Cleanup: dedupe blend logic, single-home oddsWeight

Address code-review cleanup notes:
- Extract the base/odds blend ladder (duplicated between resolveSourceElos and
  resolveRatings) into one generic `blendBaseAndOdds` helper.
- Move the futures blend weight to a single home: oddsWeight now lives only under
  inputPolicy. Manifest per-profile defaults moved from top-level config into
  inputPolicy.oddsWeight, and getSimulatorInputPolicy no longer reads a legacy
  top-level config.oddsWeight. Drops the now-dead mlb rDiffWeight config knob.
- Clarify the college_hockey oddsWeight 0 rationale (it disables the central
  blend so its internal odds blend isn't double-counted, while still letting odds
  resolve an Elo when they're the only source — a separate centralBlend flag
  would wrongly drop that sole-source path and break readiness).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QhNeB7gN6VKene7sdbBVQT

app/services/simulations/__tests__/input-policy.test.ts

@@ -280,9 +280,10 @@ describe("simulator input policy", () => {
     expect(defaults.baseEloPriority).toEqual(DEFAULT_BASE_ELO_PRIORITY);
     expect(defaults.oddsWeight).toBe(0.3);
 
-    // oddsWeight can be sourced from the top-level config or the input policy,
-    // and is clamped to [0, 1]; junk base-priority entries are dropped.
-    expect(getSimulatorInputPolicy({ oddsWeight: 0.6 }).oddsWeight).toBe(0.6);
+    // oddsWeight lives under inputPolicy and is clamped to [0, 1]; a top-level
+    // config.oddsWeight is ignored (single home); junk base-priority entries drop.
+    expect(getSimulatorInputPolicy({ inputPolicy: { oddsWeight: 0.6 } }).oddsWeight).toBe(0.6);
+    expect(getSimulatorInputPolicy({ oddsWeight: 0.6 }).oddsWeight).toBe(0.3);
     expect(getSimulatorInputPolicy({ inputPolicy: { oddsWeight: 5 } }).oddsWeight).toBe(1);
     expect(getSimulatorInputPolicy({ inputPolicy: { oddsWeight: -2 } }).oddsWeight).toBe(0);
     expect(

app/services/simulations/input-policy.ts

@@ -142,13 +142,8 @@ export function getSimulatorInputPolicy(config: Record<string, unknown>): Simula
         ? ratingStrategy
         : "block",
     baseEloPriority: parseBaseEloPriority(rawPolicy.baseEloPriority, DEFAULT_POLICY.baseEloPriority),
-    // Allow oddsWeight to live either in inputPolicy (the unified knob) or at the
-    // top level of config (legacy per-profile defaultConfig), preferring the policy.
-    oddsWeight: clamp(
-      optionalNumber(rawPolicy.oddsWeight, optionalNumber(config.oddsWeight, DEFAULT_POLICY.oddsWeight)),
-      0,
-      1
-    ),
+    // The futures blend weight lives only under inputPolicy (single home).
+    oddsWeight: clamp(optionalNumber(rawPolicy.oddsWeight, DEFAULT_POLICY.oddsWeight), 0, 1),
     fallbackElo: optionalNumber(rawPolicy.fallbackElo, DEFAULT_POLICY.fallbackElo),
     fallbackEloDelta: optionalNumber(rawPolicy.fallbackEloDelta, DEFAULT_POLICY.fallbackEloDelta),
     eloMin: optionalNumber(rawPolicy.eloMin, DEFAULT_POLICY.eloMin),
@@ -173,6 +168,32 @@ export function ratingRequirementLabel(profile: SimulatorManifestProfile): strin
   return ["rating", ...alternatives.map(simulatorInputLabel)].join(" / ");
 }
 
