<?php

namespace App\Blogs;

use Cocur\Slugify\Slugify;
use League\CommonMark\Environment\Environment;
use League\CommonMark\Extension\DisallowedRawHtml\DisallowedRawHtmlExtension;
use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
use League\CommonMark\Extension\Mention\MentionExtension;
use League\CommonMark\Extension\Table\TableExtension;
use League\CommonMark\MarkdownConverter;

class Blogs {

    private string $postsDir = __DIR__ . '/../../datas/posts';
    private string $cacheFile = __DIR__ . '/../../cache/fileIndex.json';
    private array $mdFileCache = [];
    private int $totalPost = 0;
    private int $postPerPage;
    public int $totalPage = 0;
    private array $postList = [];
    public string $postsHash;
    private array $params;
    private int $numberEntry;

    private $notFound = [
        'file' => __DIR__ . '/../../datas/pages/404.md',
        'filename' => '404',
        'created_at' => '1970-01-01',
        'modified_at' => '1970-01-01',
    ];

    /**
     * Constructs a new instance of the class
     *
     * @param array $params An array of parameters
     */
    function __construct($params) {
        if (!isset($params['config']['cron'])) {
            $params['config']['cron'] = false;
        }
        if (file_exists($this->cacheFile) && $params['config']['cron'] === false) {
            $mdFileCache = json_decode(file_get_contents($this->cacheFile), true);
        } else {
            $mdFileCache = $this->indexMdFiles();
        }
        $this->postPerPage = $params['config']['postPerPage'];
        $this->totalPost = count($mdFileCache);
        $this->totalPage = ceil($this->totalPost / $this->postPerPage);
        $this->numberEntry = $params['config']['numberOfLastItem'];
        $this->mdFileCache = $mdFileCache;
    }

    /**
     * Indexes all the markdown files in the posts directory
     *
     * @return array The indexed markdown files
     */
    private function indexMdFiles(): array {
        $directory = new \RecursiveDirectoryIterator($this->postsDir);
        $slugify = new Slugify();
        foreach (new \RecursiveIteratorIterator($directory) as $file) {
            if ($file->getExtension() === 'md') {
                $filename = $file->getBasename('.md');
                $pathParts = explode(DIRECTORY_SEPARATOR, $file->getPath());

                $year = $pathParts[count($pathParts) - 2];
                $month = $pathParts[count($pathParts) - 1];
                $nameParts = explode(' - ', $filename);

                $day = $nameParts[0];
                if (empty($nameParts['1'])) {
                    continue;
                }
                $slug = $slugify->slugify(trim($nameParts[1]));
                $createDate = \DateTimeImmutable::createFromFormat("Y-m-d H:i:s", "$year-$month-$day" . ' ' . date('H:i:s'));
                $created_at = $createDate->format("Y-m-d");

                $modifiedDate = \DateTimeImmutable::createFromFormat("U", $file->getMTime());
                $modified_at = $modifiedDate->format(\DateTimeImmutable::ATOM);

                $this->mdFileCache[$slug] = [
                    'file' => $file->getPathname(),
                    'filename' => $filename,
                    'title' => ucfirst(trim($nameParts[1])),
                    'year' => $year,
                    'month' => $month,
                    'created_at' => $created_at,
                    'modified_at' => $modified_at
                ];
            }
        }

        uasort($this->mdFileCache, function ($a, $b) {
            return strtotime($b['created_at']) <=> strtotime($a['created_at']);
        });

        file_put_contents($this->cacheFile, json_encode($this->mdFileCache));
        return $this->mdFileCache;
    }

    /**
     * Retrieves the markdown files for a given page
     *
     * @param int $page The page number
     * @return array An array of markdown files
     */
    function getFilesForPage(int $page): array {
        if ($page > $this->totalPage) {
            $page = $this->totalPage;
        }
        $offset = ($page - 1) * $this->postPerPage;
        return array_slice($this->mdFileCache, $offset, $this->postPerPage, true);
    }

    /**
     * Finds a markdown file by slug and returns its content
     *
     * @param string $slug The slug of posts/page
     * @return string The content of the markdown
     */

    public function findPostBySlug(string $slug): string {
        if (!empty($this->mdFileCache[$slug]) && file_exists($this->mdFileCache[$slug]['file'])) {
            return file_get_contents($this->mdFileCache[$slug]['file']);
        } else {
            return file_get_contents($this->notFound['file']);
        }
    }

