Add support for HasManyDeep relationships in EloquentDataTable

composer.json

@@ -29,7 +29,8 @@
         "laravel/scout": "^10.8.3",
         "meilisearch/meilisearch-php": "^1.6.1",
         "orchestra/testbench": "^10",
-        "rector/rector": "^2.0"
+        "rector/rector": "^2.0",
+        "staudenmeir/eloquent-has-many-deep": "^1.21"
     },
     "suggest": {
         "yajra/laravel-datatables-export": "Plugin for server-side exporting using livewire and queue worker.",

src/EloquentDataTable.php

@@ -15,7 +15,7 @@
 /**
  * @property EloquentBuilder $query
  */
 class EloquentDataTable extends QueryDataTable
 {
     /**
      * Flag to enable the generation of unique table aliases on eagerly loaded join columns.
@@ -160,6 +160,133 @@
         return $isMorph;
     }
 
+    /**
+     * Check if a relation is a HasManyDeep relationship.
+     *
+     * @param  \Illuminate\Database\Eloquent\Relations\Relation<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model, mixed>  $model
+     */
+    protected function isHasManyDeep($model): bool
+    {
+        return class_exists(\Staudenmeir\EloquentHasManyDeep\HasManyDeep::class)
+            && $model instanceof \Staudenmeir\EloquentHasManyDeep\HasManyDeep;
+    }
+
+    /**
+     * Get the foreign key name for a HasManyDeep relationship.
+     * This is the foreign key on the final related table that points to the intermediate table.
+     *
+     * @param  \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model>  $model
+     */
+    protected function getHasManyDeepForeignKey($model): string
+    {
+        // Try to get from relationship definition using reflection
+        $foreignKeys = $this->getForeignKeys($model);
+        if (! empty($foreignKeys)) {
+            return $this->extractColumnFromQualified(end($foreignKeys));
+        }
+
+        // Try to get the foreign key using common HasManyDeep methods
+        if (method_exists($model, 'getForeignKeyName')) {
+            return $model->getForeignKeyName();
+        }
+
+        // Fallback: try to infer from intermediate model or use related model's key
+        $intermediateTable = $this->getHasManyDeepIntermediateTable($model);
+
+        return $intermediateTable
+            ? \Illuminate\Support\Str::singular($intermediateTable).'_id'
+            : $model->getRelated()->getKeyName();
+    }
+
+    /**
+     * Get the local key name for a HasManyDeep relationship.
+     * This is the local key on the intermediate table (or parent if no intermediate).
+     *
+     * @param  \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model>  $model
+     */
+    protected function getHasManyDeepLocalKey($model): string
+    {
+        // Try to get from relationship definition using reflection
+        $localKeys = $this->getLocalKeys($model);
+        if (! empty($localKeys)) {
+            return $this->extractColumnFromQualified(end($localKeys));
+        }
+
+        // Try to get the local key using common HasManyDeep methods
+        if (method_exists($model, 'getLocalKeyName')) {
+            return $model->getLocalKeyName();
+        }
+
+        // Fallback: use the intermediate model's key name, or parent if no intermediate
+        $intermediateTable = $this->getHasManyDeepIntermediateTable($model);
+        $through = $this->getThroughModels($model);
+        if ($intermediateTable && ! empty($through)) {
+            $firstThrough = is_string($through[0]) ? $through[0] : get_class($through[0]);
+            if (class_exists($firstThrough)) {
+                return app($firstThrough)->getKeyName();
+            }
+        }
+
+        return $model->getParent()->getKeyName();
+    }
+
+    /**
+     * Get the intermediate table name for a HasManyDeep relationship.
+     *
+     * @param  \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model>  $model
+     */
+    protected function getHasManyDeepIntermediateTable($model): ?string
+    {
+        // Try to get intermediate models from the relationship
+        // HasManyDeep stores intermediate models in a protected property
+        $through = $this->getThroughModels($model);
+        if (! empty($through)) {
+            // Get the first intermediate model
+            $firstThrough = is_string($through[0]) ? $through[0] : get_class($through[0]);
+            if (class_exists($firstThrough)) {
+                $throughModel = app($firstThrough);
+
+                return $throughModel->getTable();
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Get the foreign key for joining to the intermediate table.
+     *
+     * @param  \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model>  $model
+     */
+    protected function getHasManyDeepIntermediateForeignKey($model): string
+    {
+        // The foreign key on the intermediate table that points to the parent
+        // For User -> Posts -> Comments, this would be posts.user_id
+        $parent = $model->getParent();
+
+        // Try to get from relationship definition
+        $foreignKeys = $this->getForeignKeys($model);
+        if (! empty($foreignKeys)) {
+            $firstFK = $foreignKeys[0];
+
+            return $this->extractColumnFromQualified($firstFK);
+        }
+
+        // Default: assume intermediate table has a foreign key named {parent_table}_id
+        return \Illuminate\Support\Str::singular($parent->getTable()).'_id';
+    }
+
+    /**
+     * Get the local key for joining from the parent to the intermediate table.
+     *
+     * @param  \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model>  $model
+     */
+    protected function getHasManyDeepIntermediateLocalKey($model): string
+    {
+        // The local key on the parent table
+        return $model->getParent()->getKeyName();
+    }
+
     /**
      * {@inheritDoc}
      *
@@ -269,6 +396,50 @@
                     $other = $tableAlias.'.'.$model->getOwnerKeyName();
                     break;
 
