<?php

namespace App\Services;

use FluxCms\Core\Models\CmsContent;
use Illuminate\Support\Str;

/**
 * Seitenbaum für den Inhalte-Editor (config/cms_pages.php, Nachtrag 12).
 *
 * Verbindet die Registry mit dem Datenbestand: je Sektion, ob sie in flux_cms_contents liegt
 * (dann mit `content_id`), und was sonst noch in der Datenbank steht, aber in keiner Seite
 * eingetragen ist („Nicht mehr verwendet“).
 */
class CmsPageTree
{
    /** Schlüssel des Sammelpunkts für nicht eingetragene Sektionen. */
    public const UNLISTED = 'unlisted';

    /**
     * Alle Seiten mit ihren Sektionen in Website-Reihenfolge.
     *
     * @return array<string, array{title: string, path: ?string, sections: list<array<string, mixed>>}>
     */
    public function pages(): array
    {
        $rows = CmsContent::query()
            ->get(['id', 'group', 'key'])
            ->keyBy(fn (CmsContent $row) => $row->group.'/'.$row->key);

        $pages = [];

        foreach (config('cms_pages.pages', []) as $pageKey => $page) {
            $sections = [];

            foreach ($page['sections'] ?? [] as $section) {
                $id = $section['group'].'/'.$section['key'];

                $sections[] = array_merge($section, [
                    'page' => $pageKey,
                    'path' => $section['path'] ?? $page['path'] ?? null,
                    'anchor' => $section['anchor'] ?? null,
                    'content_id' => $rows[$id]->id ?? null,
                    'theme_key' => $this->themeKey($section['group'], $section['key']),
                ]);
            }

            $pages[$pageKey] = [
                'title' => $page['title'],
                'path' => $page['path'] ?? null,
                'sections' => $sections,
            ];
        }

        $unlisted = $this->unlistedSections($rows->keys()->all(), $rows);

        if ($unlisted !== []) {
            $pages[self::UNLISTED] = [
                'title' => config('cms_pages.unlisted.title', 'Nicht mehr verwendet'),
                'path' => null,
                'sections' => $unlisted,
            ];
        }

        return $pages;
    }

    /**
     * Eine Sektion aus der Registry samt Datenbankbezug, oder null.
     *
     * @return array<string, mixed>|null
     */
    public function section(string $group, string $key): ?array
    {
        foreach ($this->pages() as $page) {
            foreach ($page['sections'] as $section) {
                if ($section['group'] === $group && $section['key'] === $key) {
                    return $section;
                }
            }
        }

        return null;
    }

    /**
     * Klartext-Beschriftung eines Feldes: Sektions-Override, dann Wörterbuch, sonst lesbar gemacht.
     */
    public function fieldLabel(string $field, ?string $group = null, ?string $key = null): string
    {
        if ($group !== null && $key !== null) {
            foreach (config('cms_pages.pages', []) as $page) {
                foreach ($page['sections'] ?? [] as $section) {
                    if ($section['group'] === $group && $section['key'] === $key && isset($section['fields'][$field])) {
                        return $section['fields'][$field];
                    }
                }
            }
        }

        $labels = config('cms_pages.field_labels', []);

        if (isset($labels[$field])) {
            return $labels[$field];
        }

        return Str::ucfirst(str_replace('_', ' ', $field));
    }

    /**
     * Adresse der Vorschau für eine Sektion: Frontend-Domain, Pfad, Cache-Brecher und Sprungmarke.
     */
    public function previewUrl(?array $section, int $version = 0): ?string
    {
        $path = $section['path'] ?? null;

        if ($path === null) {
            return null;
        }

        $url = rtrim(config('domains.protocol', 'https://').config('domains.domain_b2in'), '/')
            .'/'.ltrim($path, '/')
            .'?cms-preview='.$version;

        if (! empty($section['anchor'])) {
            $url .= '#'.$section['anchor'];
        }

        return $url;
    }

    /**
     * Theme-Section-Schlüssel (Lang-Datei) zu Gruppe/Key, für „Aus Vorlage anlegen“.
     */
    public function themeKey(string $group, string $key): ?string
    {
        foreach (config('cms_section_map.sections', []) as $themeKey => $target) {
            if ($target === [$group, $key]) {
                return $themeKey;
            }
        }

        return null;
    }

    /**
     * @param  list<string>  $ids
     * @param  \Illuminate\Support\Collection<string, CmsContent>  $rows
     * @return list<array<string, mixed>>
     */
    private function unlistedSections(array $ids, $rows): array
    {
        $listed = [];

        foreach (config('cms_pages.pages', []) as $page) {
            foreach ($page['sections'] ?? [] as $section) {
                $listed[$section['group'].'/'.$section['key']] = true;
            }
        }

        $out = [];

        foreach ($ids as $id) {
            if (isset($listed[$id])) {
                continue;
            }

            $row = $rows[$id];

            $out[] = [
                'group' => $row->group,
                'key' => $row->key,
                'page' => self::UNLISTED,
                'path' => null,
                'anchor' => null,
                'title' => $row->group.' / '.$row->key,
                'description' => null,
                'content_id' => $row->id,
                'theme_key' => null,
            ];
        }

        usort($out, fn (array $a, array $b) => [$a['group'], $a['key']] <=> [$b['group'], $b['key']]);

        return $out;
    }
}