fix(binance): support CRYPTO: prefix and USD stablecoins (#1771)

* fix(binance): support CRYPTO: prefix and USD stablecoins

Holdings processors (CoinStats, Coinbase, Kraken, SimpleFIN, Lunchflow,
Binance) store crypto securities with a "CRYPTO:" prefix, but
Provider::BinancePublic#parse_ticker only accepted Binance-search-style
tickers like "BTCUSD". As a result, every fetched price for tickers
like CRYPTO:USDT, CRYPTO:USDC, CRYPTO:SOL, CRYPTO:TRUMP, CRYPTO:KAITO
failed with "Unsupported Binance ticker".

- Strip the CRYPTO: prefix in parse_ticker.
- Short-circuit USD-pegged stablecoins (USDT, USDC, BUSD, DAI, FDUSD,
  TUSD, USDP, PYUSD) to a synthetic flat 1.0 USD price. Binance has no
  self-pair (USDTUSDT is invalid), and the few stablecoin/USDT pairs
  that do exist hover at ~1.0 with sub-cent noise.
- Default prefixed bare base assets (CRYPTO:SOL etc.) to the …USDT
  pair (USD). Only when prefixed, so unprefixed garbage like BTCBNB /
  BTCGBP still returns nil and the existing rejection tests still pass.
- fetch_security_info returns links: nil for stablecoins rather than a
  broken /trade/ URL.

Closes #1441.

* fix(binance): strip CRYPTO: prefix in search_securities

Security::Resolver calls search_provider with the raw holdings-processor
symbol (CRYPTO:SOL, CRYPTO:USDT) before any price fetch. Without prefix
handling here, first-time crypto imports never resolve to an online
Binance security and the new stablecoin/prefix paths in parse_ticker
were unreachable for that flow.

- Strip CRYPTO: from the search query.
- Short-circuit USD stablecoins to a synthetic search result (no
  exchangeInfo call, no Binance self-pair to find).
- Teach parse_ticker the "{stablecoin}USD" form produced by the
  synthetic result so price fetches route to stablecoin_prices.

---------

Co-authored-by: plind-junior <plind-junior@users.noreply.github.com>

app/models/provider/binance_public.rb

@@ -35,6 +35,16 @@ class Provider::BinancePublic < Provider
   MS_PER_DAY = 24 * 60 * 60 * 1000
   SEARCH_LIMIT = 25
 
+  # USD-pegged stablecoins. Binance has no self-pair (USDTUSDT is invalid) and
+  # the few stablecoin/USDT pairs that do exist (USDCUSDT, etc.) hover at ~1.0
+  # with sub-cent noise — synthesizing a flat 1.0 USD price is both accurate
+  # enough and avoids surfacing transient depeg ticks from market data.
+  USD_STABLECOINS = %w[USDT USDC BUSD DAI FDUSD TUSD USDP PYUSD].freeze
+
+  # Symbol prefix applied by holdings processors (CoinStats, Coinbase, Kraken,
+  # Binance, SimpleFIN, Lunchflow) to distinguish crypto from stock tickers.
+  CRYPTO_PREFIX = "CRYPTO:".freeze
+
   def initialize
     # No API key required — public market data only.
   end
@@ -58,9 +68,13 @@ class Provider::BinancePublic < Provider
 
   def search_securities(symbol, country_code: nil, exchange_operating_mic: nil)
     with_provider_response do
-      query = symbol.to_s.strip.upcase
+      query = symbol.to_s.strip.upcase.delete_prefix(CRYPTO_PREFIX)
       next [] if query.empty?
 
+      if USD_STABLECOINS.include?(query)
+        next [ stablecoin_search_result(query) ]
+      end
+
       symbols = exchange_info_symbols
 
       matches = symbols.select do |s|
@@ -128,10 +142,12 @@ class Provider::BinancePublic < Provider
       # logo_url is intentionally nil — crypto logos are set at save time by
       # Security#generate_logo_url_from_brandfetch via the /crypto/{base}
       # route, not returned from this provider.
+      links = parsed[:binance_pair] ? "https://www.binance.com/en/trade/#{parsed[:binance_pair]}" : nil
+
       SecurityInfo.new(
         symbol: symbol,
         name: parsed[:base],
-        links: "https://www.binance.com/en/trade/#{parsed[:binance_pair]}",
+        links: links,
         logo_url: nil,
         description: nil,
         kind: "crypto",
@@ -161,6 +177,10 @@ class Provider::BinancePublic < Provider
       parsed = parse_ticker(symbol)
       raise InvalidSecurityPriceError, "Unsupported Binance ticker: #{symbol}" if parsed.nil?
 
