Implemented expression conversion, tests now pass

1 files changed, 56 insertions, 21 deletions

diff --git a/src/main/java/sevenUnitsGUI/Presenter.java b/src/main/java/sevenUnitsGUI/Presenter.java
index be02364..57d353d 100644
--- a/src/main/java/sevenUnitsGUI/Presenter.java
+++ b/src/main/java/sevenUnitsGUI/Presenter.java
@@ -23,6 +23,7 @@ import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.Optional;
 import java.util.OptionalDouble;
 import java.util.Scanner;
@@ -34,6 +35,7 @@ import java.util.stream.Collectors;
 import sevenUnits.ProgramInfo;
 import sevenUnits.unit.BaseDimension;
 import sevenUnits.unit.BritishImperial;
+import sevenUnits.unit.LinearUnitValue;
 import sevenUnits.unit.Metric;
 import sevenUnits.unit.Unit;
 import sevenUnits.unit.UnitDatabase;
@@ -170,7 +172,7 @@ public final class Presenter {
 	/**
 	 * The database that this presenter communicates with (effectively the model)
 	 */
-	private final UnitDatabase database;
+	final UnitDatabase database;
 	
 	/**
 	 * The rule used for parsing input numbers. Any number-string inputted into
@@ -274,7 +276,58 @@ public final class Presenter {
 	 *                                       {@link ExpressionConversionView})
 	 * @since 2021-12-15
 	 */
-	public void convertExpressions() {}
+	public void convertExpressions() {
+		if (this.view instanceof ExpressionConversionView) {
+			final ExpressionConversionView xcview = (ExpressionConversionView) this.view;
+			
+			final String fromExpression = xcview.getFromExpression();
+			final String toExpression = xcview.getToExpression();
+			
+			// expressions must not be empty
+			if (fromExpression.isEmpty()) {
+				this.view.showErrorMessage("Parse Error",
+						"Please enter a unit expression in the From: box.");
+				return;
+			}
+			if (toExpression.isEmpty()) {
+				this.view.showErrorMessage("Parse Error",
+						"Please enter a unit expression in the To: box.");
+				return;
+			}
+			
+			// evaluate expressions
+			final LinearUnitValue from;
+			final Unit to;
+			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;
+			}
+			try {
+				to = this.database.getUnitFromExpression(toExpression);
+			} catch (final IllegalArgumentException | NoSuchElementException e) {
+				this.view.showErrorMessage("Parse Error",
+						"Could not recognize text in To entry: " + e.getMessage());
+				return;
+			}
+			
+			// convert and show output
+			if (from.getUnit().canConvertTo(to)) {
+				final double value = from.asUnitValue().convertTo(to).getValue();
+				xcview.showExpressionConversionOutput(fromExpression, toExpression,
+						value);
+			} else {
+				this.view.showErrorMessage("Conversion Error",
+						"Cannot convert between \"" + fromExpression + "\" and \""
+								+ toExpression + "\".");
+			}
+			
+		} else
+			throw new UnsupportedOperationException(
+					"This function can only be called when the view is an ExpressionConversionView");
+	}
 	
 	/**
 	 * Converts from the view's input unit to its output unit. Displays an error
@@ -326,8 +379,7 @@ public final class Presenter {
 			// convert!
 			final UnitValue initialValue = UnitValue.of(fromUnit, value);
 			final UnitValue converted = initialValue.convertTo(toUnit);
-			ucview.showUnitConversionOutput(
-					String.format("%s = %s", initialValue, converted));
+			ucview.showUnitConversionOutput(initialValue, converted);
 		} else
 			throw new UnsupportedOperationException(
 					"This function can only be called when the view is a UnitConversionView.");
@@ -365,23 +417,6 @@ public final class Presenter {
 	 */
 	public void saveSettings() {}
 	
-	/**
-	 * Returns true if and only if the unit represented by {@code unitName} has
-	 * the dimension represented by {@code dimensionName}.
-	 * 
-	 * @param unitName      name of unit to test
-	 * @param dimensionName name of dimension to test
-	 * @return whether unit has dimenision
-	 * @since 2019-04-13
-	 * @since v0.2.0
-	 */
-	boolean unitMatchesDimension(String unitName, String dimensionName) {
-		final Unit unit = this.database.getUnit(unitName);
-		final ObjectProduct<BaseDimension> dimension = this.database
-				.getDimension(dimensionName);
-		return unit.getDimension().equals(dimension);
-	}
-	
 	void unitNameSelected() {}
 	
 	/**