第十三章：稳定币生态系统集成

// 钱包集成SDK
class WalletIntegrationSDK {
    private provider: any;
    private chainConfigs: Map = new Map();
    
    constructor() {
        this.initializeChainConfigs();
    }
    
    // 检测并连接钱包
    async connectWallet(): Promise {
        // 检测注入的provider
        if (typeof window.ethereum !== 'undefined') {
            this.provider = window.ethereum;
            
            // 请求账户访问
            const accounts = await this.provider.request({ 
                method: 'eth_requestAccounts' 
            });
            
            // 获取链ID
            const chainId = await this.provider.request({ 
                method: 'eth_chainId' 
            });
            
            return {
                address: accounts[0],
                chainId: parseInt(chainId, 16),
                provider: this.provider
            };
        } else {
            throw new Error('No wallet detected');
        }
    }
    
    // 添加自定义链（用于新链上的稳定币）
    async addCustomChain(chainId: number): Promise {
        const config = this.chainConfigs.get(chainId);
        if (!config) throw new Error(`Chain ${chainId} not configured`);
        
        try {
            await this.provider.request({
                method: 'wallet_addEthereumChain',
                params: [{
                    chainId: `0x${chainId.toString(16)}`,
                    chainName: config.name,
                    nativeCurrency: config.nativeCurrency,
                    rpcUrls: config.rpcUrls,
                    blockExplorerUrls: config.blockExplorerUrls
                }]
            });
        } catch (error) {
            if (error.code === 4902) {
                throw new Error('User rejected chain addition');
            }
            throw error;
        }
    }
    
    // 添加代币到钱包
    async addTokenToWallet(tokenConfig: TokenConfig): Promise {
        try {
            const wasAdded = await this.provider.request({
                method: 'wallet_watchAsset',
                params: {
                    type: 'ERC20',
                    options: {
                        address: tokenConfig.address,
                        symbol: tokenConfig.symbol,
                        decimals: tokenConfig.decimals,
                        image: tokenConfig.logoURI
                    }
                }
            });
            return wasAdded;
        } catch (error) {
            console.error('Error adding token:', error);
            return false;
        }
    }
    
    // 高级签名功能（EIP-712）
    async signTypedData(domain: EIP712Domain, types: any, value: any): Promise {
        const msgParams = {
            domain,
            message: value,
            primaryType: 'Permit',
            types: {
                EIP712Domain: [
                    { name: 'name', type: 'string' },
                    { name: 'version', type: 'string' },
                    { name: 'chainId', type: 'uint256' },
                    { name: 'verifyingContract', type: 'address' }
                ],
                ...types
            }
        };
        
        const accounts = await this.provider.request({ 
            method: 'eth_requestAccounts' 
        });
        
        const signature = await this.provider.request({
            method: 'eth_signTypedData_v4',
            params: [accounts[0], JSON.stringify(msgParams)]
        });
        
        return signature;
    }
}

// 支持账户抽象的稳定币
contract AACompatibleStablecoin is ERC20, IAccount {
    using UserOperationLib for UserOperation;
    
    // 账户抽象入口点
    IEntryPoint private immutable entryPoint;
    
    // 支付主合约
    mapping(address => bool) public paymasters;
    
    constructor(IEntryPoint _entryPoint) ERC20("AA Stablecoin", "AAUSD") {
        entryPoint = _entryPoint;
    }
    
    // 验证用户操作
    function validateUserOp(
        UserOperation calldata userOp,
        bytes32 userOpHash,
        uint256 missingAccountFunds
    ) external override returns (uint256 validationData) {
        require(msg.sender == address(entryPoint), "Only EntryPoint");
        
        // 验证签名
        bytes32 hash = userOpHash.toEthSignedMessageHash();
        address signer = hash.recover(userOp.signature);
        
        // 检查是否是授权的操作
        if (!isValidSigner(signer)) {
            return SIG_VALIDATION_FAILED;
        }
        
        // 如果需要，从账户转移资金到EntryPoint
        if (missingAccountFunds > 0) {
            _transfer(address(this), msg.sender, missingAccountFunds);
        }
        
        return 0; // 验证成功
    }
    
    // 执行用户操作
    function execute(
        address dest,
        uint256 value,
        bytes calldata func
    ) external {
        require(msg.sender == address(entryPoint), "Only EntryPoint");
        
        if (value > 0) {
            require(address(this).balance >= value, "Insufficient balance");
        }
        
        (bool success, bytes memory result) = dest.call{value: value}(func);
        if (!success) {
            assembly {
                revert(add(result, 32), mload(result))
            }
        }
    }
    
    // 支持ERC-4337支付主合约
    function addPaymaster(address paymaster) external onlyOwner {
        paymasters[paymaster] = true;
    }
    
