<?php

declare(strict_types=1);

class Post extends DB\SQL\Mapper
{
    public const TITLE_MAX_LENGTH = 120;
    public const EXCERPT_MAX_LENGTH = 240;

    public function __construct()
    {
        parent::__construct(Base::instance()->get('DB'), 'posts');
    }

    public static function bootstrap(DB\SQL $db): void
    {
        if ($db->schema('posts', null, 0)) {
            return;
        }

        $db->exec('CREATE TABLE posts (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            title TEXT NOT NULL,
            slug TEXT NOT NULL UNIQUE,
            excerpt TEXT NOT NULL,
            body_markdown TEXT NOT NULL,
            body_html TEXT NOT NULL,
            created_at TEXT NOT NULL,
            updated_at TEXT NOT NULL
        )');
        $db->exec('CREATE INDEX idx_posts_created_at ON posts(created_at DESC)');
    }

    public static function blank(): array
    {
        return [
            'title' => '',
            'excerpt' => '',
            'body_markdown' => '',
        ];
    }

    public function page(int $page, int $perPage): array
    {
        $result = $this->paginate(max(0, $page - 1), $perPage, null, ['order' => 'created_at DESC, id DESC']);
        $items = array_map(fn(self $row): array => $this->summary($row->cast()), $result['subset'] ?: []);

        return [
            'items' => $items,
            'pagination' => [
                'page' => max(1, min($page, $result['count'] ?: 1)),
                'pages' => max(1, (int) ($result['count'] ?: 1)),
            ],
        ];
    }

    public function findBySlug(string $slug): ?array
    {
        $this->load(['slug = ?', $slug]);
        if ($this->dry()) {
            return null;
        }

        $row = $this->cast();
        $post = $this->summary($row) + ['body_html' => (string) $row['body_html']];

        return $post;
    }

    public function findForForm(int $id): ?array
    {
        $this->load(['id = ?', $id]);
        if ($this->dry()) {
            return null;
        }

        return [
            'id' => (int) $this->id,
            'title' => (string) $this->title,
            'excerpt' => (string) $this->excerpt,
            'body_markdown' => (string) $this->body_markdown,
        ];
    }

    public function savePost(array $input, ?int $id = null): int
    {
        $payload = $this->payload($input);
        $now = app_now();

        if ($id === null) {
            $this->reset();
            $payload['slug'] = $this->uniqueSlug($payload['title']);
            $payload['created_at'] = $now;
        } else {
            $this->load(['id = ?', $id]);
            if ($this->dry()) {
                throw new RuntimeException('Article introuvable.');
            }
        }

        $payload['updated_at'] = $now;
        $this->copyfrom($payload);
        $this->save();

        return (int) $this->id;
    }

    public function deleteById(int $id): void
    {
        $this->load(['id = ?', $id]);
        if ($this->dry()) {
            throw new RuntimeException('Article introuvable.');
        }

        $this->erase();
    }

    public function usesMedia(string $fileName): bool
    {
        return $this->count(['body_markdown LIKE ?', '%media:' . $fileName . '%']) > 0;
    }

    private function payload(array $input): array
    {
        $title = trim((string) ($input['title'] ?? ''));
        $excerpt = trim((string) ($input['excerpt'] ?? ''));
        $body = trim((string) ($input['body_markdown'] ?? ''));

        if ($title === '') {
            throw new RuntimeException('Ajoute un titre.');
        }
        if (mb_strlen($title) > self::TITLE_MAX_LENGTH) {
            throw new RuntimeException('Le titre est trop long.');
        }
        if ($excerpt === '') {
            throw new RuntimeException('Ajoute un extrait.');
        }
        if (mb_strlen($excerpt) > self::EXCERPT_MAX_LENGTH) {
            throw new RuntimeException('L’extrait est trop long.');
        }

        return [
            'title' => $title,
            'excerpt' => $excerpt,
            'body_markdown' => $body,
            'body_html' => MarkdownService::instance()->compile($body, new Media()),
        ];
    }

    private function uniqueSlug(string $title): string
    {
        $base = app_slug($title);
        $slug = $base;
        $n = 2;

        while ($this->count(['slug = ?', $slug]) > 0) {
            $slug = $base . '-' . $n;
            $n++;
        }

        return $slug;
    }

    private function summary(array $row): array
    {
        $thumbnail = $this->firstImage((string) ($row['body_html'] ?? ''));

        return [
            'id' => (int) $row['id'],
            'title' => (string) $row['title'],
            'slug' => (string) $row['slug'],
            'excerpt' => (string) $row['excerpt'],
            'thumbnail_url' => $thumbnail['url'],
            'thumbnail_alt' => $thumbnail['alt'],
            'created_at' => (string) $row['created_at'],
            'updated_at' => (string) $row['updated_at'],
        ];
    }

    private function firstImage(string $html): array
    {
        if ($html === '') {
            return ['url' => '', 'alt' => ''];
        }

        if (!preg_match('~(<img\s[^>]*src="([^"]+)"[^>]*>)~i', $html, $match)) {
            return ['url' => '', 'alt' => ''];
        }

        $tag = $match[1];
        $alt = '';

        if (preg_match('~alt="([^"]*)"~i', $tag, $altMatch)) {
            $alt = html_entity_decode($altMatch[1], ENT_QUOTES | ENT_HTML5, 'UTF-8');
        }

        return [
            'url' => html_entity_decode($match[2], ENT_QUOTES | ENT_HTML5, 'UTF-8'),
            'alt' => $alt,
        ];
    }
}