<?php

namespace Tests\App\Services;

use App\Services\FeeCalculationService;
use CodeIgniter\Test\CIUnitTestCase;

class FeeCalculationServiceRefundAdapterHarness extends FeeCalculationService
{
    public array $previewedEnrollmentIds = [];

    public function __construct(private array $latestByEnrollment, private array $previewByEnrollment)
    {
    }

    protected function latestWithdrawalCalculation(int $enrollmentId): ?array
    {
        return $this->latestByEnrollment[$enrollmentId] ?? null;
    }

    protected function previewWithdrawalCalculation(int $enrollmentId): array
    {
        $this->previewedEnrollmentIds[] = $enrollmentId;
        return $this->previewByEnrollment[$enrollmentId] ?? ['new_refund_request_cents' => 0];
    }
}

class FeeCalculationServiceTest extends CIUnitTestCase
{
    public function testRefundAdapterUsesWithdrawalFinancialPreviewAmounts(): void
    {
        $service = new FeeCalculationServiceRefundAdapterHarness(
            latestByEnrollment: [
                10 => ['status' => 'preview', 'new_refund_request_cents' => 12345],
                11 => ['status' => 'superseded', 'new_refund_request_cents' => 99999],
            ],
            previewByEnrollment: [
                11 => ['status' => 'preview', 'new_refund_request_cents' => 500],
            ]
        );

        $refund = $service->calculateRefund([
            ['id' => 10, 'parent_id' => 8, 'enrollment_status' => 'withdraw under review'],
            ['id' => 11, 'parent_id' => 8, 'enrollment_status' => 'refund pending'],
            ['id' => 12, 'parent_id' => 8, 'enrollment_status' => 'enrolled'],
            ['id' => 13, 'parent_id' => 9, 'enrollment_status' => 'refund pending'],
        ], 8);

        $this->assertSame(128.45, $refund);
        $this->assertSame([11], $service->previewedEnrollmentIds);
    }

    public function testRefundReversesLatestTuitionTierFirst(): void
    {
        $fees = $this->refundFeeStack(3, 2, 380.0, 280.0);

        $this->assertSame([280.0], $fees);
    }

    public function testRefundKeepsReversingAdditionalFeesBeforeFirstStudentFee(): void
    {
        $fees = $this->refundFeeStack(3, 0, 380.0, 280.0);

        $this->assertSame([280.0, 280.0, 380.0], $fees);
    }

    public function testSingleStudentWithdrawalRefundsFirstStudentFee(): void
    {
        $fees = $this->refundFeeStack(1, 0, 380.0, 280.0);

        $this->assertSame([380.0], $fees);
    }

    /**
     * @return array<int,float>
     */
    private function refundFeeStack(
        int $originalStudentCount,
        int $remainingStudentCount,
        float $firstStudentFee,
        float $additionalStudentFee
    ): array {
        $method = new \ReflectionMethod(FeeCalculationService::class, 'reverseTuitionRefundFeeStack');
        $method->setAccessible(true);

        return $method->invoke(
            new FeeCalculationService(),
            $originalStudentCount,
            $remainingStudentCount,
            $firstStudentFee,
            $additionalStudentFee
        );
    }
}