<?php
/**
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\db;

use Yii;
use yii\base\InvalidConfigException;
use yii\helpers\Inflector;
use yii\helpers\StringHelper;

/**
 * ActiveRecord is the base class for classes representing relational data in terms of objects.
 *
 * Active Record implements the [Active Record design pattern](http://en.wikipedia.org/wiki/Active_record).
 * The premise behind Active Record is that an individual [[ActiveRecord]] object is associated with a specific
 * row in a database table. The object's attributes are mapped to the columns of the corresponding table.
 * Referencing an Active Record attribute is equivalent to accessing the corresponding table column for that record.
 *
 * As an example, say that the `Customer` ActiveRecord class is associated with the `tbl_customer` table.
 * This would mean that the class's `name` attribute is automatically mapped to the `name` column in `tbl_customer`.
 * Thanks to Active Record, assuming the variable `$customer` is an object of type `Customer`, to get the value of
 * the `name` column for the table row, you can use the expression `$customer->name`.
 * In this example, Active Record is providing an object-oriented interface for accessing data stored in the database.
 * But Active Record provides much more functionality than this.
 *
 * To declare an ActiveRecord class you need to extend [[\yii\db\ActiveRecord]] and
 * implement the `tableName` method:
 *
 * ```php
 * <?php
 *
 * class Customer extends \yii\db\ActiveRecord
 * {
 *     public static function tableName()
 *     {
 *         return 'tbl_customer';
 *     }
 * }
 * ```
 *
 * The `tableName` method only has to return the name of the database table associated with the class.
 *
 * > Tip: You may also use the [Gii code generator][guide-gii] to generate ActiveRecord classes from your
 * > database tables.
 *
 * Class instances are obtained in one of two ways:
 *
 * * Using the `new` operator to create a new, empty object
 * * Using a method to fetch an existing record (or records) from the database
 *
 * Here is a short teaser how working with an ActiveRecord looks like:
 *
 * ```php
 * $user = new User();
 * $user->name = 'Qiang';
 * $user->save();  // a new row is inserted into tbl_user
 *
 * // the following will retrieve the user 'CeBe' from the database
 * $user = User::find()->where(['name' => 'CeBe'])->one();
 *
 * // this will get related records from table tbl_orders when relation is defined
 * $orders = $user->orders;
 * ```
 *
 * For more details and usage information on ActiveRecord, see the [guide article on ActiveRecord][guide-active-record].
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Carsten Brandt <mail@cebe.cc>
 * @since 2.0
 */
class ActiveRecord extends BaseActiveRecord
{
    /**
     * The insert operation. This is mainly used when overriding [[transactions()]] to specify which operations are transactional.
     */
    const OP_INSERT = 0x01;
    /**
     * The update operation. This is mainly used when overriding [[transactions()]] to specify which operations are transactional.
     */
    const OP_UPDATE = 0x02;
    /**
     * The delete operation. This is mainly used when overriding [[transactions()]] to specify which operations are transactional.
     */
    const OP_DELETE = 0x04;
    /**
     * All three operations: insert, update, delete.
     * This is a shortcut of the expression: OP_INSERT | OP_UPDATE | OP_DELETE.
     */
    const OP_ALL = 0x07;

    /**
     * Loads default values from database table schema
     *
     * @param boolean $skipIfSet if existing value should be preserved
     * @return static model instance
     */
    public function loadDefaultValues($skipIfSet = true)
    {
        foreach ($this->getTableSchema()->columns as $column) {
            if ($column->defaultValue && !($skipIfSet && $this->{$column->name} !== null)) {
                $this->{$column->name} = $column->defaultValue;
            }
        }
        return $this;
    }

    /**
     * Returns the database connection used by this AR class.
     * By default, the "db" application component is used as the database connection.
     * You may override this method if you want to use a different database connection.
     * @return Connection the database connection used by this AR class.
     */
    public static function getDb()
    {
        return \Yii::$app->getDb();
    }

