266 lines
7.6 KiB
Go
266 lines
7.6 KiB
Go
package mysql
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import (
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"context"
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"crypto/sha256"
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"database/sql"
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"encoding/hex"
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"errors"
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"fmt"
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"strings"
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"time"
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_ "github.com/go-sql-driver/mysql"
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"hyapp/pkg/xerr"
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"hyapp/services/wallet-service/internal/domain/ledger"
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)
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// Repository 是 wallet-service 的 MySQL 账本入口。
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type Repository struct {
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// db 是余额、流水和幂等记录的同一事务边界。
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db *sql.DB
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// currency 约束当前服务实例处理的账本币种，避免请求侧伪造币种。
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currency string
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// idempotencyTTL 控制幂等记录保留窗口，过期清理可以后续由后台任务执行。
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idempotencyTTL time.Duration
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}
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// Open 创建 MySQL 连接池并做启动 ping。
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func Open(ctx context.Context, dsn string, currency string, idempotencyTTLSec int64) (*Repository, error) {
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if strings.TrimSpace(dsn) == "" {
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return nil, xerr.New(xerr.InvalidArgument, "mysql_dsn is required")
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}
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if strings.TrimSpace(currency) == "" {
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return nil, xerr.New(xerr.InvalidArgument, "wallet currency is required")
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}
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if idempotencyTTLSec <= 0 {
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// 非正 TTL 会让幂等记录立即过期，本地和线上都拒绝这种配置。
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return nil, xerr.New(xerr.InvalidArgument, "wallet idempotency ttl must be positive")
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}
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db, err := sql.Open("mysql", dsn)
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if err != nil {
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return nil, err
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}
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if err := db.PingContext(ctx); err != nil {
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_ = db.Close()
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return nil, err
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}
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return &Repository{
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db: db,
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currency: currency,
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idempotencyTTL: time.Duration(idempotencyTTLSec) * time.Second,
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}, nil
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}
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// Close 释放 MySQL 连接池。
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func (r *Repository) Close() error {
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if r == nil || r.db == nil {
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return nil
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}
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return r.db.Close()
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}
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// Ping 验证 MySQL 当前可用。
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func (r *Repository) Ping(ctx context.Context) error {
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if r == nil || r.db == nil {
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return xerr.New(xerr.Unavailable, "mysql repository is not configured")
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}
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return r.db.PingContext(ctx)
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}
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// DebitGift 在一个 MySQL 事务内完成幂等检查、余额锁定、扣减和流水落账。
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func (r *Repository) DebitGift(ctx context.Context, command ledger.DebitGiftCommand) (ledger.Receipt, error) {
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if r == nil || r.db == nil {
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return ledger.Receipt{}, xerr.New(xerr.Unavailable, "mysql repository is not configured")
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}
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tx, err := r.db.BeginTx(ctx, nil)
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if err != nil {
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return ledger.Receipt{}, err
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}
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defer func() {
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// Commit 成功后 Rollback 会返回 sql.ErrTxDone；忽略它可保证所有早退路径释放事务。
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_ = tx.Rollback()
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}()
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requestHash := debitRequestHash(command)
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if receipt, exists, err := r.lookupIdempotentReceipt(ctx, tx, command, requestHash); err != nil || exists {
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return receipt, err
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}
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total := command.TotalGiftValue()
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account, err := r.lockAccount(ctx, tx, command.SenderUserID)
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if err != nil {
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return ledger.Receipt{}, err
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}
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if account.balance < total {
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return ledger.Receipt{}, xerr.New(xerr.InsufficientBalance, "insufficient balance")
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}
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nowMs := time.Now().UnixMilli()
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receipt := ledger.Receipt{
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BillingReceiptID: billingReceiptID(command.CommandID),
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TotalGiftValue: total,
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BalanceAfter: account.balance - total,
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}
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if err := r.saveDebit(ctx, tx, command, receipt, requestHash, nowMs); err != nil {
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return ledger.Receipt{}, err
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}
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if err := tx.Commit(); err != nil {
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return ledger.Receipt{}, err
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}
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return receipt, nil
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}
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type walletAccount struct {
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balance int64
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version int64
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}
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func (r *Repository) lookupIdempotentReceipt(ctx context.Context, tx *sql.Tx, command ledger.DebitGiftCommand, requestHash string) (ledger.Receipt, bool, error) {
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var billingReceiptID string
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var storedHash string
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row := tx.QueryRowContext(ctx,
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`SELECT billing_receipt_id, request_hash
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FROM wallet_idempotency
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WHERE command_id = ?
