readme.md

Evolvingweb

question one(1) how you code and what drives your decisions while coding.

Discount Service Example

This code demonstrates a simple discount system for an eCommerce platform using the Strategy Pattern in PHP.

Features:

• Flexible Discount Strategies: The code supports both percentage-based and fixed amount discounts.
• Extensible Design: New discount types can be added without modifying existing code, adhering to the Open/Closed Principle of SOLID.
• Usage Examples: The code includes example usage of the DiscountService class with different discount strategies.

Why I Coded It This Way:

• Strategy Pattern: I chose this pattern to easily swap out discount strategies, making the system more adaptable to future requirements.
• Best Practices: The code is structured to follow PSR standards and includes clear documentation to ensure maintainability.

evolvingweb.php

<?php
/**

evolvingweb question one(1), how you code and what drives your decisions while coding

**/



// Interface for defining the structure of different discount strategies
interface DiscountStrategy
{
    /**
     * Apply discount to the total amount.
     *
     * @param float $totalAmount The original total amount before discount.
     * @return float The total amount after discount is applied.
     */
    public function applyDiscount(float $totalAmount): float;
}

// Percentage-based discount strategy
class PercentageDiscount implements DiscountStrategy
{
    protected $percentage;

    public function __construct($percentage)
    {
        $this->percentage = $percentage;
    }

    /**
     * Apply a percentage discount to the total amount.
     *
     * @param float $totalAmount The original total amount before discount.
     * @return float The total amount after applying the percentage discount.
     */
    public function applyDiscount(float $totalAmount): float
    {
        return $totalAmount - ($totalAmount * $this->percentage / 100);
    }
}

// Fixed amount discount strategy
class FixedAmountDiscount implements DiscountStrategy
{
    protected $amount;

    public function __construct($amount)
    {
        $this->amount = $amount;
    }

    /**
     * Apply a fixed amount discount to the total amount.
     *
     * @param float $totalAmount The original total amount before discount.
     * @return float The total amount after applying the fixed amount discount.
     */
    public function applyDiscount(float $totalAmount): float
    {
        return max(0, $totalAmount - $this->amount);
    }
}

// Service to handle applying discounts
class DiscountService
{
    protected $discount;

    public function __construct(DiscountStrategy $discount)
    {
        $this->discount = $discount;
    }

    /**
     * Apply the discount strategy to the given total amount.
     *
     * @param float $totalAmount The original total amount before discount.
     * @return float The final amount after discount is applied.
     */
    public function apply(float $totalAmount): float
    {
        return $this->discount->applyDiscount($totalAmount);
    }
}

// Example usage:
// Assume the total amount is $100.00 and we're applying a 20% discount.

$totalAmount = 100.0;
$discountCode = 'SUMMER2024';

// Using the PercentageDiscount strategy
$percentageDiscount = new PercentageDiscount(20);
$discountService = new DiscountService($percentageDiscount);
$finalAmount = $discountService->apply($totalAmount);
echo "Total after 20% discount: $" . $finalAmount . "\n";

// Using the FixedAmountDiscount strategy
$fixedDiscount = new FixedAmountDiscount(10);
$discountService = new DiscountService($fixedDiscount);
$finalAmount = $discountService->apply($totalAmount);
echo "Total after $10 discount: $" . $finalAmount . "\n";