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

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

backend/api/watchlists/watchlists.go

@@ -0,0 +1,74 @@
+package watchlists
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// WatchlistService handles watchlist operations
+type WatchlistService struct {
+	db *pgxpool.Pool
+}
+
+// NewWatchlistService creates a new watchlist service
+func NewWatchlistService(db *pgxpool.Pool) *WatchlistService {
+	return &WatchlistService{db: db}
+}
+
+// AddToWatchlist adds an address to a user's watchlist
+func (w *WatchlistService) AddToWatchlist(ctx context.Context, userID string, chainID int, address, label string) error {
+	query := `
+		INSERT INTO watchlists (user_id, chain_id, address, label)
+		VALUES ($1, $2, $3, $4)
+		ON CONFLICT (user_id, chain_id, address) DO UPDATE SET
+			label = $4
+	`
+
+	_, err := w.db.Exec(ctx, query, userID, chainID, address, label)
+	return err
+}
+
+// RemoveFromWatchlist removes an address from watchlist
+func (w *WatchlistService) RemoveFromWatchlist(ctx context.Context, userID string, chainID int, address string) error {
+	query := `DELETE FROM watchlists WHERE user_id = $1 AND chain_id = $2 AND address = $3`
+	_, err := w.db.Exec(ctx, query, userID, chainID, address)
+	return err
+}
+
+// GetWatchlist gets a user's watchlist
+func (w *WatchlistService) GetWatchlist(ctx context.Context, userID string, chainID int) ([]WatchlistItem, error) {
+	query := `
+		SELECT chain_id, address, label, created_at
+		FROM watchlists
+		WHERE user_id = $1 AND chain_id = $2
+		ORDER BY created_at DESC
+	`
+
+	rows, err := w.db.Query(ctx, query, userID, chainID)
+	if err != nil {
+		return nil, fmt.Errorf("failed to query watchlist: %w", err)
+	}
+	defer rows.Close()
+
+	var items []WatchlistItem
+	for rows.Next() {
+		var item WatchlistItem
+		if err := rows.Scan(&item.ChainID, &item.Address, &item.Label, &item.CreatedAt); err != nil {
+			continue
+		}
+		items = append(items, item)
+	}
+
+	return items, nil
+}
+
+// WatchlistItem represents a watchlist item
+type WatchlistItem struct {
+	ChainID   int
+	Address   string
+	Label     string
+	CreatedAt string
+}
+