<?php

enum PostLanguage: string {
    case Russian = 'ru';
    case English = 'en';

    public static function getDefault(): PostLanguage {
        return self::English;
    }
}

class Post extends model {

    const DB_TABLE = 'posts';

    public int $id;
    public string $date;
    public ?string $updateTime;
    public bool $visible;
    public string $shortName;
    public string $sourceUrl;

    protected array $texts = [];

    public function edit(array $fields) {
        $fields['update_time'] = date(mysql::DATETIME_FORMAT, time());
        parent::edit($fields);
    }

    public function addText(PostLanguage $lang, string $title, string $md, string $keywords, bool $toc): ?PostText {
        $html = markup::markdownToHtml($md, lang: $lang);
        $text = markup::htmlToText($html);

        $data = [
            'title' => $title,
            'lang' => $lang->value,
            'post_id' => $this->id,
            'html' => $html,
            'text' => $text,
            'md' => $md,
            'toc' => $toc,
            'keywords' => $keywords,
        ];

        $db = DB();
        if (!$db->insert('posts_texts', $data))
            return null;

        $id = $db->insertId();

        $post_text = posts::getText($id);
        $post_text->updateImagePreviews();

        return $post_text;
    }

    public function registerText(PostText $postText): void {
        if (array_key_exists($postText->lang->value, $this->texts))
            throw new Exception("text for language {$postText->lang->value} has already been registered");
        $this->texts[$postText->lang->value] = $postText;
    }

    public function loadTexts() {
        if (!empty($this->texts))
            return;
        $db = DB();
        $q = $db->query("SELECT * FROM posts_texts WHERE post_id=?", $this->id);
        while ($row = $db->fetch($q)) {
            $text = new PostText($row);
            $this->registerText($text);
        }
    }

    /**
     * @return PostText[]
     */
    public function getTexts(): array {
        $this->loadTexts();
        return $this->texts;
    }

    public function getText(PostLanguage $lang): ?PostText {
        $this->loadTexts();
        return $this->texts[$lang->value] ?? null;
    }

    public function hasLang(PostLanguage $lang) {
        $this->loadTexts();
        foreach ($this->texts as $text) {
            if ($text->lang == $lang)
                return true;
        }
        return false;
    }

    public function getUrl(?PostLanguage $lang = null): string {
        $buf = $this->shortName != '' ? "/articles/{$this->shortName}/" : "/articles/{$this->id}/";
        if ($lang && $lang != PostLanguage::English)
            $buf .= '?lang='.$lang->value;
        return $buf;
    }

    public function getTimestamp(): int {
        return (new DateTime($this->date))->getTimestamp();
    }

    public function getDate(): string {
        return date('j M', $this->getTimestamp());
    }

    public function getYear(): int {
        return (int)date('Y', $this->getTimestamp());
    }

    public function getFullDate(): string {
        return date('j F Y', $this->getTimestamp());
    }

    public function getDateForInputField(): string {
        return date('Y-m-d', $this->getTimestamp());
    }
}

class PostText extends model {
    const DB_TABLE = 'posts_texts';

    public int $id;
    public int $postId;
    public PostLanguage $lang;
    public string $title;
    public string $md;
    public string $html;
    public string $text;
    public bool $toc;
    public string $tocHtml;
    public string $keywords;

    public function edit(array $fields) {
        if ($fields['md'] != $this->md) {
            $fields['html'] = markup::markdownToHtml($fields['md'], lang: $this->lang);
            $fields['text'] = markup::htmlToText($fields['html']);
        }

        if ((isset($fields['toc']) && $fields['toc']) || $this->toc) {
            $fields['toc_html'] = markup::toc($fields['md']);
        }

        parent::edit($fields);
        $this->updateImagePreviews();
    }

    public function updateHtml(): void {
        $html = markup::markdownToHtml($this->md, lang: $this->lang);
        $this->html = $html;
        DB()->query("UPDATE posts_texts SET html=? WHERE id=?", $html, $this->id);
    }

    public function updateText(): void {
        $html = markup::markdownToHtml($this->md, lang: $this->lang);
        $text = markup::htmlToText($html);
        $this->text = $text;
        DB()->query("UPDATE posts_texts SET text=? WHERE id=?", $text, $this->id);
    }

    public function getDescriptionPreview(int $len): string {
        if (mb_strlen($this->text) >= $len)
            return mb_substr($this->text, 0, $len-3).'...';
        return $this->text;
    }

    public function getFirstImage(): ?Upload {
        if (!preg_match('/\{image:([\w]{8})/', $this->md, $match))
            return null;
        return uploads::getUploadByRandomId($match[1]);
    }

    public function getHtml(bool $is_retina, string $theme): string {
        $html = $this->html;
        return markup::htmlImagesFix($html, $is_retina, $theme);
    }

    public function getTableOfContentsHtml(): ?string {
        return $this->toc ? $this->tocHtml : null;
    }

    public function hasTableOfContents(): bool {
        return $this->toc;
    }

    /**
     * @param bool $update Whether to overwrite preview if already exists
     * @return int
     * @throws Exception
     */
    public function updateImagePreviews(bool $update = false): int {
        $images = [];
        if (!preg_match_all('/\{image:([\w]{8}),(.*?)}/', $this->md, $matches))
            return 0;

        for ($i = 0; $i < count($matches[0]); $i++) {
            $id = $matches[1][$i];
            $w = $h = null;
            $opts = explode(',', $matches[2][$i]);
            foreach ($opts as $opt) {
                if (str_contains($opt, '=')) {
                    list($k, $v) = explode('=', $opt);
                    if ($k == 'w')
                        $w = (int)$v;
                    else if ($k == 'h')
                        $h = (int)$v;
                }
            }
            $images[$id][] = [$w, $h];
        }

        if (empty($images))
            return 0;

