<?php

namespace App\Services;

use App\Models\ClassPackage;
use App\Models\Unit;
use Illuminate\Database\Eloquent\Collection;

class ClassPackageService
{
    public function getAll(): Collection
    {
        return ClassPackage::orderBy('created_at', 'desc')->get();
    }

    public function findById(int $id): ?ClassPackage
    {
        return ClassPackage::with('units')->find($id);
    }

    public function create(array $data): ClassPackage
    {
        $unitVisibilities = $data['unit_visibilities'] ?? [];
        unset($data['unit_visibilities']);

        $package = ClassPackage::create($data);

        $this->syncUnitVisibilities($package, $unitVisibilities);

        return $package->load('units');
    }

    public function update(int $id, array $data): ?ClassPackage
    {
        $package = $this->findById($id);
        if (!$package) return null;

        $unitVisibilities = $data['unit_visibilities'] ?? null;
        unset($data['unit_visibilities']);

        $package->update($data);

        if ($unitVisibilities !== null) {
            $this->syncUnitVisibilities($package, $unitVisibilities);
        }

        return $package->fresh('units');
    }

    public function delete(int $id): bool
    {
        $package = ClassPackage::find($id);
        if (!$package) return false;

        return $package->delete();
    }

    public function getAllUnitsWithVisibility(int $packageId): \Illuminate\Support\Collection
    {
        $allUnits = Unit::orderBy('fantasy_name')->get(['id', 'fantasy_name']);
        $package = ClassPackage::with('units')->find($packageId);

        $visibilityMap = $package
            ? $package->units->keyBy('id')
            : collect();

        return $allUnits->map(fn($unit) => [
            'id'           => $unit->id,
            'fantasy_name' => $unit->fantasy_name,
            'visible'      => $visibilityMap->has($unit->id)
                ? (bool) $visibilityMap[$unit->id]->pivot->visible
                : true,
        ]);
    }

    private function syncUnitVisibilities(ClassPackage $package, array $unitVisibilities): void
    {
        $syncData = [];
        foreach ($unitVisibilities as $uv) {
            $syncData[$uv['unit_id']] = ['visible' => $uv['visible']];
        }
        $package->units()->sync($syncData);
    }
}