<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\elasticsearch;

use yii\base\InvalidCallException;
use yii\base\InvalidConfigException;
use yii\db\BaseActiveRecord;
use yii\helpers\Inflector;
use yii\helpers\Json;
use yii\helpers\StringHelper;

/**
 * ActiveRecord is the base class for classes representing relational data in terms of objects.
 *
 * This class implements the ActiveRecord pattern for the fulltext search and data storage
 * [elasticsearch](http://www.elasticsearch.org/).
 *
 * For defining a record a subclass should at least implement the [[attributes()]] method to define
 * attributes.
 * The primary key (the `_id` field in elasticsearch terms) is represented by `getId()` and `setId()`.
 * The primary key is not part of the attributes.
 *
 * The following is an example model called `Customer`:
 *
 * ```php
 * class Customer extends \yii\elasticsearch\ActiveRecord
 * {
 *     public function attributes()
 *     {
 *         return ['id', 'name', 'address', 'registration_date'];
 *     }
 * }
 * ```
 *
 * You may override [[index()]] and [[type()]] to define the index and type this record represents.
 *
 * @property float $score Returns the score of this record when it was retrieved via a [[find()]] query. This
 * property is read-only.
 *
 * @author Carsten Brandt <mail@cebe.cc>
 * @since 2.0
 */
class ActiveRecord extends BaseActiveRecord
{
	private $_id;
	private $_score;
	private $_version;

	/**
	 * Returns the database connection used by this AR class.
	 * By default, the "elasticsearch" 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->getComponent('elasticsearch');
	}

	/**
	 * @inheritdoc
	 */
	public static function find($q = null)
	{
		$query = static::createQuery();
		if (is_array($q)) {
			return $query->andWhere($q)->one();
		} elseif ($q !== null) {
			return static::get($q);
		}
		return $query;
	}

	/**
	 * Gets a record by its primary key.
	 *
	 * @param mixed $primaryKey the primaryKey value
	 * @param array $options options given in this parameter are passed to elasticsearch
	 * as request URI parameters.
	 * Please refer to the [elasticsearch documentation](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/docs-get.html)
	 * for more details on these options.
	 * @return static|null The record instance or null if it was not found.
	 */
	public static function get($primaryKey, $options = [])
	{
		if ($primaryKey === null) {
			return null;
		}
		$command = static::getDb()->createCommand();
		$result = $command->get(static::index(), static::type(), $primaryKey, $options);
		if ($result['exists']) {
			$model = static::instantiate($result);
			static::populateRecord($model, $result);
			$model->afterFind();
			return $model;
		}
		return null;
	}

	/**
	 * Gets a list of records by its primary keys.
	 *
	 * @param array $primaryKeys an array of primaryKey values
	 * @param array $options options given in this parameter are passed to elasticsearch
	 * as request URI parameters.
	 *
	 * Please refer to the [elasticsearch documentation](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/docs-get.html)
	 * for more details on these options.
	 * @return static|null The record instance or null if it was not found.
	 */

	public static function mget($primaryKeys, $options = [])
	{
		if (empty($primaryKeys)) {
			return [];
		}
		$command = static::getDb()->createCommand();
		$result = $command->mget(static::index(), static::type(), $primaryKeys, $options);
		$models = [];
		foreach($result['docs'] as $doc) {
			if ($doc['exists']) {
				$model = static::instantiate($doc);
				static::populateRecord($model, $doc);
				$model->afterFind();
				$models[] = $model;
			}
		}
		return $models;
	}

	// TODO add more like this feature http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-more-like-this.html

	// TODO add percolate functionality http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-percolate.html

	/**
	 * 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);
	}

	// TODO implement copy and move as pk change is not possible

	/**
	 * @return float returns the score of this record when it was retrieved via a [[find()]] query.
	 */
	public function getScore()
	{
		return $this->_score;
	}

	/**
	 * Sets the primary key
	 * @param mixed $value
	 * @throws \yii\base\InvalidCallException when record is not new
	 */
	public function setPrimaryKey($value)
	{
		$pk = static::primaryKey()[0];
		if ($this->getIsNewRecord() || $pk != '_id') {
			$this->$pk = $value;
		} else {
			throw new InvalidCallException('Changing the primaryKey of an already saved record is not allowed.');
		}
	}

	/**
	 * @inheritdoc
	 */
	public function getPrimaryKey($asArray = false)
	{
		$pk = static::primaryKey()[0];
		if ($asArray) {
			return [$pk => $this->$pk];
		} else {
			return $this->$pk;
		}
	}

	/**
	 * @inheritdoc
	 */
	public function getOldPrimaryKey($asArray = false)
	{
		$pk = static::primaryKey()[0];
		if ($this->getIsNewRecord()) {
			$id = null;
		} elseif ($pk == '_id') {
			$id = $this->_id;
		} else {
			$id = $this->getOldAttribute($pk);
		}
		if ($asArray) {
			return [$pk => $id];
		} else {
			return $id;
		}
	}

