# nova 4 dependency container

A Laravel Nova 4 form container for grouping fields that depend on other field values.
Dependencies can be set on any field type or value.

Features:

- working form validation inside unlimited nested containers
- support of ebess/advanced-nova-media-library

This plugin is based on [epartment/nova-dependency-container](https://github.com/epartment/nova-dependency-container)
and only supports **Nova 4.x** and **PHP 8.x**.

## Demo

![Demo](https://raw.githubusercontent.com/alexwenzel/nova-dependency-container/master/docs/demo.gif)

## Installation

The package can be installed through Composer.

```bash
composer require alexwenzel/nova-dependency-container
```

## Usage

1. Add the `Alexwenzel\DependencyContainer\HasDependencies` trait to your Nova Resource.
2. Add the `Alexwenzel\DependencyContainer\DependencyContainer` to your Nova Resource `fields()` method.
3. Add the `Alexwenzel\DependencyContainer\ActionHasDependencies` trait to your Nova Actions that you wish to use
   dependencies on.

```php
class Page extends Resource
{
    use HasDependencies;

    public function fields(Request $request)
    {
        return [
            Select::make('Name format', 'name_format')->options([
                0 => 'First Name',
                1 => 'First Name / Last Name',
                2 => 'Full Name'
            ])->displayUsingLabels(),

            DependencyContainer::make([
                Text::make('First Name', 'first_name')
            ])->dependsOn('name_format', 0),
        ];
    }
}
```

## Available dependencies

The package supports these kinds of dependencies:

1. `->dependsOn('field', 'value')`
2. `->dependsOnNot('field', 'value')`
3. `->dependsOnEmpty('field')`
4. `->dependsOnNotEmpty('field')`
5. `->dependsOnNullOrZero('field')`
6. `->dependsOnIn('field', [array])`
7. `->dependsOnNotIn('field', [array])`

These dependencies can be combined by chaining the methods on the `DependencyContainer` field:

```php
DependencyContainer::make([
  // dependency fields
])
->dependsOn('field1', 'value1')
->dependsOnNotEmpty('field2')
->dependsOn('field3', 'value3')
```

The fields used as dependencies can be of any Laravel Nova field type. Currently only two relation field types are
supported, `BelongsTo` and `MorphTo`.

Here is an example using a checkbox:

![Demo](https://raw.githubusercontent.com/alexwenzel/nova-dependency-container/master/docs/demo-2.gif)

## BelongsTo dependency

If we follow the example of a *Post model belongsTo a User model*, taken from Novas
documentation [BelongsTo](https://nova.laravel.com/docs/2.0/resources/relationships.html#belongsto), the dependency
setup has the following construction.

We use the singular form of the `belongsTo` resource in lower case, in this example `Post` becomes `post`. Then we
define in dot notation, the property of the resource we want to depend on. In this example we just use the `id`
property, as in `post.id`.

```php
BelongsTo::make('Post'),

DependencyContainer::make([
    Boolean::make('Visible')
])
->dependsOn('post.id', 2)
```

When the `Post` resource with `id` 2 is being selected, a `Boolean` field will appear.

## BelongsToMany dependency

A [BelongsToMany](https://nova.laravel.com/docs/2.0/resources/relationships.html#belongstomany) setup is similar to that
of a [BelongsTo](https://nova.laravel.com/docs/2.0/resources/relationships.html#belongsto).

The `dependsOn` method should be pointing to the name of the intermediate table. If it is called `role_user`, the setup
should be

```php
BelongsToMany::make('Roles')
	->fields(function() {
		return [
			DependencyContainer::make([
			    // pivot field rules_all
			    Boolean::make('Rules All', 'rules_all')
			])
			->dependsOn('role_user', 1)
		]
	}),
```

If the pivot field name occurs multiple times, consider
using [custom intermediate table models](https://laravel.com/docs/6.x/eloquent-relationships#defining-custom-intermediate-table-models)
and define it in the appropiate model relation methods. The only reliable solution I found was using mutators to get/set
a field which was being used multiple times. Although this may seem ugly, the events which should be fired on the
intermediate model instance, when using an Observer, would work unreliable with every new release of Nova.

> If Nova becomes reliable firing eloquent events on the intermediate table, I will update this examples with a more
> elegant approach using events instead.

Here is an (ugly) example of a get/set mutator setup for an intermediate table using a pivot field called `type`.

```php
// model User
class User ... { 
    public function roles() {
        return $this->belongsToMany->using(RoleUser::class)->withPivot('rules_all');
    }
}

// model Role
class Role ... { 
    public function users() {
        return $this->belongsToMany->using(RoleUser::class)->withPivot('rules_all');
    }
}

// intermediate table
use Illuminate\Database\Eloquent\Relations\Pivot;
class RoleUser extends Pivot {  

	protected $table 'role_user';

	public function getType1Attribute() {
	    return $this->type;
	}

	public function setType1Attribute($value) {
		$this->attributes['type'] = $value;
	}

	// ... repeat for as many types as needed
}
```

And now for the dependency container.

```php
->fields(function() {
	return [
		DependencyContainer::make([
		    // pivot field rules_all
		    Select::make('Type', 'type_1')
		    	->options([ 
		    		/* some options */ 
	    		])
		    	->displayUsingLabels()
		])
		->dependsOn('role_user', 1),
	
		DependencyContainer::make([
		    // pivot field rules_all
		    Select::make('Type', 'type_2')
		    	->options([ 
		    		/* different options */ 
	    		])
		    	->displayUsingLabels()
		])
		->dependsOn('role_user', 2),
		
		// .. and so on
	]
}),
```

## MorphTo dependency

A similar example taken from Novas documentation
for [MorphTo](https://nova.laravel.com/docs/2.0/resources/relationships.html#morphto) is called commentable. It uses 3
Models; `Comment`, `Video` and `Post`. Here `Comment` has the morphable fields `commentable_id` and `commentable_type`

For a `MorphTo` dependency, the following construction is needed.

`Commentable` becomes lower case `commentable` and the value to depend on is the resource singular form. In this example
the dependency container will add two additional fields, `Additional Text` and `Visible`, only when the `Post` resource
is selected.

```php
MorphTo::make('Commentable')->types([
    Post::class,
    Video::class,
]),

DependencyContainer::make([
    Text::make('Additional Text', 'additional'),
    Boolean::make('Visible', 'visible')
])
->dependsOn('commentable', 'Post') 
```

## Workaround for index or details page

Use the field within resource methods `fieldsForCreate` or `fieldsForUpdate`:

```php
DependencyContainer::make([
    Select::make('Parent name', 'parent_id')
        ->options(...)
])->dependsOn('code', 'column'),
```

To display some values on index or details page,
use any field you like to display the value within resource methods `fieldsForIndex` or `fieldsForDetail`:

```php
Select::make('Parent name', 'parent_id')
        ->options(...),
        
// OR

Text::make('Parent name', 'parent_id'),
```

## License

The MIT License (MIT). Please
see [License File](https://github.com/alexwenzel/nova-dependency-container/blob/master/LICENSE.md) for more information.