+      if parsed[:stablecoin]
+        next stablecoin_prices(symbol, parsed, start_date, end_date, exchange_operating_mic)
+      end
+
       binance_pair = parsed[:binance_pair]
       display_currency = parsed[:display_currency]
       prices = []
@@ -220,6 +240,36 @@ class Provider::BinancePublic < Provider
   end
 
   private
+    # Synthetic search hit for a USD-pegged stablecoin. Binance has no self-pair
+    # (USDTUSDT etc. don't exist), so we manufacture a result instead of letting
+    # the resolver fall back to an offline CRYPTO:* row. The downstream price
+    # path short-circuits via parse_ticker -> stablecoin_prices.
+    def stablecoin_search_result(base)
+      Security.new(
+        symbol: "#{base}USD",
+        name: base,
+        logo_url: ::Security.brandfetch_crypto_url(base),
+        exchange_operating_mic: BINANCE_MIC,
+        country_code: nil,
+        currency: "USD"
+      )
+    end
+
+    # Synthesize flat 1.0 USD prices for USD-pegged stablecoins across the
+    # requested range. Avoids a Binance round-trip (there is no self-pair like
+    # USDTUSDT) and produces stable values for portfolio aggregation.
+    def stablecoin_prices(symbol, parsed, start_date, end_date, exchange_operating_mic)
+      (start_date..end_date).map do |date|
+        Price.new(
+          symbol: symbol,
+          date: date,
+          price: 1.0,
+          currency: parsed[:display_currency],
+          exchange_operating_mic: exchange_operating_mic
+        )
+      end
+    end
+
     def base_url
       ENV["BINANCE_PUBLIC_URL"] || "https://data-api.binance.vision"
     end
@@ -247,11 +297,24 @@ class Provider::BinancePublic < Provider
       end
     end
 
-    # Maps a user-visible ticker (e.g. "BTCUSD", "ETHEUR") to the Binance pair
-    # symbol, base asset, and display currency. Returns nil if the ticker does
-    # not end with a supported quote currency.
+    # Maps a user-visible ticker to the Binance pair symbol, base asset, and
+    # display currency. Accepts:
+    #   - "BTCUSD"/"ETHEUR" — fiat suffix from search_securities output
+    #   - "CRYPTO:BTCUSD" — prefixed form stored by holdings processors
+    #   - "CRYPTO:SOL"/"SOL" — bare base asset; defaults to the USDT pair (USD)
+    #   - "CRYPTO:USDT"/"USDT" — USD-pegged stablecoin; binance_pair is nil and
+    #     callers short-circuit to a synthetic 1.0 USD price
+    # Returns nil only when the input is empty after stripping the prefix.
     def parse_ticker(ticker)
-      ticker_up = ticker.to_s.upcase
+      raw = ticker.to_s.upcase
+      prefixed = raw.start_with?(CRYPTO_PREFIX)
+      ticker_up = raw.delete_prefix(CRYPTO_PREFIX)
+      return nil if ticker_up.empty?
+
+      if USD_STABLECOINS.include?(ticker_up)
+        return { binance_pair: nil, base: ticker_up, display_currency: "USD", stablecoin: true }
+      end
+
       SUPPORTED_QUOTES.each do |quote|
         display_currency = QUOTE_TO_CURRENCY[quote]
         next unless ticker_up.end_with?(display_currency)
@@ -259,9 +322,22 @@ class Provider::BinancePublic < Provider
         base = ticker_up.delete_suffix(display_currency)
         next if base.empty?
 
+        # "{stablecoin}USD" form (e.g. "USDTUSD" produced by search_securities)
+        # routes to synthetic 1.0 USD pricing — there is no Binance self-pair.
+        if display_currency == "USD" && USD_STABLECOINS.include?(base)
+          return { binance_pair: nil, base: base, display_currency: "USD", stablecoin: true }
+        end
+
         return { binance_pair: "#{base}#{quote}", base: base, display_currency: display_currency }
       end
-      nil
+
+      # No fiat suffix matched. Only treat the input as a bare base asset when
+      # it arrived with the CRYPTO: prefix from a holdings processor — that
+      # tells us it really is a single coin symbol (SOL, TRUMP, KAITO), not a
+      # malformed pair like "BTCBNB" or "BTCGBP" that we want to reject.
+      return nil unless prefixed
+
+      { binance_pair: "#{ticker_up}USDT", base: ticker_up, display_currency: "USD" }
     end
 
     # Cached for 24h — exchangeInfo returns the full symbol universe (thousands

test/models/provider/binance_public_test.rb

@@ -68,6 +68,38 @@ class Provider::BinancePublicTest < ActiveSupport::TestCase
     assert_equal [ "BTCUSD" ], response.data.map(&:symbol)
   end
 
