<?php
declare(strict_types=1);

namespace App;

final class NexusDashboardService
{
    public function __construct(private ?\PDO $pdo)
    {
    }

    public function available(): bool
    {
        return $this->pdo instanceof \PDO;
    }

    public function ensureDefaultDashboard(string $ownerKey, string $title = 'Mein Dashboard'): array
    {
        $dashboards = $this->listDashboardsForOwner($ownerKey);
        if ($dashboards !== []) {
            foreach ($dashboards as $dashboard) {
                if (!empty($dashboard['is_default'])) {
                    return $dashboard;
                }
            }
            $this->setDefaultDashboard($ownerKey, (int) $dashboards[0]['id']);
            return $this->getDashboardById((int) $dashboards[0]['id']) ?? $dashboards[0];
        }

        $id = $this->createDashboard($ownerKey, [
            'title' => $title,
            'slug' => 'mein-dashboard',
            'description' => 'Persönliches Nexus-Dashboard.',
            'visibility' => 'private',
            'is_default' => true,
        ]);

        return $this->getDashboardById($id) ?? [];
    }

    public function listDashboardsForOwner(string $ownerKey): array
    {
        if (!$this->available() || $ownerKey === '') {
            return [];
        }

        $stmt = $this->pdo->prepare(
            "SELECT *
             FROM nexus_dashboards
             WHERE owner_key = :owner
             ORDER BY is_default DESC, sort_order ASC, title ASC, id ASC"
        );
        $stmt->execute(['owner' => $ownerKey]);

        return $this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []);
    }

    public function listAccessibleDashboards(string $ownerKey, array $groups = []): array
    {
        if (!$this->available()) {
            return [];
        }

        $rows = [];
        $seen = [];
        foreach ($this->listDashboardsForOwner($ownerKey) as $dashboard) {
            $id = (int) ($dashboard['id'] ?? 0);
            if ($id > 0) {
                $rows[] = $dashboard;
                $seen[$id] = true;
            }
        }

        $stmt = $this->pdo->prepare(
            "SELECT *
             FROM nexus_dashboards
             WHERE visibility = 'public'
             ORDER BY sort_order ASC, title ASC, id ASC"
        );
        $stmt->execute();
        foreach ($this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []) as $dashboard) {
            $id = (int) ($dashboard['id'] ?? 0);
            if ($id > 0 && !isset($seen[$id])) {
                $rows[] = $dashboard;
                $seen[$id] = true;
            }
        }

        if ($ownerKey !== '') {
            $shared = $this->listSharedDashboardIds($ownerKey, $groups);
            foreach ($shared as $dashboardId) {
                if (isset($seen[$dashboardId])) {
                    continue;
                }
                $dashboard = $this->getDashboardById($dashboardId);
                if ($dashboard !== null) {
                    $rows[] = $dashboard;
                    $seen[$dashboardId] = true;
                }
            }
        }

        usort($rows, static function (array $left, array $right): int {
            return [$left['sort_order'] ?? 0, (string) ($left['title'] ?? ''), (int) ($left['id'] ?? 0)]
                <=> [$right['sort_order'] ?? 0, (string) ($right['title'] ?? ''), (int) ($right['id'] ?? 0)];
        });

        return $rows;
    }

    public function resolveHomeDashboard(?string $ownerKey, array $groups, bool $authenticated, int $preferredId = 0): ?array
    {
        if (!$this->available()) {
            return null;
        }

        if ($authenticated && $ownerKey !== null && $ownerKey !== '') {
            if ($preferredId > 0) {
                $preferred = $this->getDashboardById($preferredId);
                if ($preferred !== null && $this->canAccessDashboard($preferred, $ownerKey, $groups)) {
                    return $preferred;
                }
            }

            $dashboards = $this->listAccessibleDashboards($ownerKey, $groups);
            foreach ($dashboards as $dashboard) {
                if (!empty($dashboard['is_default']) && $this->canAccessDashboard($dashboard, $ownerKey, $groups)) {
                    return $dashboard;
                }
            }
            foreach ($dashboards as $dashboard) {
                if ($this->canAccessDashboard($dashboard, $ownerKey, $groups)) {
                    return $dashboard;
                }
            }
        }

        $publicId = (int) (($this->settings()['global_home_dashboard_id'] ?? 0));
        if ($publicId > 0) {
            $dashboard = $this->getDashboardById($publicId);
            if ($dashboard !== null && (string) ($dashboard['visibility'] ?? '') === 'public') {
                return $dashboard;
            }
        }

        foreach ($this->listPublicDashboards() as $dashboard) {
            return $dashboard;
        }

        return null;
    }

    public function listPublicDashboards(): array
    {
        if (!$this->available()) {
            return [];
        }

