<?php

namespace phpweb\News;

class Entry
{
    public const CATEGORIES = [
        'frontpage' => 'PHP.net frontpage news',
        'releases' => 'New PHP release',
        'conferences' => 'Conference announcement',
        'cfp' => 'Call for Papers',
    ];

    public const WEBROOT = "https://www.php.net";

    public const PHPWEB = __DIR__ . '/../../';

    public const ARCHIVE_FILE_REL = 'archive/archive.xml';

    public const ARCHIVE_FILE_ABS = self::PHPWEB . self::ARCHIVE_FILE_REL;

    public const ARCHIVE_ENTRIES_REL = 'archive/entries/';

    public const ARCHIVE_ENTRIES_ABS = self::PHPWEB . self::ARCHIVE_ENTRIES_REL;

    public const IMAGE_PATH_REL = 'images/news/';

    public const IMAGE_PATH_ABS = self::PHPWEB . self::IMAGE_PATH_REL;

    protected $title = '';

    protected $categories = [];

    protected $conf_time = 0;

    protected $image = [];

    protected $content = '';

    protected $id = '';

    public function setTitle(string $title): self {
        $this->title = $title;
        return $this;
    }

    public function setCategories(array $cats): self {
        foreach ($cats as $cat) {
            if (!isset(self::CATEGORIES[$cat])) {
                throw new \Exception("Unknown category: $cat");
            }
        }
        $this->categories = $cats;
        return $this;
    }

    public function addCategory(string $cat): self {
        if (!isset(self::CATEGORIES[$cat])) {
            throw new \Exception("Unknown category: $cat");
        }
        if (!in_array($cat, $this->categories, false)) {
            $this->categories[] = $cat;
        }
        return $this;
    }

    public function isConference(): bool {
        return (bool)array_intersect($this->categories, ['cfp', 'conferences']);
    }

    public function setConfTime(int $time): self {
        $this->conf_time = $time;
        return $this;
    }

    public function setImage(string $path, string $title, ?string $link): self {
        if (basename($path) !== $path) {
            throw new \Exception('path must be a simple file name under ' . self::IMAGE_PATH_REL);
        }
        if (!file_exists(self::IMAGE_PATH_ABS . $path)) {
            throw new \Exception('Image not found at web-php/' . self::IMAGE_PATH_REL . $path);
        }
        $this->image = [
            'path' => $path,
            'title' => $title,
            'link' => $link,
        ];
        return $this;
    }

    public function setContent(string $content): self {
        if (empty($content)) {
            throw new \Exception('Content must not be empty');
        }
        $this->content = $content;
        return $this;
    }

    public function getId(): string {
        return $this->id;
    }

    public function save(): self {
        if (empty($this->id)) {
            $this->id = self::selectNextId();
        }

        // Create the XML document.
        $dom = new \DOMDocument("1.0", "utf-8");
        $dom->formatOutput = true;
        $dom->preserveWhiteSpace = false;
        $item = $dom->createElementNs("http://www.w3.org/2005/Atom", "entry");

        $href = self::WEBROOT . ($this->isConference() ? '/conferences/index.php' : '/index.php');
        $archive = self::WEBROOT . "/archive/" . date('Y', $_SERVER['REQUEST_TIME']) . ".php#{$this->id}";
        $link = ($this->image['link'] ?? null) ?: $archive;

        self::ce($dom, "title", $this->title, [], $item);
        self::ce($dom, "id", $archive, [], $item);
        self::ce($dom, "published", date(DATE_ATOM), [], $item);
        self::ce($dom, "updated", date(DATE_ATOM), [], $item);
        self::ce($dom, "link", null, ['href' => "{$href}#{$this->id}", "rel" => "alternate", "type" => "text/html"], $item);
        self::ce($dom, "link", null, ['href' => $link, 'rel' => 'via', 'type' => 'text/html'], $item);

        if (!empty($this->conf_time)) {
            $item->appendChild($dom->createElementNs("http://php.net/ns/news", "finalTeaserDate", date("Y-m-d", $this->conf_time)));
        }

        foreach ($this->categories as $cat) {
            self::ce($dom, "category", null, ['term' => $cat, "label" => self::CATEGORIES[$cat]], $item);
        }

        if ($this->image['path'] ?? '') {
            $image = $item->appendChild($dom->createElementNs("http://php.net/ns/news", "newsImage", $this->image['path']));
            $image->setAttribute("link", $this->image['link']);
            $image->setAttribute("title", $this->image['title']);
        }

        $content = self::ce($dom, "content", null, [], $item);

        // Slurp content into our DOM.
        $tdoc = new \DOMDocument("1.0", "utf-8");
        $tdoc->formatOutput = true;
        if ($tdoc->loadXML("<div>{$this->content}    </div>")) {
            $content->setAttribute("type", "xhtml");
            $div = $content->appendChild($dom->createElement("div"));
            $div->setAttribute("xmlns", "http://www.w3.org/1999/xhtml");
            foreach ($tdoc->firstChild->childNodes as $node) {
                $div->appendChild($dom->importNode($node, true));
            }
        } else {
            fwrite(STDERR, "There is something wrong with your xhtml, falling back to html");
            $content->setAttribute("type", "html");
            $content->nodeValue = $this->content;
        }

        $dom->appendChild($item);
        $dom->save(self::ARCHIVE_ENTRIES_ABS . $this->id . ".xml");

        return $this;
    }

    public function updateArchiveXML(): self {
        if (empty($this->id)) {
            throw new \Exception('Entry must be saved before updating archive XML');
        }

        $arch = new \DOMDocument("1.0", "utf-8");
        $arch->formatOutput = true;
        $arch->preserveWhiteSpace = false;
        $arch->load(self::ARCHIVE_FILE_ABS);

        $first = $arch->createElementNs("http://www.w3.org/2001/XInclude", "xi:include");
        $first->setAttribute("href", "entries/{$this->id}.xml");

        $second = $arch->getElementsByTagNameNs("http://www.w3.org/2001/XInclude", "include")->item(0);
        $arch->documentElement->insertBefore($first, $second);
        $arch->save(self::ARCHIVE_FILE_ABS);

        return $this;
    }

    private static function selectNextId(): string {
        $filename = date("Y-m-d", $_SERVER["REQUEST_TIME"]);
        $count = 0;
        do {
            $count++;
            $id = $filename . "-" . $count;
            $basename = "{$id}.xml";
        } while (file_exists(self::ARCHIVE_ENTRIES_ABS . $basename));

        return $id;
    }

    private static function ce(\DOMDocument $d, string $name, $value, array $attrs = [], ?\DOMNode $to = null) {
        if ($value) {
            $n = $d->createElement($name, $value);
        } else {
            $n = $d->createElement($name);
        }
        foreach ($attrs as $k => $v) {
            $n->setAttribute($k, $v);
        }
        if ($to) {
            return $to->appendChild($n);
        }
        return $n;
    }
}