    /**
     * Creates an [[ActiveQuery]] instance with a given SQL statement.
     *
     * Note that because the SQL statement is already specified, calling additional
     * query modification methods (such as `where()`, `order()`) on the created [[ActiveQuery]]
     * instance will have no effect. However, calling `with()`, `asArray()` or `indexBy()` is
     * still fine.
     *
     * Below is an example:
     *
     * ~~~
     * $customers = Customer::findBySql('SELECT * FROM tbl_customer')->all();
     * ~~~
     *
     * @param string $sql the SQL statement to be executed
     * @param array $params parameters to be bound to the SQL statement during execution.
     * @return ActiveQuery the newly created [[ActiveQuery]] instance
     */
    public static function findBySql($sql, $params = [])
    {
        $query = static::createQuery();
        $query->sql = $sql;

        return $query->params($params);
    }

    /**
     * Updates the whole table using the provided attribute values and conditions.
     * For example, to change the status to be 1 for all customers whose status is 2:
     *
     * ~~~
     * Customer::updateAll(['status' => 1], 'status = 2');
     * ~~~
     *
     * @param array $attributes attribute values (name-value pairs) to be saved into the table
     * @param string|array $condition the conditions that will be put in the WHERE part of the UPDATE SQL.
     * Please refer to [[Query::where()]] on how to specify this parameter.
     * @param array $params the parameters (name => value) to be bound to the query.
     * @return integer the number of rows updated
     */
    public static function updateAll($attributes, $condition = '', $params = [])
    {
        $command = static::getDb()->createCommand();
        $command->update(static::tableName(), $attributes, $condition, $params);

        return $command->execute();
    }

    /**
     * Updates the whole table using the provided counter changes and conditions.
     * For example, to increment all customers' age by 1,
     *
     * ~~~
     * Customer::updateAllCounters(['age' => 1]);
     * ~~~
     *
     * @param array $counters the counters to be updated (attribute name => increment value).
     * Use negative values if you want to decrement the counters.
     * @param string|array $condition the conditions that will be put in the WHERE part of the UPDATE SQL.
     * Please refer to [[Query::where()]] on how to specify this parameter.
     * @param array $params the parameters (name => value) to be bound to the query.
     * Do not name the parameters as `:bp0`, `:bp1`, etc., because they are used internally by this method.
     * @return integer the number of rows updated
     */
    public static function updateAllCounters($counters, $condition = '', $params = [])
    {
        $n = 0;
        foreach ($counters as $name => $value) {
            $counters[$name] = new Expression("[[$name]]+:bp{$n}", [":bp{$n}" => $value]);
            $n++;
        }
        $command = static::getDb()->createCommand();
        $command->update(static::tableName(), $counters, $condition, $params);

        return $command->execute();
    }

    /**
     * Deletes rows in the table using the provided conditions.
     * WARNING: If you do not specify any condition, this method will delete ALL rows in the table.
     *
     * For example, to delete all customers whose status is 3:
     *
     * ~~~
     * Customer::deleteAll('status = 3');
     * ~~~
     *
     * @param string|array $condition the conditions that will be put in the WHERE part of the DELETE SQL.
     * Please refer to [[Query::where()]] on how to specify this parameter.
     * @param array $params the parameters (name => value) to be bound to the query.
     * @return integer the number of rows deleted
     */
    public static function deleteAll($condition = '', $params = [])
    {
        $command = static::getDb()->createCommand();
        $command->delete(static::tableName(), $condition, $params);

        return $command->execute();
    }

    /**
     * Creates an [[ActiveQuery]] instance.
     *
     * This method is called by [[find()]], [[findBySql()]] to start a SELECT query but also
     * by [[hasOne()]] and [[hasMany()]] to create a relational query.
     * You may override this method to return a customized query (e.g. `CustomerQuery` specified
     * written for querying `Customer` purpose.)
     *
     * You may also define default conditions that should apply to all queries unless overridden:
     *
     * ```php
     * public static function createQuery($config = [])
     * {
     *     return parent::createQuery($config)->where(['deleted' => false]);
     * }
     * ```
     *
     * Note that all queries should use [[Query::andWhere()]] and [[Query::orWhere()]] to keep the
     * default condition. Using [[Query::where()]] will override the default condition.
     *
     * @param array $config the configuration passed to the ActiveQuery class.
     * @return ActiveQuery the newly created [[ActiveQuery]] instance.
     */
    public static function createQuery($config = [])
    {
        $config['modelClass'] = get_called_class();

        return new ActiveQuery($config);
    }

    /**
     * Declares the name of the database table associated with this AR class.
     * By default this method returns the class name as the table name by calling [[Inflector::camel2id()]]
     * with prefix [[Connection::tablePrefix]]. For example if [[Connection::tablePrefix]] is 'tbl_',
     * 'Customer' becomes 'tbl_customer', and 'OrderItem' becomes 'tbl_order_item'. You may override this method
     * if the table is not named after this convention.
     * @return string the table name
     */
    public static function tableName()
    {
        return '{{%' . Inflector::camel2id(StringHelper::basename(get_called_class()), '_') . '}}';
    }