        $stmt = $this->pdo->prepare(
            "SELECT *
             FROM nexus_dashboards
             WHERE visibility = 'public'
             ORDER BY is_default DESC, sort_order ASC, title ASC, id ASC"
        );
        $stmt->execute();
        return $this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []);
    }

    public function getDashboardById(int $id): ?array
    {
        if (!$this->available() || $id <= 0) {
            return null;
        }

        $stmt = $this->pdo->prepare("SELECT * FROM nexus_dashboards WHERE id = :id LIMIT 1");
        $stmt->execute(['id' => $id]);
        $row = $stmt->fetch(\PDO::FETCH_ASSOC);

        return is_array($row) ? $this->hydrateRow($row) : null;
    }

    public function createDashboard(string $ownerKey, array $data): int
    {
        if (!$this->available() || $ownerKey === '') {
            return 0;
        }

        $title = trim((string) ($data['title'] ?? 'Neues Dashboard'));
        $slug = $this->uniqueSlug('nexus_dashboards', $ownerKey, (string) ($data['slug'] ?? $title), 0);
        $description = trim((string) ($data['description'] ?? ''));
        $visibility = $this->normalizeVisibility((string) ($data['visibility'] ?? 'private'));
        $sortOrder = (int) ($data['sort_order'] ?? $this->nextSortOrder('nexus_dashboards', 'owner_key', $ownerKey));
        $isDefault = !empty($data['is_default']);
        $config = $this->encodeJson((array) ($data['config'] ?? []));

        $stmt = $this->pdo->prepare(
            "INSERT INTO nexus_dashboards
                (owner_key, title, slug, description, visibility, sort_order, is_default, config, created_at, updated_at)
             VALUES
                (:owner_key, :title, :slug, :description, :visibility, :sort_order, :is_default, :config, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)"
        );
        $stmt->execute([
            'owner_key' => $ownerKey,
            'title' => $title !== '' ? $title : 'Neues Dashboard',
            'slug' => $slug,
            'description' => $description,
            'visibility' => $visibility,
            'sort_order' => $sortOrder,
            'is_default' => $isDefault ? 1 : 0,
            'config' => $config,
        ]);

        $id = (int) $this->pdo->lastInsertId();
        if ($isDefault) {
            $this->setDefaultDashboard($ownerKey, $id);
        }

        return $id;
    }

    public function updateDashboard(int $id, string $ownerKey, array $data): void
    {
        if (!$this->available() || $id <= 0 || $ownerKey === '') {
            return;
        }

        $dashboard = $this->getOwnedDashboard($id, $ownerKey);
        if ($dashboard === null) {
            return;
        }

        $title = trim((string) ($data['title'] ?? ($dashboard['title'] ?? 'Dashboard')));
        $slug = $this->uniqueSlug('nexus_dashboards', $ownerKey, (string) ($data['slug'] ?? $title), $id);
        $description = trim((string) ($data['description'] ?? ($dashboard['description'] ?? '')));
        $visibility = $this->normalizeVisibility((string) ($data['visibility'] ?? ($dashboard['visibility'] ?? 'private')));
        $sortOrder = isset($data['sort_order']) ? (int) $data['sort_order'] : (int) ($dashboard['sort_order'] ?? 0);
        $config = $this->encodeJson((array) ($data['config'] ?? ($dashboard['config'] ?? [])));
        $isDefault = !empty($data['is_default']);

        $stmt = $this->pdo->prepare(
            "UPDATE nexus_dashboards
             SET title = :title,
                 slug = :slug,
                 description = :description,
                 visibility = :visibility,
                 sort_order = :sort_order,
                 is_default = :is_default,
                 config = :config,
                 updated_at = CURRENT_TIMESTAMP
             WHERE id = :id AND owner_key = :owner_key"
        );
        $stmt->execute([
            'id' => $id,
            'owner_key' => $ownerKey,
            'title' => $title !== '' ? $title : 'Dashboard',
            'slug' => $slug,
            'description' => $description,
            'visibility' => $visibility,
            'sort_order' => $sortOrder,
            'is_default' => $isDefault ? 1 : 0,
            'config' => $config,
        ]);

        if ($isDefault) {
            $this->setDefaultDashboard($ownerKey, $id);
        }
    }

    public function deleteDashboard(int $id, string $ownerKey): void
    {
        if (!$this->available() || $id <= 0 || $ownerKey === '') {
            return;
        }

