add API option to return inverse price (#61)

src/main/java/org/qortal/api/resource/CrossChainResource.java

@@ -264,7 +264,12 @@ public class CrossChainResource {
 					description = "Maximum number of trades to include in price calculation",
 					example = "10",
 					schema = @Schema(type = "integer", defaultValue = "10")
-			) @QueryParam("maxtrades") Integer maxtrades) {
+			) @QueryParam("maxtrades") Integer maxtrades,
+			@Parameter(
+					description = "Display price in terms of foreign currency per unit QORT",
+					example = "false",
+					schema = @Schema(type = "boolean", defaultValue = "false")
+			) @QueryParam("inverse") Boolean inverse) {
 		// foreignBlockchain is required
 		if (foreignBlockchain == null)
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
@@ -295,7 +300,7 @@ public class CrossChainResource {
 				}
 			}
 
-			return Amounts.scaledDivide(totalQort, totalForeign);
+			return inverse ? Amounts.scaledDivide(totalForeign, totalQort) : Amounts.scaledDivide(totalQort, totalForeign);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}