<?php
/**
 * Connection class file
 *
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\db\redis;

use \yii\base\Component;
use yii\base\NotSupportedException;
use yii\base\InvalidConfigException;
use \yii\db\Exception;

/**
 *
 *
 *
 *
 * @since 2.0
 */
class Connection extends Component
{
	/**
	 * @event Event an event that is triggered after a DB connection is established
	 */
	const EVENT_AFTER_OPEN = 'afterOpen';

	/**
	 * @var string the Data Source Name, or DSN, contains the information required to connect to the database.
	 * DSN format: redis://[auth@][server][:port][/db]
	 * @see charset
	 */
	public $dsn;
	/**
	 * @var string the username for establishing DB connection. Defaults to empty string.
	 */
	public $username = '';
	/**
	 * @var string the password for establishing DB connection. Defaults to empty string.
	 */
	public $password = '';
	/**
	 * @var boolean whether to enable profiling for the SQL statements being executed.
	 * Defaults to false. This should be mainly enabled and used during development
	 * to find out the bottleneck of SQL executions.
	 * @see getStats
	 */
	public $enableProfiling = false;
	/**
	 * @var string the common prefix or suffix for table names. If a table name is given
	 * as `{{%TableName}}`, then the percentage character `%` will be replaced with this
	 * property value. For example, `{{%post}}` becomes `{{tbl_post}}` if this property is
	 * set as `"tbl_"`. Note that this property is only effective when [[enableAutoQuoting]]
	 * is true.
	 * @see enableAutoQuoting
	 */
	public $keyPrefix;

