre-WS-5c) to
 * FormFieldConditionalLogicService::assertNoCycles. Contract preserved;
 * implementation now reads the relational tree instead of walking JSON.
 */
final class ConditionalLogicCycleDetectionTest extends TestCase
{
    use RefreshDatabase;

    public function test_two_node_cycle_rejected(): void
    {
        [$schema, $fieldA, $fieldB] = $this->seedSchemaWithTwoFields();
        $service = app(FormFieldConditionalLogicService::class);

        // A depends on B.
        $service->replaceLogic($fieldA, [
            'operator' => 'all',
            'children' => [
                ['field_slug' => $fieldB->slug, 'operator' => 'equals', 'value' => 'y'],
            ],
        ]);

        // Proposing B depends on A would close the A → B → A cycle.
        $this->expectException(CyclicDependencyException::class);
        $service->assertNoCycles($fieldB, [
            'operator' => 'all',
            'children' => [
                ['field_slug' => $fieldA->slug, 'operator' => 'equals', 'value' => 'x'],
            ],
        ]);
    }

    public function test_three_node_cycle_rejected(): void
    {
        [$schema, $fieldA, $fieldB, $fieldC] = $this->seedSchemaWithThreeFields();
        $service = app(FormFieldConditionalLogicService::class);

        // A → B, B → C
        $service->replaceLogic($fieldA, [
            'operator' => 'all',
            'children' => [['field_slug' => $fieldB->slug, 'operator' => 'equals', 'value' => 'y']],
        ]);
        $service->replaceLogic($fieldB, [
            'operator' => 'all',
            'children' => [['field_slug' => $fieldC->slug, 'operator' => 'equals', 'value' => 'y']],
        ]);

        // Proposing C → A closes A → B → C → A.
        $this->expectException(CyclicDependencyException::class);
        $service->assertNoCycles($fieldC, [
            'operator' => 'all',
            'children' => [['field_slug' => $fieldA->slug, 'operator' => 'equals', 'value' => 'x']],
        ]);
    }

    public function test_diamond_is_accepted_no_cycle(): void
    {
        [$schema, $fieldA, $fieldB, $fieldC] = $this->seedSchemaWithThreeFields();
        $service = app(FormFieldConditionalLogicService::class);

        // A → B and C → B (two fields depend on the same field, no cycle).
        $service->replaceLogic($fieldA, [
            'operator' => 'all',
            'children' => [['field_slug' => $fieldB->slug, 'operator' => 'equals', 'value' => 'y']],
        ]);

        $service->assertNoCycles($fieldC, [
            'operator' => 'all',
            'children' => [['field_slug' => $fieldB->slug, 'operator' => 'equals', 'value' => 'y']],
        ]);

        $this->expectNotToPerformAssertions();
    }

    public function test_self_reference_rejected(): void
    {
        [$schema, $fieldA] = $this->seedSchemaWithTwoFields();
        $service = app(FormFieldConditionalLogicService::class);

        $this->expectException(CyclicDependencyException::class);
        $service->assertNoCycles($fieldA, [
            'operator' => 'all',
            'children' => [['field_slug' => $fieldA->slug, 'operator' => 'equals', 'value' => 'x']],
        ]);
    }

    /** @return array{0:FormSchema,1:FormField,2:FormField} */
    private function seedSchemaWithTwoFields(): array
    {
        $org = Organisation::factory()->create();
        $schema = FormSchema::factory()->create(['organisation_id' => $org->id]);
        $fieldA = FormField::factory()->create(['form_schema_id' => $schema->id, 'slug' => 'a']);
        $fieldB = FormField::factory()->create(['form_schema_id' => $schema->id, 'slug' => 'b']);

        return [$schema, $fieldA, $fieldB];
    }

    /** @return array{0:FormSchema,1:FormField,2:FormField,3:FormField} */
    private function seedSchemaWithThreeFields(): array
    {
        $org = Organisation::factory()->create();
        $schema = FormSchema::factory()->create(['organisation_id' => $org->id]);
        $fieldA = FormField::factory()->create(['form_schema_id' => $schema->id, 'slug' => 'a']);
        $fieldB = FormField::factory()->create(['form_schema_id' => $schema->id, 'slug' => 'b']);
        $fieldC = FormField::factory()->create(['form_schema_id' => $schema->id, 'slug' => 'c']);

        return [$schema, $fieldA, $fieldB, $fieldC];
    }
}