// 문제 1: 상속으로 기능 추가 → 클래스 폭발
public class SimpleCoffee {
    public int cost() { return 10; }
}

public class MilkCoffee extends SimpleCoffee {
    public int cost() { return super.cost() + 5; }
}

public class SugarCoffee extends SimpleCoffee {
    public int cost() { return super.cost() + 2; }
}

public class MilkSugarCoffee extends SimpleCoffee {
    public int cost() { return super.cost() + 7; }
}

// 휘핑크림, 시럽, 초콜릿... 조합 폭발! 💥
// 우유+설탕+휘핑+시럽 = 별도 클래스 필요!

// 문제 2: 런타임에 기능 추가/제거 불가
public class TextEditor {
    private boolean bold = false;
    private boolean italic = false;
    private boolean underline = false;
    
    public void setBold(boolean b) { this.bold = b; }
    public void setItalic(boolean i) { this.italic = i; }
    public void setUnderline(boolean u) { this.underline = u; }
    
    // 모든 조합을 미리 구현해야 함!
    public String format(String text) {
        if (bold && italic && underline) {
            return "<b><i><u>" + text + "</u></i></b>";
        } else if (bold && italic) {
            return "<b><i>" + text + "</i></b>";
        }
        // ... 8가지 조합!
    }
}

// 문제 3: 기존 클래스 수정 필요
public class FileReader {
    public String read(String path) {
        // 파일 읽기
    }
}

// 암호화 기능 추가하려면?
// → FileReader 수정 (OCP 위반!)
// → 상속 (단일 상속 제약)

// 문제 4: 기능의 순서가 중요한 경우
public class DataProcessor {
    public String process(String data) {
        // 1. 압축
        // 2. 암호화
        // 3. Base64 인코딩
        // 순서 바꾸기 어려움!
    }
}

// Before: 상속으로 기능 추가
Coffee milkSugarCoffee = new MilkSugarCoffee();

// After: 데코레이터로 동적 조합
Coffee coffee = new SimpleCoffee();
coffee = new MilkDecorator(coffee);
coffee = new SugarDecorator(coffee);
// 런타임에 기능 추가! ✨

/**
 * Component: 커피 인터페이스
 */
public interface Coffee {
    String getDescription();
    int cost();
}

/**
 * ConcreteComponent: 기본 커피
 */
public class SimpleCoffee implements Coffee {
    @Override
    public String getDescription() {
        return "Simple Coffee";
    }
    
    @Override
    public int cost() {
        return 10;
    }
}

/**
 * Decorator: 추상 데코레이터
 */
public abstract class CoffeeDecorator implements Coffee {
    protected Coffee coffee;
    
    public CoffeeDecorator(Coffee coffee) {
        this.coffee = coffee;
    }
    
    @Override
    public String getDescription() {
        return coffee.getDescription();
    }
    
    @Override
    public int cost() {
        return coffee.cost();
    }
}

/**
 * ConcreteDecorator 1: 우유 추가
 */
public class MilkDecorator extends CoffeeDecorator {
    public MilkDecorator(Coffee coffee) {
        super(coffee);
    }
    
    @Override
    public String getDescription() {
        return coffee.getDescription() + ", Milk";
    }
    
    @Override
    public int cost() {
        return coffee.cost() + 5;
    }
}

/**
 * ConcreteDecorator 2: 설탕 추가
 */
public class SugarDecorator extends CoffeeDecorator {
    public SugarDecorator(Coffee coffee) {
        super(coffee);
    }
    
    @Override
    public String getDescription() {
        return coffee.getDescription() + ", Sugar";
    }
    
    @Override
    public int cost() {
        return coffee.cost() + 2;
    }
}

/**
 * ConcreteDecorator 3: 휘핑크림 추가
 */
public class WhipDecorator extends CoffeeDecorator {
    public WhipDecorator(Coffee coffee) {
        super(coffee);
    }
    
    @Override
    public String getDescription() {
        return coffee.getDescription() + ", Whip Cream";
    }
    
    @Override
    public int cost() {
        return coffee.cost() + 7;
    }
}

/**
 * ConcreteDecorator 4: 바닐라 시럽 추가
 */
public class VanillaDecorator extends CoffeeDecorator {
    public VanillaDecorator(Coffee coffee) {
        super(coffee);
    }
    
