<?php

namespace api\blog;

use api\utils\feedGenerator\FeedWriter;
use api\utils\imgUtils;
use DOMDocument;
use PDO;
use Psr\Http\Message\UploadedFileInterface;
use function DI\string;
use const api\utils\feedGenerator\ATOM;
use const api\utils\feedGenerator\RSS2;

require_once __DIR__ . "/../utils/config.php";
require_once __DIR__ . "/../utils/imgUtils.php";
require_once __DIR__ . "/../utils/feedGenerator/FeedWriter.php";

/**
 * Blog Data Class
 * Define all functions which either get, update, create or delete posts
 */
class blogData
{
    /**
     * Get all blog posts
     * @return array<array> - Array of all blog posts or error message
     */
    public function getBlogPosts(): array
    {
        $conn = dbConn();
        $stmt = $conn->prepare("SELECT ID, title, DATE_FORMAT(dateCreated, '%Y-%m-%dT%TZ') AS dateCreated, 
                                       DATE_FORMAT(dateModified, '%Y-%m-%dT%TZ') AS dateModified, featured, abstract, 
                                       headerImg, body, bodyText, categories, folderID FROM blog ORDER BY featured DESC, 
                                       dateCreated DESC;");
        $stmt->execute();

        // set the resulting array to associative
        $result = $stmt->fetchAll(PDO::FETCH_ASSOC);

        if ($result)
        {
            return $result;
        }

        return array("errorMessage" => "Error, blog data not found");
    }

    /**
     * Get a blog post with the given ID
     * @param string $title - Title of the blog post
     * @return array - Array of blog post or error message
     */
    public function getBlogPost(string $title): array
    {
        $conn = dbConn();
        $stmt = $conn->prepare("SELECT ID, title, DATE_FORMAT(dateCreated, '%Y-%m-%dT%TZ') AS dateCreated, 
                                       DATE_FORMAT(dateModified, '%Y-%m-%dT%TZ') AS dateModified, featured, abstract, 
                                       headerImg, body, bodyText, categories, folderID  FROM blog WHERE 
                                       title = :title;");
        $stmt->bindParam(":title", $title);
        $stmt->execute();

        // set the resulting array to associative
        $result = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($result)
        {
            return $result;
        }

        return array("errorMessage" => "Error, blog post could not found");
    }

    /**
     * Get the latest blog post
     * @return array - Array of the latest blog post or error message
     */
    public function getLatestBlogPost(): array
    {
        $conn = dbConn();
        $stmt = $conn->prepare("SELECT ID, title, DATE_FORMAT(dateCreated, '%Y-%m-%dT%TZ') AS dateCreated, 
                                       DATE_FORMAT(dateModified, '%Y-%m-%dT%TZ') AS dateModified, featured, abstract, 
                                       headerImg, body, bodyText, categories, folderID FROM blog ORDER BY 
                                       dateCreated DESC LIMIT 1;");
        $stmt->execute();

        // set the resulting array to associative
        $result = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($result)
        {
            return $result;
        }

        return array("errorMessage" => "Error, blog post could not found");
    }

    /**
     * Get featured blog post
     * @return array - Array of the featured blog post or error message
     */
    public function getFeaturedBlogPost(): array
    {
        $conn = dbConn();
        $stmt = $conn->prepare("SELECT ID, title, DATE_FORMAT(dateCreated, '%Y-%m-%dT%TZ') AS dateCreated, 
                                       DATE_FORMAT(dateModified, '%Y-%m-%dT%TZ') AS dateModified, featured, abstract, 
                                       headerImg, body, bodyText, categories, folderID FROM blog WHERE featured = 1;");
        $stmt->execute();

        $result = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($result)
        {
            return $result;
        }

        return array("errorMessage" => "Error, blog post could not found");
    }

    /**
     * Get all unique categories
     * @return string[] - Array of all categories or error message
     */
    public function getCategories(): array
    {
        $conn = dbConn();
        $stmt = $conn->prepare("SELECT DISTINCT categories FROM blog;");
        $stmt->execute();

