Rename Option/Account to Market/Ledger, add Result-based error handling

Split GuessMarketContext into a separate CatalogContext for read-only
event listing, wrap fallible operations in Result<T> instead of throwing,
and wire load/save of events and users through a JSON Wrapper.

9 files changed, 75 insertions, 25 deletions

diff --git a/api/src/main/java/market/guess/api/CatalogContext.java b/api/src/main/java/market/guess/api/CatalogContext.java
new file mode 100644
index 0000000..7e80042
--- /dev/null
+++ b/api/src/main/java/market/guess/api/CatalogContext.java
@@ -0,0 +1,12 @@
+package market.guess.api;
+
+import java.nio.file.Path;
+import java.util.List;
+
+public interface CatalogContext {
+  Result<LoadResultDTO> loadEvents(Path path);
+
+  Result<List<EventSummaryDTO>> getAllEvents();
+
+  Result<EventDetailDTO> getEvent(String eventKey);
+}
diff --git a/api/src/main/java/market/guess/api/EventStatus.java b/api/src/main/java/market/guess/api/EventStatus.java
index acd7542..6580157 100644
--- a/api/src/main/java/market/guess/api/EventStatus.java
+++ b/api/src/main/java/market/guess/api/EventStatus.java
@@ -1,7 +1,7 @@
 package market.guess.api;
 
 public enum EventStatus {
-  NOT_STARTED,
+  DRAFT,
   ACTIVE,
-  CLOSED
+  SETTLED
 }
diff --git a/api/src/main/java/market/guess/api/EventSummaryDTO.java b/api/src/main/java/market/guess/api/EventSummaryDTO.java
index 361656b..d185103 100644
--- a/api/src/main/java/market/guess/api/EventSummaryDTO.java
+++ b/api/src/main/java/market/guess/api/EventSummaryDTO.java
@@ -3,7 +3,7 @@ package market.guess.api;
 import java.util.List;
 
 public record EventSummaryDTO(
-    String eventKey,
+    String key,
     int displayId,
     String name,
     String description,
diff --git a/api/src/main/java/market/guess/api/GuessMarketContext.java b/api/src/main/java/market/guess/api/GuessMarketContext.java
index d959de6..4eee37e 100644
--- a/api/src/main/java/market/guess/api/GuessMarketContext.java
+++ b/api/src/main/java/market/guess/api/GuessMarketContext.java
@@ -1,27 +1,16 @@
 package market.guess.api;
 
 import java.nio.file.Path;
-import java.util.List;
-import market.guess.exception.GuessMarketException;
 
 public interface GuessMarketContext {
-  LoadResultDTO loadEvents(Path path);
+  Result<PurchaseReceiptDTO> buyShares(
+      String userName, String eventKey, String optionKey, int quantity);
 
-  List<EventSummaryDTO> listEvents();
+  Result<EventDetailDTO> closeEvent(String userName, String eventKey, String winningOptionKey);
 
-  boolean isLoaded();
+  Result<AccountDTO> account(String userName);
 
-  EventDetailDTO getEvent(String eventKey);
+  Result<Void> saveState(Path path);
 
-  PurchaseReceiptDTO buyShares(String userName, String eventKey, String optionKey, int quantity)
-      throws GuessMarketException;
-
-  EventDetailDTO closeEvent(String userName, String eventKey, String winningOptionKey)
-      throws GuessMarketException;
-
-  AccountDTO account(String userName);
-
-  void saveState(Path path) throws GuessMarketException;
-
-  LoadResultDTO restoreState(Path path);
+  Result<LoadResultDTO> restoreState(Path path);
 }
diff --git a/api/src/main/java/market/guess/api/MarketDTO.java b/api/src/main/java/market/guess/api/MarketDTO.java
new file mode 100644
index 0000000..b7c48a2
--- /dev/null
+++ b/api/src/main/java/market/guess/api/MarketDTO.java
@@ -0,0 +1,3 @@
+package market.guess.api;
+
+public record MarketDTO(String key, String name, String price, String volume) {}
diff --git a/api/src/main/java/market/guess/api/MarketStateDTO.java b/api/src/main/java/market/guess/api/MarketStateDTO.java
index f49b2aa..1f7e79b 100644
--- a/api/src/main/java/market/guess/api/MarketStateDTO.java
+++ b/api/src/main/java/market/guess/api/MarketStateDTO.java
@@ -5,6 +5,6 @@ import java.util.List;
 public record MarketStateDTO(
     String eventKey,
     MechanismType mechanism,
-    List<OptionStateDTO> options,
+    List<MarketDTO> markets,
     String accountBalance,
     String commissionCollected) {}
diff --git a/api/src/main/java/market/guess/api/OptionStateDTO.java b/api/src/main/java/market/guess/api/OptionStateDTO.java
deleted file mode 100644
index c002fdd..0000000
--- a/api/src/main/java/market/guess/api/OptionStateDTO.java
+++ /dev/null
@@ -1,3 +0,0 @@
-package market.guess.api;
-
-public record OptionStateDTO(String optionKey, String name, String price, long sharesOutstanding) {}
diff --git a/api/src/main/java/market/guess/api/Result.java b/api/src/main/java/market/guess/api/Result.java
new file mode 100644
index 0000000..15ac5db
--- /dev/null
+++ b/api/src/main/java/market/guess/api/Result.java
@@ -0,0 +1,49 @@
+package market.guess.api;
+
+import java.time.Instant;
+
+public final class Result<T> {
+  private final boolean success;
+  private final String message;
+  private final T data;
+  private final Instant timeStamp;
+
+  private Result(boolean success, String message, T data) {
+    this.success = success;
+    this.message = message;
+    this.data = data;
+    this.timeStamp = Instant.now();
+  }
+
+  public static <T> Result<T> ok() {
+    return new Result<T>(true, "Operation successful", null);
+  }
+
+  public static <T> Result<T> ok(T data) {
+    return new Result<>(true, "Operation successful", data);
+  }
+
+  public static <T> Result<T> error(String message, T data) {
+    return new Result<>(false, message, data);
+  }
+
+  public static <T> Result<T> error(String message) {
+    return new Result<>(false, message, null);
+  }
+
+  public boolean isSuccess() {
+    return success;
+  }
+
+  public String getMessage() {
+    return message;
+  }
+
+  public T getData() {
+    return data;
+  }
+
+  public Instant getTimestamp() {
+    return timeStamp;
+  }
+}
diff --git a/api/src/main/java/market/guess/api/TradeRowDTO.java b/api/src/main/java/market/guess/api/TradeRowDTO.java
index 7331bb1..68d159a 100644
--- a/api/src/main/java/market/guess/api/TradeRowDTO.java
+++ b/api/src/main/java/market/guess/api/TradeRowDTO.java
@@ -1,4 +1,4 @@
 package market.guess.api;
 
 public record TradeRowDTO(
-    String at, String userName, String optionName, long quantity, String pricePaid) {}
+    String at, String userName, String optionName, String quantity, String pricePaid) {}