From 7b2d020128dc46553069355cb6a320698793c570 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Thu, 7 May 2020 11:48:52 +0200
Subject: [PATCH] [poincare] Unit: implement IsIS

---
 poincare/include/poincare/unit.h        |  2 ++
 poincare/src/unit.cpp                   | 30 +++++++++++++++++++++++++
 poincare/test/expression_properties.cpp | 10 +++++++--
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/poincare/include/poincare/unit.h b/poincare/include/poincare/unit.h
index e78b58905..d286d4bc6 100644
--- a/poincare/include/poincare/unit.h
+++ b/poincare/include/poincare/unit.h
@@ -766,6 +766,7 @@ public:
   static Unit Watt() { return Builder(PowerDimension, WattRepresentative, &EmptyPrefix); }
   static Expression BuildTimeSplit(double seconds, Context * context, Preferences::ComplexFormat complexFormat, Preferences::AngleUnit angleUnit);
 
+  static bool IsIS(Expression & e);
   static bool IsISSpeed(Expression & e);
   static bool IsISVolume(Expression & e);
   static bool IsISEnergy(Expression & e);
@@ -788,6 +789,7 @@ private:
   static constexpr double MonthPerYear = 12.0;
   static constexpr double DaysPerMonth = DaysPerYear/MonthPerYear;
   UnitNode * node() const { return static_cast<UnitNode *>(Expression::node()); }
+  bool isIS() const;
   static void ChooseBestMultipleForValue(Expression * units, double * value, bool tuneRepresentative, ExpressionNode::ReductionContext reductionContext);
   void chooseBestMultipleForValue(double * value, const int exponent, bool tuneRepresentative, ExpressionNode::ReductionContext reductionContext);
   Expression removeUnit(Expression * unit);
diff --git a/poincare/src/unit.cpp b/poincare/src/unit.cpp
index 769e575a3..9065a1ccc 100644
--- a/poincare/src/unit.cpp
+++ b/poincare/src/unit.cpp
@@ -408,6 +408,36 @@ bool Unit::isKilogram() const {
   return node()->dimension() == MassDimension && node()->representative() == KilogramRepresentative && node()->prefix() == &KiloPrefix;
 }
 
+bool Unit::isIS() const {
+  UnitNode * unitNode = node();
+  const Dimension * dim = unitNode->dimension();
+  const Representative * rep = unitNode->representative();
+  return rep == dim->stdRepresentative() &&
+         rep->definition() == nullptr &&
+         unitNode->prefix() == dim->stdRepresentativePrefix();
+}
+
+bool Unit::IsIS(Expression & e) {
+  if (e.type() == ExpressionNode::Type::Multiplication) {
+    for (int i = 0; i < e.numberOfChildren(); i++) {
+      Expression child = e.childAtIndex(i);
+      assert(child.type() == ExpressionNode::Type::Power || child.type() == ExpressionNode::Type::Unit);
+      if (!IsIS(child)) {
+        return false;
+      }
+    }
+    return true;
+  }
+  if (e.type() == ExpressionNode::Type::Power) {
+    assert(e.childAtIndex(1).type() == ExpressionNode::Type::Rational && e.childAtIndex(1).convert<Rational>().isInteger());
+    Expression child = e.childAtIndex(0);
+    assert(child.type() == ExpressionNode::Type::Unit);
+    return IsIS(child);
+  }
+  assert(e.type() == ExpressionNode::Type::Unit);
+  return static_cast<Unit &>(e).isIS();
+}
+
 bool Unit::IsISSpeed(Expression & e) {
   // Form m*s^-1
   return e.type() == ExpressionNode::Type::Multiplication && e.numberOfChildren() == 2 &&
diff --git a/poincare/test/expression_properties.cpp b/poincare/test/expression_properties.cpp
index 03074eb3e..e2b0133f2 100644
--- a/poincare/test/expression_properties.cpp
+++ b/poincare/test/expression_properties.cpp
@@ -400,7 +400,7 @@ void assert_seconds_split_to(double totalSeconds, const char * splittedTime, Con
 
 Expression extract_unit(const char * expression) {
   Shared::GlobalContext globalContext;
-  ExpressionNode::ReductionContext reductionContext = ExpressionNode::ReductionContext(&globalContext, Cartesian, Degree, User);
+  ExpressionNode::ReductionContext reductionContext = ExpressionNode::ReductionContext(&globalContext, Cartesian, Degree, User, ReplaceAllSymbolsWithUndefined, NoUnitConversion);
   Expression e = parse_expression(expression, &globalContext, false).reduce(reductionContext);
   Expression unit;
   e.removeUnit(&unit);
@@ -428,5 +428,11 @@ QUIZ_CASE(poincare_expression_unit_helper) {
   // 4. Energy
   Expression kilogramMeter2PerSecond2 = extract_unit("_kg×_m^2×_s^-2");
   quiz_assert(Unit::IsISEnergy(kilogramMeter2PerSecond2));
-}
 
+  // 5. International System
+  quiz_assert(Unit::IsIS(kilogramMeter2PerSecond2));
+  quiz_assert(Unit::IsIS(meter3));
+  quiz_assert(Unit::IsIS(meterPerSecond));
+  Expression joule = extract_unit("_J");
+  quiz_assert(!Unit::IsIS(joule));
+}