From 8a69ca9f7360bdf9228ef4bb7e3f5d11df1583b5 Mon Sep 17 00:00:00 2001
From: Garrett Mills <shout@garrettmills.dev>
Date: Wed, 28 Oct 2026 22:03:45 -0500
Subject: [PATCH] Deck builder: cost tiles for unowned cards and cards in other
 decks Idea and Building decks get two more Deck analysis tiles: what the
 copies you don't own would cost, and what the owned copies other
 building/built decks are holding are worth. Both count copies, not cards.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 src/deckAnalysis.ts    | 17 ++++++++++++++---
 src/views/DeckView.tsx |  6 ++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/deckAnalysis.ts b/src/deckAnalysis.ts
index b9b8ef1..746553d 100644
--- a/src/deckAnalysis.ts
+++ b/src/deckAnalysis.ts
@@ -6,6 +6,10 @@ import { COLORS, Deck, DeckEntry, isPhysical, legalStatusFor, Partner } from "./
 /** Copies of a deck card you'd need to acquire to cover the deck. */
 export const shortBy = (e: DeckEntry) => Math.max(0, e.quantity - e.quantity_owned);
 
+/** Owned copies of a deck card you can't use because other building/built
+ *  decks claim them. */
+export const claimedElsewhere = (e: DeckEntry) => Math.max(0, Math.min(e.quantity, e.quantity_owned) - e.quantity_spare);
+
 export interface DeckStats {
   totalCards: number;
   uniqueCards: number;
@@ -14,6 +18,10 @@ export interface DeckStats {
   /** USD for every copy in the deck, commander included; cards without a
    *  known price count as $0. */
   totalCost: number;
+  /** USD for the copies you'd need to buy (see `shortBy`). */
+  unownedCost: number;
+  /** USD for the owned copies other decks are holding (see `claimedElsewhere`). */
+  elsewhereCost: number;
   curve: {
     label: string;
     count: number;
@@ -102,9 +110,10 @@ export function computeDeckStats(contents: DeckEntry[]): DeckStats {
   }
 
   // Unlike the rest, cost counts the commander: it's a card you have to buy.
-  const totalCost = contents
-    .filter((e) => !e.is_maybeboard)
-    .reduce((sum, e) => sum + e.price_usd * e.quantity, 0);
+  const mainboard = contents.filter((e) => !e.is_maybeboard);
+  const totalCost = mainboard.reduce((sum, e) => sum + e.price_usd * e.quantity, 0);
+  const unownedCost = mainboard.reduce((sum, e) => sum + e.price_usd * shortBy(e), 0);
+  const elsewhereCost = mainboard.reduce((sum, e) => sum + e.price_usd * claimedElsewhere(e), 0);
 
   return {
     totalCards,
@@ -112,6 +121,8 @@ export function computeDeckStats(contents: DeckEntry[]): DeckStats {
     landCount,
     avgManaValue,
     totalCost,
+    unownedCost,
+    elsewhereCost,
     curve,
     colorCounts,
     colorlessCount,
diff --git a/src/views/DeckView.tsx b/src/views/DeckView.tsx
index b9e6de0..b85d828 100644
--- a/src/views/DeckView.tsx
+++ b/src/views/DeckView.tsx
@@ -1299,6 +1299,12 @@ function DeckBuilder({
                 <StatTile value={deckStats.landCount} label="lands" />
                 <StatTile value={deckStats.avgManaValue.toFixed(2)} label="avg MV" />
                 <StatTile value={formatCost(deckStats.totalCost)} label="cost" />
+                {(deck.status === "idea" || deck.status === "building") && (
+                  <>
+                    <StatTile value={formatCost(deckStats.unownedCost)} label="not owned" />
+                    <StatTile value={formatCost(deckStats.elsewhereCost)} label="in other decks" />
+                  </>
+                )}
               </div>
               <div className="deck-stats-body">
                 <div className="deck-stats-numbers">