    @Override
    public String getDescription() {
        return coffee.getDescription() + ", Vanilla Syrup";
    }
    
    @Override
    public int cost() {
        return coffee.cost() + 3;
    }
}

/**
 * 사용 예제
 */
public class DecoratorExample {
    public static void main(String[] args) {
        // 1. 기본 커피
        System.out.println("=== 주문 1: 기본 커피 ===");
        Coffee coffee1 = new SimpleCoffee();
        printOrder(coffee1);
        
        // 2. 우유 커피
        System.out.println("\n=== 주문 2: 우유 커피 ===");
        Coffee coffee2 = new SimpleCoffee();
        coffee2 = new MilkDecorator(coffee2);
        printOrder(coffee2);
        
        // 3. 우유 + 설탕 커피
        System.out.println("\n=== 주문 3: 우유 설탕 커피 ===");
        Coffee coffee3 = new SimpleCoffee();
        coffee3 = new MilkDecorator(coffee3);
        coffee3 = new SugarDecorator(coffee3);
        printOrder(coffee3);
        
        // 4. 풀옵션 커피
        System.out.println("\n=== 주문 4: 풀옵션 커피 ===");
        Coffee coffee4 = new SimpleCoffee();
        coffee4 = new MilkDecorator(coffee4);
        coffee4 = new SugarDecorator(coffee4);
        coffee4 = new WhipDecorator(coffee4);
        coffee4 = new VanillaDecorator(coffee4);
        printOrder(coffee4);
        
        // 5. 한 줄로 작성
        System.out.println("\n=== 주문 5: 카라멜 마키아또 스타일 ===");
        Coffee coffee5 = new VanillaDecorator(
                            new WhipDecorator(
                                new MilkDecorator(
                                    new SimpleCoffee()
                                )
                            )
                         );
        printOrder(coffee5);
    }
    
    private static void printOrder(Coffee coffee) {
        System.out.println("☕ " + coffee.getDescription());
        System.out.println("💰 가격: " + coffee.cost() + "원");
    }
}

/**
 * Component: 데이터 스트림
 */
public interface DataStream {
    void write(String data);
    String read();
}

/**
 * ConcreteComponent: 기본 스트림
 */
public class FileDataStream implements DataStream {
    private String fileName;
    private String data;
    
    public FileDataStream(String fileName) {
        this.fileName = fileName;
    }
    
    @Override
    public void write(String data) {
        this.data = data;
        System.out.println("📁 파일에 쓰기: " + fileName);
        System.out.println("   데이터: " + data);
    }
    
    @Override
    public String read() {
        System.out.println("📖 파일에서 읽기: " + fileName);
        return data;
    }
}

/**
 * Decorator: 스트림 데코레이터
 */
public abstract class DataStreamDecorator implements DataStream {
    protected DataStream stream;
    
    public DataStreamDecorator(DataStream stream) {
        this.stream = stream;
    }
    
    @Override
    public void write(String data) {
        stream.write(data);
    }
    
    @Override
    public String read() {
        return stream.read();
    }
}

/**
 * ConcreteDecorator 1: 압축
 */
public class CompressionDecorator extends DataStreamDecorator {
    public CompressionDecorator(DataStream stream) {
        super(stream);
    }
    
    @Override
    public void write(String data) {
        String compressed = compress(data);
        System.out.println("🗜️ 압축: " + data.length() + " → " + compressed.length() + " bytes");
        stream.write(compressed);
    }
    
    @Override
    public String read() {
        String data = stream.read();
        String decompressed = decompress(data);
        System.out.println("📦 압축 해제: " + data.length() + " → " + decompressed.length() + " bytes");
        return decompressed;
    }
    
    private String compress(String data) {
        // 실제로는 GZIP 등 사용
        return "[COMPRESSED]" + data;
    }
    
    private String decompress(String data) {
        return data.replace("[COMPRESSED]", "");
    }
}

/**
 * ConcreteDecorator 2: 암호화
 */
public class EncryptionDecorator extends DataStreamDecorator {
    public EncryptionDecorator(DataStream stream) {
        super(stream);
    }
    
    @Override
    public void write(String data) {
        String encrypted = encrypt(data);
        System.out.println("🔒 암호화: " + data + " → " + encrypted);
        stream.write(encrypted);
    }
    
