php -S localhost:3000

// one line comment
/*
This is a multiple-lines comment block
that spans over multiple
lines
*/

// PHP opening/closing tag
<?php
     echo "Hello World";
?>
// if no closing tag the rest of the file will be considered PHP

// Short syntax for PHP echo
<?= "Hello World" ?>

//Enable strict typing (first line of your PHP file)
<? declare(strict_types=1);

// Include a PHP file
require 'app/Product.php'

// Create a namespace
namespace App;

// Use a namespace
use App\Product;

$firstName = 'Mike'  // camelCase
function updateProduct() // camelCase
class ProductItem // StudlyCaps
const ACCESS_KEY = '123abc'; // all upper case with underscore separators

echo 'Hello World';

// Debug output
var_dump($names);
print_r($products);

// Input from console
$name = readline('What is your name : ');

$name = 'Mike'; //string
$isActive = true; //boolean
$number = 25; //integer
$amount = 99.95; //float
$fruits = ['orange', 'apple', 'banana'] //array
const MAX_USERS = 50; //constant
define('MAX_USERS', 50); //constant

// Assign 'by reference' with the & keyword
$name_2 = &$name_1

// Type conversion
$age = (int)readline('Your age: ');
echo 'Your age is' . (string)$age;

echo gettype($age); // int

echo is_int($age) // true
echo is_float(12.5) // true
echo is_string($name) // true

// String can use single quote
$name = 'Mike'
// or double quote
$name = "Mike"

// Double quote string can escape characters \n = new line  \t = tab  \\ = backslash
echo "Hello Mike\nHello David";

// Double quote string can do interpolation
echo "Hello $name";

// string concat
echo 'Hello ' . $name;

// string length
echo strlen($name);

// Remove space(s) before and after
echo trim($text)

// Convert to lowercase / uppercase
echo strtolower($email);
echo strtoupper($name);

// Converts the first character to uppercase
echo ucfirst($name);  // 'Mike'

// Replace text a by text b in $text
echo str_replace('a', 'b', $text);

// String Contains (PHP 8)
echo str_contains($name, 'ke')  # true

// Find numeric position of first occurrence
$pos = strpos($name, 'k'); # 2

// Returns portion of string (offset / length)
echo substr($name, 0, $pos); # Mi

// Shortcut addition assignment
$value = 10
$value++ // 11
// or
$value += 1 // 11

// Shortcut subtraction assignment
$value = 10
$value-- // 9
// or
$value -= 1 // 9

// Check if numeric
echo is_numeric('59.99'); # true

// Round a number
echo round(0.80);  // returns 1

// Round a number with precision
echo round(1.49356, 2));  // returns 1.49

// Random number
echo(rand(10, 100)); # 89

// If / elseif / else
if ($condition == 10) {
     echo 'condition 10'
} elseif  ($condition == 5) {
     echo 'condition 5'
} else {
     echo 'all other conditions'
}

// And condition = &&
if ($condition === 10 && $condition2 === 5) {
     echo '10 and 5'
}

// Or condition = ||
if ($condition === 10 || $condition2 === 5) {
     echo '10 or 5'
}

// One line
if ($isActive) return true;

// Null check
if (is_null($name)) {
     do something...
}

//Comparaison operation
== // equal no type check
=== // equal with type check
!= //not equal
|| //or
&& //and
> //greater than
< //less than

// Ternary operator (true : false)
echo $isValid ? 'user valid' : 'user not valid';

//Null Coalesce Operator
echo $name ?? 'Mike';  //output 'Mike' if $name is null

//Null Coalesce Assignment
$name ??= 'Mike';

// Null Safe Operator (PHP 8) will return null if one ? is null
echo $user?->profile?->activate();

// Null Safe + Null Coalesce (if null will return 'No user profile')
echo $user?->profile?->activate() ?? 'Not  applicable';

//Spaceship operator return -1 0 1
$names = ['Mike', 'Paul', 'John']
usort($names, function($a, $b) {
     return $a <=> $b;
}
// ['John', 'Mike', 'Paul']

// Return false when convert as boolean
false, 0, 0.0, null, unset, '0', '', []

// Compare same variable with multiple values
switch ($color) {
      case 'red':
          echo 'The color is red';
	         break;
     case 'yellow':
          echo 'The color is yellow';
          break;
     case 'red':
          echo 'The color is red';
          break;
     default:
         echo 'The color is unknown';
}

