PART 1. Prepare-for-Techncal-Interview-and-Coding-Task-for-PHP-Laravel

function isPalindrome(string $str): bool {
    $reversed = strrev($str);
    return $str === $reversed;
}
// OR
 
// Create the function findNumericalPalindrome
// which takes two positive integers as its argument and returns the numerical palindromes
// as an array of $n numerical palindromes that come after $num, including $num.
// Define a function to find numerical palindromes
function findNumericalPalindrome($num, $n)
{
    // Initialize an array to store the palindromes
    $palindromes = array(); 
    
    // Loop until the desired number of palindromes is found
    while (count($palindromes) < $n) {
        // Check if the current number is a palindrome (reads the same forwards and backwards)
        if ($num == strrev($num)) {
            // If yes, add it to the list of palindromes
            $palindromes[] = $num; 
        }
        // Increment the number to check the next one
        $num++; 
    }
    
    // Return the list of palindromes
    return $palindromes; 
}
    
    // Set the number of palindromes to find
    $n = 10; 
    // Set the starting number
    $num = 100; 
    // Call the function to find palindromes
    $palindromes = findNumericalPalindrome($num, $n); 
    // print_r ($palindromes);
    
    // Loop through each palindrome and print it
    foreach ($palindromes as $palindrome) {
        // Print each palindrome and move to the next line
        echo $palindrome . PHP_EOL .'<br>'; 
    }
Task 3: Create a function to find the second-largest element in an array of integers.
function findSecondLargest(array $numbers): int {
    rsort($numbers);
    return $numbers[1];
}
2. API Design and Implementation(PHP)
Task 1: Design an API endpoint to retrieve a user's profile information by their ID.
Solution:
The API endpoint
GET /api/users/{user_id}
Response1 (JSON):
{
  "user_id": 1,
  "name": "Gilbert Ozioma",
  "email": "gilbertozioma0@gmail.com",
  "bio": "Backend Web Developer",
  "url": "https://about.me/gilbertozioma",
  "created_at": "2023-08-07T12:34:56Z"
}
Pseudo-code implementation of the API endpoint:
<?php

// Function to retrieve user profile by ID
function get_user_profile($user_id) {

    // Fetch user profile from the database or any other data source
    $user_profile = getUserProfileFromDatabase($user_id);
    return $user_profile;
}

// Check if the request method is GET and the user_id parameter exists
if ($_SERVER['REQUEST_METHOD'] === 'GET' && isset($_GET['user_id'])) {
    $user_id = $_GET['user_id'];
    $user_profile = get_user_profile($user_id);
    
    // Set the appropriate content type and status code
    header('Content-Type: application/json');
    if ($user_profile) {
        http_response_code(200);
        echo json_encode($user_profile);
    } else {
        http_response_code(404);
        echo json_encode(array("error" => "User not found"));
    }
} else {
    // Return an error for unsupported requests
    http_response_code(405);
    echo json_encode(array("error" => "Method Not Allowed"));
}
?>
Task 2: Implement an API endpoint to create a new post with title and content.
Solution:
The API endpoint:
POST /api/posts
Request (JSON):
{
  "title": "New Post Title",
  "content": "This is the content of the new post."
}
Response2 (JSON):
{
  "status": "success",
  "message": "Post created successfully",
  "post_id": 12345
}
<?php
// Function to create a new post
function create_new_post($data) {
    // Generate a unique post ID
    $post_id = generateUniqueId();
    
    // Save the post to the database with the provided title and content
    savePostToDatabase($post_id, $data['title'], $data['content']);
    
    return $post_id;
}
// Check if the request method is POST
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    
    // Get the JSON data from the request body
    $data = json_decode(file_get_contents('php://input'), true);
    
    // Ensure that the required fields are provided (title and content)
    if (isset($data['title']) && isset($data['content'])) {
        // Create the new post
        $post_id = create_new_post($data);
        
        // Set the appropriate content type and status code
        header('Content-Type: application/json');
        http_response_code(201);
        
        // Respond with the success message and the new post's ID
        echo json_encode(array(
            "status" => "success",
            "message" => "Post created successfully",
            "post_id" => $post_id
        ));
    } else {
        // Return an error if title and content are not provided
        http_response_code(400);
        echo json_encode(array("error" => "Title and content are required"));
    }
} else {
    // Return an error for unsupported requests
    http_response_code(405);
    echo json_encode(array("error" => "Method Not Allowed"));
}
3. Database Queries(PHP)
Task 1: Write a SQL query to retrieve all users from the "users" table with their names and email addresses.
Solution:
SELECT name, email FROM users;
Task 2: Write a SQL query to calculate the average age of all users in the "users" table.
Solution:
SELECT AVG(age) AS average_age FROM users;
Task 3: Write a SQL query to find the top 5 products with the highest sales in the "sales" table.
Solution:
SELECT product_name, SUM(quantity) AS total_sales
FROM sales
GROUP BY product_name
ORDER BY total_sales DESC
LIMIT 5;

4. API Design and Implementation (Laravel)
Task 1: Design an API endpoint to retrieve a list of all products with their details from the "products" table.
Solution:
// Route definition using Laravel's routing
Route::get('/api/products', 'ProductController@index');

// Controller method to handle the request
public function index() {
    $products = Product::all();
    return response()->json($products);
}

Task 2: Implement an API endpoint to create a new order for a customer with multiple products.
Solution:
// Route definition using Laravel's routing
Route::post('/api/orders', 'OrderController@store');

// Controller method to handle the request
public function store(Request $request) {
    $validatedData = $request->validate([
        'customer_id' => 'required|integer',
        'products' => 'required|array',
    ]);

    // Create the order and store it in the database
    $order = Order::create([
        'customer_id' => $validatedData['customer_id'],
    ]);

    // Attach products to the order
    $order->products()->attach($validatedData['products']);

    return response()->json(['message' => 'Order created successfully'], 201);
}

Task 3: Design an API endpoint to delete a specific user from the "users" table.
Solution:
// Route definition using Laravel's routing
Route::delete('/api/users/{id}', 'UserController@destroy');

// Controller method to handle the request
public function destroy($id) {
    $user = User::find($id);

    if (!$user) {
        return response()->json(['message' => 'User not found'], 404);
    }

    // Delete the user from the database
    $user->delete();

    return response()->json(['message' => 'User deleted successfully'], 200);
}