	/**
	 * @var array List of available redis commands http://redis.io/commands
	 */
	public $redisCommands = array(
		'BRPOP', // key [key ...] timeout Remove and get the last element in a list, or block until one is available
		'BRPOPLPUSH', // source destination timeout Pop a value from a list, push it to another list and return it; or block until one is available
		'CLIENT KILL', // ip:port Kill the connection of a client
		'CLIENT LIST', // Get the list of client connections
		'CLIENT GETNAME', // Get the current connection name
		'CLIENT SETNAME', // connection-name Set the current connection name
		'CONFIG GET', // parameter Get the value of a configuration parameter
		'CONFIG SET', // parameter value Set a configuration parameter to the given value
		'CONFIG RESETSTAT', // Reset the stats returned by INFO
		'DBSIZE', // Return the number of keys in the selected database
		'DEBUG OBJECT', // key Get debugging information about a key
		'DEBUG SEGFAULT', // Make the server crash
		'DECR', // key Decrement the integer value of a key by one
		'DECRBY', // key decrement Decrement the integer value of a key by the given number
		'DEL', // key [key ...] Delete a key
		'DISCARD', // Discard all commands issued after MULTI
		'DUMP', // key Return a serialized version of the value stored at the specified key.
		'ECHO', // message Echo the given string
		'EVAL', // script numkeys key [key ...] arg [arg ...] Execute a Lua script server side
		'EVALSHA', // sha1 numkeys key [key ...] arg [arg ...] Execute a Lua script server side
		'EXEC', // Execute all commands issued after MULTI
		'EXISTS', // key Determine if a key exists
		'EXPIRE', // key seconds Set a key's time to live in seconds
		'EXPIREAT', // key timestamp Set the expiration for a key as a UNIX timestamp
		'FLUSHALL', // Remove all keys from all databases
		'FLUSHDB', // Remove all keys from the current database
		'GET', // key Get the value of a key
		'GETBIT', // key offset Returns the bit value at offset in the string value stored at key
		'GETRANGE', // key start end Get a substring of the string stored at a key
		'GETSET', // key value Set the string value of a key and return its old value
		'HDEL', // key field [field ...] Delete one or more hash fields
		'HEXISTS', // key field Determine if a hash field exists
		'HGET', // key field Get the value of a hash field
		'HGETALL', // key Get all the fields and values in a hash
		'HINCRBY', // key field increment Increment the integer value of a hash field by the given number
		'HINCRBYFLOAT', // key field increment Increment the float value of a hash field by the given amount
		'HKEYS', // key Get all the fields in a hash
		'HLEN', // key Get the number of fields in a hash
		'HMGET', // key field [field ...] Get the values of all the given hash fields
		'HMSET', // key field value [field value ...] Set multiple hash fields to multiple values
		'HSET', // key field value Set the string value of a hash field
		'HSETNX', // key field value Set the value of a hash field, only if the field does not exist
		'HVALS', // key Get all the values in a hash
		'INCR', // key Increment the integer value of a key by one
		'INCRBY', // key increment Increment the integer value of a key by the given amount
		'INCRBYFLOAT', // key increment Increment the float value of a key by the given amount
		'INFO', // [section] Get information and statistics about the server
		'KEYS', // pattern Find all keys matching the given pattern
		'LASTSAVE', // Get the UNIX time stamp of the last successful save to disk
		'LINDEX', // key index Get an element from a list by its index
		'LINSERT', // key BEFORE|AFTER pivot value Insert an element before or after another element in a list
		'LLEN', // key Get the length of a list
		'LPOP', // key Remove and get the first element in a list
		'LPUSH', // key value [value ...] Prepend one or multiple values to a list
		'LPUSHX', // key value Prepend a value to a list, only if the list exists
		'LRANGE', // key start stop Get a range of elements from a list
		'LREM', // key count value Remove elements from a list
		'LSET', // key index value Set the value of an element in a list by its index
		'LTRIM', // key start stop Trim a list to the specified range
		'MGET', // key [key ...] Get the values of all the given keys
		'MIGRATE', // host port key destination-db timeout Atomically transfer a key from a Redis instance to another one.
		'MONITOR', // Listen for all requests received by the server in real time
		'MOVE', // key db Move a key to another database
		'MSET', // key value [key value ...] Set multiple keys to multiple values
		'MSETNX', // key value [key value ...] Set multiple keys to multiple values, only if none of the keys exist
		'MULTI', // Mark the start of a transaction block
		'OBJECT', // subcommand [arguments [arguments ...]] Inspect the internals of Redis objects
		'PERSIST', // key Remove the expiration from a key
		'PEXPIRE', // key milliseconds Set a key's time to live in milliseconds
		'PEXPIREAT', // key milliseconds-timestamp Set the expiration for a key as a UNIX timestamp specified in milliseconds
		'PING', // Ping the server
		'PSETEX', // key milliseconds value Set the value and expiration in milliseconds of a key
		'PSUBSCRIBE', // pattern [pattern ...] Listen for messages published to channels matching the given patterns
		'PTTL', // key Get the time to live for a key in milliseconds
		'PUBLISH', // channel message Post a message to a channel
		'PUNSUBSCRIBE', // [pattern [pattern ...]] Stop listening for messages posted to channels matching the given patterns
		'QUIT', // Close the connection
		'RANDOMKEY', // Return a random key from the keyspace
		'RENAME', // key newkey Rename a key
		'RENAMENX', // key newkey Rename a key, only if the new key does not exist
		'RESTORE', // key ttl serialized-value Create a key using the provided serialized value, previously obtained using DUMP.
		'RPOP', // key Remove and get the last element in a list
		'RPOPLPUSH', // source destination Remove the last element in a list, append it to another list and return it
		'RPUSH', // key value [value ...] Append one or multiple values to a list
		'RPUSHX', // key value Append a value to a list, only if the list exists
		'SADD', // key member [member ...] Add one or more members to a set
		'SAVE', // Synchronously save the dataset to disk
		'SCARD', // key Get the number of members in a set
		'SCRIPT EXISTS', // script [script ...] Check existence of scripts in the script cache.
		'SCRIPT FLUSH', // Remove all the scripts from the script cache.
		'SCRIPT KILL', // Kill the script currently in execution.
		'SCRIPT LOAD', // script Load the specified Lua script into the script cache.
		'SDIFF', // key [key ...] Subtract multiple sets
		'SDIFFSTORE', // destination key [key ...] Subtract multiple sets and store the resulting set in a key
		'SELECT', // index Change the selected database for the current connection
		'SET', // key value Set the string value of a key
		'SETBIT', // key offset value Sets or clears the bit at offset in the string value stored at key
		'SETEX', // key seconds value Set the value and expiration of a key
		'SETNX', // key value Set the value of a key, only if the key does not exist
		'SETRANGE', // key offset value Overwrite part of a string at key starting at the specified offset
		'SHUTDOWN', // [NOSAVE] [SAVE] Synchronously save the dataset to disk and then shut down the server
		'SINTER', // key [key ...] Intersect multiple sets
		'SINTERSTORE', // destination key [key ...] Intersect multiple sets and store the resulting set in a key
		'SISMEMBER', // key member Determine if a given value is a member of a set
		'SLAVEOF', // host port Make the server a slave of another instance, or promote it as master
		'SLOWLOG', // subcommand [argument] Manages the Redis slow queries log
		'SMEMBERS', // key Get all the members in a set
		'SMOVE', // source destination member Move a member from one set to another
		'SORT', // key [BY pattern] [LIMIT offset count] [GET pattern [GET pattern ...]] [ASC|DESC] [ALPHA] [STORE destination] Sort the elements in a list, set or sorted set
		'SPOP', // key Remove and return a random member from a set
		'SRANDMEMBER', // key [count] Get one or multiple random members from a set
		'SREM', // key member [member ...] Remove one or more members from a set
		'STRLEN', // key Get the length of the value stored in a key
		'SUBSCRIBE', // channel [channel ...] Listen for messages published to the given channels
		'SUNION', // key [key ...] Add multiple sets
		'SUNIONSTORE', // destination key [key ...] Add multiple sets and store the resulting set in a key
		'SYNC', // Internal command used for replication
		'TIME', // Return the current server time
		'TTL', // key Get the time to live for a key
		'TYPE', // key Determine the type stored at key
		'UNSUBSCRIBE', // [channel [channel ...]] Stop listening for messages posted to the given channels
		'UNWATCH', // Forget about all watched keys
		'WATCH', // key [key ...] Watch the given keys to determine execution of the MULTI/EXEC block
		'ZADD', // key score member [score member ...] Add one or more members to a sorted set, or update its score if it already exists
		'ZCARD', // key Get the number of members in a sorted set
		'ZCOUNT', // key min max Count the members in a sorted set with scores within the given values
		'ZINCRBY', // key increment member Increment the score of a member in a sorted set
		'ZINTERSTORE', // destination numkeys key [key ...] [WEIGHTS weight [weight ...]] [AGGREGATE SUM|MIN|MAX] Intersect multiple sorted sets and store the resulting sorted set in a new key
		'ZRANGE', // key start stop [WITHSCORES] Return a range of members in a sorted set, by index
		'ZRANGEBYSCORE', // key min max [WITHSCORES] [LIMIT offset count] Return a range of members in a sorted set, by score
		'ZRANK', // key member Determine the index of a member in a sorted set
		'ZREM', // key member [member ...] Remove one or more members from a sorted set
		'ZREMRANGEBYRANK', // key start stop Remove all members in a sorted set within the given indexes
		'ZREMRANGEBYSCORE', // key min max Remove all members in a sorted set within the given scores
		'ZREVRANGE', // key start stop [WITHSCORES] Return a range of members in a sorted set, by index, with scores ordered from high to low
		'ZREVRANGEBYSCORE', // key max min [WITHSCORES] [LIMIT offset count] Return a range of members in a sorted set, by score, with scores ordered from high to low
		'ZREVRANK', // key member Determine the index of a member in a sorted set, with scores ordered from high to low
		'ZSCORE', // key member Get the score associated with the given member in a sorted set
		'ZUNIONSTORE', // destination numkeys key [key ...] [WEIGHTS weight [weight ...]] [AGGREGATE SUM|MIN|MAX] Add multiple sorted sets and store the resulting sorted set in a new key
	);
	/**
	 * @var Transaction the currently active transaction
	 */
	private $_transaction;
	/**
	 * @var resource redis socket connection
	 */
	private $_socket;

