<?php

namespace App\Set\UseCases\DeleteSet;

use App\Element\Element;
use App\Element\ElementRepository;
use App\Exceptions\BadRequestException;
use App\Exceptions\NotFoundException;
use App\Set\SetRepository;
use App\Shared\Files\Filesystem;

class DeleteSet
{
    /**
     * @var array<string, true>
     */
    private array $managedFilePaths = [];

    public function __construct(
        private SetRepository $setRepository,
        private ElementRepository $elementRepository,
        private Filesystem $filesystem,
    ) {
    }

    /**
     * @throws BadRequestException
     * @throws NotFoundException
     */
    public function execute(DeleteSetRequest $request): void
    {
        if ($request->id === null) {
            throw new BadRequestException('setId is required');
        }

        $set = $this->setRepository->find($request->id);
        if ($set === null) {
            throw new NotFoundException('Set not found');
        }

        $this->managedFilePaths = [];
        $this->rememberManagedFile($set->getIconImageUrl());

        $elements = $this->elementRepository->findBySet($set);
        foreach ($elements as $element) {
            $this->rememberManagedFile($element->getIconImageUrl());
            $this->rememberManagedFile($element->getShortPdfPath());
            $this->rememberManagedFile($element->getLongPdfPath());
        }

        foreach ($this->deepestElementsFirst($elements) as $element) {
            $this->elementRepository->delete($element);
        }

        $this->setRepository->delete($set);
        foreach (array_keys($this->managedFilePaths) as $path) {
            $this->filesystem->delete($path);
        }
    }

    /**
     * @param Element[] $elements
     * @return Element[]
     */
    private function deepestElementsFirst(array $elements): array
    {
        usort($elements, function (
            Element $firstElement,
            Element $secondElement,
        ): int {
            $firstDepth = $this->elementDepth($firstElement);
            $secondDepth = $this->elementDepth($secondElement);
            if ($firstDepth === $secondDepth) {
                return $secondElement->getId() <=> $firstElement->getId();
            }

            return $secondDepth <=> $firstDepth;
        });

        return $elements;
    }

    private function elementDepth(Element $element): int
    {
        $depth = 0;
        $parentElement = $element->getParentElement();
        while ($parentElement !== null) {
            $depth++;
            $parentElement = $parentElement->getParentElement();
        }

        return $depth;
    }

    private function rememberManagedFile(?string $path): void
    {
        if ($path === null) {
            return;
        }

        if (! $this->isManagedFilePath($path)) {
            return;
        }

        $this->managedFilePaths[$path] = true;
    }

    private function isManagedFilePath(string $path): bool
    {
        return str_starts_with($path, 'set-icons/')
            || str_starts_with($path, 'element-icons/')
            || str_starts_with($path, 'element-pdfs/short/')
            || str_starts_with($path, 'element-pdfs/long/');
    }
}