Решение тестовой задачи

php/.gitignore

@@ -0,0 +1,4 @@
+/composer.lock
+/composer.phar
+/vendor/
+/vendor

php/composer.json

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+{
+  "minimum-stability": "stable",
+  "require": {
+    "php": ">=7.4",
+    "ext-pdo": "*",
+    "ext-json": "*"
+  },
+  "require-dev": {
+  },
+  "autoload": {
+    "psr-4": {
+      "\\": "src/"
+    }
+  },
+  "repositories": [
+    {
+      "type": "composer",
+      "url": "https://asset-packagist.org"
+    }
+  ]
+}

php/docker-compose.yml

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+version: '3.3'
+services:
+  db:
+    image: mysql:8
+    restart: always
+    environment:
+      MYSQL_DATABASE: 'db'
+      # So you don't have to use root, but you can if you like
+      MYSQL_USER: 'dbuser'
+      # You can use whatever password you like
+      MYSQL_PASSWORD: 'dbpass'
+      # Password for root access
+      MYSQL_ROOT_PASSWORD: 'password'
+    ports:
+      # <Port exposed> : < MySQL Port running inside container>
+      - '3306:3306'
+    expose:
+      # Opens port 3306 on the container
+      - '3306'
+      # Where our data will be persisted
+    volumes:
+      - my-db:/var/lib/mysql
+# Names our volume
+volumes:
+  my-db:

php/readme.md

@@ -1,2 +1,3 @@
 ### Тестовое задание для разработчика на PHP
-Мы ожидаем, что Вы найдете все возможные ошибки (синтаксические, проектирования, безопасности и т.д.)
+
+Насчёт ошибок проектирования сложновато судить, так как непонятна конечная цель в виду отсутствия конкретной задачи. Поэтому оставил примерно как есть.

php/src/Db/Command.php

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+<?php
+
+namespace Db;
+
+class Command
+{
+    private const TYPE_MAP = [
+        'boolean'  => \PDO::PARAM_BOOL,
+        'integer'  => \PDO::PARAM_INT,
+        'string'   => \PDO::PARAM_STR,
+        'resource' => \PDO::PARAM_LOB,
+        'NULL'     => \PDO::PARAM_NULL,
+    ];
+    /**
+     * @var string|null
+     */
+    private ?string $sql;
+    /**
+     * @var array
+     */
+    private array $params;
+    /**
+     * @var \PDOStatement|null
+     */
+    private ?\PDOStatement $pdoStatement = null;
+
+    public function __construct(?string $sql = null, array $params = [])
+    {
+        $this->sql = $sql;
+        $this->params = $params;
+    }
+
+    public function queryAll(): array
+    {
+        return $this->queryInternal('fetchAll');
+    }
+
+    public function queryOne(): ?array
+    {
+        $result = $this->queryInternal('fetch');
+        return  (false === $result) ? null : $result;
+    }
+
+    public function execute(): void
+    {
+        $this->prepare();
+        $this->pdoStatement()->execute();
+    }
+
+    public function insert()
+    {
+        $this->execute();
+        return Db::i()->pdo()->lastInsertId();
+    }
+
+    /**
+     * @param array $params
+     *
+     * @return $this
+     */
+    public function setParams(array $params): self
+    {
+        $this->params = $params;
+        return $this;
+    }
+
+    /**
+     * @param array $params
+     *
+     * @return $this
+     */
+    public function addParams(array $params): self
+    {
+        foreach ($params as $param => $value) {
+            $this->params[$param] = $value;
+        }
+        return $this;
+    }
+
+    /**
+     * @return \PDOStatement
+     */
+    public function pdoStatement(): \PDOStatement
+    {
+        return $this->pdoStatement ?? ($this->pdoStatement = Db::i()->pdo()->prepare($this->requireSql()));
+    }
+
+    /**
+     * @param string $sql
+     *
+     * @return $this
+     */
+    public function setSql(string $sql): self
+    {
+        $this->sql = $sql;
+        return $this;
+    }
+
+    /**
+     * @return string
+     */
+    public function requireSql(): string
+    {
+        if (null === $this->sql) {
+            throw new \RuntimeException('SQL statement required');
+        }
+
+        return $this->sql;
+    }
+
+    private function prepare(): void
+    {
+        $this->bindParams();
+    }
+
+    private function queryInternal(string $method)
+    {
+        $this->prepare();
+        $pdoStatement = $this->pdoStatement();
+        $result = $pdoStatement->$method(\PDO::FETCH_ASSOC);
+        $pdoStatement->closeCursor();
+
+        return $result;
+    }
+
+    private function bindParams(): void
+    {
+        $pdoStatement = $this->pdoStatement();
+        foreach ($this->params as $param => $value) {
+            $pdoStatement->bindParam($param, $value, $this->paramType($value));
+        }
+    }
+
+    private function paramType($value)
+    {
+        $type = \gettype($value);
+
+        return self::TYPE_MAP[$type] ?? \PDO::PARAM_STR;
+    }
+}

php/src/Db/Db.php

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+<?php
+
+namespace Db;
+
+use PDO;
+
+class Db
+{
+    /**
+     * @var static|null
+     */
+    private static ?Db $instance = null;
+    /**
+     * @var \PDO|null
+     */
+    private ?PDO $pdo = null;
+
+    public static function i(): self
+    {
+        return self::$instance ?? (self::$instance = new static());
+    }
+
+    public static function command(string $sql, array $params = []): Command
+    {
+        return new Command($sql, $params);
+    }
+
+    public function pdo(): PDO
+    {
+        return $this->pdo ?? ($this->pdo = new PDO('mysql:dbname=db;host=127.0.0.1', 'dbuser', 'dbpass'));
+    }
+}