        // set the resulting array to associative
        $result = $stmt->fetchAll(PDO::FETCH_ASSOC);

        if ($result)
        {
            return $result;
        }

        return array("errorMessage" => "Error, blog post could not found");
    }

    /**
     * Delete a blog post with the given ID
     * @param int $ID - ID of the blog post to delete
     * @return string - Success or error message
     */
    public function deletePost(int $ID): string
    {
        $conn = dbConn();

        $stmtCheckPost = $conn->prepare("SELECT * FROM blog WHERE ID = :ID");
        $stmtCheckPost->bindParam(":ID", $ID);
        $stmtCheckPost->execute();
        $result = $stmtCheckPost->fetch(PDO::FETCH_ASSOC);

        if (!$result)
        {
            return "post not found";
        }

        if ($result["featured"] === 1)
        {
            return "cannot delete";
        }

        $stmt = $conn->prepare("DELETE FROM blog WHERE ID = :ID");
        $stmt->bindParam(":ID", $ID);

        if ($stmt->execute())
        {
            $imagUtils = new imgUtils();
            $imagUtils->deleteDirectory("../blog/imgs/" . $result["title"] . "_" . $result["folderID"] . "/");
            return "success";
        }

        return "error";
    }

    /**
     * Update the blog post with the given ID
     * @param int $ID - ID of the blog post to update
     * @param string $title - Title of the blog post
     * @param bool $featured - Whether the blog post is featured or not
     * @param string $abstract - Abstract of the blog post i.e. a short description
     * @param string $body - Body of the blog post
     * @param string $bodyText - Body of the blog post as plain text
     * @param string $dateModified - Date the blog post was modified
     * @param string $categories - Categories of the blog post
     * @return bool|string - Success or error message
     */
    public function updatePost(int $ID, string $title, bool $featured, string $abstract, string $body, string $bodyText, string $dateModified, string $categories): bool|string
    {
        $conn = dbConn();

        $stmtCheckPost = $conn->prepare("SELECT * FROM blog WHERE ID = :ID");
        $stmtCheckPost->bindParam(":ID", $ID);
        $stmtCheckPost->execute();
        $result = $stmtCheckPost->fetch(PDO::FETCH_ASSOC);

        if (!$result)
        {
            return "post not found";
        }

        if (!$featured && $result["featured"] === 1)
        {
            return "unset feature";
        }

        if ($featured)
        {
            $stmtUnsetFeatured = $conn->prepare("UPDATE blog SET featured = 0 WHERE featured = 1;");
            $stmtUnsetFeatured->execute();
        }

        $to = "../blog/imgs/" . $title . "_" . $result["folderID"] . "/";
        if ($result["title"] !== $title)
        {
            $from = "../blog/imgs/" . $result["title"] . "_" . $result["folderID"] . "/";
            mkdir($to, 0777, true);
            rename($result["headerImg"], $to . basename($result["headerImg"]));
            $body = $this->changeHTMLSrc($body, $to, $from);
            rmdir($from);
        }

        $from = "../blog/imgs/tmp/";
        $newBody = $this->changeHTMLSrc($body, $to, $from);

        $stmt = $conn->prepare("UPDATE blog SET title = :title, featured = :featured, abstract = :abstract, body = :body, bodyText = :bodyText, dateModified = :dateModified, categories = :categories WHERE ID = :ID;");
        $stmt->bindParam(":ID", $ID);
        $stmt->bindParam(":title", $title);
        $stmt->bindParam(":featured", $featured);
        $stmt->bindParam(":abstract", $abstract);
        $stmt->bindParam(":body", $newBody);
        $stmt->bindParam(":bodyText", $bodyText);
        $stmt->bindParam(":dateModified", $dateModified);
        $stmt->bindParam(":categories", $categories);