    /**
     * Returns the schema information of the DB table associated with this AR class.
     * @return TableSchema the schema information of the DB table associated with this AR class.
     * @throws InvalidConfigException if the table for the AR class does not exist.
     */
    public static function getTableSchema()
    {
        $schema = static::getDb()->getTableSchema(static::tableName());
        if ($schema !== null) {
            return $schema;
        } else {
            throw new InvalidConfigException("The table does not exist: " . static::tableName());
        }
    }

    /**
     * Returns the primary key name(s) for this AR class.
     * The default implementation will return the primary key(s) as declared
     * in the DB table that is associated with this AR class.
     *
     * If the DB table does not declare any primary key, you should override
     * this method to return the attributes that you want to use as primary keys
     * for this AR class.
     *
     * Note that an array should be returned even for a table with single primary key.
     *
     * @return string[] the primary keys of the associated database table.
     */
    public static function primaryKey()
    {
        return static::getTableSchema()->primaryKey;
    }

    /**
     * Returns the list of all attribute names of the model.
     * The default implementation will return all column names of the table associated with this AR class.
     * @return array list of attribute names.
     */
    public function attributes()
    {
        return array_keys(static::getTableSchema()->columns);
    }

    /**
     * Declares which DB operations should be performed within a transaction in different scenarios.
     * The supported DB operations are: [[OP_INSERT]], [[OP_UPDATE]] and [[OP_DELETE]],
     * which correspond to the [[insert()]], [[update()]] and [[delete()]] methods, respectively.
     * By default, these methods are NOT enclosed in a DB transaction.
     *
     * In some scenarios, to ensure data consistency, you may want to enclose some or all of them
     * in transactions. You can do so by overriding this method and returning the operations
     * that need to be transactional. For example,
     *
     * ~~~
     * return [
     *     'admin' => self::OP_INSERT,
     *     'api' => self::OP_INSERT | self::OP_UPDATE | self::OP_DELETE,
     *     // the above is equivalent to the following:
     *     // 'api' => self::OP_ALL,
     *
     * ];
     * ~~~
     *
     * The above declaration specifies that in the "admin" scenario, the insert operation ([[insert()]])
     * should be done in a transaction; and in the "api" scenario, all the operations should be done
     * in a transaction.
     *
     * @return array the declarations of transactional operations. The array keys are scenarios names,
     * and the array values are the corresponding transaction operations.
     */
    public function transactions()
    {
        return [];
    }

    /**
     * @inheritdoc
     */
    public static function populateRecord($record, $row)
    {
        $columns = static::getTableSchema()->columns;
        foreach ($row as $name => $value) {
            if (isset($columns[$name])) {
                $row[$name] = $columns[$name]->typecast($value);
            }
        }
        parent::populateRecord($record, $row);
    }

