<?php

class Database {

    private static $instance = null;
    private $results,
            $sqlParams = array(),
            $sql,
            $db;

    private function __construct() {
        try {
            return $this->db = new PDO('mysql:host=127.0.0.1;dbname=cms', 'root', '');
        } catch (PDOException $e) {
            echo $e->getMessage();
        }
    }

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

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

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

    public function select($fields = ['*'], $table = 'users') {
        $fields = implode(', ', $fields);
        $this->sql = "SELECT {$fields} FROM {$table}";
        return $this;
    }

    public function insert($table, $values) {
        $fields = implode(', ', array_keys($values));
        $this->sql = "INSERT INTO {$table} ($fields) VALUES (";
        for($i = 0; count($values) > $i; $i++) {
            $this->sql .= "?, ";
        }
        $this->sql = rtrim($this->sql, ', ');
        $this->sql .= ")";
    }

    public function update($table) {
        $this->sql = "UPDATE {$table} SET ";

        return $this;
    }

    public function delete() {
        $this->sql = "DELETE FROM {$table} WHERE usersname = ?";
    }

    public function set($fieldParams) {
        array_push($this->sqlParams, array_values($fieldParams));
        $fields = null;
        foreach ($fieldParams as $field => $field_value) {
            echo $field_value.'<br>';
            $this->sql .= "{$field} = ?, ";
        }
        $this->sql = rtrim($this->sql, ', ');

        return $this;
    }

    public function where($whereString, $whereParams, $operator = "AND") {
        foreach ($whereParams as $value) {
            array_push($this->sqlParams, $value);
            echo $value.'<br>';
        }
        $this->sqlParams = array_push($this->sqlParams, $whereParams);
        $where = implode(" {$operator} " , $whereString);
        $this->sql .= " WHERE {$where}";

        return $this;
    }

    public function order($order = ['id', 'DESC']) {
        $order = implode(' ', $order);
        $this->sql .= " ORDER BY {$order}";
        return $this;
    }

    public function limit($number = 1) {
        $this->sql .= " LIMIT {$number}";
        return $this;
    }

    public function make() {
        $sql = $this->sql;
        $params = $this->sqlParams;
        echo '<pre>' , print_r($this->sqlParams) , '</pre>';

        $query = $this->db->prepare($sql);

        for ($i = 0, $j = 1; count($params) > $i; $i++, $j++) {
            $query->bindParam($j, $params[$i]);
        }

        $query->execute();
        $results = $query->fetchAll(PDO::FETCH_OBJ);

        return $this->results($results);
    }

    public function getSqlParams() {
        return $this->sqlParams;
    }

    public function getSQL() {
        return $this->sql;
    }

}