	/**
	 * This method defines the attribute that uniquely identifies a record.
	 *
	 * The primaryKey for elasticsearch documents is the `_id` field by default. This field is not part of the
	 * ActiveRecord attributes so you should never add `_id` to the list of [[attributes()|attributes]].
	 *
	 * You may overide this method to define the primary key name when you have defined
	 * [path mapping](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/mapping-id-field.html)
	 * for the `_id` field so that it is part of the `_source` and thus part of the [[attributes()|attributes]].
	 *
	 * Note that elasticsearch only supports _one_ attribute to be the primary key. However to match the signature
	 * of the [[\yii\db\ActiveRecordInterface|ActiveRecordInterface]] this methods returns an array instead of a
	 * single string.
	 *
	 * @return string[] array of primary key attributes. Only the first element of the array will be used.
	 */
	public static function primaryKey()
	{
		return ['_id'];
	}

	/**
	 * Returns the list of all attribute names of the model.
	 *
	 * This method must be overridden by child classes to define available attributes.
	 *
	 * Attributes are names of fields of the corresponding elasticsearch document.
	 * The primaryKey for elasticsearch documents is the `_id` field by default which is not part of the attributes.
	 * You may define [path mapping](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/mapping-id-field.html)
	 * for the `_id` field so that it is part of the `_source` fields and thus becomes part of the attributes.
	 *
	 * @return string[] list of attribute names.
	 */
	public function attributes()
	{
		throw new InvalidConfigException('The attributes() method of elasticsearch ActiveRecord has to be implemented by child classes.');
	}

	/**
	 * @return string the name of the index this record is stored in.
	 */
	public static function index()
	{
		return Inflector::pluralize(Inflector::camel2id(StringHelper::basename(get_called_class()), '-'));
	}

	/**
	 * @return string the name of the type of this record.
	 */
	public static function type()
	{
		return Inflector::camel2id(StringHelper::basename(get_called_class()), '-');
	}

	/**
	 * @inheritdoc
	 */
	public static function populateRecord($record, $row)
	{
		parent::populateRecord($record, $row['_source']);
		$pk = static::primaryKey()[0];
		if ($pk === '_id') {
			$record->_id = $row['_id'];
		}
		$record->_score = isset($row['_score']) ? $row['_score'] : null;
		$record->_version = isset($row['_version']) ? $row['_version'] : null; // TODO version should always be available...
	}

	/**
	 * Creates an active record instance.
	 *
	 * This method is called together with [[populateRecord()]] by [[ActiveQuery]].
	 * It is not meant to be used for creating new records directly.
	 *
	 * You may override this method if the instance being created
	 * depends on the row data to be populated into the record.
	 * For example, by creating a record based on the value of a column,
	 * you may implement the so-called single-table inheritance mapping.
	 * @param array $row row data to be populated into the record.
	 * This array consists of the following keys:
	 * - `_source`: refers to the attributes of the record.
	 * - `_type`: the type this record is stored in.
	 * - `_index`: the index this record is stored in.
	 * @return static the newly created active record
	 */
	public static function instantiate($row)
	{
		return new static;
	}

	/**
	 * Inserts a document into the associated index 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 [[primaryKey|primary key]] is not set (null) during insertion,
	 * it will be populated with a
	 * [randomly generated value](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/docs-index_.html#_automatic_id_generation)
	 * 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 will be saved.
	 * @param array $options options given in this parameter are passed to elasticsearch
	 * as request URI parameters. These are among others:
	 *
	 * - `routing` define shard placement of this record.
	 * - `parent` by giving the primaryKey of another record this defines a parent-child relation
	 * - `timestamp` specifies the timestamp to store along with the document. Default is indexing time.
	 *
	 * Please refer to the [elasticsearch documentation](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/docs-index_.html)
	 * for more details on these options.
	 *
	 * By default the `op_type` is set to `create`.
	 * @return boolean whether the attributes are valid and the record is inserted successfully.
	 */
	public function insert($runValidation = true, $attributes = null, $options = ['op_type' => 'create'])
	{
		if ($runValidation && !$this->validate($attributes)) {
			return false;
		}
		if ($this->beforeSave(true)) {
			$values = $this->getDirtyAttributes($attributes);

			$response = static::getDb()->createCommand()->insert(
				static::index(),
				static::type(),
				$values,
				$this->getPrimaryKey(),
				$options
			);

			if (!isset($response['ok'])) {
				return false;
			}
			$pk = static::primaryKey()[0];
			$this->$pk = $response['_id'];
			if ($pk != '_id') {
				$values[$pk] = $response['_id'];
			}
			$this->_version = $response['_version'];
			$this->_score = null;
			$this->setOldAttributes($values);
			$this->afterSave(true);
			return true;
		}
		return false;
	}