    /**
     * Inserts a row into the associated database table using the attribute values of this record.
     *
     * This method performs the following steps in order:
     *
     * 1. call [[beforeValidate()]] when `$runValidation` is true. If validation
     *    fails, it will skip the rest of the steps;
     * 2. call [[afterValidate()]] when `$runValidation` is true.
     * 3. call [[beforeSave()]]. If the method returns false, it will skip the
     *    rest of the steps;
     * 4. insert the record into database. If this fails, it will skip the rest of the steps;
     * 5. call [[afterSave()]];
     *
     * In the above step 1, 2, 3 and 5, events [[EVENT_BEFORE_VALIDATE]],
     * [[EVENT_BEFORE_INSERT]], [[EVENT_AFTER_INSERT]] and [[EVENT_AFTER_VALIDATE]]
     * will be raised by the corresponding methods.
     *
     * Only the [[dirtyAttributes|changed attribute values]] will be inserted into database.
     *
     * If the table's primary key is auto-incremental and is null during insertion,
     * it will be populated with the actual value after insertion.
     *
     * For example, to insert a customer record:
     *
     * ~~~
     * $customer = new Customer;
     * $customer->name = $name;
     * $customer->email = $email;
     * $customer->insert();
     * ~~~
     *
     * @param boolean $runValidation whether to perform validation before saving the record.
     * If the validation fails, the record will not be inserted into the database.
     * @param array $attributes list of attributes that need to be saved. Defaults to null,
     * meaning all attributes that are loaded from DB will be saved.
     * @return boolean whether the attributes are valid and the record is inserted successfully.
     * @throws \Exception in case insert failed.
     */
    public function insert($runValidation = true, $attributes = null)
    {
        if ($runValidation && !$this->validate($attributes)) {
            Yii::info('Model not inserted due to validation error.', __METHOD__);
            return false;
        }
        $db = static::getDb();
        if ($this->isTransactional(self::OP_INSERT)) {
            $transaction = $db->beginTransaction();
            try {
                $result = $this->insertInternal($attributes);
                if ($result === false) {
                    $transaction->rollBack();
                } else {
                    $transaction->commit();
                }
            } catch (\Exception $e) {
                $transaction->rollBack();
                throw $e;
            }
        } else {
            $result = $this->insertInternal($attributes);
        }

        return $result;
    }

    /**
     * Inserts an ActiveRecord into DB without considering transaction.
     * @param array $attributes list of attributes that need to be saved. Defaults to null,
     * meaning all attributes that are loaded from DB will be saved.
     * @return boolean whether the record is inserted successfully.
     */
    protected function insertInternal($attributes = null)
    {
        if (!$this->beforeSave(true)) {
            return false;
        }
        $values = $this->getDirtyAttributes($attributes);
        if (empty($values)) {
            foreach ($this->getPrimaryKey(true) as $key => $value) {
                $values[$key] = $value;
            }
        }
        $db = static::getDb();
        $command = $db->createCommand()->insert($this->tableName(), $values);
        if (!$command->execute()) {
            return false;
        }
        $table = $this->getTableSchema();
        if ($table->sequenceName !== null) {
            foreach ($table->primaryKey as $name) {
                if ($this->getAttribute($name) === null) {
                    $id = $db->getLastInsertID($table->sequenceName);
                    $this->setAttribute($name, $id);
                    $this->setOldAttribute($name, $id);
                    break;
                }
            }
        }

        $this->afterSave(true);
        $this->setOldAttributes($values);

        return true;
    }

    /**
     * Saves the changes to this active record into the associated database table.
     *
     * This method performs the following steps in order:
     *
     * 1. call [[beforeValidate()]] when `$runValidation` is true. If validation
     *    fails, it will skip the rest of the steps;
     * 2. call [[afterValidate()]] when `$runValidation` is true.
     * 3. call [[beforeSave()]]. If the method returns false, it will skip the
     *    rest of the steps;
     * 4. save the record into database. If this fails, it will skip the rest of the steps;
     * 5. call [[afterSave()]];
     *
     * In the above step 1, 2, 3 and 5, events [[EVENT_BEFORE_VALIDATE]],
     * [[EVENT_BEFORE_UPDATE]], [[EVENT_AFTER_UPDATE]] and [[EVENT_AFTER_VALIDATE]]
     * will be raised by the corresponding methods.
     *
     * Only the [[dirtyAttributes|changed attribute values]] will be saved into database.
     *
     * For example, to update a customer record:
     *
     * ~~~
     * $customer = Customer::find($id);
     * $customer->name = $name;
     * $customer->email = $email;
     * $customer->update();
     * ~~~
     *
     * Note that it is possible the update does not affect any row in the table.
     * In this case, this method will return 0. For this reason, you should use the following
     * code to check if update() is successful or not:
     *
     * ~~~
     * if ($this->update() !== false) {
     *     // update successful
     * } else {
     *     // update failed
     * }
     * ~~~
     *
     * @param boolean $runValidation whether to perform validation before saving the record.
     * If the validation fails, the record will not be inserted into the database.
     * @param array $attributes list of attributes that need to be saved. Defaults to null,
     * meaning all attributes that are loaded from DB will be saved.
     * @return integer|boolean the number of rows affected, or false if validation fails
     * or [[beforeSave()]] stops the updating process.
     * @throws StaleObjectException if [[optimisticLock|optimistic locking]] is enabled and the data
     * being updated is outdated.
     * @throws \Exception in case update failed.
     */
    public function update($runValidation = true, $attributes = null)
    {
        if ($runValidation && !$this->validate($attributes)) {
            Yii::info('Model not updated due to validation error.', __METHOD__);
            return false;
        }
        $db = static::getDb();
        if ($this->isTransactional(self::OP_UPDATE)) {
            $transaction = $db->beginTransaction();
            try {
                $result = $this->updateInternal($attributes);
                if ($result === false) {
                    $transaction->rollBack();
                } else {
                    $transaction->commit();
                }
            } catch (\Exception $e) {
                $transaction->rollBack();
                throw $e;
            }
        } else {
            $result = $this->updateInternal($attributes);
        }

