skip price_ratio on avg_cost fallback

src/commands/audit.zig

@@ -477,6 +477,36 @@ pub const SchwabAccountComparison = struct {
     has_discrepancy: bool,
 };
 
+/// Resolved position value for audit display: effective per-share price
+/// and total market value, with correct `price_ratio` handling based on
+/// the price's provenance.
+///
+/// Two sources feed `prices`:
+///   1. Live candle close — NOT preadjusted for the lot's share class,
+///      so `price_ratio` must be applied.
+///   2. `pos.avg_cost` fallback — already in the lot's share-class
+///      terms (user paid institutional-class prices to open the lot),
+///      so `price_ratio` must be skipped.
+///
+/// See the "Pricing model" block in `models/portfolio.zig` for the full
+/// treatment. This helper is the audit-side mirror of the snapshot
+/// side's `buildFallbackPrices` + `manual_set` pair.
+const ResolvedValue = struct { price: f64, value: f64 };
+
+fn resolvePositionValue(pos: zfin.Position, prices: std.StringHashMap(f64)) ResolvedValue {
+    if (prices.get(pos.symbol)) |live| {
+        return .{
+            .price = pos.effectivePrice(live, false),
+            .value = pos.marketValue(live, false),
+        };
+    }
+    // Fallback: avg_cost. Already preadjusted.
+    return .{
+        .price = pos.effectivePrice(pos.avg_cost, true),
+        .value = pos.marketValue(pos.avg_cost, true),
+    };
+}
+
 /// Compare Schwab summary against portfolio.srf account totals.
 pub fn compareSchwabSummary(
     allocator: std.mem.Allocator,
@@ -788,15 +818,9 @@ pub fn compareAccounts(
                         !std.mem.eql(u8, pos.lot_symbol, bp.symbol))
                         continue;
                     pf_shares = pos.shares;
-                    // NOTE: always-false for is_preadjusted preserves
-                    // pre-refactor audit behavior. This is the latent
-                    // bug called out in the "Pricing model" block in
-                    // models/portfolio.zig: when `price` came from
-                    // `pos.avg_cost`, it's already preadjusted and
-                    // multiplying by price_ratio here is wrong.
-                    const price = prices.get(pos.symbol) orelse pos.avg_cost;
-                    pf_price = pos.effectivePrice(price, false);
-                    pf_value = pos.marketValue(price, false);
+                    const v = resolvePositionValue(pos, prices);
+                    pf_price = v.price;
+                    pf_value = v.value;
                     try matched_symbols.put(pos.symbol, {});
                     try matched_symbols.put(pos.lot_symbol, {});
                     found_stock = true;
@@ -866,9 +890,8 @@ pub fn compareAccounts(
 
                 try matched_symbols.put(pos.symbol, {});
 
-                const price = prices.get(pos.symbol) orelse pos.avg_cost;
-                // See latent-bug note above — preserves pre-refactor behavior.
-                const mv = pos.marketValue(price, false);
+                const v = resolvePositionValue(pos, prices);
+                const mv = v.value;
                 portfolio_total += mv;
 