	/**
	 * Closes the connection when this component is being serialized.
	 * @return array
	 */
	public function __sleep()
	{
		$this->close();
		return array_keys(get_object_vars($this));
	}

	/**
	 * Returns a value indicating whether the DB connection is established.
	 * @return boolean whether the DB connection is established
	 */
	public function getIsActive()
	{
		return $this->_socket !== null;
	}

	/**
	 * Establishes a DB connection.
	 * It does nothing if a DB connection has already been established.
	 * @throws Exception if connection fails
	 */
	public function open()
	{
		if ($this->_socket === null) {
			if (empty($this->dsn)) {
				throw new InvalidConfigException('Connection.dsn cannot be empty.');
			}
			// TODO parse DSN
			$host = 'localhost';
			$port = 6379;
			try {
				\Yii::trace('Opening DB connection: ' . $this->dsn, __CLASS__);
				$this->_socket = stream_socket_client($host . ':' . $port);
				// TODO auth
				// TODO select database
				$this->initConnection();
			}
			catch (\PDOException $e) {
				\Yii::error("Failed to open DB connection ({$this->dsn}): " . $e->getMessage(), __CLASS__);
				$message = YII_DEBUG ? 'Failed to open DB connection: ' . $e->getMessage() : 'Failed to open DB connection.';
				throw new Exception($message, (int)$e->getCode(), $e->errorInfo);
			}
		}
	}

