[update] migrate aggregate and union models to data package

src/Model/Aggregate.php

@@ -0,0 +1,334 @@
+<?php
+
+declare(strict_types=1);
+
+namespace atk4\data\Model;
+
+use atk4\data\Exception;
+use atk4\data\Field;
+use atk4\data\FieldSqlExpression;
+use atk4\data\Model;
+use atk4\data\Reference;
+use atk4\dsql\Query;
+
+/**
+ * Aggregate model allows you to query using "group by" clause on your existing model.
+ * It's quite simple to set up.
+ *
+ * $aggregate = new Aggregate($mymodel);
+ * $aggregate->groupBy(['first','last'], ['salary'=>'sum([])'];
+ *
+ * your resulting model will have 3 fields:
+ *  first, last, salary
+ *
+ * but when querying it will use the original model to calculate the query, then add grouping and aggregates.
+ *
+ * If you wish you can add more fields, which will be passed through:
+ * $aggregate->addField('middle');
+ *
+ * If this field exist in the original model it will be added and you'll get exception otherwise. Finally you are
+ * permitted to add expressions.
+ *
+ * The base model must not be Union model or another Aggregate model, however it's possible to use Aggregate model as nestedModel inside Union model.
+ * Union model implements identical grouping rule on its own.
+ *
+ * You can also pass seed (for example field type) when aggregating:
+ * $aggregate->groupBy(['first','last'], ['salary' => ['sum([])', 'type'=>'money']];
+ */
+class Aggregate extends Model
+{
+    /** @const string */
+    public const HOOK_AFTER_SELECT = self::class . '@afterSelect';
+
+    /**
+     * @deprecated use HOOK_AFTER_SELECT instead - will be removed dec-2020
+     */
+    public const HOOK_AFTER_GROUP_SELECT = self::HOOK_AFTER_SELECT;
+
+    /**
+     * GroupModel should always be read-only.
+     *
+     * @var bool
+     */
+    public $read_only = true;
+
+    /** @var Model */
+    public $master_model;
+
+    /** @var string */
+    public $id_field;
+
+    /** @var array */
+    public $group = [];
+
+    /** @var array */
+    public $aggregate = [];
+
+    /** @var array */
+    public $system_fields = [];
+
+    /**
+     * Constructor.
+     */
+    public function __construct(Model $model, array $defaults = [])
+    {
+        $this->master_model = $model;
+        $this->table = $model->table;
+
+        //$this->_default_class_addExpression = $model->_default_class_addExpression;
+        parent::__construct($model->persistence, $defaults);
+
+        // always use table prefixes for this model
+        $this->persistence_data['use_table_prefixes'] = true;
+    }
+
+    /**
+     * Specify a single field or array of fields on which we will group model.
+     *
+     * @param array $group     Array of field names
+     * @param array $aggregate Array of aggregate mapping
+     *
+     * @return $this
+     */
+    public function groupBy(array $group, array $aggregate = [])
+    {
+        $this->group = $group;
+        $this->aggregate = $aggregate;
+
+        $this->system_fields = array_unique($this->system_fields + $group);
+        foreach ($group as $fieldName) {
+            $this->addField($fieldName);
+        }
+
+        foreach ($aggregate as $fieldName => $expr) {
+            $seed = is_array($expr) ? $expr : [$expr];
+
+            $args = [];
+            // if field originally defined in the parent model, then it can be used as part of expression
+            if ($this->master_model->hasField($fieldName)) {
+                $args = [$this->master_model->getField($fieldName)]; // @TODO Probably need cloning here
+            }
+
+            $seed['expr'] = $this->master_model->expr($seed[0] ?? $seed['expr'], $args);
+
+            // now add the expressions here
+            $this->addExpression($fieldName, $seed);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Return reference field.
+     *
+     * @param string $link
+     */
+    public function getRef($link): Reference
+    {
+        return $this->master_model->getRef($link);
+    }
+
+    /**
+     * Adds new field into model.
+     *
+     * @param string       $name
+     * @param array|object $seed
+     *
+     * @return Field
+     */
+    public function addField($name, $seed = [])
+    {
+        $seed = is_array($seed) ? $seed : [$seed];
+
+        if (isset($seed[0]) && $seed[0] instanceof FieldSqlExpression) {
+            return parent::addField($name, $seed[0]);
+        }
+
+        if ($seed['never_persist'] ?? false) {
+            return parent::addField($name, $seed);
+        }
+
+        if ($this->master_model->hasField($name)) {
+            $field = clone $this->master_model->getField($name);
+            $field->owner = null; // will be new owner
+        } else {
+            $field = null;
+        }
+
+        return $field
+            ? parent::addField($name, $field)->setDefaults($seed)
+            : parent::addField($name, $seed);
+    }
+
+    /**
+     * Given a query, will add safe fields in.