+/**
+ * Combine a participant's base strength value and its odds-derived value into the
+ * single value that feeds the simulator, by `oddsWeight`: 0 = base only,
+ * 1 = odds only, in between = weighted blend. Odds-derived and blended results
+ * pass through `clampDerived` (they are mapped onto the configured band by
+ * design); a base value is returned untouched (a directly entered Elo/rating is
+ * trusted as-is, a projection-derived Elo was already clamped upstream). Returns
+ * undefined when neither source is present (the caller falls back to its
+ * missing-input strategy). Shared by Elo and rating resolution.
+ */
+function blendBaseAndOdds<M extends string>(
+  base: { value: number; method: M } | undefined,
+  odds: number | undefined,
+  oddsWeight: number,
+  clampDerived: (value: number) => number
+): { value: number; method: M | "sourceOdds" | "blend" } | undefined {
+  if (base !== undefined && odds !== undefined) {
+    if (oddsWeight <= 0) return { value: base.value, method: base.method };
+    if (oddsWeight >= 1) return { value: clampDerived(odds), method: "sourceOdds" };
+    return { value: clampDerived((1 - oddsWeight) * base.value + oddsWeight * odds), method: "blend" };
+  }
+  if (base !== undefined) return { value: base.value, method: base.method };
+  if (odds !== undefined) return { value: clampDerived(odds), method: "sourceOdds" };
+  return undefined;
+}
+
 export function resolveSourceElos(
   inputs: ParticipantInputForPolicy[],
   profile: Pick<SimulatorManifestProfile, "derivableInputs">,
@@ -240,42 +261,23 @@ export function resolveSourceElos(
   }
 
   // 3. Blend base + odds into the single Elo that feeds the simulator.
-  //    Only odds-derived / blended / fallback values are clamped+rounded onto the
-  //    [eloMin, eloMax] band (they are mapped onto it by design). A base Elo is
-  //    passed through untouched: a directly entered Elo is trusted as-is (some
-  //    sports use ratings above the default ceiling, e.g. snooker ~2450) and a
-  //    projection-derived Elo was already clamped by projectionToElo.
-  const w = policy.oddsWeight;
+  //    Directly entered Elos (some sports use ratings above the default ceiling,
+  //    e.g. snooker ~2450) pass through unclamped; only derived values are
+  //    clamped onto [eloMin, eloMax].
   const clampDerived = (elo: number): number => clamp(Math.round(elo), policy.eloMin, policy.eloMax);
   for (const input of inputs) {
     const base = baseElo.get(input.participantId);
-    const odds = oddsElo.get(input.participantId);
-    let sourceElo: number;
-    let method: ResolvedSourceElo["method"];
-    if (base !== undefined && odds !== undefined) {
-      if (w <= 0) {
-        sourceElo = base.elo;
-        method = base.method;
-      } else if (w >= 1) {
-        sourceElo = clampDerived(odds);
-        method = "sourceOdds";
-      } else {
-        sourceElo = clampDerived((1 - w) * base.elo + w * odds);
-        method = "blend";
-      }
-    } else if (base !== undefined) {
-      sourceElo = base.elo;
-      method = base.method;
-    } else if (odds !== undefined) {
-      sourceElo = clampDerived(odds);
-      method = "sourceOdds";
-    } else {
-      continue;
-    }
+    const blended = blendBaseAndOdds(
+      base ? { value: base.elo, method: base.method } : undefined,
+      oddsElo.get(input.participantId),
+      policy.oddsWeight,
+      clampDerived
+    );
+    if (!blended) continue;
     resolved.set(input.participantId, {
       participantId: input.participantId,
-      sourceElo,
-      method,
+      sourceElo: blended.value,
+      method: blended.method,
     });
   }
 
@@ -349,39 +351,22 @@ export function resolveRatings(
     }
   }
 
-  // As with Elo: only odds-derived / blended values are clamped onto the rating
-  // band; a directly entered rating is trusted as-is (matching prior behavior).
-  const w = policy.oddsWeight;
+  // As with Elo: a directly entered rating passes through untouched; only
+  // derived values are clamped onto the rating band.
   const clampDerived = (rating: number): number => clamp(rating, policy.ratingMin, policy.ratingMax);
   for (const input of inputs) {
     const base = baseRating.get(input.participantId);
-    const odds = oddsRating.get(input.participantId);
-    let rating: number;
-    let method: ResolvedRating["method"];
-    if (base !== undefined && odds !== undefined) {
-      if (w <= 0) {
-        rating = base;
-        method = "direct";
-      } else if (w >= 1) {
-        rating = clampDerived(odds);
-        method = "sourceOdds";
-      } else {
-        rating = clampDerived((1 - w) * base + w * odds);
-        method = "blend";
-      }
-    } else if (base !== undefined) {
-      rating = base;
-      method = "direct";
-    } else if (odds !== undefined) {
-      rating = clampDerived(odds);
-      method = "sourceOdds";
-    } else {
-      continue;
-    }
+    const blended = blendBaseAndOdds(
+      base !== undefined ? { value: base, method: "direct" as const } : undefined,
+      oddsRating.get(input.participantId),
+      policy.oddsWeight,
+      clampDerived
+    );
+    if (!blended) continue;
     resolved.set(input.participantId, {
       participantId: input.participantId,
-      rating,
-      method,
+      rating: blended.value,
+      method: blended.method,
     });
   }
 

