Add buys query table from exchange_to_wallet events

Denormalized read table with id, event_id, occurred_at, wallet, sats,
fee_sats, and amount_eur. Projected on event creation and rebuildable
via POST /api/buys/rebuild. Fiat amounts converted to EUR using
Frankfurter rates.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

resources/migrations/20260316000000-create-buys.down.sql

@@ -0,0 +1 @@
+DROP TABLE IF EXISTS buys;

resources/migrations/20260316000000-create-buys.up.sql

@@ -0,0 +1,7 @@
+CREATE TABLE buys (
+  id          BIGSERIAL PRIMARY KEY,
+  event_id    BIGINT NOT NULL REFERENCES events(id) UNIQUE,
+  occurred_at DATE NOT NULL,
+  wallet      TEXT NOT NULL,
+  amount_eur  NUMERIC(18,2) NOT NULL
+);

resources/migrations/20260316100000-buys-add-sats.down.sql

@@ -0,0 +1,3 @@
+ALTER TABLE buys DROP COLUMN fee_sats;
+--;;
+ALTER TABLE buys DROP COLUMN sats;

resources/migrations/20260316100000-buys-add-sats.up.sql

@@ -0,0 +1,3 @@
+ALTER TABLE buys ADD COLUMN sats BIGINT NOT NULL DEFAULT 0;
+--;;
+ALTER TABLE buys ADD COLUMN fee_sats BIGINT;

resources/queries.sql

@@ -155,6 +155,30 @@ SELECT id, event_id, occurred_at, exchange, fiat_amount, fiat_currency,
 FROM deposits
 ORDER BY occurred_at DESC, id DESC
 
+-- :name truncate-buys! :! :n
+-- :doc Delete all rows from the buys read table
+TRUNCATE buys
+
+-- :name get-buy-events :? :*
+-- :doc Get exchange_to_wallet events with wallet name, oldest first
+SELECT e.id, e.occurred_at, e.sats, e.fee_sats, e.fiat_amount, e.fiat_currency,
+       e.to_wallet_id, tw.name AS wallet
+FROM events e
+LEFT JOIN wallets tw ON tw.id = e.to_wallet_id
+WHERE e.event_type = 'exchange_to_wallet'
+ORDER BY e.occurred_at ASC, e.id ASC
+
+-- :name insert-buy! :! :n
+-- :doc Insert a projected buy row
+INSERT INTO buys (event_id, occurred_at, wallet, sats, fee_sats, amount_eur)
+VALUES (:event-id, :occurred-at, :wallet, :sats, :fee-sats, :amount-eur)
+
+-- :name get-all-buys :? :*
+-- :doc Get all projected buys ordered by date descending
+SELECT id, event_id, occurred_at, wallet, sats, fee_sats, amount_eur
+FROM buys
+ORDER BY occurred_at DESC, id DESC
+
 -- :name get-kraken-hour-latest-24 :? :*
 -- :doc Get the 24 most recent Kraken hourly candles
 SELECT ts, open, high, low, close, vwap, volume, trade_count, created_at

src/clj/pmagnus/btcdata/web/controllers/transactions.clj

@@ -69,6 +69,29 @@
     (catch Exception e
       (log/error e "Failed to project deposit for event" event-id))))
 
+(defn- project-buy!
+  "Project an exchange_to_wallet event into the buys read table."
+  [{:keys [query-fn frankfurter]} event-id occurred-at to-wallet-id sats fee-sats fiat-amount fiat-currency]
+  (try
+    (let [wallet-name (or (:name (query-fn :get-wallet-by-id {:id to-wallet-id})) "Unknown")
+          amount-eur  (if (= fiat-currency "EUR")
+                        (bigdec fiat-amount)
+                        (let [rates (or (query-fn :get-currency-rates-by-date {:rate-date occurred-at})
+                                        (rates/fetch-and-persist-for-date!
+                                          (:client frankfurter) (:url frankfurter)
+                                          query-fn occurred-at))]
+                          (:amount-eur (convert-amount fiat-amount fiat-currency rates))))]
+      (when amount-eur
+        (query-fn :insert-buy!
+                  {:event-id    event-id
+                   :occurred-at occurred-at
+                   :wallet      wallet-name
+                   :sats        (or sats 0)
+                   :fee-sats    fee-sats
+                   :amount-eur  amount-eur})))
+    (catch Exception e
+      (log/error e "Failed to project buy for event" event-id))))
+
 (defn create-event! [{:keys [query-fn] :as opts} req]
   (let [params (:body-params req)
         event-type (:event_type params)]
@@ -93,6 +116,13 @@
                             (:fiat_amount params)
                             (:fiat_currency params)
                             (:note params)))
+        (when (and (= event-type "exchange_to_wallet") (:fiat_amount params))
+          (project-buy! opts (:id result) occurred-at
+                         (some-> (:to_wallet_id params) UUID/fromString)
+                         (:sats params)
+                         (:fee_sats params)
+                         (:fiat_amount params)
+                         (:fiat_currency params)))
         (response/created "/api/events" {:status "ok"})))))
 
 (defn list-deposits [{:keys [query-fn]} _req]
@@ -128,6 +158,40 @@
                  0 events)]
     (response/ok {:rebuilt n})))
 
+(defn list-buys [{:keys [query-fn]} _req]
+  (response/ok (query-fn :get-all-buys {})))
+
+(defn rebuild-buys! [{:keys [query-fn frankfurter]} _req]
+  (query-fn :truncate-buys! {})
+  (let [events (query-fn :get-buy-events {})
+        n      (reduce
+                 (fn [cnt {:keys [id occurred_at sats fee_sats fiat_amount fiat_currency wallet]}]
+                   (if-not fiat_amount
+                     cnt
+                     (try
+                       (let [amount-eur
+                             (if (= fiat_currency "EUR")
+                               (bigdec fiat_amount)
+                               (let [rates (or (query-fn :get-currency-rates-by-date {:rate-date occurred_at})
+                                               (rates/fetch-and-persist-for-date!
+                                                 (:client frankfurter) (:url frankfurter)
+                                                 query-fn occurred_at))]
+                                 (:amount-eur (convert-amount fiat_amount fiat_currency rates))))]
+                         (when amount-eur
+                           (query-fn :insert-buy!
+                                     {:event-id    id
+                                      :occurred-at occurred_at
+                                      :wallet      (or wallet "Unknown")
+                                      :sats        (or sats 0)
+                                      :fee-sats    fee_sats
+                                      :amount-eur  amount-eur}))
+                         (inc cnt))
+                       (catch Exception e
+                         (log/error e "Failed to rebuild buy for event" id)
+                         cnt))))
+                 0 events)]
+    (response/ok {:rebuilt n})))
+
 (defn list-events [{:keys [query-fn]} req]
   (let [event-type (get-in req [:query-params "type"])]
     (if event-type

src/clj/pmagnus/btcdata/web/routes/api.clj

@@ -202,6 +202,10 @@
     {:get (fn [req] (tx/list-deposits opts req))}]
    ["/deposits/rebuild"
     {:post (fn [req] (tx/rebuild-deposits! opts req))}]
+   ["/buys"
+    {:get (fn [req] (tx/list-buys opts req))}]
+   ["/buys/rebuild"
+    {:post (fn [req] (tx/rebuild-buys! opts req))}]
    ["/kraken-hour"
     {:get (fn [req] (kraken-hour-handler opts req))}]
    ["/kraken-minute"