[Base]retrieve unit text

Co-authored-by: Chris Hennes <chennes@pioneerlibrarysystem.org>

src/Base/UnitsApi.cpp

@@ -66,6 +66,11 @@ std::string UnitsApi::getBasicLengthUnit()
     return schemas->currentSchema()->getBasicLengthUnit();
 }
 
+std::string UnitsApi::getUnitText(const Quantity& quant)
+{
+    return schemas->currentSchema()->getUnitText(quant);
+}
+
 void UnitsApi::setDecimals(const int prec)
 {
     decimals = prec;

src/Base/UnitsApi.h

@@ -68,6 +68,7 @@ public:
     static bool isMultiUnitAngle();
     static bool isMultiUnitLength();
     static std::string getBasicLengthUnit();
+    static std::string getUnitText(const Quantity& quant);
 
     static std::size_t getDefSchemaNum()
     {

src/Base/UnitsSchema.cpp

@@ -35,6 +35,8 @@
 #include "Exception.h"
 #include "Quantity.h"
 
+#include "Console.h"
+
 using Base::UnitsSchema;
 using Base::UnitsSchemaSpec;
 
@@ -143,3 +145,34 @@ int UnitsSchema::getNum() const
 {
     return static_cast<int>(spec.num);
 }
+
+
+//! return the unit text for this quantity in this schema. ex 10 mm => "mm"
+//! a more general approach than getBasicLengthUnit.
+//! TODO: some common code here with translate()
+std::string UnitsSchema::getUnitText(const Base::Quantity& quant) const
+{
+    std::string typeString = quant.getUnit().getTypeString();  // "Area", "Mass", ...
+    const auto value = quant.getValue();
+
+    // TODO: some common code here with translate()
+    if (!spec.translationSpecs.contains(typeString)) {
+        Base::Console().log("Schema %s has no entry for %s\n",
+                            getName().c_str(),
+                            typeString.c_str());
+        return {};
+    }
+    auto unitSpecs = spec.translationSpecs.at(typeString);
+
+    auto isSuitable = [&](const UnitTranslationSpec& row) {
+        return row.threshold > value || row.threshold == 0;
+    };
+
+    const auto unitSpec = std::ranges::find_if(unitSpecs, isSuitable);
+    if (unitSpec == unitSpecs.end()) {
+        throw RuntimeError("Suitable threshold not found (2). Schema: " + spec.name
+                           + " value: " + std::to_string(value));
+    }
+
+    return unitSpec->unitString;
+}

src/Base/UnitsSchema.h

@@ -50,6 +50,7 @@ public:
     [[nodiscard]] std::string getName() const;
     [[nodiscard]] std::string getDescription() const;
     [[nodiscard]] int getNum() const;
+    [[nodiscard]] std::string getUnitText(const Quantity& quant) const;
 
     std::string translate(const Quantity& quant) const;
     std::string translate(const Quantity& quant, double& factor, std::string& unitString) const;