                 has_discrepancies = true;
@@ -876,7 +899,7 @@ pub fn compareAccounts(
                     .symbol = pos.symbol,
                     .portfolio_shares = pos.shares,
                     .brokerage_shares = null,
-                    .portfolio_price = pos.effectivePrice(price, false),
+                    .portfolio_price = v.price,
                     .brokerage_price = null,
                     .portfolio_value = mv,
                     .brokerage_value = null,
@@ -1591,3 +1614,94 @@ test "parseSchwabCsv basic" {
     try std.testing.expectApproxEqAbs(@as(f64, 8271.12), parsed.positions[1].current_value.?, 0.01);
     try std.testing.expect(parsed.positions[1].quantity == null);
 }
+
+// ── resolvePositionValue ──────────────────────────────────────
+//
+// Pins the audit-side price-provenance rule: live-from-cache prices
+// get price_ratio applied; avg_cost-fallback prices do not. This
+// closes the latent bug where institutional-share-class positions
+// (price_ratio != 1.0) that missed the cache would have their value
+// over-reported by the ratio factor.
+
+test "resolvePositionValue: live cache hit applies price_ratio" {
+    const allocator = std.testing.allocator;
+    var prices = std.StringHashMap(f64).init(allocator);
+    defer prices.deinit();
+    try prices.put("VTTHX", 27.78); // retail-class close
+
+    const pos: zfin.Position = .{
+        .symbol = "VTTHX",
+        .lot_symbol = "VTTHX",
+        .shares = 100,
+        .avg_cost = 106.18,
+        .total_cost = 10618,
+        .open_lots = 1,
+        .closed_lots = 0,
+        .realized_gain_loss = 0,
+        .account = "401k",
+        .price_ratio = 5.185,
+    };
+
+    const v = resolvePositionValue(pos, prices);
+    // price_ratio applied: 27.78 * 5.185 = 144.04
+    try std.testing.expectApproxEqAbs(@as(f64, 144.04), v.price, 0.01);
+    try std.testing.expectApproxEqAbs(@as(f64, 14403.93), v.value, 0.01);
+}
+
+test "resolvePositionValue: avg_cost fallback skips price_ratio" {
+    const allocator = std.testing.allocator;
+    // Empty prices map — simulate cache miss for VTTHX.
+    var prices = std.StringHashMap(f64).init(allocator);
+    defer prices.deinit();
+
+    const pos: zfin.Position = .{
+        .symbol = "VTTHX",
+        .lot_symbol = "VTTHX",
+        .shares = 100,
+        .avg_cost = 106.18, // already institutional-class terms
+        .total_cost = 10618,
+        .open_lots = 1,
+        .closed_lots = 0,
+        .realized_gain_loss = 0,
+        .account = "401k",
+        .price_ratio = 5.185,
+    };
+
+    const v = resolvePositionValue(pos, prices);
+    // Pre-fix behavior would have multiplied: 106.18 * 5.185 = 550.55.
+    // Correct behavior: avg_cost is already in lot share-class terms.
+    try std.testing.expectApproxEqAbs(@as(f64, 106.18), v.price, 0.01);
+    try std.testing.expectApproxEqAbs(@as(f64, 10618.0), v.value, 0.01);
+}
+
+test "resolvePositionValue: ratio-1.0 position unaffected by provenance" {
+    // Sanity: when price_ratio == 1.0, the bug never fired. Both paths
+    // should give the same answer.
+    const allocator = std.testing.allocator;
+    var prices_hit = std.StringHashMap(f64).init(allocator);
+    defer prices_hit.deinit();
+    try prices_hit.put("AAPL", 200.0);
+
+    var prices_miss = std.StringHashMap(f64).init(allocator);
+    defer prices_miss.deinit();
+
+    const pos: zfin.Position = .{
+        .symbol = "AAPL",
+        .lot_symbol = "AAPL",
+        .shares = 10,
+        .avg_cost = 150.0,
+        .total_cost = 1500,
+        .open_lots = 1,
+        .closed_lots = 0,
+        .realized_gain_loss = 0,
+        .account = "Roth",
+    };
+
+    const hit = resolvePositionValue(pos, prices_hit);
+    const miss = resolvePositionValue(pos, prices_miss);
+
+    try std.testing.expectApproxEqAbs(@as(f64, 200.0), hit.price, 0.01);
+    try std.testing.expectApproxEqAbs(@as(f64, 2000.0), hit.value, 0.01);
+    try std.testing.expectApproxEqAbs(@as(f64, 150.0), miss.price, 0.01);
+    try std.testing.expectApproxEqAbs(@as(f64, 1500.0), miss.value, 0.01);
+}

src/models/portfolio.zig

@@ -54,14 +54,15 @@ const Candle = @import("candle.zig").Candle;
 // the lot needs." The `manual_set` (from `buildFallbackPrices`) then
 // tells readers which entries are preadjusted.
 //
-// ## Known limitation (tracked as a follow-up)
+// ## avg_cost fallback
 //
-// `audit.zig` unconditionally passes `is_preadjusted = false` even
-// when its raw price came from `pos.avg_cost` — which IS preadjusted
-// by the rules above. That mismatch is a latent bug, preserved here
-// with a TODO to maintain the pre-refactor audit behavior. Fix is a
-// one-line change once we're ready to verify the audit report
-// deltas.
+// When a symbol has no live price AND no manual override, callers fall
+// back to `position.avg_cost` (the weighted average lot open-price).
+// That value is already in the lot's share-class terms — the user paid
+// institutional-class prices to open the lot — so `is_preadjusted = true`.
+// Both snapshot and audit honor this: snapshot via `buildFallbackPrices`
+// + `manual_set`, audit via inline `prices.get(sym) orelse avg_cost`
+// with a matching `is_preadjusted` flag per branch.
 
 // ── Money-market / stable-NAV classification ────────────────
 //