<?php

namespace App\Services;

use App\Models\WebCrawl;
use GuzzleHttp\Client;
use Illuminate\Support\Facades\Log;

class WebCrawlerService
{
  protected $webClient;

  public function __construct()
  {
    $this->webClient = new Client();
  }

  public function getAllCrawls()
  {
    $allCrawls = WebCrawl::all();
    return response()->json($allCrawls);
  }

  public function crawlWebsite($url, $depth, $refresh)
  {
    $webCrawl = WebCrawl::where('url', $url)->first();
    if ($webCrawl && !$refresh) {
      Log::error("This URL already exists in the database: $url");
      return response()->json([
        'error' => 'This URL already exists in the database',
      ], 400);
    }

    $response = $this->scan($url);
    if ($response->getStatusCode() >= 200 && $response->getStatusCode() < 300) {
      $crawler = $webCrawl ?? new WebCrawl();
      $crawler->url = $url;
      $crawler->content = $response->getBody()->getContents();
      $linksFromPage = $this->getLinksFromPage($crawler->content);
      try {
        $crawler->save();
      } catch (\Exception $e) {
        Log::error($e->getMessage());
        return response()->json([
          'error' => 'Failed to save the URL to the database',
        ], 500);
      }
      if ($depth > 0 && count($linksFromPage) > 0) {
        $results = [];
        foreach ($linksFromPage as $link) {
          $results[] = $this->crawlWebsiteRecursive($link, $depth - 1);
        }
        return response()->json([
          'message' => 'Crawling completed successfully',
          'data' => $url
        ]);
      }
    } else {
      Log::error("Failed to retrieve the URL: $url");
      return response()->json([
        'error' => 'Failed to retrieve the URL',
      ], 500);
    }

    Log::info("Crawling completed successfully for URL: $url");
    return response()->json([
      'message' => 'Crawling completed successfully',
    ]);
  }

  public function deleteCrawl($id)
  {
    $webCrawl = WebCrawl::find($id);
    if ($webCrawl) {
      $webCrawl->delete();
      Log::info("Web crawl deleted successfully for ID: $id");
      return response()->json([
        'message' => 'Web crawl deleted successfully',
      ]);
    }
    Log::error("Web crawl not found for ID: $id");
    return response()->json([
      'error' => 'Web crawl not found',
    ], 404);
  }

  public function deleteAllCrawls()
  {
    WebCrawl::truncate();
    Log::info("All web crawls deleted successfully");
    return response()->json([
      'message' => 'All web crawls deleted successfully',
    ]);
  }

  protected function crawlWebsiteRecursive($url, $depth)
  {
    $webCrawl = WebCrawl::where('url', $url)->first();
    if ($webCrawl) {
      return [];
    }

    $response = $this->scan($url);
    if ($response->getStatusCode() >= 200 && $response->getStatusCode() < 300) {
      $crawler = new WebCrawl();
      $crawler->url = $url;
      $crawler->content = $response->getBody()->getContents();
      $linksFromPage = $this->getLinksFromPage($crawler->content);
      try {
        $crawler->save();
        Log::info("URL saved to the database: $url");
      } catch (\Exception $e) {
        Log::error("Can't save the URL to the database: $url");
        return [];
      }
      if ($depth > 0 && count($linksFromPage) > 0) {
        $results = [];
        foreach ($linksFromPage as $link) {
          $results = array_merge($results, $this->crawlWebsiteRecursive($link, $depth - 1));
        }
        return $results;
      }
    }

    return [];
  }

  protected function getLinksFromPage($crawlerContent)
  {
    $dom = new \DOMDocument();
    @$dom->loadHTML($crawlerContent);
    $links = $dom->getElementsByTagName('a');
    $linksFromPage = [];
    foreach ($links as $link) {
      if ($link->getAttribute('href') && filter_var($link->getAttribute('href'), FILTER_VALIDATE_URL)) {
        $linksFromPage[] = $link->getAttribute('href');
      }
    }
    return $linksFromPage;
  }

  protected function scan($url)
  {
    try {
      $result = $this->webClient->request('GET', $url);
    } catch (\Exception $e) {
      return response()->json([
        'error' => 'Failed to retrieve the URL',
      ], 500);
    }
    return $result;
  }
}