    // 允许支付主合约代付gas费
    function sponsorUserOperation(
        UserOperation calldata userOp
    ) external view returns (bool) {
        return paymasters[userOp.paymaster];
    }
}

// 稳定币支付网关服务
class StablecoinPaymentGateway {
    private merchants: Map = new Map();
    private payments: Map = new Map();
    
    // 创建支付请求
    async createPaymentRequest(params: PaymentRequestParams): Promise {
        const merchant = this.merchants.get(params.merchantId);
        if (!merchant) throw new Error('Invalid merchant');
        
        const paymentId = generatePaymentId();
        const paymentAddress = await this.generatePaymentAddress(paymentId);
        
        const request: PaymentRequest = {
            id: paymentId,
            merchantId: params.merchantId,
            amount: params.amount,
            currency: params.currency,
            stablecoin: params.acceptedStablecoins || ['USDC', 'USDT', 'DAI'],
            paymentAddress: paymentAddress,
            memo: params.memo,
            createdAt: Date.now(),
            expiresAt: Date.now() + (params.ttl || 3600000), // 1小时默认
            status: 'pending',
            callbackUrl: params.callbackUrl,
            metadata: params.metadata
        };
        
        // 生成支付链接和二维码
        request.paymentUrl = this.generatePaymentUrl(request);
        request.qrCode = await this.generateQRCode(request.paymentUrl);
        
        this.payments.set(paymentId, request);
        
        // 开始监控支付
        this.monitorPayment(paymentId);
        
        return request;
    }
    
    // 监控链上支付
    private async monitorPayment(paymentId: string) {
        const payment = this.payments.get(paymentId);
        if (!payment) return;
        
        const provider = new ethers.JsonRpcProvider(process.env.RPC_URL);
        
        // 监听转账事件
        const stablecoinContracts = this.getStablecoinContracts(payment.stablecoin);
        
        for (const contract of stablecoinContracts) {
            const filter = contract.filters.Transfer(null, payment.paymentAddress);
            
            contract.on(filter, async (from, to, amount, event) => {
                // 验证支付金额
                const expectedAmount = ethers.parseUnits(
                    payment.amount.toString(),
                    await contract.decimals()
                );
                
                if (amount >= expectedAmount) {
                    // 更新支付状态
                    payment.status = 'confirmed';
                    payment.txHash = event.transactionHash;
                    payment.paidAmount = amount;
                    payment.paidToken = await contract.symbol();
                    payment.payer = from;
                    payment.confirmedAt = Date.now();
                    
                    // 通知商户
                    await this.notifyMerchant(payment);
                    
                    // 自动转换和结算
                    if (payment.autoConvert) {
                        await this.convertAndSettle(payment);
                    }
                }
            });
        }
        
        // 超时处理
        setTimeout(() => {
            if (payment.status === 'pending') {
                payment.status = 'expired';
                this.notifyMerchant(payment);
            }
        }, payment.expiresAt - Date.now());
    }
    
    // 自动转换和结算
    private async convertAndSettle(payment: Payment) {
        const merchant = this.merchants.get(payment.merchantId);
        
        // 通过聚合器获取最佳兑换路径
        const swapRoute = await this.findBestSwapRoute(
            payment.paidToken,
            merchant.settlementCurrency,
            payment.paidAmount
        );
        
        // 执行兑换
        const swapResult = await this.executeSwap(swapRoute);
        
        // 结算到商户账户
        await this.settleMerchant(
            merchant,
            swapResult.outputAmount,
            payment
        );
    }
    
    // Webhook通知系统
    private async notifyMerchant(payment: Payment) {
        const merchant = this.merchants.get(payment.merchantId);
        
        const notification = {
            event: payment.status === 'confirmed' ? 'payment.confirmed' : 'payment.expired',
            paymentId: payment.id,
            merchantId: payment.merchantId,
            amount: payment.amount,
            currency: payment.currency,
            paidAmount: payment.paidAmount,
            paidToken: payment.paidToken,
            txHash: payment.txHash,
            timestamp: Date.now(),
            signature: this.signWebhook(payment)
        };
        
        // 重试机制
        let retries = 0;
        while (retries < 3) {
            try {
                const response = await fetch(payment.callbackUrl, {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json',
                        'X-Signature': notification.signature
                    },
                    body: JSON.stringify(notification)
                });
                
                if (response.ok) break;
            } catch (error) {
                retries++;
                await new Promise(resolve => setTimeout(resolve, 1000 * retries));
            }
        }
    }
}

// 跨链桥接合约（源链）
contract CrossChainBridge is Ownable, Pausable {
    using SafeERC20 for IERC20;
    
    struct BridgeRequest {
        address token;
        address sender;
        address recipient;
        uint256 amount;
        uint256 targetChainId;
        uint256 nonce;
        uint256 timestamp;
        bytes32 requestHash;
    }
    
