Fix map connections.

Since map constants can be inferred from map names, but not the other
way around, create a mapping between map constants and map names and use
that to find the connected map.

map.cpp

@@ -4,6 +4,7 @@
 #include <QDebug>
 #include <QPainter>
 #include <QImage>
+#include <QRegularExpression>
 
 Map::Map(QObject *parent) : QObject(parent)
 {
@@ -16,6 +17,24 @@ Map::Map(QObject *parent) : QObject(parent)
     paint_elevation = 3;
 }
 
+void Map::setName(QString mapName) {
+    name = mapName;
+    constantName = mapConstantFromName(mapName);
+}
+
+QString Map::mapConstantFromName(QString mapName) {
+    // Transform map names of the form 'GraniteCave_B1F` into map constants like 'MAP_GRANITE_CAVE_B1F'.
+    QString nameWithUnderscores = mapName.replace(QRegularExpression("([a-z])([A-Z])"), "\\1_\\2");
+    QString withMapAndUppercase = "MAP_" + nameWithUnderscores.toUpper();
+    QString constantName = withMapAndUppercase.replace(QRegularExpression("_+"), "_");
+
+    // Handle special cases.
+    // SSTidal needs to be SS_TIDAL, rather than SSTIDAL
+    constantName = constantName.replace("SSTIDAL", "SS_TIDAL");
+
+    return constantName;
+}
+
 int Map::getWidth() {
     return width.toInt(nullptr, 0);
 }