package com.icoderoad.service;


import java.math.BigDecimal;


public interface AccountService {
    boolean tryDeduct(String accountId, BigDecimal amount); // 凍結(jié)資金
    boolean confirmDeduct(String accountId, BigDecimal amount); // 實(shí)際扣款
    boolean cancelDeduct(String accountId, BigDecimal amount); // 釋放凍結(jié)
}
package com.icoderoad.service.impl;


import com.icoderoad.dao.AccountDao;
import com.icoderoad.entity.Account;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.math.BigDecimal;


@Service
public class AccountServiceImpl implements AccountService {
    private final AccountDao accountDao;


    public AccountServiceImpl(AccountDao accountDao) {
        this.accountDao = accountDao;
    }


    @Override
    @Transactional
    public boolean tryDeduct(String accountId, BigDecimal amount) {
        Account account = accountDao.selectForUpdate(accountId);
        if (account.getBalance().compareTo(amount) >= 0) {
            account.setFrozenAmount(account.getFrozenAmount().add(amount));
            accountDao.update(account);
            return true;
        }
        return false;
    }
}

@Override
@Transactional
public boolean confirmDeduct(String accountId, BigDecimal amount) {
    Account account = accountDao.select(accountId);
    account.setBalance(account.getBalance().subtract(amount));
    account.setFrozenAmount(account.getFrozenAmount().subtract(amount));
    accountDao.update(account);
    return true;
}

@Override
@Transactional
public boolean cancelDeduct(String accountId, BigDecimal amount) {
    Account account = accountDao.select(accountId);
    account.setFrozenAmount(account.getFrozenAmount().subtract(amount));
    accountDao.update(account);
    return true;
}

@Override
@Transactional
public boolean cancelDeduct(String accountId,BigDecimal amount){
    Account account = accountDao.select(accountId);
    if(account.getFrozenAmount().compareTo(amount)<0){
        log.warn("空回滾，直接返回");
        return true;
    }
    return true;
}

public class TransactionLog {
    private String txId;
    private int status; // 0-init, 1-try, 2-confirm, 3-cancel
}
@Override
public boolean confirmDeduct(String txId, String accountId, BigDecimal amount) {
    if (transactionLogDao.existsByTxIdAndStatus(txId, 2)) {
        return true;
    }
    return true;
}

@Override
public boolean tryDeduct(String txId, String accountId, BigDecimal amount) {
    if (transactionLogDao.existsByTxIdAndStatus(txId, 3)) {
        log.error("事務(wù)已回滾，拒絕 Try 操作");
        return false;
    }
    return true;
}