	/**
	 * Updates all records whos primary keys are given.
	 * For example, to change the status to be 1 for all customers whose status is 2:
	 *
	 * ~~~
	 * Customer::updateAll(['status' => 1], [2, 3, 4]);
	 * ~~~
	 *
	 * @param array $attributes attribute values (name-value pairs) to be saved into the table
	 * @param array $condition the conditions that will be put in the WHERE part of the UPDATE SQL.
	 * Please refer to [[ActiveQuery::where()]] on how to specify this parameter.
	 * @return integer the number of rows updated
	 */
	public static function updateAll($attributes, $condition = [])
	{
		$pkName = static::primaryKey()[0];
		if (count($condition) == 1 && isset($condition[$pkName])) {
			$primaryKeys = is_array($condition[$pkName]) ? $condition[$pkName] : [$condition[$pkName]];
		} else {
			$primaryKeys = static::find()->where($condition)->column($pkName); // TODO check whether this works with default pk _id
		}
		if (empty($primaryKeys)) {
			return 0;
		}
		$bulk = '';
		foreach($primaryKeys as $pk) {
			$action = Json::encode([
				"update" => [
					"_id" => $pk,
					"_type" => static::type(),
					"_index" => static::index(),
				],
			]);
			$data = Json::encode([
				"doc" => $attributes
			]);
			$bulk .= $action . "\n" . $data . "\n";
		}

		// TODO do this via command
		$url = [static::index(), static::type(), '_bulk'];
		$response = static::getDb()->post($url, [], $bulk);
		$n=0;
		$errors = [];
		foreach($response['items'] as $item) {
			if (isset($item['update']['error'])) {
				$errors[] = $item['update'];
			} elseif ($item['update']['ok']) {
				$n++;
			}
		}
		if (!empty($errors)) {
			throw new Exception(__METHOD__ . ' failed updating records.', $errors);
		}
		return $n;
	}

	/**
	 * Updates all matching records 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 $condition the conditions that will be put in the WHERE part of the UPDATE SQL.
	 * Please refer to [[Query::where()]] on how to specify this parameter.
	 * @return integer the number of rows updated
	 */
	public static function updateAllCounters($counters, $condition = [])
	{
		$pkName = static::primaryKey()[0];
		if (count($condition) == 1 && isset($condition[$pkName])) {
			$primaryKeys = is_array($condition[$pkName]) ? $condition[$pkName] : [$condition[$pkName]];
		} else {
			$primaryKeys = static::find()->where($condition)->column($pkName); // TODO check whether this works with default pk _id
		}
		if (empty($primaryKeys) || empty($counters)) {
			return 0;
		}
		$bulk = '';
		foreach($primaryKeys as $pk) {
			$action = Json::encode([
				"update" => [
					"_id" => $pk,
					"_type" => static::type(),
					"_index" => static::index(),
				],
			]);
			$script = '';
			foreach($counters as $counter => $value) {
				$script .= "ctx._source.$counter += $counter;\n";
			}
			$data = Json::encode([
				"script" => $script,
                "params" => $counters
			]);
			$bulk .= $action . "\n" . $data . "\n";
		}

		// TODO do this via command
		$url = [static::index(), static::type(), '_bulk'];
		$response = static::getDb()->post($url, [], $bulk);
		$n=0;
		$errors = [];
		foreach($response['items'] as $item) {
			if (isset($item['update']['error'])) {
				$errors[] = $item['update'];
			} elseif ($item['update']['ok']) {
				$n++;
			}
		}
		if (!empty($errors)) {
			throw new Exception(__METHOD__ . ' failed updating records counters.', $errors);
		}
		return $n;
	}

	/**
	 * 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 array $condition the conditions that will be put in the WHERE part of the DELETE SQL.
	 * Please refer to [[ActiveQuery::where()]] on how to specify this parameter.
	 * @return integer the number of rows deleted
	 */
	public static function deleteAll($condition = [])
	{
		$pkName = static::primaryKey()[0];
		if (count($condition) == 1 && isset($condition[$pkName])) {
			$primaryKeys = is_array($condition[$pkName]) ? $condition[$pkName] : [$condition[$pkName]];
		} else {
			$primaryKeys = static::find()->where($condition)->column($pkName); // TODO check whether this works with default pk _id
		}
		if (empty($primaryKeys)) {
			return 0;
		}
		$bulk = '';
		foreach($primaryKeys as $pk) {
			$bulk .= Json::encode([
				"delete" => [
					"_id" => $pk,
					"_type" => static::type(),
					"_index" => static::index(),
				],
			]) . "\n";
		}

		// TODO do this via command
		$url = [static::index(), static::type(), '_bulk'];
		$response = static::getDb()->post($url, [], $bulk);
		$n=0;
		$errors = [];
		foreach($response['items'] as $item) {
			if (isset($item['delete']['error'])) {
				$errors[] = $item['delete'];
			} elseif ($item['delete']['found'] && $item['delete']['ok']) {
				$n++;
			}
		}
		if (!empty($errors)) {
			throw new Exception(__METHOD__ . ' failed deleting records.', $errors);
		}
		return $n;
	}
}