// Match Expression (PHP 8)
$type = match($color) {
     'red' => 'danger',
     'yellow', 'orange' => 'warning',
     'green' => 'success',
     default => 'Unknown'
};

// Check if variable declare
isset($color['red']);  # true

//for loop
for ($i = 0; $i < 20; $i++) {
    echo "i value = " . i;
}

//while loop
$number = 1;
while ($number < 10) {
    echo 'value : ' . $number ;
    $number += 1;
}

//do while
$number = 1;
do {
    echo 'value : '  . $number ;
    $number += 1;
} while ($number < 10);

// foreach with break / continue exemple
$values = ['one', 'two', 'three'];
foreach ($values as $value) {
    if ($value === 'two') {
        break; // exit loop
    } elseif ($value === 'three') {
        continue; // next loop iteration
    }
}

//Array declaration can contain any types
$example = ['Mike', 50.2, true, ['10', '20'];

//Array declaration
$names = ['Mike', 'Peter', 'Shawn', 'John'];

// Direct access to a specific element
$name[1] //output Peter

// How to access an array in an array
$example[3][1] // 20

//add a element to an array
$names[] = 'Micheal';

// Array merge
$array3 = array_merge($array1, $array2);

// Array Concat with Spread Operator
$names = ['Mike', 'Peter', 'Paul'];
$people = ['John', ...$names]; // ['John', 'Mike', 'Peter', 'Paul']

//Remove array entry:
unset($names['Peter']);

//Array to string
echo implode(', ', $names) //output Mike, Shawn, John, Micheal

// String to Array
echo explode(',', $text); // ['Mike', 'Shawn', 'John']


//loop for each array entry
foreach($names as $name) {
    echo 'Hello ' . $name;
}

// Number of items in a Array
echo count($names);

//Associative array declaration (key => value):
$person = ['age' => 45, 'genre' => 'men'];

//Add to ass. array:
$person['name'] = 'Mike';

//loop ass. array key => value:
foreach($names as $key => $value) {
    echo $key . ' : ' . $value
}

// Check if a specific key exist
echo array_key_exists('age', $person);

// Return keys
echo array_keys($person); // ['age', 'genre']

// Return values
echo array_values($person) // [45, 'men']

//Array filter (return a filtered array)
$filteredPeople = array_filter($people, function   ($person) {
    return $names->active;
})

// Array map (return transform array):
$onlyNames = array_map(function($person) {
    return ['name' => $person->name];
}, $people)

# Search associative array
$items = [
    ['id' => '100', 'name' => 'product 1'],
    ['id' => '200', 'name' => 'product 2'],
    ['id' => '300', 'name' => 'product 3'],
    ['id' => '400', 'name' => 'product 4'],
	];

# search all value in the 'name' column
$found_key = array_search('product 3',  array_column($items, 'name'));
# return 2

//function declararion
function name($firstName, $lastName = 'defaultvalue') {
    return "$firstName $lastName"
}

//function call
name('Mike', 'Taylor');

//function call with named parameters (PHP 8)
name(firstName: 'Mike', lastName: 'Taylor'); // order can change

//function variables params
function name(...$params) {
    return $params[0] . “ “ . params[1];
}

// Closure function
Route::get('/', function () {
    return view('welcome');
});

// Arrow functions
Route::get('/', fn () => view('welcome');


// Typed parameter and typed return
function display(string $first, string $last) : string {
    return "$first $last";
}

// Typed or null
function display(?string $name) {
    ...
}

// Get the current dir
$current_dir = __DIR__;

// Check if file exist
if (file_exists('/posts/first.txt')) {
	do some stuff
}

// Read file content into one variable
$post = file_get_contents($file);

//File read
$file = fopen("test.txt", "r");

//Output lines until EOF is reached
while(! feof($file)) {
	$line = fgets($file);
	echo $line. "<br>";
}
fclose($file);

// File write
$file = fopen('export.csv', 'a');
$array = ['name' => 'Mike', 'age' => 45];

//Write key name as csv header
fputcsv($file, array_keys($array[0]));

//Write lines (format as csv)
foreach ($array as $row) {
	fputcsv($file, $row);
}
fclose($file);

//Throw Error
if (someCondition) {
	throw new Exception('Data format error');
}

//Catch the Error
try {
	$db->checkData($data);
} catch (Exception $e) {
	echo $e->getMessage();
}