        $dashboard = $this->getOwnedDashboard($id, $ownerKey);
        if ($dashboard === null) {
            return;
        }

        $stmt = $this->pdo->prepare("DELETE FROM nexus_dashboard_items WHERE dashboard_id = :dashboard_id");
        $stmt->execute(['dashboard_id' => $id]);

        $stmt = $this->pdo->prepare("DELETE FROM nexus_dashboard_shares WHERE dashboard_id = :dashboard_id");
        $stmt->execute(['dashboard_id' => $id]);

        $stmt = $this->pdo->prepare("DELETE FROM nexus_dashboards WHERE id = :id AND owner_key = :owner_key");
        $stmt->execute(['id' => $id, 'owner_key' => $ownerKey]);

        if (!empty($dashboard['is_default'])) {
            $remaining = $this->listDashboardsForOwner($ownerKey);
            if ($remaining !== []) {
                $this->setDefaultDashboard($ownerKey, (int) $remaining[0]['id']);
            }
        }
    }

    public function setDefaultDashboard(string $ownerKey, int $dashboardId): void
    {
        if (!$this->available() || $ownerKey === '' || $dashboardId <= 0) {
            return;
        }

        $stmt = $this->pdo->prepare("UPDATE nexus_dashboards SET is_default = 0, updated_at = CURRENT_TIMESTAMP WHERE owner_key = :owner_key");
        $stmt->execute(['owner_key' => $ownerKey]);

        $stmt = $this->pdo->prepare("UPDATE nexus_dashboards SET is_default = 1, updated_at = CURRENT_TIMESTAMP WHERE id = :id AND owner_key = :owner_key");
        $stmt->execute(['id' => $dashboardId, 'owner_key' => $ownerKey]);
    }

    public function listItems(int $dashboardId): array
    {
        if (!$this->available() || $dashboardId <= 0) {
            return [];
        }

        $stmt = $this->pdo->prepare(
            "SELECT *
             FROM nexus_dashboard_items
             WHERE dashboard_id = :dashboard_id
             ORDER BY sort_order ASC, id ASC"
        );
        $stmt->execute(['dashboard_id' => $dashboardId]);

        return $this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []);
    }

    public function createItem(int $dashboardId, string $ownerKey, array $data): int
    {
        if (!$this->available() || $dashboardId <= 0) {
            return 0;
        }

        $dashboard = $this->getOwnedDashboard($dashboardId, $ownerKey);
        if ($dashboard === null) {
            return 0;
        }

        $itemType = $this->normalizeItemType((string) ($data['item_type'] ?? 'link'));
        $title = trim((string) ($data['title'] ?? 'Element'));
        $description = trim((string) ($data['description'] ?? ''));
        $gridColumn = $this->nullableInt($data['grid_column'] ?? null);
        $gridRow = $this->nullableInt($data['grid_row'] ?? null);
        $columnSpan = max(1, min(4, (int) ($data['column_span'] ?? 1)));
        $rowSpan = max(1, min(4, (int) ($data['row_span'] ?? 1)));
        $sortOrder = (int) ($data['sort_order'] ?? $this->nextItemSortOrder($dashboardId));
        $config = $this->encodeJson((array) ($data['config'] ?? []));

        $stmt = $this->pdo->prepare(
            "INSERT INTO nexus_dashboard_items
                (dashboard_id, item_type, title, description, grid_column, grid_row, column_span, row_span, sort_order, config, created_at, updated_at)
             VALUES
                (:dashboard_id, :item_type, :title, :description, :grid_column, :grid_row, :column_span, :row_span, :sort_order, :config, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)"
        );
        $stmt->execute([
            'dashboard_id' => $dashboardId,
            'item_type' => $itemType,
            'title' => $title !== '' ? $title : 'Element',
            'description' => $description,
            'grid_column' => $gridColumn,
            'grid_row' => $gridRow,
            'column_span' => $columnSpan,
            'row_span' => $rowSpan,
            'sort_order' => $sortOrder,
            'config' => $config,
        ]);

        return (int) $this->pdo->lastInsertId();
    }

    public function deleteItem(int $itemId, int $dashboardId, string $ownerKey): void
    {
        if (!$this->available() || $itemId <= 0 || $dashboardId <= 0) {
            return;
        }

        $dashboard = $this->getOwnedDashboard($dashboardId, $ownerKey);
        if ($dashboard === null) {
            return;
        }