    @Override
    public String read() {
        String data = stream.read();
        String decrypted = decrypt(data);
        System.out.println("🔓 복호화: " + data + " → " + decrypted);
        return decrypted;
    }
    
    private String encrypt(String data) {
        // 실제로는 AES 등 사용
        return new StringBuilder(data).reverse().toString();
    }
    
    private String decrypt(String data) {
        return new StringBuilder(data).reverse().toString();
    }
}

/**
 * ConcreteDecorator 3: Base64 인코딩
 */
public class Base64Decorator extends DataStreamDecorator {
    public Base64Decorator(DataStream stream) {
        super(stream);
    }
    
    @Override
    public void write(String data) {
        String encoded = Base64.getEncoder().encodeToString(data.getBytes());
        System.out.println("🔤 Base64 인코딩");
        stream.write(encoded);
    }
    
    @Override
    public String read() {
        String data = stream.read();
        String decoded = new String(Base64.getDecoder().decode(data));
        System.out.println("🔡 Base64 디코딩");
        return decoded;
    }
}

/**
 * 사용 예제
 */
public class StreamDecoratorExample {
    public static void main(String[] args) {
        String message = "Hello, Decorator Pattern!";
        
        // 1. 기본 스트림
        System.out.println("### 기본 파일 스트림 ###");
        DataStream stream1 = new FileDataStream("file1.txt");
        stream1.write(message);
        System.out.println("읽은 데이터: " + stream1.read());
        
        // 2. 압축 스트림
        System.out.println("\n### 압축 스트림 ###");
        DataStream stream2 = new CompressionDecorator(
            new FileDataStream("file2.txt.gz")
        );
        stream2.write(message);
        System.out.println("읽은 데이터: " + stream2.read());
        
        // 3. 암호화 + 압축 스트림
        System.out.println("\n### 암호화 + 압축 스트림 ###");
        DataStream stream3 = new CompressionDecorator(
            new EncryptionDecorator(
                new FileDataStream("file3.enc.gz")
            )
        );
        stream3.write(message);
        System.out.println("읽은 데이터: " + stream3.read());
        
        // 4. Base64 + 암호화 + 압축 스트림
        System.out.println("\n### Base64 + 암호화 + 압축 스트림 ###");
        DataStream stream4 = new Base64Decorator(
            new EncryptionDecorator(
                new CompressionDecorator(
                    new FileDataStream("file4.b64.enc.gz")
                )
            )
        );
        stream4.write(message);
        System.out.println("읽은 데이터: " + stream4.read());
    }
}

/**
 * Component: 알림 인터페이스
 */
public interface Notifier {
    void send(String message);
}

/**
 * ConcreteComponent: 기본 이메일 알림
 */
public class EmailNotifier implements Notifier {
    private String email;
    
    public EmailNotifier(String email) {
        this.email = email;
    }
    
    @Override
    public void send(String message) {
        System.out.println("📧 Email to " + email + ": " + message);
    }
}

/**
 * Decorator: 알림 데코레이터
 */
public abstract class NotifierDecorator implements Notifier {
    protected Notifier notifier;
    
    public NotifierDecorator(Notifier notifier) {
        this.notifier = notifier;
    }
    
    @Override
    public void send(String message) {
        notifier.send(message);
    }
}

/**
 * ConcreteDecorator 1: SMS 추가
 */
public class SMSDecorator extends NotifierDecorator {
    private String phoneNumber;
    
    public SMSDecorator(Notifier notifier, String phoneNumber) {
        super(notifier);
        this.phoneNumber = phoneNumber;
    }
    
    @Override
    public void send(String message) {
        super.send(message);
        System.out.println("📱 SMS to " + phoneNumber + ": " + message);
    }
}

/**
 * ConcreteDecorator 2: Slack 추가
 */
public class SlackDecorator extends NotifierDecorator {
    private String channel;
    
    public SlackDecorator(Notifier notifier, String channel) {
        super(notifier);
        this.channel = channel;
    }
    
    @Override
    public void send(String message) {
        super.send(message);
        System.out.println("💬 Slack to #" + channel + ": " + message);
    }
}

/**
 * ConcreteDecorator 3: Facebook 추가
 */
public class FacebookDecorator extends NotifierDecorator {
    private String accountName;
    
    public FacebookDecorator(Notifier notifier, String accountName) {
        super(notifier);
        this.accountName = accountName;
    }
    
    @Override
    public void send(String message) {
        super.send(message);
        System.out.println("👥 Facebook to " + accountName + ": " + message);
    }
}