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FOR UPDATE`,
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command.CommandID,
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)
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if err := row.Scan(&billingReceiptID, &storedHash); err != nil {
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if errors.Is(err, sql.ErrNoRows) {
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// 没有幂等记录说明该账务命令尚未成功提交。
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return ledger.Receipt{}, false, nil
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}
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return ledger.Receipt{}, false, err
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}
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if storedHash != requestHash {
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// 同一个 command_id 携带不同扣费内容不能回放旧回执，否则会掩盖上游幂等键复用错误。
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return ledger.Receipt{}, true, xerr.New(xerr.LedgerConflict, "billing command idempotency conflict")
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}
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receipt, err := r.getReceipt(ctx, tx, command.CommandID, billingReceiptID)
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return receipt, true, err
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}
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func (r *Repository) getReceipt(ctx context.Context, tx *sql.Tx, commandID string, billingReceiptID string) (ledger.Receipt, error) {
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row := tx.QueryRowContext(ctx,
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`SELECT billing_receipt_id, amount, balance_after
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FROM wallet_ledger
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WHERE command_id = ? AND billing_receipt_id = ? AND currency = ?
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LIMIT 1`,
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commandID,
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billingReceiptID,
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r.currency,
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)
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var receipt ledger.Receipt
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if err := row.Scan(&receipt.BillingReceiptID, &receipt.TotalGiftValue, &receipt.BalanceAfter); err != nil {
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if errors.Is(err, sql.ErrNoRows) {
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// 幂等记录存在但流水缺失代表事务外数据被破坏，不能当作可重试业务错误。
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return ledger.Receipt{}, xerr.New(xerr.Internal, "wallet ledger record is missing")
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}
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return ledger.Receipt{}, err
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}
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return receipt, nil
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}
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func (r *Repository) lockAccount(ctx context.Context, tx *sql.Tx, userID int64) (walletAccount, error) {
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row := tx.QueryRowContext(ctx,
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`SELECT balance, version
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FROM wallet_accounts
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WHERE user_id = ? AND currency = ?
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FOR UPDATE`,
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userID,
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r.currency,
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)
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var account walletAccount
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if err := row.Scan(&account.balance, &account.version); err != nil {
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if errors.Is(err, sql.ErrNoRows) {
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// 未开户在扣费语义上等价于没有可用余额，避免向房间链路暴露账务内部结构。
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return walletAccount{}, xerr.New(xerr.InsufficientBalance, "insufficient balance")
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}
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return walletAccount{}, err
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}
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return account, nil
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}
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func (r *Repository) saveDebit(ctx context.Context, tx *sql.Tx, command ledger.DebitGiftCommand, receipt ledger.Receipt, requestHash string, nowMs int64) error {
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if _, err := tx.ExecContext(ctx,
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`UPDATE wallet_accounts
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SET balance = ?, version = version + 1, updated_at_ms = ?
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WHERE user_id = ? AND currency = ?`,
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receipt.BalanceAfter,
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nowMs,
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command.SenderUserID,
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r.currency,
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); err != nil {
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return err
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}
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if _, err := tx.ExecContext(ctx,
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`INSERT INTO wallet_ledger (
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billing_receipt_id, command_id, user_id, room_id, counterparty_user_id,
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currency, amount, direction, balance_after, biz_type, created_at_ms
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) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
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receipt.BillingReceiptID,
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command.CommandID,
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command.SenderUserID,
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command.RoomID,
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command.TargetUserID,
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r.currency,
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receipt.TotalGiftValue,
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"debit",
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receipt.BalanceAfter,
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"gift",
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nowMs,
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); err != nil {
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return err
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}
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_, err := tx.ExecContext(ctx,
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`INSERT INTO wallet_idempotency (
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command_id, billing_receipt_id, request_hash, expires_at_ms, created_at_ms
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) VALUES (?, ?, ?, ?, ?)`,
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command.CommandID,
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receipt.BillingReceiptID,
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requestHash,
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nowMs+r.idempotencyTTL.Milliseconds(),
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nowMs,
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)
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return err
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}
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func debitRequestHash(command ledger.DebitGiftCommand) string {
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// 哈希覆盖会影响扣费结果的全部字段，用于识别同一 command_id 的错误复用。
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sum := sha256.Sum256([]byte(fmt.Sprintf("%s|%d|%d|%s|%d|%d",
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command.RoomID,
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command.SenderUserID,
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command.TargetUserID,
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command.GiftID,
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command.GiftCount,
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command.GiftUnitValue,
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)))
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return hex.EncodeToString(sum[:])
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}
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func billingReceiptID(commandID string) string {
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sum := sha256.Sum256([]byte(commandID))
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// receipt_id 有 96 字符上限，使用哈希避免上游 command_id 过长导致落账失败。
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return "bill_" + hex.EncodeToString(sum[:])
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}
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