<?php

namespace libs\db;

use PDO;
use PDOException;

class DbConnection
{
    /**
     * 数据库配置信息
     * @var array
     */
    protected $settings;
    /**
     * pdo实例
     * @var
     */
    protected $pdo;

    /**
     * sql的参数
     * @var array
     */
    protected $parameters = array();

    /**
     * 预处理语句
     * @var array
     */
    protected $sQuery;

    /**
     * 构造函数
     */
    public function __construct($config, $charset = 'utf8')
    {
        $this->settings = array(
            'driver'   => $config['driver'],
            'host'     => $config['host'],
            'port'     => $config['port'],
            'user'     => $config['user'],
            'password' => $config['password'],
            'dbname'   => $config['dbname'],
            'charset'  => $config['charset'] ?? $charset
        );
        $this->connect();
    }

    /**
     * 创建pdo实例
     */
    public function connect()
    {
        $dsn       = sprintf(
            "%s:dbname=%s;host=%s;port=%s",
            $this->settings["driver"],
            $this->settings["dbname"],
            $this->settings["host"],
            $this->settings["port"]
        );
        $options   = [
            PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES ' . (!empty($this->settings['charset']) ? $this->settings['charset'] : 'utf8')
        ];
        $this->pdo = new PDO($dsn, $this->settings["user"], $this->settings["password"], $options);
        $this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $this->pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
    }

    /**
     * 获取一行数据
     * @param string $query
     * @param int $fetchmode
     * @return null
     */
    public function fetch($query = '', $fetchmode = PDO::FETCH_ASSOC)
    {
        if (strpos(strtolower($query), "limit") == false) {
            $query = rtrim($query, ";") . " limit 1;";
        }
        $this->execute($query);

        $result = $this->sQuery->fetchAll($fetchmode);

        if (!empty($result)) {
            return $result[0];
        }

        return null;
    }

    /**
     * 获取多行数据
     * @param string $query
     * @param int $fetchmode
     * @return null
     */
    public function fetchAll($query = '', $fetchmode = PDO::FETCH_ASSOC)
    {
        $this->execute($query);

        $result = $this->sQuery->fetchAll($fetchmode);

        if (!empty($result)) {
            return $result;
        }

        return null;
    }

    /**
     * 新增
     * @param $table
     * @param array $params
     * @param int $fetchmode
     * @return string|null
     */
    public function insert($table, $data = [], $fetchmode = PDO::FETCH_ASSOC)
    {
        if (count($data) == 0) {
            return null;
        }

        $key_str = '';
        $val_str = '';
        foreach ($data as $key => $val) {
            $key_str .= "\"$key\",";
            if(is_string($val)){
                $val_str .= "'{$val}',";
            }else{
                $val_str .= "{$val},";
            }
        }
        $key_str = rtrim($key_str, ",");
        $val_str = rtrim($val_str, ",");


        $query = "INSERT INTO {$table} ({$key_str}) VALUES ({$val_str})";

        $this->execute($query);

        if ($this->sQuery->rowCount() > 0) {
            return $this->lastInsertId();
        }

        return null;
    }

    /**
     * 修改
     * @param $table
     * @param array $params
     * @return null
     */
    public function update($table, $data = [], $params = [])
    {
        if (count($data) == 0) {
            return null;
        }
        if (count($params) == 0) {
            return null;
        }

        $str = '';
        foreach ($data as $key => $val) {
            $str .= "\"" . $key . "\"='$val',";
        }
        $str   = rtrim($str, ",");
        $query = "UPDATE \"{$table}\" SET {$str} ";
        $query .= " WHERE ";

        $count = 0;
        foreach ($params as $k => $v) {
            $count++;
            if ($count === count($params)) {
                $query .= "\"$k\"='$v' ";
            } else {
                $query .= "\"$k\"='$v' AND ";
            }
        }

        $this->execute($query);

        return $this->sQuery->rowCount();
    }

    /**
     * 删除
     * @param $table
     * @param array $params
     * @return null
     */
    public function delete($table, $params = [])
    {
        if (count($params) == 0) {
            return null;
        }

        $str   = '';
        $count = 0;
        foreach ($params as $k => $v) {
            $count++;
            if ($count === count($params)) {
                $str .= "\"$k\"='$v' ";
            } else {
                $str .= "\"$k\"='$v' AND ";
            }
        }

        $query = "DELETE FROM \"{$table}\" WHERE {$str}";

        $this->execute($query);

        return $this->sQuery->rowCount();
    }

    /**
     * 执行SQL
     * @param string $query
     * @param array $params
     * @param int $fetchmode
     * @return mixed
     */
    public function query($query = '', $params = null, $fetchmode = PDO::FETCH_ASSOC)
    {
        $this->execute($query, $params);
        $rawStatement = explode(" ", $query);

        $statement = strtolower(trim($rawStatement[0]));
        if ($statement === 'select' || $statement === 'show') {
            $result = $this->sQuery->fetchAll($fetchmode);
            if (strpos(strtolower($query), 'limit') !== false) {
                return $result[0];
            } else {
                return $result;
            }
        } elseif ($statement === 'update' || $statement === 'delete') {
            return $this->sQuery->rowCount();
        } elseif ($statement === 'insert') {
            if ($this->sQuery->rowCount() > 0) {
                return $this->lastInsertId();
            }
        } else {
            return NULL;
        }
    }

    /**
     * 执行
     * @param string $query
     * @param string $parameters
     */
    protected function execute($query, $parameters = "")
    {
        try {
            $this->sQuery = $this->pdo->prepare($query);

            if (is_array($parameters)) {
                foreach ($parameters as $key => $param) {
                    $this->sQuery->bindParam($key + 1, $param);
                }
            }

            $this->sQuery->execute();

        } catch (PDOException $e) {
            $errorCode = $e->getCode();

            // 写入错误sql信息
            record_sql_log($e->getMessage(),$query);

            // 服务端断开时重连一次
            if ($errorCode == 'HY000' || $errorCode == '57P01' || $errorCode == '08006' || $errorCode == '08003') {

                $this->closeConnection();
                $this->connect();
                try {
                    $this->sQuery = $this->pdo->prepare($query);

                    if (is_array($parameters)) {
                        foreach ($parameters as $key => $param) {
                            $this->sQuery->bindParam($key + 1, $param);
                        }
                    }
                    $this->sQuery->execute();
                } catch (PDOException $ex) {
                    $this->rollBackTrans();

                    throw $ex;
                }
            } else {
                $this->rollBackTrans();
                throw $e;
            }
        }
        $this->parameters = array();
    }

    /**
     * 关闭连接
     */
    public function closeConnection()
    {
        $this->pdo = null;
    }

    /**
     * 返回lastInsertId
     * @return string
     */
    public function lastInsertId()
    {
        return $this->pdo->lastInsertId();
    }

    /**
     * 开始事务
     */

    public function beginTrans()
    {
        $this->pdo->beginTransaction();
    }

    /**
     * 提交事务
     */

    public function commitTrans()
    {
        $this->pdo->commit();
    }

    /**
     * 事务回滚
     */

    public function rollBackTrans()
    {
        if ($this->pdo->inTransaction()) {
            $this->pdo->rollBack();
        }
    }
}