        return $stmt->execute();
    }

    /**
     * Creates a new post di rectory, uploads the header image and moves the images from the
     * temp folder to the new folder, then updates the post html to point to the new images, finally
     * it creates the post in the database
     * @param string $title - Title of the blog post
     * @param string $abstract - Abstract of the blog post i.e. a short description
     * @param string $body - Body of the blog post
     * @param string $bodyText - Body of the blog post as plain text
     * @param string $dateCreated - Date the blog post was created
     * @param bool $featured - Whether the blog post is featured or not
     * @param string $categories - Categories of the blog post
     * @param UploadedFileInterface $headerImg - Header image of the blog post
     * @return int|string - ID of the blog post or error message
     */
    public function createPost(string $title, string $abstract, string $body, string $bodyText, string $dateCreated, bool $featured, string $categories, UploadedFileInterface $headerImg): int|string
    {
        $conn = dbConn();
        $folderID = uniqid();
        $targetFile = array("imgLocation" => "../blog/imgs/placeholder.png");

        $targetDir = "../blog/imgs/" . $title . "_" . $folderID . "/";
        mkdir($targetDir, 0777, true);

        if ($headerImg !== null)
        {
            $imagUtils = new imgUtils();
            $targetFile = $imagUtils->uploadFile($targetDir, $headerImg);
        }


        if (!is_array($targetFile))
        {
            return $targetFile;
        }

        $newBody = $this->changeHTMLSrc($body, $targetDir, "../blog/imgs/tmp/");


        if ($featured)
        {
            $stmtMainProject = $conn->prepare("UPDATE blog SET featured = 0 WHERE featured = 1;");
            $stmtMainProject->execute();
        }

        $stmt = $conn->prepare("INSERT INTO blog (title, dateCreated, dateModified, featured, headerImg, abstract, body, bodyText, categories, folderID) 
                                       VALUES (:title, :dateCreated, :dateModified, :featured, :headerImg, :abstract, :body, :bodyText, :categories, :folderID);");
        $stmt->bindParam(":title", $title);
        $stmt->bindParam(":dateCreated", $dateCreated);
        $stmt->bindParam(":dateModified", $dateCreated);
        $isFeatured = $featured ? 1 : 0;
        $stmt->bindParam(":featured", $isFeatured);
        $stmt->bindParam(":headerImg", $targetFile["imgLocation"]);
        $stmt->bindParam(":abstract", $abstract);
        $stmt->bindParam(":body", $newBody);
        $stmt->bindParam(":bodyText", $bodyText);
        $stmt->bindParam(":categories", $categories);
        $stmt->bindParam(":folderID", $folderID);

        if ($stmt->execute())
        {
            return intval($conn->lastInsertId());
        }

        return "Error, couldn't create post";
    }

    /**
     * Upload the images in the post to temp folder and return image location
     * @param UploadedFileInterface $img - Image to upload
     * @return string|array - String with error message or array with the location of the uploaded file
     */
    public function uploadPostImage(UploadedFileInterface $img): string|array
    {
        $targetDir = "../blog/imgs/tmp/";
        $imagUtils = new imgUtils();
        $targetFile = $imagUtils->uploadFile($targetDir, $img);

        $file = $targetDir . basename($img->getClientFilename());

        if (file_exists($file))
        {
            return array("url" => $file);
        }

        if (!is_array($targetFile))
        {
            return $targetFile;
        }

        if (file_exists($targetFile["imgLocation"]))
        {
            return array("url" => $targetFile["imgLocation"]);
        }

        return "Couldn't upload the image";
    }

    /**
     * Upload the header image of the post and update the database
     * @param int $ID - ID of the post
     * @param UploadedFileInterface $img - Image to upload
     * @return string|array - String with error message or array with the location of the uploaded file
     */
    public function uploadHeaderImage(int $ID, UploadedFileInterface $img): string|array
    {
        $conn = dbConn();
        $stmt = $conn->prepare("SELECT * FROM blog WHERE ID = :ID;");
        $stmt->bindParam(":ID", $ID);
        $stmt->execute();
        $result = $stmt->fetch(PDO::FETCH_ASSOC);

        if (!$result)
        {
            return "Couldn't find the post";
        }

        $targetDir = "../blog/imgs/" . $result["title"] . "_" . $result["folderID"] . "/";
        $imagUtils = new imgUtils();
        $targetFile = $imagUtils->uploadFile($targetDir, $img);

