/**
 * 任务二：银行取款自定义异常
 * 文件内含：InsufficientFundsException + Account + main 测试
 */

// ── 自定义异常：继承 Exception（Checked，强迫调用方处理）──
class InsufficientFundsException extends Exception {
    private final double balance;   // 当前余额
    private final double amount;    // 尝试取款金额

    public InsufficientFundsException(double balance, double amount) {
        super(String.format("余额不足！当前余额 %.2f 元，尝试取款 %.2f 元，差额 %.2f 元",
                balance, amount, amount - balance));
        this.balance = balance;
        this.amount  = amount;
    }

    public double getBalance() { return balance; }
    public double getAmount()  { return amount; }
}

// ── Account 类 ──
class Account {
    private final String owner;
    private double balance;

    public Account(String owner, double initialBalance) {
        this.owner   = owner;
        this.balance = initialBalance;
    }

    /**
     * 取款：余额不足时抛出 InsufficientFundsException，并携带当前余额信息
     */
    public void withdraw(double amount) throws InsufficientFundsException {
        if (amount <= 0) {
            throw new IllegalArgumentException("取款金额必须大于 0");
        }
        if (amount > balance) {
            throw new InsufficientFundsException(balance, amount);
        }
        balance -= amount;
        System.out.printf("  取款成功：%.2f 元，剩余余额：%.2f 元%n", amount, balance);
    }

    public double getBalance() { return balance; }
    public String getOwner()   { return owner; }
}

// ── 测试入口 ──
public class BankAccount {
    public static void main(String[] args) {
        Account acc = new Account("张三", 500.00);
        System.out.println("账户：" + acc.getOwner() + "，初始余额：" + acc.getBalance());

        // 正常取款
        System.out.println("\n--- 取款 200 元 ---");
        try {
            acc.withdraw(200);
        } catch (InsufficientFundsException e) {
            System.out.println("  提示：" + e.getMessage());
        }

        // 余额不足
        System.out.println("\n--- 取款 400 元（余额不足）---");
        try {
            acc.withdraw(400);
        } catch (InsufficientFundsException e) {
            System.out.println("  提示：" + e.getMessage());
            System.out.printf("  当前余额：%.2f 元，建议最多取 %.2f 元%n",
                    e.getBalance(), e.getBalance());
        }

        // 非法金额
        System.out.println("\n--- 取款 -50 元（非法金额）---");
        try {
            acc.withdraw(-50);
        } catch (InsufficientFundsException e) {
            System.out.println("  提示：" + e.getMessage());
        } catch (IllegalArgumentException e) {
            System.out.println("  错误：" + e.getMessage());
        }
    }
}