    /**
     * Finds all the markdown files for a given year
     *
     * @param int $year
     * @return array An array of markdown file
     */
    public function findPostByYear(int $year): array {
        $result = array();
        foreach ($this->mdFileCache as $key => $post) {
            if ((int)$post['year'] === $year) {
                $result[$key] = $post;
            }
        }
        $this->mdFileCache = $result;
        $this->totalPage = ceil(count($this->mdFileCache) / $this->postPerPage);
        return $result;
    }


    /**
     * Finds all the markdown files for a given month
     *
     * @param int $month
     * @return array An array of markdown file
     */
    public function findPostByMonth(int $month): array {
        $result = array();
        foreach ($this->mdFileCache as $key => $post) {
            if ((int)$post['year'] === $month) {
                $result[$key] = $post;
            }
        }
        $this->mdFileCache = $result;
        $this->totalPage = ceil(count($this->mdFileCache) / $this->postPerPage);
        return $result;
    }

    /**
     * Returns the information of a markdown file for given slug
     *
     * @param string $slug The slug of post/page
     * @return array The information of the markdown file
     */
    public function returnPostInfo(string $slug): array {
        if (isset($this->mdFileCache[$slug])) {
            return $this->mdFileCache[$slug];
        }
        return [];
    }

    /**
     * Returns the most recent post
     *
     * @return array An array of the most recent mdFileCache
     */
    public function getLastPost(): array {
        if ($this->totalPost > 0) {
            $this->postList = array_slice($this->mdFileCache, 0, $this->numberEntry);
        }
        return $this->postList;
    }

    /**
     * Generates the HTML for the pagination links
     *
     * @param int $page The current page number
     * @return string The generated HTML for the pagination links
     */
    public function makePagination(int $page): string {
        $html = '';
        for ($i = 1; $i <= $this->totalPage; $i++) {
            if ($i === $page) {
                $class = 'class="current" ';
            } else {
                $class = null;
            }
            $html .= '<li>
              <a ' . $class . 'href="/posts/' . $i . '">' . $i . '</a>
            </li>';
        }
        return $html;
    }

    /**
     * Generates the HTML for the list of posts
     *
     * @return string|null The generated HTML for the list of posts or null
     */
    public function makeList(): string {
        if (!empty($this->postList)) {
            $htmlPost = '<ul data-lastUpdate="' . date("Y-m-d") . '">';
            foreach ($this->postList as $key => $value) {
                $htmlPost .=
                    '
                <li>
                  <a href="' . '/post/' . $key . '">' . $value['title'] . '</a>
                </li>';
            }
            $htmlPost .= '
            </ul>';

            $this->postsHash = sha1($htmlPost);
            return $htmlPost;
        }
        $this->postsHash = sha1('empty');
        return '';
    }

    /**
     * Converts markdown content to HTML
     *
     * @param string $content The markdown content to convert to HTML
     * @return string The converted HTML content
     */
    function markdownToHtml(string $content): string {
        $config = [
            'disallowed_raw_html' => [
                'disallowed_tags' => ['title', 'textarea', 'style', 'xmp', 'iframe', 'noembed', 'noframes', 'script', 'plaintext'],
            ],
            'table' => [
                'wrap' => [
                    'enabled' => false,
                    'tag' => 'div',
                    'attributes' => [],
                ],
                'alignment_attributes' => [
                    'left'   => ['align' => 'left'],
                    'center' => ['align' => 'center'],
                    'right'  => ['align' => 'right'],
                ],
            ],
            'mentions' => [
                'tag_handle' => [
                    'prefix'    => '#',
                    'pattern'   => '[a-z\d](?:[a-z\d]|-(?=[a-z\d])){0,38}(?!\w)',
                    'generator' => '/tag/%s',
                ]
            ],
        ];

        $environment = new Environment($config);
        $environment->addExtension(new CommonMarkCoreExtension());
        $environment->addExtension(new MentionExtension());
        $environment->addExtension(new TableExtension());

        $converter = new MarkdownConverter($environment);
        return $converter->convert($content);
    }

    /**
     * Extracts the lead paragraph from a post
     *
     * @param string $markdownContent The markdown content to extract the lead paragraph from
     * @return string|null The extracted lead paragraph or null
     */
    static function extractLead(string $markdownFile): ?string {
        if (file_exists($markdownFile)) {
            $markdownContent = file_get_contents($markdownFile);
            $pattern = '/---\s*(.*?)\s*---/s';
            if (preg_match($pattern, $markdownContent, $matches)) {
                return trim($matches[1]);
            }
        }
        return null;
    }
}