プロジェクト：名刺管理システム

1. 名刺追加 — 名前、電話番号、メールを入力
2. 全名刺表示 — 表形式で一覧表示
3. 名刺検索 — 名前で検索（曖昧検索対応）
4. 名刺修正 — 名前で情報を更新
5. 名刺削除 — 名前で削除
6. 統計表示 — 総数、メールドメイン統計
7. プログラム終了

# 各カードは辞書
# すべてのカードはリストに保存
[
    {"name": "Zhang San", "phone": "13800138000", "email": "zhangsan@example.com"},
    {"name": "Li Si", "phone": "13900139000", "email": "lisi@test.com"},
]

# ====== 名刺管理システム ======

# データ保存
cards = []

def show_menu():
    """メインメニューを表示"""
    print("\n" + "=" * 35)
    print("Business Card Management System")
    print("=" * 35)
    print("1. Add Card")
    print("2. List All Cards")
    print("3. Search Cards")
    print("4. Modify Card")
    print("5. Delete Card")
    print("6. Statistics")
    print("7. Exit")
    print("=" * 35)


def add_card():
    """名刺を追加"""
    print("\n--- Add Card ---")
    name = input("Name: ").strip()
    if not name:
        print("Name cannot be empty!")
        return

    phone = input("Phone: ").strip()
    email = input("Email: ").strip()

    # 重複する名前をチェック
    for card in cards:
        if card["name"] == name:
            print(f"A card named {name} already exists. Cannot add duplicate.")
            return

    cards.append({"name": name, "phone": phone, "email": email})
    print(f"Card for {name} added.")


def list_cards():
    """すべての名刺を表示"""
    if not cards:
        print("\nNo cards yet.")
        return

    print("\n--- All Cards ---")
    print(f"{'#':<4}{'Name':<10}{'Phone':<15}{'Email':<25}")
    print("-" * 54)

    for i, card in enumerate(cards, 1):
        print(f"{i:<4}{card['name']:<10}{card['phone']:<15}{card['email']:<25}")

    print(f"\nTotal: {len(cards)} cards")


def search_card():
    """名刺を検索（曖昧検索対応）"""
    if not cards:
        print("\nNo cards yet.")
        return

    keyword = input("\nEnter name to search (partial match supported): ").strip()
    if not keyword:
        print("Please enter a keyword!")
        return

    # リスト内包表記 + in で曖昧検索
    results = [card for card in cards if keyword in card["name"]]

    if not results:
        print(f"No cards found matching '{keyword}'.")
        return

    print(f"\n--- Found {len(results)} cards ---")
    for card in results:
        print(f"Name: {card['name']}")
        print(f"Phone: {card['phone']}")
        print(f"Email: {card['email']}")
        print("-" * 20)


def modify_card():
    """名刺を修正"""
    if not cards:
        print("\nNo cards yet.")
        return

    name = input("\nEnter the name to modify: ").strip()
    for card in cards:
        if card["name"] == name:
            print(f"Found card for {name}. Enter new info (press Enter to keep current):")

            new_name = input(f"Name ({card['name']}): ").strip()
            new_phone = input(f"Phone ({card['phone']}): ").strip()
            new_email = input(f"Email ({card['email']}): ").strip()

            if new_name:
                card["name"] = new_name
            if new_phone:
                card["phone"] = new_phone
            if new_email:
                card["email"] = new_email

            print(f"Card for {name} has been updated.")
            return

    print(f"No card found for {name}.")


def delete_card():
    """名刺を削除"""
    if not cards:
        print("\nNo cards yet.")
        return

    name = input("\nEnter the name to delete: ").strip()
    for i, card in enumerate(cards):
        if card["name"] == name:
            confirm = input(f"Are you sure you want to delete {name}'s card? (y/n): ")
            if confirm.lower() == "y":
                cards.pop(i)
                print(f"Card for {name} has been deleted.")
            else:
                print("Deletion cancelled.")
            return

    print(f"No card found for {name}.")


def show_stats():
    """データ統計を表示"""
    if not cards:
        print("\nNo cards yet.")
        return

    print("\n--- Statistics ---")
    print(f"Total cards: {len(cards)}")

    # メールドメインをカウント
    domains = {}
    for card in cards:
        email = card["email"]
        if "@" in email:
            domain = email.split("@")[1]
            domains[domain] = domains.get(domain, 0) + 1

    if domains:
        print("\nEmail domain distribution:")
        for domain, count in sorted(domains.items(), key=lambda x: x[1], reverse=True):
            print(f"  {domain}: {count}")

    # 電話番号とメールの有無をカウント
    has_phone = sum(1 for card in cards if card["phone"])
    has_email = sum(1 for card in cards if card["email"])
    print(f"\nWith phone: {has_phone}")
    print(f"With email: {has_email}")


# ====== メインプログラム ======
print("Welcome to the Business Card Management System!")
print("Enter the corresponding number to select a function.")

while True:
    show_menu()
    choice = input("Select option (1-7): ").strip()

    if choice == "1":
        add_card()
    elif choice == "2":
        list_cards()
    elif choice == "3":
        search_card()
    elif choice == "4":
        modify_card()
    elif choice == "5":
        delete_card()
    elif choice == "6":
        show_stats()
    elif choice == "7":
        print("Thank you for using! Goodbye!")
        break
    else:
        print("Invalid choice. Please enter a number between 1 and 7.")