        if (!is_array($targetFile))
        {
            return $targetFile;
        }

        if (file_exists($targetFile["imgLocation"]))
        {
            unlink($result["headerImg"]);
            $stmt = $conn->prepare("UPDATE blog SET headerImg = :headerImg WHERE ID = :ID;");
            $stmt->bindParam(":ID", $ID);
            $stmt->bindParam(":headerImg", $targetFile["imgLocation"]);
            $stmt->execute();
            if ($stmt->rowCount() > 0)
            {
                return $targetFile;
            }

            return "Couldn't update the post";
        }

        return "Couldn't upload the image";
    }

    /**
     * Change the HTML src of the images in the post to point to the new location
     * @param string $body - Body of the post
     * @param string $to - New location of the images
     * @param string $from - Old location of the images
     * @return string - Body of the post with the new image locations
     */
    public function changeHTMLSrc(string $body, string $to, string $from): string
    {
        $htmlDoc = new DOMDocument();
        $htmlDoc->loadHTML($body, LIBXML_NOERROR);
        $doc = $htmlDoc->getElementsByTagName('body')->item(0);
        $imgs = $doc->getElementsByTagName('img');

        $srcList = array();

        foreach ($imgs as $img)
        {
            $src = $img->getAttribute("src");
            $src = urldecode($src);
            $srcList[] = $src;
            $fileName = basename($src);

            $img->setAttribute("src", substr($to, 2) . $fileName);
        }

        $files = scandir($from);
        foreach ($files as $file)
        {
            if ($file != "." && $file != "..")
            {
                if (!in_array($from . $file, $srcList))
                {
                    unlink($from . $file);
                    continue;
                }

                rename($from . $file, $to . $file);
            }
        }

        $newBody = '';
        foreach ($doc->childNodes as $node)
        {
            $newBody .= $htmlDoc->saveHTML($node);
        }
        return $newBody;
    }

    /**
     * Get all posts with the given category
     * @param string $category - Category of the post
     * @return array<array> - Array of all posts with the given category or error message
     */
    public function getPostsByCategory(string $category): array
    {
        $conn = dbConn();
        $stmt = $conn->prepare("SELECT * FROM blog WHERE LOCATE(:category, categories) > 0;");
        $stmt->bindParam(":category", $category);
        $stmt->execute();
        return $stmt->fetchAll(PDO::FETCH_ASSOC);
    }

    /**
     * Search for a blog post with the given search term
     * @param string $searchTerm - Search term
     * @return array<array> - Array of all posts with the given search term or error message
     */
    public function searchBlog(string $searchTerm): array
    {
        $conn = dbConn();
        $stmt = $conn->prepare("SELECT * FROM blog WHERE MATCH(title, bodyText) AGAINST(:searchTerm IN NATURAL LANGUAGE MODE);");
        $stmt->bindParam(":searchTerm", $searchTerm);
        $stmt->execute();
        $result = $stmt->fetchAll(PDO::FETCH_ASSOC);

        if ($result)
        {
            for ($i = 0; $i < count($result); $i++)
            {
                $result[$i]["abstract"] = $this->getShortPost($searchTerm, stripcslashes($result[$i]["bodyText"]));
            }

            return $result;
        }

        return array("errorMessage" => "Error, could not find posts");
    }

    /**
     * Get the short post with the search term
     * @param string $searchTerm - Search term
     * @param $text - Body of the post as plain text
     * @return string - Short post with the search term
     */
    private function getShortPost(string $searchTerm, $text): string
    {
        $pattern = '/([,:;!?.-]+)/u';
        $parts = preg_split($pattern, $text, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);

        $cleanedParts = [];

        foreach ($parts as $part)
        {
            $part = trim($part); // Remove leading/trailing spaces and newline characters
            if (!empty($part))
            {
                $cleanedParts[] = $part;
            }
        }

        $combinedParts = [];
        $currentPart = '';

        foreach ($cleanedParts as $part)
        {
            if (preg_match('/[,:;!?.-]/u', $part))
            {
                $currentPart .= $part;
            }
            else
            {
                if (!empty($currentPart))
                {
                    $combinedParts[] = trim($currentPart);
                }
                $currentPart = rtrim($part);
            }
        }

        if (!empty($currentPart))
        {
            $combinedParts[] = trim($currentPart);
        }

