# Structural Pages

Drupal 11 module that implements hierarchical editorial structure and contextual navigation for institutional sites. Designed for higher education institutions but generic enough for other institutional contexts.

## Problem

In Drupal, content is added in a flat manner (non-hierarchical), and menus are traditionally used to organize content into hierarchical structures. This creates user experience problems because content editors typically do not have permission to administer menus.

## Solution

The module implements two complementary structures:

1. **Taxonomic Structure** (primary) — Organization based on the `site_sections` hierarchical taxonomy vocabulary, applied to the `section_page` content type. Governs breadcrumbs and URLs via Pathauto.
2. **Parent-Child Structure** (subsidiary) — Direct hierarchy between pages via `field_parent_page` (Dynamic Entity Reference), applied to the `content_page` content type. Supports multiple parent entity types: nodes, taxonomy terms, users, and groups.

## Requirements

- Drupal 11
- Core modules: `node`, `taxonomy`, `views`, `field`, `text`
- Contrib modules:
  - [Token](https://www.drupal.org/project/token)
  - [Pathauto](https://www.drupal.org/project/pathauto)
  - [Dynamic Entity Reference](https://www.drupal.org/project/dynamic_entity_reference)
- Optional:
  - `content_translation` — for multilingual taxonomy term names
  - [Group](https://www.drupal.org/project/group) — for group entity support (via `structural_pages_group` submodule)

## Installation

```bash
drush en structural_pages -y
drush cr
```

The module automatically creates:
- Taxonomy vocabulary `site_sections` with default hierarchical terms
- Content types `section_page` and `content_page` with configured fields
- Pathauto patterns for both content types and taxonomy terms
- A `child_pages` View (block display)
- Content translations for term names (if `content_translation` is enabled)

### Group support

```bash
drush en structural_pages_group -y
```

Requires the Group module. Adds group entities as a parent type for content pages.

## Configuration

**Settings form**: `/admin/config/local-modules/structural-pages`

Allows administrators to select which entity types and bundles can be used as parents for content pages. Changes automatically update the `field_parent_page` field configuration.

## Content Types

### section_page

Pages organized by site section. Each page belongs to a `site_sections` taxonomy term.

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `field_site_section` | Entity reference (taxonomy) | Yes | Site section |
| `body` | Formatted text | No | Page content |

### content_page

Pages with hierarchical parent-child structure. The parent can be a node, taxonomy term, user, or group.

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `field_parent_page` | Dynamic entity reference | No | Parent entity |
| `field_site_section` | Entity reference (taxonomy) | Conditional | Site section (inherited or manual) |
| `body` | Formatted text | No | Page content |

**Site section inheritance rules:**
- Parent is a `taxonomy_term` → uses the term as site section
- Parent is a `node` → inherits `field_site_section` from the parent node
- Parent is a `user` or `group` → clears `field_site_section` (context is the entity itself)
- No parent (root page) → must be filled manually

## Features

### Automatic breadcrumbs

Custom breadcrumb builder for `section_page` and `content_page` that traverses the parent chain:

- **Taxonomy context**: Home > Term Hierarchy > Parent Nodes > Current Page
- **User context**: Home > User Name > Parent Nodes > Current Page
- **Group context**: Home > Group Name > Parent Nodes > Current Page

### Pathauto tokens

| Token | Description | Example |
|-------|-------------|---------|
| `[node:site-section-path]` | Hierarchical path from taxonomy | `undergraduate/courses` |
| `[term:hierarchy-path]` | Term path including ancestors | `institutional/news` |

Suggested URL pattern: `[node:site-section-path]/[node:title]` → `/undergraduate/courses/software-engineering`

### Structural Pages Menu block

Dynamic menu block that renders hierarchical navigation based on content structure.

| Option | Default | Description |
|--------|---------|-------------|
| Maximum depth | 3 | Number of levels to display (1-10) |
| Show ancestor title | Yes | Display ancestor entity title as header |
| Expand active trail | Yes | Highlight the path to current page |

### Child Pages View

Block display that lists child pages of the current `content_page`, filtered by `field_parent_page`.

## Extensibility

The module uses an attribute-based plugin system (`ParentEntityHandler`) to support different parent entity types. Built-in handlers:

| Handler | Entity Type | Clears Site Section | Bundle Restrictions |
|---------|-------------|---------------------|---------------------|
| TaxonomyTermHandler | taxonomy_term | No | site_sections |
| NodeHandler | node | No | content_page, section_page |
| UserHandler | user | Yes | - |
| GroupHandler* | group | Yes | - |

*Provided by the `structural_pages_group` submodule.

To add support for a new entity type, create a plugin in `src/Plugin/ParentEntityHandler/`:

```php
#[ParentEntityHandler(
  id: 'my_entity',
  label: new TranslatableMarkup('My Entities'),
  entity_type_id: 'my_entity',
  clears_site_section: FALSE,
  sort_field: 'title',
)]
class MyEntityHandler extends ParentEntityHandlerBase {
  // Override methods as needed.
}
```

See `docs/DESIGN.md` for full architecture details and `docs/PLUGIN_SYSTEM_PLAN.md` for the plugin system design.