+                case $this->isHasManyDeep($model):
+                    // HasManyDeep relationships can traverse multiple intermediate models
+                    // We need to join through all intermediate models to reach the final related table
+                    /** @var \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model> $model */
+                    $related = $model->getRelated();
+
+                    // For HasManyDeep, we need to join through intermediate models
+                    // The relationship query already knows the structure, so we'll use it
+                    // First, join to the first intermediate model (if not already joined)
+                    $intermediateTable = $this->getHasManyDeepIntermediateTable($model);
+
+                    if ($intermediateTable && $intermediateTable !== $lastAlias) {
+                        // Join to intermediate table first
+                        if ($this->enableEagerJoinAliases) {
+                            $intermediateAlias = $tableAlias.'_intermediate';
+                            $intermediate = $intermediateTable.' as '.$intermediateAlias;
+                        } else {
+                            $intermediateAlias = $intermediateTable;
+                            $intermediate = $intermediateTable;
+                        }
+
+                        $intermediateFK = $this->getHasManyDeepIntermediateForeignKey($model);
+                        $intermediateLocal = $this->getHasManyDeepIntermediateLocalKey($model);
+                        $this->performJoin($intermediate, $intermediateAlias.'.'.$intermediateFK, ltrim($lastAlias.'.'.$intermediateLocal, '.'));
+                        $lastAlias = $intermediateAlias;
+                    }
+
+                    // Now join to the final related table
+                    if ($this->enableEagerJoinAliases) {
+                        $table = $related->getTable().' as '.$tableAlias;
+                    } else {
+                        $table = $tableAlias = $related->getTable();
+                    }
+
+                    // Get the foreign key on the related table (points to intermediate)
+                    $foreignKey = $this->getHasManyDeepForeignKey($model);
+                    $localKey = $this->getHasManyDeepLocalKey($model);
+
+                    $foreign = $tableAlias.'.'.$foreignKey;
+                    $other = ltrim($lastAlias.'.'.$localKey, '.');
+
+                    $lastQuery->addSelect($tableAlias.'.'.$relationColumn);
+                    break;
+
                 default:
                     throw new Exception('Relation '.$model::class.' is not yet supported.');
             }
@@ -312,4 +483,99 @@
             $this->getBaseQueryBuilder()->join($table, $foreign, '=', $other, $type);
         }
     }
+
+    /**
+     * Extract the array of foreign keys from a HasManyDeep relationship using reflection.
+     *
+     * @param  \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model>  $model
+     */
+    private function getForeignKeys($model): array
+    {
+        try {
+            $reflection = new \ReflectionClass($model);
+            if ($reflection->hasProperty('foreignKeys')) {
+                $property = $reflection->getProperty('foreignKeys');
+                // Safe: Accessing protected property from third-party package (staudenmeir/eloquent-has-many-deep)
+                // The property exists and is part of the package's internal API
+                $property->setAccessible(true); // NOSONAR
+                $foreignKeys = $property->getValue($model); // NOSONAR
+                if (is_array($foreignKeys) && ! empty($foreignKeys)) {
+                    return $foreignKeys;
+                }
+            }
+        } catch (\Exception) {
+            // Reflection failed - fall back to empty array
+            // This is safe because callers handle empty arrays appropriately
+        }
+
+        return [];
+    }
+
+    /**
+     * Extract the array of local keys from a HasManyDeep relationship using reflection.
+     *
+     * @param  \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model>  $model
+     */
+    private function getLocalKeys($model): array
+    {
+        try {
+            $reflection = new \ReflectionClass($model);
+            if ($reflection->hasProperty('localKeys')) {
+                $property = $reflection->getProperty('localKeys');
+                // Safe: Accessing protected property from third-party package (staudenmeir/eloquent-has-many-deep)
+                // The property exists and is part of the package's internal API
+                $property->setAccessible(true); // NOSONAR
+                $localKeys = $property->getValue($model); // NOSONAR
+                if (is_array($localKeys) && ! empty($localKeys)) {
+                    return $localKeys;
+                }
+            }
+        } catch (\Exception) {
+            // Reflection failed - fall back to empty array
+            // This is safe because callers handle empty arrays appropriately
+        }
+
+        return [];
+    }
+
+    /**
+     * Extract the array of through models from a HasManyDeep relationship using reflection.
+     *
+     * @param  \Staudenmeir\EloquentHasManyDeep\HasManyDeep<\Illuminate\Database\Eloquent\Model, \Illuminate\Database\Eloquent\Model>  $model
+     */
+    private function getThroughModels($model): array
+    {
+        try {
+            $reflection = new \ReflectionClass($model);
+            if ($reflection->hasProperty('through')) {
+                $property = $reflection->getProperty('through');
+                // Safe: Accessing protected property from third-party package (staudenmeir/eloquent-has-many-deep)
+                // The property exists and is part of the package's internal API
+                $property->setAccessible(true); // NOSONAR
+                $through = $property->getValue($model); // NOSONAR
+                if (is_array($through) && ! empty($through)) {
+                    return $through;
+                }
+            }
+        } catch (\Exception) {
+            // Reflection failed - fall back to empty array
+            // This is safe because callers handle empty arrays appropriately
+        }
+
+        return [];
+    }
+
+    /**
+     * Extract the column name from a qualified column name (e.g., 'table.column' -> 'column').
+     */
+    private function extractColumnFromQualified(string $qualified): string
+    {
+        if (str_contains($qualified, '.')) {
+            $parts = explode('.', $qualified);
+
+            return end($parts);
+        }
+
+        return $qualified;
+    }
 }