app/services/simulations/manifest.ts

@@ -66,7 +66,7 @@ const PROFILES: Record<SimulatorType, Omit<SimulatorManifestProfile, "simulatorT
     setupSections: ["participants", "futuresOdds", "bracket"],
   },
   ucl_bracket: {
-    defaultConfig: { ...BASE_CONFIG, oddsWeight: 0.3 },
+    defaultConfig: { ...BASE_CONFIG, inputPolicy: { oddsWeight: 0.3 } },
     requiredInputs: ["sourceElo"],
     optionalInputs: ["sourceOdds"],
     derivableInputs: { sourceElo: ["sourceOdds"] },
@@ -143,7 +143,7 @@ const PROFILES: Record<SimulatorType, Omit<SimulatorManifestProfile, "simulatorT
     setupSections: ["participants", "surfaceElo", "events"],
   },
   mlb_bracket: {
-    defaultConfig: { ...BASE_CONFIG, rDiffWeight: 0.7, oddsWeight: 0.3, seasonGames: 162 },
+    defaultConfig: { ...BASE_CONFIG, seasonGames: 162, inputPolicy: { oddsWeight: 0.3 } },
     requiredInputs: ["sourceElo"],
     optionalInputs: ["sourceOdds", "projectedWins"],
     derivableInputs: { sourceElo: ["projectedWins", "sourceOdds"] },
@@ -157,7 +157,7 @@ const PROFILES: Record<SimulatorType, Omit<SimulatorManifestProfile, "simulatorT
     setupSections: ["participants", "eloRatings", "regularStandings"],
   },
   world_cup: {
-    defaultConfig: { ...BASE_CONFIG, iterations: 10_000, oddsWeight: 0.3 },
+    defaultConfig: { ...BASE_CONFIG, iterations: 10_000, inputPolicy: { oddsWeight: 0.3 } },
     requiredInputs: ["sourceElo"],
     optionalInputs: ["sourceOdds", "worldRanking"],
     derivableInputs: { sourceElo: ["sourceOdds"] },
@@ -176,7 +176,7 @@ const PROFILES: Record<SimulatorType, Omit<SimulatorManifestProfile, "simulatorT
     setupSections: ["participants", "eloRatings", "rankings", "cs2Setup", "events"],
   },
   ncaa_football_bracket: {
-    defaultConfig: { ...BASE_CONFIG, bracketSize: 12, oddsWeight: 0.4 },
+    defaultConfig: { ...BASE_CONFIG, bracketSize: 12, inputPolicy: { oddsWeight: 0.4 } },
     requiredInputs: ["sourceElo"],
     optionalInputs: ["sourceOdds", "worldRanking"],
     derivableInputs: { sourceElo: ["sourceOdds"] },
@@ -189,10 +189,12 @@ const PROFILES: Record<SimulatorType, Omit<SimulatorManifestProfile, "simulatorT
     setupSections: ["participants", "futuresOdds"],
   },
   college_hockey_bracket: {
-    // College hockey already blends odds into Elo internally (and also uses NPI
-    // rank, which the central resolver can't), so the central blend is disabled
-    // (oddsWeight 0) to avoid double-counting the odds.
-    defaultConfig: { ...BASE_CONFIG, bracketSize: 16, parityFactor: 850, oddsWeight: 0 },
+    // College hockey blends odds into Elo internally (and also uses NPI rank,
+    // which the central resolver can't represent). oddsWeight 0 makes the central
+    // resolver leave a present base Elo untouched (no double-count), while still
+    // letting odds resolve a participant's Elo when they are the only source — so
+    // readiness and the sim's own internal odds blend both keep working.
+    defaultConfig: { ...BASE_CONFIG, bracketSize: 16, parityFactor: 850, inputPolicy: { oddsWeight: 0 } },
     requiredInputs: ["sourceElo"],
     optionalInputs: ["sourceOdds", "worldRanking"],
     derivableInputs: { sourceElo: ["sourceOdds"] },