    // 支持的链和代币映射
    mapping(uint256 => mapping(address => address)) public tokenMappings;
    mapping(bytes32 => bool) public processedRequests;
    mapping(address => uint256) public nonces;
    
    // 验证者集合
    mapping(address => bool) public validators;
    uint256 public requiredValidations;
    mapping(bytes32 => mapping(address => bool)) public validations;
    mapping(bytes32 => uint256) public validationCounts;
    
    // 流动性池
    mapping(address => uint256) public liquidity;
    
    event BridgeRequestCreated(
        bytes32 indexed requestHash,
        address indexed sender,
        uint256 targetChainId,
        uint256 amount
    );
    
    event BridgeRequestValidated(
        bytes32 indexed requestHash,
        address indexed validator
    );
    
    event BridgeRequestExecuted(
        bytes32 indexed requestHash,
        address indexed recipient,
        uint256 amount
    );
    
    // 发起跨链转账
    function bridge(
        address token,
        uint256 amount,
        uint256 targetChainId,
        address recipient
    ) external whenNotPaused {
        require(tokenMappings[targetChainId][token] != address(0), "Unsupported token/chain");
        require(amount > 0, "Invalid amount");
        
        // 锁定代币
        IERC20(token).safeTransferFrom(msg.sender, address(this), amount);
        
        // 创建桥接请求
        uint256 nonce = nonces[msg.sender]++;
        bytes32 requestHash = keccak256(abi.encodePacked(
            token,
            msg.sender,
            recipient,
            amount,
            targetChainId,
            nonce,
            block.timestamp
        ));
        
        BridgeRequest memory request = BridgeRequest({
            token: token,
            sender: msg.sender,
            recipient: recipient,
            amount: amount,
            targetChainId: targetChainId,
            nonce: nonce,
            timestamp: block.timestamp,
            requestHash: requestHash
        });
        
        emit BridgeRequestCreated(requestHash, msg.sender, targetChainId, amount);
    }
    
    // 验证者签名验证
    function validateBridgeRequest(
        BridgeRequest calldata request,
        bytes[] calldata signatures
    ) external {
        require(validators[msg.sender], "Not a validator");
        require(!validations[request.requestHash][msg.sender], "Already validated");
        
        // 验证请求哈希
        bytes32 calculatedHash = keccak256(abi.encodePacked(
            request.token,
            request.sender,
            request.recipient,
            request.amount,
            request.targetChainId,
            request.nonce,
            request.timestamp
        ));
        require(calculatedHash == request.requestHash, "Invalid request hash");
        
        // 记录验证
        validations[request.requestHash][msg.sender] = true;
        validationCounts[request.requestHash]++;
        
        emit BridgeRequestValidated(request.requestHash, msg.sender);
        
        // 如果达到所需验证数，执行桥接
        if (validationCounts[request.requestHash] >= requiredValidations) {
            _executeBridgeRequest(request);
        }
    }
    
    // 执行跨链释放（目标链）
    function _executeBridgeRequest(BridgeRequest memory request) private {
        require(!processedRequests[request.requestHash], "Already processed");
        processedRequests[request.requestHash] = true;
        
        // 从流动性池释放代币
        address targetToken = tokenMappings[block.chainid][request.token];
        require(liquidity[targetToken] >= request.amount, "Insufficient liquidity");
        
        liquidity[targetToken] -= request.amount;
        IERC20(targetToken).safeTransfer(request.recipient, request.amount);
        
        emit BridgeRequestExecuted(request.requestHash, request.recipient, request.amount);
    }
    
    // 流动性提供者功能
    function addLiquidity(address token, uint256 amount) external {
        IERC20(token).safeTransferFrom(msg.sender, address(this), amount);
        liquidity[token] += amount;
    }
    
    function removeLiquidity(address token, uint256 amount) external onlyOwner {
        require(liquidity[token] >= amount, "Insufficient liquidity");
        liquidity[token] -= amount;
        IERC20(token).safeTransfer(msg.sender, amount);
    }
}

// DeFi聚合器集成服务
class DeFiAggregatorService {
    private providers: Map = new Map();
    
    constructor() {
        // 初始化主流聚合器
        this.providers.set('1inch', new OneInchProvider());
        this.providers.set('0x', new ZeroXProvider());
        this.providers.set('paraswap', new ParaSwapProvider());
    }
    
    // 获取最佳交换路径
    async getBestSwapRoute(params: SwapParams): Promise {
        const quotes = await Promise.all(
            Array.from(this.providers.values()).map(provider => 
                provider.getQuote(params).catch(() => null)
            )
        );
        
