<?php

namespace App\Services;

use App\Models\StudentContract;
use Carbon\Carbon;
use Illuminate\Database\Eloquent\Collection;

class StudentContractService
{
    public function getAll(int $unitId, ?int $studentId = null): Collection
    {
        return StudentContract::where('unit_id', $unitId)
            ->when($studentId, fn ($q) => $q->where('student_id', $studentId))
            ->orderBy('created_at', 'desc')
            ->get();
    }

    public function findById(int $id): ?StudentContract
    {
        return StudentContract::find($id);
    }

    public function create(array $data): StudentContract
    {
        if (!empty($data['due_date'])) {
            $data['recurring_day'] = Carbon::parse($data['due_date'])->day;
        }

        return StudentContract::create($data);
    }

    public function update(int $id, array $data): ?StudentContract
    {
        $model = $this->findById($id);

        if (!$model) {
            return null;
        }

        if (!empty($data['due_date'])) {
            $data['recurring_day'] = Carbon::parse($data['due_date'])->day;
        }

        $model->update($data);
        return $model->fresh();
    }

    public function delete(int $id): bool
    {
        $model = $this->findById($id);

        if (!$model) {
            return false;
        }

        return $model->delete();
    }
}