<?php
/****************************************************************************************
* MySQL Database library by ZeusAFK Technologies
* Version 0.1a | 2017-07-27
****************************************************************************************/

namespace ZeusAFK;

if(!class_exists('ZeusAFK\Database')){
	class Database{

		private static $instance;

		private $connection;
		private $results;
		private $handlers;
		private $error;
		private $on_error;
		private $has_errors;
		private $charset;

		public static function getInstance(){
			if(!self::$instance instanceof self){
				self::$instance = new self;
			}
			return self::$instance;
		}

		function __construct(){
			$this->results = array();
			$this->handlers = array();
			$this->has_errors = false;
			$this->charset = 'utf8';
			$this->on_error = function($type, $description){
				return false;
			};

			$that = $this;

			$this->RegisterHandler('FETCH_ROWS_HANDLER', function($results){
				$row = array();
				foreach($results as $key => $value) $row[$key] = $value;
				$this->AppendResults($row);
			});

			$this->RegisterHandler('FETCH_ROW_HANDLER', function($results){
				$row = array();
				foreach($results as $key => $value) $row[$key] = $value;
				$this->SetResults($row);
			});

			$this->RegisterHandler('FETCH_FIELD_HANDLER', function($results){
				foreach($results as $key => $value) $this->SetResults($value);
			});
		}

		public function CreateConnection($host, $user, $password, $database, $port = 3306){
			@$this->connection = new \mysqli($host, $user, $password, $database, $port);

			if($this->connection->connect_errno){
				$this->has_errors = true;
				$this->error = $connection->connect_errno;
				$this->on_error && $this->on_error('connection_creation', $this->error);
			}else{
				$this->connection->set_charset($this->charset);
			}

			return $this;
		}

		public function SetConnection($connection){
			$this->connection = $connection;
			return $this;
		}

		public function GetConnection(){
			return $this->connection;
		}

		function RegisterHandler($name, $function){
			$this->handlers[$name] = $function;
			return $this;
		}

		function GetHandler($name){
			return $this->handlers[$name];
		}

		function GetResults(){
			return $this->results;
		}

		function SetResults($results){
			$this->results = $results;
			return $this;
		}

		function AppendResults($results){
			$this->results[] = $results;
			return $this;
		}

		function ClearResults(){
			$this->results = array();
			return $this;
		}

		function SetErrorHandler($on_error){
			$this->on_error = $on_error;
			return $this;
		}

		function Success(){
			return $this->has_errors == false;
		}

		function GetError(){
			return $this->error;
		}

		public function Query($query, $types = false, $params = false, $results = false, $callback = false, &$fetch = false, $connection = false){
			$this->ClearResults();

			if(!$connection){
				$connection = $this->connection;
			}

			$new_prepared_statement = true;

			if($query instanceof mysqli_stmt){
				$stmt = $query;
				$new_prepared_statement = false;
			}else if(!($stmt = $connection->prepare($query))){
				$this->has_errors = true;
				$this->error = $connection->error;
				$error_handler = $this->on_error;
				$error_handler && $error_handler('statement_prepare_error', $this->error);
				return $this;
			}

			if($types && $params){
				if(!is_array($params)){
					$params = array($params);
				}

				$referencedParams = array();
				foreach($params as $k => $param){
					$referencesParams[$k] = &$params[$k];
				}

				if(sizeof($params) > 0){
					call_user_func_array(array($stmt, "bind_param"), array_merge(array($types), $referencesParams));
				}
			}

			$executed = $stmt->execute();

			if(!$executed){
				$this->has_errors = true;
				$error_handler = $this->on_error;
				$error_handler && $error_handler('execute_error', $this->error);
				return false;
			}else if(!$results){
				$result = $stmt->result_metadata();
				if($result){
					$info_fields = $result->fetch_fields();
					$results = array();
					foreach ($info_fields as $field){
						$count = 0;
						$field_name = $field->name;
						while(in_array($field_name, $results)){
							$count++;
							$field_name = $field->name.$count;
						}
						$results[] = $field->name.($count > 0 ? $count : '');
					}
				}
			}

			if($results){
				$formattedResults = array();
				$valuesContainer = array();
				foreach($results as $k => $value){
					$valuesContainer[$k] = null;
					$formattedResults[$value] = &$valuesContainer[$k];
				}

				if(sizeof($results) > 0){
					call_user_func_array(array($stmt, "bind_result"), $formattedResults);
				}
			}

			if(function_exists('mysqli_fetch_all')){
				do {
					$stmt->store_result();
					$rows = array();
					$row = array();

					if(!$callback){
						if($stmt->num_rows == 1 && sizeof($results) == 1)
							$callback = $this->GetHandler('FETCH_FIELD_HANDLER');
						else if($stmt->num_rows == 1 && sizeof($results) > 1)
							$callback = $this->GetHandler('FETCH_ROW_HANDLER');
						else
							$callback = $this->GetHandler('FETCH_ROWS_HANDLER');
					}

					while($stmt->fetch()){
						if($fetch){
							$row = array();
							foreach($formattedResults as $key => $value) $row[$key] = $value;
							$rows[] = $row;
						}
						if($callback) $callback($formattedResults);
					}
				} while ($stmt->more_results() && $stmt->next_result());
			}else{
				$stmt->store_result();
				$rows = array();
				$row = array();

				if(!$callback){
					if($stmt->num_rows == 1 && sizeof($results) == 1)
						$callback = $this->GetHandler('FETCH_FIELD_HANDLER');
					else if($stmt->num_rows == 1 && sizeof($results) > 1)
						$callback = $this->GetHandler('FETCH_ROW_HANDLER');
					else
						$callback = $this->GetHandler('FETCH_ROWS_HANDLER');
				}

				while($stmt->fetch()){
					if($fetch){
						$row = array();
						foreach($formattedResults as $key => $value) $row[$key] = $value;
						$rows[] = $row;
					}
					if($callback) $callback($formattedResults);
				}
				$stmt->free_result();
				if($new_prepared_statement){
					$stmt->close();
				}
				while ($connection->more_results()){
					$connection->next_result();
					$result = $connection->use_result();
					if ($result instanceof mysqli_result) {
						$result->free();
					}
				}
			}

			return $this;
		}
	}
}