        // 过滤有效报价并排序
        const validQuotes = quotes
            .filter(q => q !== null)
            .sort((a, b) => b.outputAmount - a.outputAmount);
        
        if (validQuotes.length === 0) {
            throw new Error('No valid quotes found');
        }
        
        const bestQuote = validQuotes[0];
        
        // 构建优化的交换路径
        return {
            provider: bestQuote.provider,
            inputToken: params.inputToken,
            outputToken: params.outputToken,
            inputAmount: params.inputAmount,
            outputAmount: bestQuote.outputAmount,
            path: bestQuote.path,
            pools: bestQuote.pools,
            gasEstimate: bestQuote.gasEstimate,
            priceImpact: this.calculatePriceImpact(bestQuote),
            calldata: bestQuote.calldata
        };
    }
    
    // 执行聚合交换
    async executeAggregatedSwap(route: SwapRoute, userAddress: string): Promise {
        // 构建交易参数
        const txParams = {
            to: route.provider.routerAddress,
            data: route.calldata,
            value: route.inputToken === 'ETH' ? route.inputAmount : 0,
            gasLimit: route.gasEstimate * 1.2, // 20%缓冲
            from: userAddress
        };
        
        // 如果是ERC20，需要先授权
        if (route.inputToken !== 'ETH') {
            await this.ensureApproval(
                route.inputToken,
                userAddress,
                route.provider.routerAddress,
                route.inputAmount
            );
        }
        
        // 执行交易
        const tx = await this.sendTransaction(txParams);
        
        // 监控交易
        return this.monitorTransaction(tx.hash);
    }
    
    // 套利机会检测
    async findArbitrageOpportunities(
        baseToken: string,
        quoteTokens: string[],
        amount: bigint
    ): Promise {
        const opportunities: ArbitrageOpportunity[] = [];
        
        for (const quoteToken of quoteTokens) {
            // 获取各个DEX的价格
            const prices = await this.getAllPrices(baseToken, quoteToken, amount);
            
            // 寻找价差
            for (let i = 0; i < prices.length; i++) {
                for (let j = i + 1; j < prices.length; j++) {
                    const priceDiff = Math.abs(prices[i].price - prices[j].price);
                    const profitRatio = priceDiff / Math.min(prices[i].price, prices[j].price);
                    
                    // 如果价差超过阈值（考虑gas成本）
                    if (profitRatio > 0.005) { // 0.5%
                        const buyFrom = prices[i].price < prices[j].price ? prices[i] : prices[j];
                        const sellTo = prices[i].price > prices[j].price ? prices[i] : prices[j];
                        
                        const estimatedProfit = this.calculateProfit(
                            amount,
                            buyFrom,
                            sellTo
                        );
                        
                        if (estimatedProfit > 0) {
                            opportunities.push({
                                buyDex: buyFrom.dex,
                                sellDex: sellTo.dex,
                                token: baseToken,
                                quoteToken: quoteToken,
                                profitRatio: profitRatio,
                                estimatedProfit: estimatedProfit,
                                requiredCapital: amount,
                                gasEstimate: buyFrom.gasEstimate + sellTo.gasEstimate
                            });
                        }
                    }
                }
            }
        }
        
        return opportunities.sort((a, b) => b.estimatedProfit - a.estimatedProfit);
    }
}

// 微信支付宝的理财功能
class TraditionalFinance {
    // 余额宝：简单的活期理财
    async depositToYuebao(amount) {
        // 一键转入，T+1计息
        const result = await api.deposit({
            amount: amount,
            product: 'yuebao'
        });
        return {
            expectedAPY: '2.3%',
            liquidity: 'T+0',
            risk: 'low'
        };
    }
}

// 稳定币DeFi理财
class DeFiFinance {
    // 更高收益但操作复杂
    async depositToAave(amount) {
        // 1. 批准代币
        await stablecoin.approve(aavePool, amount);
        
        // 2. 存入资金池
        await aavePool.supply(stablecoin.address, amount, user, 0);
        
        // 3. 实时计息，收益率动态变化
        return {
            currentAPY: '4-8%',
            liquidity: 'instant',
            risk: 'smart contract risk'
        };
    }
    
    // 流动性挖矿：更复杂但收益更高
    async provideLiquidity(tokenA, tokenB, amountA, amountB) {
        // 1. 批准两种代币
        await tokenA.approve(router, amountA);
        await tokenB.approve(router, amountB);
        
        // 2. 添加流动性
        await router.addLiquidity(
            tokenA.address, tokenB.address,
            amountA, amountB,
            amountA * 0.95, amountB * 0.95, // 滑点保护
            user, deadline
        );
        
        // 3. 质押LP代币挖矿
        await farmContract.stake(lpAmount);
        
        return {
            lpTokens: lpAmount,
            farmingAPR: '20-50%',
            impermanentLossRisk: true
        };
    }
}