        $result = "";


        for ($i = 0; $i < count($combinedParts); $i++)
        {
            $part = $combinedParts[$i];

            if (stripos($part, $searchTerm) !== false)
            {
                $before = ($i > 0) ? $combinedParts[$i - 1] : "";
                $after = ($i < count($combinedParts) - 1) ? $combinedParts[$i + 1] : "";

                if ($before === "" && $i > 0)
                {
                    $before = $combinedParts[$i - 1];
                }

                $result = $before . " " . $part . " " . $after;

                // If the search term is found, we don't need to continue checking subsequent parts
                break;
            }
        }

        return $result;
    }

    /**
     * Generate the XML feed
     * @param mixed $type - Type of feed
     * @return array|string - Error message or the XML feed
     */
    private function generateXMLFeed(mixed $type): array|string
    {
        ob_start();
        $feed = new FeedWriter($type);
        $feed->setTitle("Rohit Pai's Blog");
        $feed->setLink('https://rohitpai.co.uk/blog');
        $feed->setFeedURL('https://rohitpai.co.uk/api/blog/feed/atom');
        $feed->setChannelElement('updated', date(DATE_ATOM, time()));
        $feed->setChannelElement('author', ['name' => 'Rohit Pai']);
        $posts = $this->getBlogPosts();

        if (isset($posts["errorMessage"]))
        {
            return $posts;
        }

        foreach ($posts as $post)
        {
            $newItem = $feed->createNewItem();
            $newItem->setTitle($post["title"]);
            $newItem->setLink("https://rohitpai.co.uk/blog/post/" . rawurlencode($post["title"]) . "#disqus_thread");
            $newItem->setDate($post["dateModified"]);
            $newItem->setDescription($post["body"]);
            $feed->addItem($newItem);
        }

        $feed->generateFeed();
        $atom = ob_get_contents();
        ob_end_clean();
        return $atom;
    }

    /**
     * Generate the JSON feed
     * @return array|array[] - Error message or the JSON feed
     */
    private function generateJSONFeed(): array
    {
        $posts = $this->getBlogPosts();

        if (isset($posts["errorMessage"]))
        {
            return $posts;
        }

        $json = array();
        $json["version"] = "https://jsonfeed.org/version/1.1";
        $json["title"] = "Rohit Pai's Blog";
        $json["home_page_url"] = "https://rohitpai.co.uk/blog";
        $json["feed_url"] = "https://rohitpai.co.uk/api/blog/feed/json";
        $json["description"] = "Rohit Pai's personal blog on all things self hosting and various other tech topics";
        $json["author"] = array(
            "name" => "Rohit Pai",
            "url" => "https://rohitpai.co.uk",
            "avatar" => "https://rohitpai.co.uk/imgs/profile.jpg"
        );
        $items = array();
        foreach ($posts as $post)
        {
            $items[] = array(
                "id" => string($post["ID"]),
                "url" => "https://rohitpai.co.uk/blog/post/" . rawurlencode($post["title"]) . "#disqus_thread",
                "title" => $post["title"],
                "date_published" => date($post["dateCreated"]),
                "date_modified" => date($post["dateModified"]),
//                "description" => $post["abstract"],
                "banner_image" => "https://rohitpai.co.uk/" . rawurlencode($post["headerImg"]),
                "content_html" => $post["body"]
            );
        }
        $json["items"] = $items;
        return $json;
    }

    /**
     * Generate the RSS feed based on type
     * @param string $type - Type of feed
     * @return string|array - RSS feed or an error message
     */
    public function getFeed(string $type): string|array
    {
        $feed = "";
        if ($type == "atom")
        {
            $feed = $this->generateXMLFeed(ATOM);
        }

        if ($type == "rss")
        {
            $feed = $this->generateXMLFeed(RSS2);
        }

        if ($type == "json")
        {
            $feed = $this->generateJSONFeed();
        }

        return $feed;
    }
}