        $stmt = $this->pdo->prepare("DELETE FROM nexus_dashboard_items WHERE id = :id AND dashboard_id = :dashboard_id");
        $stmt->execute([
            'id' => $itemId,
            'dashboard_id' => $dashboardId,
        ]);
    }

    public function listIntegrationsForOwner(string $ownerKey): array
    {
        if (!$this->available() || $ownerKey === '') {
            return [];
        }

        $stmt = $this->pdo->prepare(
            "SELECT *
             FROM nexus_integrations
             WHERE owner_key = :owner_key
             ORDER BY is_active DESC, name ASC, id ASC"
        );
        $stmt->execute(['owner_key' => $ownerKey]);

        return $this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []);
    }

    public function createIntegration(string $ownerKey, array $data): int
    {
        if (!$this->available() || $ownerKey === '') {
            return 0;
        }

        $stmt = $this->pdo->prepare(
            "INSERT INTO nexus_integrations
                (owner_key, type, name, base_url, visibility, is_active, config, secrets, created_at, updated_at)
             VALUES
                (:owner_key, :type, :name, :base_url, :visibility, :is_active, :config, :secrets, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)"
        );
        $stmt->execute([
            'owner_key' => $ownerKey,
            'type' => trim((string) ($data['type'] ?? 'generic')) ?: 'generic',
            'name' => trim((string) ($data['name'] ?? 'Integration')) ?: 'Integration',
            'base_url' => trim((string) ($data['base_url'] ?? '')),
            'visibility' => $this->normalizeVisibility((string) ($data['visibility'] ?? 'private')),
            'is_active' => !empty($data['is_active']) ? 1 : 0,
            'config' => $this->encodeJson((array) ($data['config'] ?? [])),
            'secrets' => $this->encodeJson((array) ($data['secrets'] ?? [])),
        ]);

        return (int) $this->pdo->lastInsertId();
    }

    public function deleteIntegration(int $id, string $ownerKey): void
    {
        if (!$this->available() || $id <= 0 || $ownerKey === '') {
            return;
        }

        $stmt = $this->pdo->prepare("DELETE FROM nexus_integrations WHERE id = :id AND owner_key = :owner_key");
        $stmt->execute(['id' => $id, 'owner_key' => $ownerKey]);
    }

    public function listPageModulesForOwner(string $ownerKey): array
    {
        if (!$this->available() || $ownerKey === '') {
            return [];
        }

        $stmt = $this->pdo->prepare(
            "SELECT *
             FROM nexus_page_modules
             WHERE owner_key = :owner_key
             ORDER BY is_active DESC, title ASC, id ASC"
        );
        $stmt->execute(['owner_key' => $ownerKey]);

        return $this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []);
    }

    public function listAccessiblePageModules(string $ownerKey, array $groups = []): array
    {
        if (!$this->available()) {
            return [];
        }

        $rows = [];
        $seen = [];
        foreach ($this->listPageModulesForOwner($ownerKey) as $module) {
            $id = (int) ($module['id'] ?? 0);
            if ($id > 0) {
                $rows[] = $module;
                $seen[$id] = true;
            }
        }

        $stmt = $this->pdo->prepare(
            "SELECT *
             FROM nexus_page_modules
             WHERE visibility = 'public'
             ORDER BY title ASC, id ASC"
        );
        $stmt->execute();
        foreach ($this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []) as $module) {
            $id = (int) ($module['id'] ?? 0);
            if ($id > 0 && !isset($seen[$id])) {
                $rows[] = $module;
                $seen[$id] = true;
            }
        }

        foreach ($groups as $group) {
            $group = trim((string) $group);
            if ($group === '') {
                continue;
            }
            $stmt = $this->pdo->prepare(
                "SELECT *
                 FROM nexus_page_modules
                 WHERE visibility = 'group'"
            );
            $stmt->execute();
            foreach ($this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []) as $module) {
                $id = (int) ($module['id'] ?? 0);
                if ($id <= 0 || isset($seen[$id])) {
                    continue;
                }
                if (in_array($group, (array) ($module['config']['groups'] ?? []), true)) {
                    $rows[] = $module;
                    $seen[$id] = true;
                }
            }
        }

        return $rows;
    }

    public function createPageModule(string $ownerKey, array $data): int
    {
        if (!$this->available() || $ownerKey === '') {
            return 0;
        }

        $title = trim((string) ($data['title'] ?? 'Seitenmodul')) ?: 'Seitenmodul';
        $slug = $this->uniqueSlug('nexus_page_modules', $ownerKey, (string) ($data['slug'] ?? $title), 0);