/**
 * 사용 예제
 */
public class NotifierDecoratorExample {
    public static void main(String[] args) {
        // 1. 기본 이메일만
        System.out.println("=== 이메일만 ===");
        Notifier notifier1 = new EmailNotifier("[email protected]");
        notifier1.send("서버 점검 안내");
        
        // 2. 이메일 + SMS
        System.out.println("\n=== 이메일 + SMS ===");
        Notifier notifier2 = new SMSDecorator(
            new EmailNotifier("[email protected]"),
            "010-1234-5678"
        );
        notifier2.send("긴급 알림!");
        
        // 3. 이메일 + SMS + Slack
        System.out.println("\n=== 이메일 + SMS + Slack ===");
        Notifier notifier3 = new SlackDecorator(
            new SMSDecorator(
                new EmailNotifier("[email protected]"),
                "010-1234-5678"
            ),
            "general"
        );
        notifier3.send("배포 완료");
        
        // 4. 모든 채널
        System.out.println("\n=== 모든 채널 ===");
        Notifier notifier4 = new FacebookDecorator(
            new SlackDecorator(
                new SMSDecorator(
                    new EmailNotifier("[email protected]"),
                    "010-1234-5678"
                ),
                "general"
            ),
            "Company Page"
        );
        notifier4.send("중요 공지사항");
    }
}

/**
 * Component
 */
public interface Text {
    String getContent();
}

/**
 * ConcreteComponent
 */
public class PlainText implements Text {
    private String content;
    
    public PlainText(String content) {
        this.content = content;
    }
    
    @Override
    public String getContent() {
        return content;
    }
}

/**
 * Decorator
 */
public abstract class TextDecorator implements Text {
    protected Text text;
    
    public TextDecorator(Text text) {
        this.text = text;
    }
    
    @Override
    public String getContent() {
        return text.getContent();
    }
}

/**
 * ConcreteDecorator: Bold
 */
public class BoldDecorator extends TextDecorator {
    public BoldDecorator(Text text) {
        super(text);
    }
    
    @Override
    public String getContent() {
        return "<b>" + text.getContent() + "</b>";
    }
}

/**
 * ConcreteDecorator: Italic
 */
public class ItalicDecorator extends TextDecorator {
    public ItalicDecorator(Text text) {
        super(text);
    }
    
    @Override
    public String getContent() {
        return "<i>" + text.getContent() + "</i>";
    }
}

/**
 * ConcreteDecorator: Underline
 */
public class UnderlineDecorator extends TextDecorator {
    public UnderlineDecorator(Text text) {
        super(text);
    }
    
    @Override
    public String getContent() {
        return "<u>" + text.getContent() + "</u>";
    }
}

/**
 * ConcreteDecorator: Color
 */
public class ColorDecorator extends TextDecorator {
    private String color;
    
    public ColorDecorator(Text text, String color) {
        super(text);
        this.color = color;
    }
    
    @Override
    public String getContent() {
        return "<span style='color:" + color + "'>" + 
               text.getContent() + "</span>";
    }
}

/**
 * 사용 예제
 */
public class TextDecoratorExample {
    public static void main(String[] args) {
        String content = "Hello, World!";
        
        // 다양한 조합
        Text text1 = new BoldDecorator(new PlainText(content));
        System.out.println("Bold: " + text1.getContent());
        
        Text text2 = new ItalicDecorator(
            new BoldDecorator(new PlainText(content))
        );
        System.out.println("Bold + Italic: " + text2.getContent());
        
        Text text3 = new UnderlineDecorator(
            new ItalicDecorator(
                new BoldDecorator(new PlainText(content))
            )
        );
        System.out.println("Bold + Italic + Underline: " + text3.getContent());
        
        Text text4 = new ColorDecorator(
            new UnderlineDecorator(
                new BoldDecorator(new PlainText(content))
            ),
            "red"
        );
        System.out.println("Bold + Underline + Red: " + text4.getContent());
    }
}

// 잘못된 예: 너무 많은 레이어
Text text = new ColorDecorator(
    new SizeDecorator(
        new FontDecorator(
            new UnderlineDecorator(
                new ItalicDecorator(
                    new BoldDecorator(
                        new PlainText("Hello")
                    )
                )
            )
        )
    ),
    "red"
);
// 가독성 떨어짐!