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

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

backend/indexer/reorg/reorg.go

@@ -0,0 +1,127 @@
+package reorg
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// ReorgHandler handles blockchain reorganizations
+type ReorgHandler struct {
+	db      *pgxpool.Pool
+	client  *ethclient.Client
+	chainID int
+}
+
+// NewReorgHandler creates a new reorg handler
+func NewReorgHandler(db *pgxpool.Pool, client *ethclient.Client, chainID int) *ReorgHandler {
+	return &ReorgHandler{
+		db:      db,
+		client:  client,
+		chainID: chainID,
+	}
+}
+
+// DetectReorg detects if a reorg has occurred
+func (rh *ReorgHandler) DetectReorg(ctx context.Context, blockNumber int64) (bool, int64, error) {
+	// Get stored block hash
+	var storedHash string
+	query := `SELECT hash FROM blocks WHERE chain_id = $1 AND number = $2`
+	err := rh.db.QueryRow(ctx, query, rh.chainID, blockNumber).Scan(&storedHash)
+	if err != nil {
+		return false, 0, err
+	}
+
+	// Get current block hash from chain
+	block, err := rh.client.BlockByNumber(ctx, big.NewInt(blockNumber))
+	if err != nil {
+		return false, 0, err
+	}
+
+	currentHash := block.Hash().Hex()
+
+	// Compare hashes
+	if storedHash != currentHash {
+		// Reorg detected, find common ancestor
+		commonAncestor, err := rh.findCommonAncestor(ctx, blockNumber)
+		if err != nil {
+			return false, 0, err
+		}
+		return true, commonAncestor, nil
+	}
+
+	return false, 0, nil
+}
+
+// findCommonAncestor finds the common ancestor block
+func (rh *ReorgHandler) findCommonAncestor(ctx context.Context, startBlock int64) (int64, error) {
+	// Binary search to find common ancestor
+	low := int64(0)
+	high := startBlock
+
+	for low <= high {
+		mid := (low + high) / 2
+
+		var storedHash string
+		err := rh.db.QueryRow(ctx,
+			`SELECT hash FROM blocks WHERE chain_id = $1 AND number = $2`,
+			rh.chainID, mid,
+		).Scan(&storedHash)
+
+		if err != nil {
+			high = mid - 1
+			continue
+		}
+
+		block, err := rh.client.BlockByNumber(ctx, big.NewInt(mid))
+		if err != nil {
+			high = mid - 1
+			continue
+		}
+
+		if storedHash == block.Hash().Hex() {
+			low = mid + 1
+		} else {
+			high = mid - 1
+		}
+	}
+
+	return high, nil
+}
+
+// HandleReorg handles a detected reorg
+func (rh *ReorgHandler) HandleReorg(ctx context.Context, commonAncestor int64) error {
+	log.Printf("Handling reorg: common ancestor at block %d", commonAncestor)
+
+	tx, err := rh.db.Begin(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to begin transaction: %w", err)
+	}
+	defer tx.Rollback(ctx)
+
+	// Mark blocks as orphaned
+	_, err = tx.Exec(ctx, `
+		UPDATE blocks 
+		SET orphaned = true, orphaned_at = NOW()
+		WHERE chain_id = $1 AND number > $2 AND orphaned = false
+	`, rh.chainID, commonAncestor)
+	if err != nil {
+		return fmt.Errorf("failed to mark blocks as orphaned: %w", err)
+	}
+
+	// Delete orphaned data (cascade will handle related records)
+	_, err = tx.Exec(ctx, `
+		DELETE FROM blocks 
+		WHERE chain_id = $1 AND number > $2 AND orphaned = true
+	`, rh.chainID, commonAncestor)
+	if err != nil {
+		return fmt.Errorf("failed to delete orphaned blocks: %w", err)
+	}
+
+	return tx.Commit(ctx)
+}
+