        $stmt = $this->pdo->prepare(
            "INSERT INTO nexus_page_modules
                (owner_key, title, slug, module_type, target_url, description, visibility, open_mode, is_active, config, created_at, updated_at)
             VALUES
                (:owner_key, :title, :slug, :module_type, :target_url, :description, :visibility, :open_mode, :is_active, :config, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)"
        );
        $stmt->execute([
            'owner_key' => $ownerKey,
            'title' => $title,
            'slug' => $slug,
            'module_type' => $this->normalizePageModuleType((string) ($data['module_type'] ?? 'link')),
            'target_url' => trim((string) ($data['target_url'] ?? '')),
            'description' => trim((string) ($data['description'] ?? '')),
            'visibility' => $this->normalizeVisibility((string) ($data['visibility'] ?? 'private')),
            'open_mode' => $this->normalizeOpenMode((string) ($data['open_mode'] ?? 'embed')),
            'is_active' => !empty($data['is_active']) ? 1 : 0,
            'config' => $this->encodeJson((array) ($data['config'] ?? [])),
        ]);

        return (int) $this->pdo->lastInsertId();
    }

    public function deletePageModule(int $id, string $ownerKey): void
    {
        if (!$this->available() || $id <= 0 || $ownerKey === '') {
            return;
        }

        $stmt = $this->pdo->prepare("DELETE FROM nexus_page_modules WHERE id = :id AND owner_key = :owner_key");
        $stmt->execute(['id' => $id, 'owner_key' => $ownerKey]);
    }

    public function getPageModule(int $id, string $ownerKey = '', array $groups = []): ?array
    {
        if (!$this->available() || $id <= 0) {
            return null;
        }

        $stmt = $this->pdo->prepare("SELECT * FROM nexus_page_modules WHERE id = :id LIMIT 1");
        $stmt->execute(['id' => $id]);
        $row = $stmt->fetch(\PDO::FETCH_ASSOC);
        if (!is_array($row)) {
            return null;
        }

        $module = $this->hydrateRow($row);
        if ($module['owner_key'] === $ownerKey || $module['visibility'] === 'public') {
            return $module;
        }
        if ($module['visibility'] === 'group' && $ownerKey !== '') {
            foreach ($groups as $group) {
                if (in_array($group, (array) ($module['config']['groups'] ?? []), true)) {
                    return $module;
                }
            }
        }

        return null;
    }

    public function listWidgetTemplates(string $ownerKey, bool $includePublic = true): array
    {
        if (!$this->available()) {
            return [];
        }

        $clauses = [];
        $params = [];
        if ($ownerKey !== '') {
            $clauses[] = 'owner_key = :owner_key';
            $params['owner_key'] = $ownerKey;
        }
        if ($includePublic) {
            $clauses[] = "visibility = 'public'";
        }
        if ($clauses === []) {
            return [];
        }

        $stmt = $this->pdo->prepare(
            'SELECT * FROM nexus_widget_templates WHERE ' . implode(' OR ', $clauses) . ' ORDER BY name ASC, id ASC'
        );
        $stmt->execute($params);

        $rows = [];
        $seen = [];
        foreach ($this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []) as $row) {
            $id = (int) ($row['id'] ?? 0);
            if ($id > 0 && !isset($seen[$id])) {
                $rows[] = $row;
                $seen[$id] = true;
            }
        }
        return $rows;
    }

    public function createWidgetTemplate(string $ownerKey, array $data): int
    {
        if (!$this->available() || $ownerKey === '') {
            return 0;
        }

        $stmt = $this->pdo->prepare(
            "INSERT INTO nexus_widget_templates
                (owner_key, name, widget_type, description, visibility, config, created_at, updated_at)
             VALUES
                (:owner_key, :name, :widget_type, :description, :visibility, :config, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)"
        );
        $stmt->execute([
            'owner_key' => $ownerKey,
            'name' => trim((string) ($data['name'] ?? '')) ?: 'Widget',
            'widget_type' => $this->normalizeItemType((string) ($data['widget_type'] ?? 'link')),
            'description' => trim((string) ($data['description'] ?? '')),
            'visibility' => $this->normalizeVisibility((string) ($data['visibility'] ?? 'private')),
            'config' => $this->encodeJson((array) ($data['config'] ?? [])),
        ]);

        return (int) $this->pdo->lastInsertId();
    }

    public function deleteWidgetTemplate(int $id, string $ownerKey): void
    {
        if (!$this->available() || $id <= 0 || $ownerKey === '') {
            return;
        }