        return $result;
    }

    /**
     * Deletes the table row corresponding to this active record.
     *
     * This method performs the following steps in order:
     *
     * 1. call [[beforeDelete()]]. If the method returns false, it will skip the
     *    rest of the steps;
     * 2. delete the record from the database;
     * 3. call [[afterDelete()]].
     *
     * In the above step 1 and 3, events named [[EVENT_BEFORE_DELETE]] and [[EVENT_AFTER_DELETE]]
     * will be raised by the corresponding methods.
     *
     * @return integer|boolean the number of rows deleted, or false if the deletion is unsuccessful for some reason.
     * Note that it is possible the number of rows deleted is 0, even though the deletion execution is successful.
     * @throws StaleObjectException if [[optimisticLock|optimistic locking]] is enabled and the data
     * being deleted is outdated.
     * @throws \Exception in case delete failed.
     */
    public function delete()
    {
        $db = static::getDb();
        if ($this->isTransactional(self::OP_DELETE)) {
            $transaction = $db->beginTransaction();
            try {
                $result = $this->deleteInternal();
                if ($result === false) {
                    $transaction->rollBack();
                } else {
                    $transaction->commit();
                }
            } catch (\Exception $e) {
                $transaction->rollBack();
                throw $e;
            }
        } else {
            $result = $this->deleteInternal();
        }

        return $result;
    }

    /**
     * Deletes an ActiveRecord without considering transaction.
     * @return integer|boolean the number of rows deleted, or false if the deletion is unsuccessful for some reason.
     * Note that it is possible the number of rows deleted is 0, even though the deletion execution is successful.
     * @throws StaleObjectException
     */
    protected function deleteInternal()
    {
        $result = false;
        if ($this->beforeDelete()) {
            // we do not check the return value of deleteAll() because it's possible
            // the record is already deleted in the database and thus the method will return 0
            $condition = $this->getOldPrimaryKey(true);
            $lock = $this->optimisticLock();
            if ($lock !== null) {
                $condition[$lock] = $this->$lock;
            }
            $result = $this->deleteAll($condition);
            if ($lock !== null && !$result) {
                throw new StaleObjectException('The object being deleted is outdated.');
            }
            $this->setOldAttributes(null);
            $this->afterDelete();
        }

        return $result;
    }

    /**
     * Returns a value indicating whether the given active record is the same as the current one.
     * The comparison is made by comparing the table names and the primary key values of the two active records.
     * If one of the records [[isNewRecord|is new]] they are also considered not equal.
     * @param ActiveRecord $record record to compare to
     * @return boolean whether the two active records refer to the same row in the same database table.
     */
    public function equals($record)
    {
        if ($this->isNewRecord || $record->isNewRecord) {
            return false;
        }

        return $this->tableName() === $record->tableName() && $this->getPrimaryKey() === $record->getPrimaryKey();
    }

    /**
     * Returns a value indicating whether the specified operation is transactional in the current [[scenario]].
     * @param integer $operation the operation to check. Possible values are [[OP_INSERT]], [[OP_UPDATE]] and [[OP_DELETE]].
     * @return boolean whether the specified operation is transactional in the current [[scenario]].
     */
    public function isTransactional($operation)
    {
        $scenario = $this->getScenario();
        $transactions = $this->transactions();

        return isset($transactions[$scenario]) && ($transactions[$scenario] & $operation);
    }
}