HasPrimary.php

<?php

namespace App\Concerns;

use Illuminate\Contracts\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

trait HasPrimary
{
    /**
     * Automatically apply default values and casts.
     */
    public function initializeHasPrimary(): void
    {
        $this->attributes['is_primary'] ??= false;
        $this->casts['is_primary'] = 'boolean';
    }

    /**
     * The "booted" method of the model.
     */
    protected static function bootHasPrimary(): void
    {
        static::saved(function (Model $model) {
            if ($model->is_primary) {
                // Ensure only one primary exists
                static::getHasPrimaryQueryBuilder($model)
                    ->whereKeyNot($model->getKey())
                    ->update([
                        static::getHasPrimaryField() => false,
                    ])
                ;
            } else {
                // If no primary exists, set this as primary
                $hasPrimary = static::getHasPrimaryQueryBuilder($model)
                    ->where(static::getHasPrimaryField(), true)
                    ->exists()
                ;

                if (! $hasPrimary) {
                    $model->forceFill([static::getHasPrimaryField() => true])->saveQuietly();
                }
            }
        });

        static::deleted(function (Model $model) {
            if ($model->is_primary) {
                static::getHasPrimaryQueryBuilder($model)
                    ->whereKeyNot($model->getKey())
                    ->first()?->update([
                        static::getHasPrimaryField() => true,
                    ])
                ;
            }
        });
    }

    /**
     * Scope a query to only include default records.
     */
    public function scopePrimary(Builder $query): void
    {
        $query->where(static::getHasPrimaryField(), true);
    }

    public static function getHasPrimaryField(): string
    {
        return 'is_primary';
    }

    /**
     * Check if the model is primary.
     */
    public function isPrimary(): bool
    {
        return (bool) $this->{static::getHasPrimaryField()};
    }

    /**
     * Base query builder that ensures soft deletes are handled.
     */
    public static function getHasPrimaryQueryBuilder(Model $model): Builder
    {
        $query = $model->newQuery();

        // Apply model-specific constraints
        static::applyHasPrimaryQueryFilters($query, $model);

        // Ensure soft-deleted records are ignored
        if (in_array(SoftDeletes::class, class_uses_recursive($model))) {
            $query->withoutTrashed();
        }

        return $query;
    }

    /**
     * Allow models to define their own constraints on the query.
     */
    protected static function applyHasPrimaryQueryFilters(Builder $query, Model $model): void
    {
        // Models can override this method to apply custom filtering logic.
    }
}