Add full monorepo: virtual-banker, backend, frontend, docs, scripts, deployment

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/mempool/fee/oracle.go

@@ -0,0 +1,95 @@
+package fee
+
+import (
+	"context"
+	"fmt"
+	"math/big"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// Oracle provides gas price estimates
+type Oracle struct {
+	db      *pgxpool.Pool
+	chainID int
+}
+
+// NewOracle creates a new fee oracle
+func NewOracle(db *pgxpool.Pool, chainID int) *Oracle {
+	return &Oracle{
+		db:      db,
+		chainID: chainID,
+	}
+}
+
+// FeeEstimate represents gas price estimates
+type FeeEstimate struct {
+	Slow     string `json:"slow"`
+	Standard string `json:"standard"`
+	Fast     string `json:"fast"`
+	Urgent   string `json:"urgent"`
+}
+
+// GetFeeEstimates gets current fee estimates
+func (o *Oracle) GetFeeEstimates(ctx context.Context) (*FeeEstimate, error) {
+	// Get recent gas prices from last 100 blocks
+	query := `
+		SELECT avg_gas_price
+		FROM gas_price_history
+		WHERE chain_id = $1
+		ORDER BY time DESC
+		LIMIT 100
+	`
+
+	rows, err := o.db.Query(ctx, query, o.chainID)
+	if err != nil {
+		return nil, fmt.Errorf("failed to query gas prices: %w", err)
+	}
+	defer rows.Close()
+
+	var prices []int64
+	for rows.Next() {
+		var price int64
+		if err := rows.Scan(&price); err == nil {
+			prices = append(prices, price)
+		}
+	}
+
+	if len(prices) == 0 {
+		// Return default estimates if no data
+		return &FeeEstimate{
+			Slow:     "20000000000",
+			Standard: "30000000000",
+			Fast:     "50000000000",
+			Urgent:   "100000000000",
+		}, nil
+	}
+
+	// Calculate percentiles
+	p25 := percentile(prices, 0.25)
+	p50 := percentile(prices, 0.50)
+	p75 := percentile(prices, 0.75)
+	p95 := percentile(prices, 0.95)
+
+	return &FeeEstimate{
+		Slow:     big.NewInt(p25).String(),
+		Standard: big.NewInt(p50).String(),
+		Fast:     big.NewInt(p75).String(),
+		Urgent:   big.NewInt(p95).String(),
+	}, nil
+}
+
+// percentile calculates percentile of sorted slice
+func percentile(data []int64, p float64) int64 {
+	if len(data) == 0 {
+		return 0
+	}
+
+	index := int(float64(len(data)) * p)
+	if index >= len(data) {
+		index = len(data) - 1
+	}
+
+	return data[index]
+}
+

backend/mempool/tracker.go

@@ -0,0 +1,94 @@
+package mempool
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// Tracker tracks pending transactions in the mempool
+type Tracker struct {
+	db      *pgxpool.Pool
+	client  *ethclient.Client
+	chainID int
+}
+
+// NewTracker creates a new mempool tracker
+func NewTracker(db *pgxpool.Pool, client *ethclient.Client, chainID int) *Tracker {
+	return &Tracker{
+		db:      db,
+		client:  client,
+		chainID: chainID,
+	}
+}
+
+// TrackPendingTransaction tracks a pending transaction
+func (t *Tracker) TrackPendingTransaction(ctx context.Context, tx *types.Transaction) error {
+	from, _ := types.Sender(types.LatestSignerForChainID(tx.ChainId()), tx)
+
+	var toAddress sql.NullString
+	if tx.To() != nil {
+		toAddress.String = tx.To().Hex()
+		toAddress.Valid = true
+	}
+
+	var maxFeePerGas, maxPriorityFeePerGas sql.NullInt64
+	if tx.Type() == types.DynamicFeeTxType {
+		if tx.GasFeeCap() != nil {
+			maxFeePerGas.Int64 = tx.GasFeeCap().Int64()
+			maxFeePerGas.Valid = true
+		}
+		if tx.GasTipCap() != nil {
+			maxPriorityFeePerGas.Int64 = tx.GasTipCap().Int64()
+			maxPriorityFeePerGas.Valid = true
+		}
+	}
+
+	query := `
+		INSERT INTO mempool_transactions (
+			time, chain_id, hash, from_address, to_address, value,
+			gas_price, max_fee_per_gas, max_priority_fee_per_gas,
+			gas_limit, nonce, input_data_length, first_seen, status
+		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14)
+		ON CONFLICT (time, chain_id, hash) DO UPDATE SET
+			status = $14,
+			updated_at = NOW()
+	`
+
+	_, err := t.db.Exec(ctx, query,
+		time.Now(),
+		t.chainID,
+		tx.Hash().Hex(),
+		from.Hex(),
+		toAddress,
+		tx.Value().String(),
+		tx.GasPrice().Int64(),
+		maxFeePerGas,
+		maxPriorityFeePerGas,
+		tx.Gas(),
+		tx.Nonce(),
+		len(tx.Data()),
+		time.Now(),
+		"pending",
+	)
+
+	return err
+}
+
+// UpdateTransactionStatus updates transaction status when confirmed
+func (t *Tracker) UpdateTransactionStatus(ctx context.Context, txHash common.Hash, blockNumber int64, status string) error {
+	query := `
+		UPDATE mempool_transactions
+		SET status = $1, confirmed_block_number = $2, confirmed_at = NOW()
+		WHERE chain_id = $3 AND hash = $4
+	`
+
+	_, err := t.db.Exec(ctx, query, status, blockNumber, t.chainID, txHash.Hex())
+	return err
+}
+