+  test "search_securities strips CRYPTO: prefix from holdings-processor symbols" do
+    @provider.stubs(:exchange_info_symbols).returns(sample_exchange_info)
+
+    response = @provider.search_securities("CRYPTO:BTC")
+
+    assert response.success?
+    assert_includes response.data.map(&:symbol), "BTCUSD"
+  end
+
+  test "search_securities returns a synthetic stablecoin result without hitting exchangeInfo" do
+    @provider.expects(:exchange_info_symbols).never
+
+    response = @provider.search_securities("CRYPTO:USDT")
+
+    assert response.success?
+    assert_equal 1, response.data.size
+    row = response.data.first
+    assert_equal "USDTUSD", row.symbol
+    assert_equal "USDT", row.name
+    assert_equal "USD", row.currency
+    assert_equal "BNCX", row.exchange_operating_mic
+    assert_nil row.country_code
+  end
+
+  test "parse_ticker treats stablecoin/USD search-result form as stablecoin" do
+    parsed = @provider.send(:parse_ticker, "USDTUSD")
+    assert parsed[:stablecoin]
+    assert_nil parsed[:binance_pair]
+    assert_equal "USDT", parsed[:base]
+    assert_equal "USD", parsed[:display_currency]
+  end
+
   test "search_securities returns empty array when query does not match" do
     @provider.stubs(:exchange_info_symbols).returns(sample_exchange_info)
 
@@ -162,6 +194,95 @@ class Provider::BinancePublicTest < ActiveSupport::TestCase
     assert_nil @provider.send(:parse_ticker, "GIBBERISH")
   end
 
+  test "parse_ticker strips CRYPTO: prefix from holdings processors" do
+    parsed = @provider.send(:parse_ticker, "CRYPTO:BTCUSD")
+    assert_equal "BTCUSDT", parsed[:binance_pair]
+    assert_equal "BTC", parsed[:base]
+    assert_equal "USD", parsed[:display_currency]
+  end
+
+  test "parse_ticker flags USD stablecoins for synthetic pricing" do
+    %w[USDT USDC BUSD DAI FDUSD TUSD USDP PYUSD].each do |stable|
+      parsed = @provider.send(:parse_ticker, "CRYPTO:#{stable}")
+      assert parsed[:stablecoin], "expected #{stable} to be flagged as stablecoin"
+      assert_nil parsed[:binance_pair]
+      assert_equal stable, parsed[:base]
+      assert_equal "USD", parsed[:display_currency]
+    end
+  end
+
+  test "parse_ticker defaults prefixed bare base assets to the USDT pair" do
+    parsed = @provider.send(:parse_ticker, "CRYPTO:SOL")
+    assert_equal "SOLUSDT", parsed[:binance_pair]
+    assert_equal "SOL", parsed[:base]
+    assert_equal "USD", parsed[:display_currency]
+  end
+
+  test "parse_ticker still rejects unprefixed malformed tickers" do
+    # No CRYPTO: prefix → behaves like a Binance-search ticker (must end in a
+    # supported fiat). Protects against false defaults like "BTCBNB" → "BTCBNBUSDT".
+    assert_nil @provider.send(:parse_ticker, "SOL")
+    assert_nil @provider.send(:parse_ticker, "BTCBNB")
+  end
+
+  test "fetch_security_prices returns synthetic 1.0 USD prices for stablecoins" do
+    # No HTTP call expected — short-circuited entirely.
+    @provider.expects(:client).never
+
+    response = @provider.fetch_security_prices(
+      symbol: "CRYPTO:USDT",
+      exchange_operating_mic: "BNCX",
+      start_date: Date.parse("2026-01-01"),
+      end_date: Date.parse("2026-01-03")
+    )
+
+    assert response.success?
+    assert_equal 3, response.data.size
+    assert response.data.all? { |p| p.price == 1.0 && p.currency == "USD" }
+    assert_equal Date.parse("2026-01-01"), response.data.first.date
+    assert_equal Date.parse("2026-01-03"), response.data.last.date
+  end
+
+  test "fetch_security_price returns 1.0 USD for a stablecoin single day" do
+    @provider.expects(:client).never
+
+    response = @provider.fetch_security_price(
+      symbol: "CRYPTO:USDT",
+      exchange_operating_mic: "BNCX",
+      date: Date.parse("2026-01-15")
+    )
+
+    assert response.success?
+    assert_equal 1.0, response.data.price
+    assert_equal "USD", response.data.currency
+  end
+
+  test "fetch_security_info handles stablecoin (no Binance pair link)" do
+    response = @provider.fetch_security_info(symbol: "CRYPTO:USDT", exchange_operating_mic: "BNCX")
+
+    assert response.success?
+    assert_equal "USDT", response.data.name
+    assert_equal "crypto", response.data.kind
+    assert_nil response.data.links
+  end
+
+  test "fetch_security_prices resolves a bare CRYPTO: ticker against the USDT pair" do
+    rows = [ kline_row("2026-01-15", "150.25") ]
+    mock_client_returning_klines(rows)
+
+    response = @provider.fetch_security_prices(
+      symbol: "CRYPTO:SOL",
+      exchange_operating_mic: "BNCX",
+      start_date: Date.parse("2026-01-15"),
+      end_date: Date.parse("2026-01-15")
+    )
+
+    assert response.success?
+    assert_equal 1, response.data.size
+    assert_equal "USD", response.data.first.currency
+    assert_in_delta 150.25, response.data.first.price
+  end
+
   # ================================
   #       Single price
   # ================================