        $stmt = $this->pdo->prepare("DELETE FROM nexus_widget_templates WHERE id = :id AND owner_key = :owner_key");
        $stmt->execute(['id' => $id, 'owner_key' => $ownerKey]);
    }

    public function listSearchEngines(string $ownerKey, bool $includePublic = true): array
    {
        if (!$this->available()) {
            return [];
        }

        $clauses = [];
        $params = [];
        if ($ownerKey !== '') {
            $clauses[] = 'owner_key = :owner_key';
            $params['owner_key'] = $ownerKey;
        }
        if ($includePublic) {
            $clauses[] = "visibility = 'public'";
        }
        $stmt = $this->pdo->prepare(
            'SELECT * FROM nexus_search_engines WHERE ' . implode(' OR ', $clauses) . ' ORDER BY is_default DESC, name ASC, id ASC'
        );
        $stmt->execute($params);

        $rows = [];
        $seen = [];
        foreach ($this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []) as $row) {
            $id = (int) ($row['id'] ?? 0);
            if ($id > 0 && !isset($seen[$id])) {
                $rows[] = $row;
                $seen[$id] = true;
            }
        }
        return $rows;
    }

    public function createSearchEngine(string $ownerKey, array $data): int
    {
        if (!$this->available() || $ownerKey === '') {
            return 0;
        }

        $shortCode = $this->normalizeShortCode((string) ($data['short_code'] ?? ''));
        if ($shortCode === '') {
            $shortCode = 's' . random_int(100, 999);
        }
        $shortCode = $this->uniqueSearchShortCode($ownerKey, $shortCode, 0);

        $stmt = $this->pdo->prepare(
            "INSERT INTO nexus_search_engines
                (owner_key, name, short_code, engine_type, template_url, integration_id, visibility, is_default, config, created_at, updated_at)
             VALUES
                (:owner_key, :name, :short_code, :engine_type, :template_url, :integration_id, :visibility, :is_default, :config, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)"
        );
        $stmt->execute([
            'owner_key' => $ownerKey,
            'name' => trim((string) ($data['name'] ?? '')) ?: 'Suche',
            'short_code' => $shortCode,
            'engine_type' => trim((string) ($data['engine_type'] ?? 'template')) ?: 'template',
            'template_url' => trim((string) ($data['template_url'] ?? '')),
            'integration_id' => !empty($data['integration_id']) ? (int) $data['integration_id'] : null,
            'visibility' => $this->normalizeVisibility((string) ($data['visibility'] ?? 'private')),
            'is_default' => !empty($data['is_default']) ? 1 : 0,
            'config' => $this->encodeJson((array) ($data['config'] ?? [])),
        ]);
        $id = (int) $this->pdo->lastInsertId();
        if (!empty($data['is_default'])) {
            $this->setDefaultSearchEngine($ownerKey, $id);
        }
        return $id;
    }

    public function setDefaultSearchEngine(string $ownerKey, int $id): void
    {
        if (!$this->available() || $ownerKey === '' || $id <= 0) {
            return;
        }
        $stmt = $this->pdo->prepare("UPDATE nexus_search_engines SET is_default = 0, updated_at = CURRENT_TIMESTAMP WHERE owner_key = :owner_key");
        $stmt->execute(['owner_key' => $ownerKey]);
        $stmt = $this->pdo->prepare("UPDATE nexus_search_engines SET is_default = 1, updated_at = CURRENT_TIMESTAMP WHERE id = :id AND owner_key = :owner_key");
        $stmt->execute(['id' => $id, 'owner_key' => $ownerKey]);
    }

    public function deleteSearchEngine(int $id, string $ownerKey): void
    {
        if (!$this->available() || $id <= 0 || $ownerKey === '') {
            return;
        }

        $stmt = $this->pdo->prepare("DELETE FROM nexus_search_engines WHERE id = :id AND owner_key = :owner_key");
        $stmt->execute(['id' => $id, 'owner_key' => $ownerKey]);
    }

    public function listApps(string $ownerKey, bool $includePublic = true): array
    {
        if (!$this->available()) {
            return [];
        }

        $clauses = [];
        $params = [];
        if ($ownerKey !== '') {
            $clauses[] = 'owner_key = :owner_key';
            $params['owner_key'] = $ownerKey;
        }
        if ($includePublic) {
            $clauses[] = "visibility = 'public'";
        }
        $stmt = $this->pdo->prepare(
            'SELECT * FROM nexus_apps WHERE ' . implode(' OR ', $clauses) . ' ORDER BY name ASC, id ASC'
        );
        $stmt->execute($params);