	/**
	 * Closes the currently active DB connection.
	 * It does nothing if the connection is already closed.
	 */
	public function close()
	{
		if ($this->_socket !== null) {
			\Yii::trace('Closing DB connection: ' . $this->dsn, __CLASS__);
			$this->__call('CLOSE', array()); // TODO improve API
			stream_socket_shutdown($this->_socket, STREAM_SHUT_RDWR);
			$this->_socket = null;
			$this->_transaction = null;
		}
	}

	/**
	 * Initializes the DB connection.
	 * This method is invoked right after the DB connection is established.
	 * The default implementation turns on `PDO::ATTR_EMULATE_PREPARES`
	 * if [[emulatePrepare]] is true, and sets the database [[charset]] if it is not empty.
	 * It then triggers an [[EVENT_AFTER_OPEN]] event.
	 */
	protected function initConnection()
	{
		$this->trigger(self::EVENT_AFTER_OPEN);
	}

	/**
	 * Returns the currently active transaction.
	 * @return Transaction the currently active transaction. Null if no active transaction.
	 */
	public function getTransaction()
	{
		return $this->_transaction && $this->_transaction->isActive ? $this->_transaction : null;
	}

	/**
	 * Starts a transaction.
	 * @return Transaction the transaction initiated
	 */
	public function beginTransaction()
	{
		$this->open();
		$this->_transaction = new Transaction(array(
			'db' => $this,
		));
		$this->_transaction->begin();
		return $this->_transaction;
	}

	/**
	 * Returns the name of the DB driver for the current [[dsn]].
	 * @return string name of the DB driver
	 */
	public function getDriverName()
	{
		if (($pos = strpos($this->dsn, ':')) !== false) {
			return strtolower(substr($this->dsn, 0, $pos));
		} else {
			return 'redis';
		}
	}

	/**
	 * http://redis.io/topics/protocol
	 * https://github.com/ptrofimov/tinyredisclient/blob/master/src/TinyRedisClient.php
	 *
	 * @param string $name
	 * @param array $params
	 * @return mixed
	 */
	public function __call($name, $params)
	{
		// TODO set active to true?
		if (in_array($name, $this->redisCommands))
		{
			array_unshift($params, $name);
			$command = '*' . count($params) . "\r\n";
			foreach($params as $arg) {
				$command .= '$' . strlen($arg) . "\r\n" . $arg . "\r\n";
			}
			\Yii::trace("Executing Redis Command: {$command}", __CLASS__);
			fwrite($this->_socket, $command);
			return $this->parseResponse($command);
		}
		else {
			return parent::__call($name, $params);
		}
	}

	private function parseResponse($command)
	{
		if(($line = fgets($this->_socket))===false) {
			throw new Exception("Failed to read from socket.\nRedis command was: " . $command);
		}
		$type = $line[0];
		$line = substr($line, 1, -2);
		switch($type)
		{
			case '+': // Status reply
				return true;
			case '-': // Error reply
				throw new Exception("Redis error: " . $line . "\nRedis command was: " . $command);
			case ':': // Integer reply
				// no cast to integer as it is in the range of a signed 64 bit integer
				return $line;
			case '$': // Bulk replies
				if ($line == '-1') {
					return null;
				}
				$data = fread($this->_socket, $line + 2);
				if($data===false) {
					throw new Exception("Failed to read from socket.\nRedis command was: " . $command);
				}
				return substr($data, 0, -2);
			case '*': // Multi-bulk replies
				$count = (int) $line;
				$data = array();
				for($i = 0; $i < $count; $i++) {
					$data[] = $this->parseResponse($command);
				}
				return $data;
			default:
				throw new Exception('Received illegal data from redis: ' . substr($line, 0, -2) . "\nRedis command was: " . $command);
		}
	}

	/**
	 * Returns the statistical results of SQL queries.
	 * The results returned include the number of SQL statements executed and
	 * the total time spent.
	 * In order to use this method, [[enableProfiling]] has to be set true.
	 * @return array the first element indicates the number of SQL statements executed,
	 * and the second element the total time spent in SQL execution.
	 * @see \yii\logging\Logger::getProfiling()
	 */
	public function getQuerySummary()
	{
		$logger = \Yii::getLogger();
		$timings = $logger->getProfiling(array('yii\db\redis\Connection::command'));
		$count = count($timings);
		$time = 0;
		foreach ($timings as $timing) {
			$time += $timing[1];
		}
		return array($count, $time);
	}
}