        $images_affected = 0;
        $uploads = uploads::getUploadsByRandomId(array_keys($images), true);
        foreach ($uploads as $upload_key => $u) {
            if ($u === null) {
                logError(__METHOD__.': upload '.$upload_key.' is null');
                continue;
            }
            foreach ($images[$u->randomId] as $s) {
                list($w, $h) = $s;
                list($w, $h) = $u->getImagePreviewSize($w, $h);
                if ($u->createImagePreview($w, $h, $update, $u->imageMayHaveAlphaChannel()))
                    $images_affected++;
            }
        }

        return $images_affected;
    }

}

class posts {

    static function getCount(bool $include_hidden = false): int {
        $db = DB();
        $sql = "SELECT COUNT(*) FROM posts";
        if (!$include_hidden) {
            $sql .= " WHERE visible=1";
        }
        return (int)$db->result($db->query($sql));
    }

    /**
     * @return Post[]
     */
    static function getList(int $offset = 0,
                            int $count = -1,
                            bool $include_hidden = false,
                            ?PostLanguage $filter_by_lang = null
    ): array {
        $db = DB();
        $sql = "SELECT * FROM posts";
        if (!$include_hidden)
            $sql .= " WHERE visible=1";
        $sql .= " ORDER BY `date` DESC";
        if ($offset != 0 || $count != -1)
            $sql .=  " LIMIT $offset, $count";
        $q = $db->query($sql);
        $posts = [];
        while ($row = $db->fetch($q)) {
            $posts[$row['id']] = $row;
        }

        if (!empty($posts)) {
            foreach ($posts as &$post)
                $post = new Post($post);
            $q = $db->query("SELECT * FROM posts_texts WHERE post_id IN (".implode(',', array_keys($posts)).")");
            while ($row = $db->fetch($q)) {
                $posts[$row['post_id']]->registerText(new PostText($row));
            }
        }

        if ($filter_by_lang !== null)
            $posts = array_filter($posts, fn(Post $post) => $post->hasLang($filter_by_lang));

        return array_values($posts);
    }

    static function add(array $data = []): ?Post {
        $db = DB();
        if (!$db->insert('posts', $data))
            return null;
        return self::get($db->insertId());
    }

    static function delete(Post $post): void {
        $db = DB();
        $db->query("DELETE FROM posts WHERE id=?", $post->id);
        $db->query("DELETE FROM posts_texts WHERE post_id=?", $post->id);
    }

    static function get(int $id): ?Post {
        $db = DB();
        $q = $db->query("SELECT * FROM posts WHERE id=?", $id);
        return $db->numRows($q) ? new Post($db->fetch($q)) : null;
    }

    static function getText(int $text_id): ?PostText {
        $db = DB();
        $q = $db->query("SELECT * FROM posts_texts WHERE id=?", $text_id);
        return $db->numRows($q) ? new PostText($db->fetch($q)) : null;
    }

    static function getByName(string $short_name): ?Post {
        $db = DB();
        $q = $db->query("SELECT * FROM posts WHERE short_name=?", $short_name);
        return $db->numRows($q) ? new Post($db->fetch($q)) : null;
    }

    static function getPostsById(array $ids, bool $flat = false): array {
        if (empty($ids)) {
            return [];
        }

        $db = DB();
        $posts = array_fill_keys($ids, null);

        $q = $db->query("SELECT * FROM posts WHERE id IN(".implode(',', $ids).")");

        while ($row = $db->fetch($q)) {
            $posts[(int)$row['id']] = new Post($row);
        }

        if ($flat) {
            $list = [];
            foreach ($ids as $id) {
                $list[] = $posts[$id];
            }
            unset($posts);
            return $list;
        }

        return $posts;
    }

    static function getPostTextsById(array $ids, bool $flat = false): array {
        if (empty($ids)) {
            return [];
        }

        $db = DB();
        $posts = array_fill_keys($ids, null);

        $q = $db->query("SELECT * FROM posts_texts WHERE id IN(".implode(',', $ids).")");

        while ($row = $db->fetch($q)) {
            $posts[(int)$row['id']] = new PostText($row);
        }

        if ($flat) {
            $list = [];
            foreach ($ids as $id) {
                $list[] = $posts[$id];
            }
            unset($posts);
            return $list;
        }

        return $posts;
    }

    /**
     * @param Upload $upload
     * @return PostText[]  Array of PostTexts that includes specified upload
     */
    static function getTextsWithUpload(Upload $upload): array {
        $db = DB();
        $q = $db->query("SELECT id FROM posts_texts WHERE md LIKE '%{image:{$upload->randomId}%'");
        $ids = [];
        while ($row = $db->fetch($q))
            $ids[] = (int)$row['id'];
        return self::getPostTextsById($ids, true);
    }

}