        $rows = [];
        $seen = [];
        foreach ($this->hydrateRows($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: []) as $row) {
            $id = (int) ($row['id'] ?? 0);
            if ($id > 0 && !isset($seen[$id])) {
                $rows[] = $row;
                $seen[$id] = true;
            }
        }
        return $rows;
    }

    public function createApp(string $ownerKey, array $data): int
    {
        if (!$this->available() || $ownerKey === '') {
            return 0;
        }

        $stmt = $this->pdo->prepare(
            "INSERT INTO nexus_apps
                (owner_key, name, description, app_url, icon_url, integration_id, visibility, config, created_at, updated_at)
             VALUES
                (:owner_key, :name, :description, :app_url, :icon_url, :integration_id, :visibility, :config, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)"
        );
        $stmt->execute([
            'owner_key' => $ownerKey,
            'name' => trim((string) ($data['name'] ?? '')) ?: 'App',
            'description' => trim((string) ($data['description'] ?? '')),
            'app_url' => trim((string) ($data['app_url'] ?? '')),
            'icon_url' => trim((string) ($data['icon_url'] ?? '')),
            'integration_id' => !empty($data['integration_id']) ? (int) $data['integration_id'] : null,
            'visibility' => $this->normalizeVisibility((string) ($data['visibility'] ?? 'private')),
            'config' => $this->encodeJson((array) ($data['config'] ?? [])),
        ]);

        return (int) $this->pdo->lastInsertId();
    }

    public function deleteApp(int $id, string $ownerKey): void
    {
        if (!$this->available() || $id <= 0 || $ownerKey === '') {
            return;
        }

        $stmt = $this->pdo->prepare("DELETE FROM nexus_apps WHERE id = :id AND owner_key = :owner_key");
        $stmt->execute(['id' => $id, 'owner_key' => $ownerKey]);
    }

    private function listSharedDashboardIds(string $ownerKey, array $groups): array
    {
        $result = [];
        $stmt = $this->pdo->prepare(
            "SELECT dashboard_id, share_type, share_value
             FROM nexus_dashboard_shares
             WHERE share_type = 'user' AND share_value = :share_value"
        );
        $stmt->execute(['share_value' => $ownerKey]);
        foreach ($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: [] as $row) {
            $result[] = (int) ($row['dashboard_id'] ?? 0);
        }

        foreach ($groups as $group) {
            $group = trim((string) $group);
            if ($group === '') {
                continue;
            }
            $stmt = $this->pdo->prepare(
                "SELECT dashboard_id
                 FROM nexus_dashboard_shares
                 WHERE share_type = 'group' AND share_value = :share_value"
            );
            $stmt->execute(['share_value' => $group]);
            foreach ($stmt->fetchAll(\PDO::FETCH_ASSOC) ?: [] as $row) {
                $result[] = (int) ($row['dashboard_id'] ?? 0);
            }
        }

        return array_values(array_unique(array_filter($result, static fn (int $id): bool => $id > 0)));
    }

    private function getOwnedDashboard(int $id, string $ownerKey): ?array
    {
        $dashboard = $this->getDashboardById($id);
        if ($dashboard === null || (string) ($dashboard['owner_key'] ?? '') !== $ownerKey) {
            return null;
        }

        return $dashboard;
    }

    private function uniqueSlug(string $table, string $ownerKey, string $candidate, int $ignoreId): string
    {
        $slug = $this->slugify($candidate);
        $suffix = 1;
        while ($this->slugExists($table, $ownerKey, $slug, $ignoreId)) {
            $suffix++;
            $slug = $this->slugify($candidate) . '-' . $suffix;
        }
        return $slug;
    }

    private function slugExists(string $table, string $ownerKey, string $slug, int $ignoreId): bool
    {
        $sql = "SELECT id FROM {$table} WHERE owner_key = :owner_key AND slug = :slug";
        if ($ignoreId > 0) {
            $sql .= " AND id <> :id";
        }
        $sql .= " LIMIT 1";
        $stmt = $this->pdo->prepare($sql);
        $params = ['owner_key' => $ownerKey, 'slug' => $slug];
        if ($ignoreId > 0) {
            $params['id'] = $ignoreId;
        }
        $stmt->execute($params);
        return (bool) $stmt->fetchColumn();
    }

    private function slugify(string $value): string
    {
        $value = trim(mb_strtolower($value));
        $value = preg_replace('/[^a-z0-9]+/u', '-', $value) ?? '';
        $value = trim($value, '-');
        return $value !== '' ? $value : 'eintrag';
    }

