#!/usr/bin/env bellos
# File: functions.bellos

# Defining and using functions

# Simple function
function greet() {
    echo "Hello, $1!"
}

echo "Testing simple function:"
greet "World"
greet "Bellos"

# Function with return value
function add() {
    local result=$(($1 + $2))
    echo $result
}

echo "\nTesting function with return value:"
sum=$(add 5 3)
echo "5 + 3 = $sum"

# Function with local variables
function calculate_rectangle_area() {
    local length=$1
    local width=$2
    local area=$((length * width))
    echo "The area of a rectangle with length $length and width $width is $area"
}

echo "\nTesting function with local variables:"
calculate_rectangle_area 4 5

# Recursive function (factorial)
function factorial() {
    if [ $1 -le 1 ]; then
        echo 1
    else
        local sub_fact=$(factorial $(($1 - 1)))
        echo $(($1 * sub_fact))
    }
}

echo "\nTesting recursive function (factorial):"
for i in 0 1 2 3 4 5; do
    result=$(factorial $i)
    echo "Factorial of $i is $result"
done

# Function with default parameter
function greet_with_default() {
    local name=${1:-"Guest"}
    echo "Hello, $name!"
}

echo "\nTesting function with default parameter:"
greet_with_default
greet_with_default "Alice"

# Function that modifies a global variable
global_var=10

function modify_global() {
    global_var=$((global_var + 5))
}

echo "\nTesting function that modifies a global variable:"
echo "Before: global_var = $global_var"
modify_global
echo "After: global_var = $global_var"