<?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(DB\SQL $db)
    {
        parent::__construct($db, 'posts');
    }

    public static function bootstrap(DB\SQL $db): void
    {
        $db->exec('CREATE TABLE IF NOT EXISTS 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,
            cover_media_id INTEGER DEFAULT NULL,
            created_at TEXT NOT NULL,
            updated_at TEXT NOT NULL,
            FOREIGN KEY (cover_media_id) REFERENCES media(id) ON DELETE SET NULL
        )');
        $db->exec('CREATE INDEX IF NOT EXISTS idx_posts_created_at ON posts(created_at DESC)');
    }

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

    public function paginateList(int $page = 1, int $perPage = 12): array
    {
        $result = $this->paginate(
            max(0, $page - 1),
            $perPage,
            null,
            ['order' => 'created_at DESC, id DESC']
        );

        $posts = array_map(fn (self $p): array => $this->summaryRow($p->cast()), $result['subset']);
        $covers = $this->loadCovers($posts);

        foreach ($posts as &$post) {
            $cover = $covers[$post['cover_media_id']] ?? null;
            $post['cover_url'] = $cover ? app_media_url((string) $cover['file_name']) : '';
        }

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

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

        $post = $this->summaryRow($this->cast());
        $covers = $this->loadCovers([$post]);
        $cover = $covers[$post['cover_media_id']] ?? null;
        $post['cover_url'] = $cover ? app_media_url((string) $cover['file_name']) : '';
        $post['body_html'] = (string) $this->body_html;

        return $post;
    }

    public function findForEdit(int $id): ?array
    {
        if ($id <= 0) {
            return null;
        }

        $this->load(['id = ?', $id]);
        if ($this->dry()) {
            return null;
        }

        return [
            'id' => (int) $this->get('id'),
            'title' => (string) $this->title,
            'excerpt' => (string) $this->excerpt,
            'body_markdown' => (string) $this->body_markdown,
            'cover_media_id' => $this->cover_media_id !== null ? (string) ((int) $this->cover_media_id) : '',
        ];
    }

    public function create(array $input): int
    {
        $payload = $this->payload($input);
        $slug = app_unique_slug($payload['title'], fn (string $candidate): bool => $this->slugExists($candidate));
        $now = app_now();

        $this->reset();
        $this->copyfrom($payload + [
            'slug'       => $slug,
            'created_at' => $now,
            'updated_at' => $now,
        ]);
        $this->save();

        return (int) $this->get('id');
    }

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

        $payload = $this->payload($input);
        $this->copyfrom($payload + ['updated_at' => app_now()]);
        $this->save();

        return true;
    }

    public function delete(int $id): void
    {
        $this->load(['id = ?', $id]);
        if (!$this->dry()) {
            $this->erase();
        }
    }

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

        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.");
        }

        $media = new Media($this->db);

        $coverId = null;
        if ($coverMediaId !== '') {
            $coverId = (int) $coverMediaId;
            if ($media->findById($coverId) === null) {
                throw new RuntimeException('Image de couverture introuvable.');
            }
        }

        $bodyHtml = MarkdownService::compile($bodyMarkdown, $media);

        return [
            'title' => $title,
            'excerpt' => $excerpt,
            'body_markdown' => $bodyMarkdown,
            'body_html' => $bodyHtml,
            'cover_media_id' => $coverId,
        ];
    }

    private function slugExists(string $slug): bool
    {
        return $this->count(['slug = ?', $slug]) > 0;
    }

    private function summaryRow(array $row): array
    {
        return [
            'id' => (int) $row['id'],
            'title' => (string) $row['title'],
            'slug' => (string) $row['slug'],
            'excerpt' => (string) $row['excerpt'],
            'cover_media_id' => (int) ($row['cover_media_id'] ?? 0),
            'created_at' => (string) $row['created_at'],
            'created_at_label' => app_format_datetime_fr((string) $row['created_at']),
            'updated_at' => (string) $row['updated_at'],
            'updated_at_label' => app_format_datetime_fr((string) $row['updated_at']),
            'has_updated_at' => (string) $row['updated_at'] !== (string) $row['created_at'],
        ];
    }

    private function loadCovers(array $posts): array
    {
        $ids = array_filter(array_unique(array_column($posts, 'cover_media_id')));
        if ($ids === []) {
            return [];
        }

        $placeholders = implode(',', array_fill(0, count($ids), '?'));
        $rows = $this->db->exec(
            "SELECT id, file_name FROM media WHERE id IN ($placeholders)",
            array_values($ids)
        );

        $map = [];
        foreach ($rows as $row) {
            $map[(int) $row['id']] = $row;
        }

        return $map;
    }
}