    private function nextSortOrder(string $table, string $field, string $value): int
    {
        $stmt = $this->pdo->prepare("SELECT COALESCE(MAX(sort_order), 0) + 10 FROM {$table} WHERE {$field} = :value");
        $stmt->execute(['value' => $value]);
        return (int) $stmt->fetchColumn();
    }

    private function nextItemSortOrder(int $dashboardId): int
    {
        $stmt = $this->pdo->prepare("SELECT COALESCE(MAX(sort_order), 0) + 10 FROM nexus_dashboard_items WHERE dashboard_id = :dashboard_id");
        $stmt->execute(['dashboard_id' => $dashboardId]);
        return (int) $stmt->fetchColumn();
    }

    private function normalizeVisibility(string $value): string
    {
        $value = trim($value);
        return in_array($value, ['private', 'group', 'public'], true) ? $value : 'private';
    }

    private function normalizeItemType(string $value): string
    {
        $value = trim($value);
        return in_array($value, ['link', 'iframe', 'page_module', 'bookmark_group', 'module_link', 'app', 'widget_template'], true) ? $value : 'link';
    }

    private function normalizePageModuleType(string $value): string
    {
        $value = trim($value);
        return in_array($value, ['link', 'iframe', 'bookmark_group', 'external_status'], true) ? $value : 'link';
    }

    private function normalizeOpenMode(string $value): string
    {
        $value = trim($value);
        return in_array($value, ['embed', 'new_tab', 'same_tab'], true) ? $value : 'embed';
    }

    private function encodeJson(array $value): string
    {
        $encoded = json_encode($value, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        return $encoded === false ? '{}' : $encoded;
    }

    private function decodeJson(mixed $value): array
    {
        if (!is_string($value) || trim($value) === '') {
            return [];
        }
        $decoded = json_decode($value, true);
        return is_array($decoded) ? $decoded : [];
    }

    private function hydrateRows(array $rows): array
    {
        return array_values(array_map(fn (array $row): array => $this->hydrateRow($row), $rows));
    }

    private function hydrateRow(array $row): array
    {
        foreach (['config', 'secrets'] as $jsonField) {
            if (array_key_exists($jsonField, $row)) {
                $row[$jsonField] = $this->decodeJson($row[$jsonField]);
            }
        }

        foreach (['is_default', 'is_active'] as $boolField) {
            if (array_key_exists($boolField, $row)) {
                $row[$boolField] = !empty($row[$boolField]);
            }
        }

        return $row;
    }

    private function nullableInt(mixed $value): ?int
    {
        if ($value === null || $value === '') {
            return null;
        }
        return (int) $value;
    }

    private function settings(): array
    {
        return function_exists('nexus_settings') ? nexus_settings() : [];
    }

    private function canAccessDashboard(array $dashboard, string $ownerKey, array $groups): bool
    {
        if ((string) ($dashboard['owner_key'] ?? '') === $ownerKey) {
            return true;
        }
        $visibility = (string) ($dashboard['visibility'] ?? 'private');
        if ($visibility === 'public') {
            return true;
        }
        if ($visibility === 'group') {
            $sharedIds = $this->listSharedDashboardIds($ownerKey, $groups);
            return in_array((int) ($dashboard['id'] ?? 0), $sharedIds, true);
        }
        return false;
    }

    private function normalizeShortCode(string $value): string
    {
        $value = strtolower(trim($value));
        $value = preg_replace('/[^a-z0-9_-]+/', '', $value) ?? '';
        return substr($value, 0, 24);
    }

    private function uniqueSearchShortCode(string $ownerKey, string $candidate, int $ignoreId): string
    {
        $shortCode = $candidate;
        $suffix = 1;
        while ($this->searchShortCodeExists($ownerKey, $shortCode, $ignoreId)) {
            $suffix++;
            $shortCode = substr($candidate, 0, 20) . $suffix;
        }
        return $shortCode;
    }

    private function searchShortCodeExists(string $ownerKey, string $shortCode, int $ignoreId): bool
    {
        $sql = "SELECT id FROM nexus_search_engines WHERE owner_key = :owner_key AND short_code = :short_code";
        if ($ignoreId > 0) {
            $sql .= " AND id <> :id";
        }
        $sql .= " LIMIT 1";
        $stmt = $this->pdo->prepare($sql);
        $params = ['owner_key' => $ownerKey, 'short_code' => $shortCode];
        if ($ignoreId > 0) {
            $params['id'] = $ignoreId;
        }
        $stmt->execute($params);
        return (bool) $stmt->fetchColumn();
    }
}