From 72ca258d06c51e55c9fa5983bb11186250eb24b0 Mon Sep 17 00:00:00 2001
From: Adrien Hopkins <adrien.p.hopkins@gmail.com>
Date: Fri, 16 Aug 2024 18:13:16 -0500
Subject: Allow named unit-sets to be used as to expression

---
 src/main/java/sevenUnitsGUI/Presenter.java | 39 +++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

(limited to 'src/main/java/sevenUnitsGUI/Presenter.java')

diff --git a/src/main/java/sevenUnitsGUI/Presenter.java b/src/main/java/sevenUnitsGUI/Presenter.java
index 4512e01..f085dba 100644
--- a/src/main/java/sevenUnitsGUI/Presenter.java
+++ b/src/main/java/sevenUnitsGUI/Presenter.java
@@ -400,7 +400,10 @@ public final class Presenter {
 			}
 			
 			final Optional<UnitConversionRecord> uc;
-			if (toExpression.contains(";")) {
+			if (this.database.containsUnitSetName(toExpression)) {
+				uc = this.convertExpressionToNamedMultiUnit(fromExpression,
+						toExpression);
+			} else if (toExpression.contains(";")) {
 				final String[] toExpressions = toExpression.split(";");
 				uc = this.convertExpressionToMultiUnit(fromExpression,
 						toExpressions);
@@ -523,6 +526,40 @@ public final class Presenter {
 				UnitConversionRecord.valueOf(fromExpression, toExpression, "", ""));
 	}
 	
+	/**
+	 * Convert an expression to a MultiUnit with a name from the database. If an
+	 * error happened, it is shown to the view and Optional.empty() is returned.
+	 *
+	 * @since 2024-08-15
+	 */
+	private Optional<UnitConversionRecord> convertExpressionToNamedMultiUnit(
+			String fromExpression, String toName) {
+		final LinearUnitValue from;
+		try {
+			from = this.database.evaluateUnitExpression(fromExpression);
+		} catch (final IllegalArgumentException | NoSuchElementException e) {
+			this.view.showErrorMessage("Parse Error",
+					"Could not recognize text in From entry: " + e.getMessage());
+			return Optional.empty();
+		}
+		
+		final List<LinearUnit> toUnits = this.database.getUnitSet(toName);
+		final List<LinearUnitValue> toValues;
+		try {
+			toValues = from.convertToMultiple(toUnits);
+		} catch (final IllegalArgumentException e) {
+			this.view.showErrorMessage("Unit Error",
+					"Invalid units separated by ';': " + e.getMessage());
+			return Optional.empty();
+		}
+		
+		final String toExpression = toValues.stream().map(
+				v -> this.numberDisplayRule.apply(v.getValue()) + " " + v.getUnit())
+				.collect(Collectors.joining(" + "));
+		return Optional.of(
+				UnitConversionRecord.valueOf(fromExpression, toExpression, "", ""));
+	}
+	
 	/**
 	 * Converts from the view's input unit to its output unit. Displays an error
 	 * message if any of the required fields are invalid.
-- 
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