+     */
+    public function queryFields(Query $query, array $fields = []): Query
+    {
+        $this->persistence->initQueryFields($this, $query, $fields);
+
+        return $query;
+    }
+
+    /**
+     * Adds grouping in query.
+     */
+    public function addGrouping(Query $query)
+    {
+        // use table alias of master model
+        $this->table_alias = $this->master_model->table_alias;
+
+        foreach ($this->group as $field) {
+            if ($this->master_model->hasField($field)) {
+                $expression = $this->master_model->getField($field);
+            } else {
+                $expression = $this->expr($field);
+            }
+
+            $query->group($expression);
+        }
+    }
+
+    /**
+     * Sets limit.
+     *
+     * @param int      $count
+     * @param int|null $offset
+     *
+     * @return $this
+     *
+     * @todo Incorrect implementation
+     */
+    public function setLimit($count, $offset = null)
+    {
+        $this->master_model->setLimit($count, $offset);
+
+        return $this;
+    }
+
+    /**
+     * Sets order.
+     *
+     * @param mixed     $field
+     * @param bool|null $desc
+     *
+     * @return $this
+     *
+     * @todo Incorrect implementation
+     */
+    public function setOrder($field, $desc = null)
+    {
+        $this->master_model->setOrder($field, $desc);
+
+        return $this;
+    }
+
+    /**
+     * Execute action.
+     *
+     * @param string $mode
+     * @param array  $args
+     *
+     * @return Query
+     */
+    public function action($mode, $args = [])
+    {
+        $subquery = null;
+        switch ($mode) {
+            case 'select':
+                $fields = $this->only_fields ?: array_keys($this->getFields());
+
+                // select but no need your fields
+                $query = $this->master_model->action($mode, [false]);
+                $query = $this->queryFields($query, array_unique($fields + $this->system_fields));
+
+                $this->addGrouping($query);
+                $this->initQueryConditions($query);
+
+                $this->hook(self::HOOK_AFTER_SELECT, [$query]);
+
+                return $query;
+            case 'count':
+                $query = $this->master_model->action($mode, $args);
+
+                $query->reset('field')->field($this->expr('1'));
+                $this->addGrouping($query);
+
+                $this->hook(self::HOOK_AFTER_SELECT, [$query]);
+
+                return $query->dsql()->field('count(*)')->table($this->expr('([]) der', [$query]));
+            case 'field':
+                if (!isset($args[0])) {
+                    throw (new Exception('This action requires one argument with field name'))
+                        ->addMoreInfo('mode', $mode);
+                }
+
+                if (!is_string($args[0])) {
+                    throw (new Exception('action "field" only support string fields'))
+                        ->addMoreInfo('field', $args[0]);
+                }
+
+                $subquery = $this->getSubQuery([$args[0]]);
+
+                break;
+            case 'fx':
+                $subquery = $this->getSubAction('fx', [$args[0], $args[1], 'alias' => 'val']);
+
+                $args = [$args[0], $this->expr('val')];
+
+                break;
+            default:
+                throw (new Exception('Aggregate model does not support this action'))
+                    ->addMoreInfo('mode', $mode);
+        }
+
+        // Substitute FROM table with our subquery expression
+        return parent::action($mode, $args)->reset('table')->table($subquery);
+    }
+
+    /**
+     * Our own way applying conditions, where we use "having" for
+     * fields.
+     */
+    public function initQueryConditions(Query $query, Model\Scope\AbstractScope $condition = null): void
+    {
+        $condition = $condition ?? $this->scope();
+
+        if (!$condition->isEmpty()) {
+            // peel off the single nested scopes to convert (((field = value))) to field = value
+            $condition = $condition->simplify();
+
+            // simple condition
+            if ($condition instanceof Model\Scope\Condition) {
+                $query = $query->having(...$condition->toQueryArguments());
+            }
+
+            // nested conditions
+            if ($condition instanceof Model\Scope) {
+                $expression = $condition->isOr() ? $query->orExpr() : $query->andExpr();
+
+                foreach ($condition->getNestedConditions() as $nestedCondition) {
+                    $this->initQueryConditions($expression, $nestedCondition);
+                }
+
+                $query = $query->having($expression);
+            }
+        }
+    }
+
+    // {{{ Debug Methods
+
+    /**
+     * Returns array with useful debug info for var_dump.
+     */
+    public function __debugInfo(): array
+    {
+        return array_merge(parent::__debugInfo(), [
+            'group' => $this->group,
+            'aggregate' => $this->aggregate,
+            'master_model' => $this->master_model->__debugInfo(),
+        ]);
+    }
+
+    // }}}
+}