2 files changed, 127 insertions, 6 deletions

diff --git a/src/openvic-simulation/misc/Modifier.cpp b/src/openvic-simulation/misc/Modifier.cpp
index e201fdd..333bb20 100644
--- a/src/openvic-simulation/misc/Modifier.cpp
+++ b/src/openvic-simulation/misc/Modifier.cpp
@@ -49,7 +49,7 @@ bool ModifierValue::empty() const {
 	return values.empty();
 }
 
-fixed_point_t ModifierValue::get_effect(ModifierEffect const* effect, bool* successful) {
+fixed_point_t ModifierValue::get_effect(ModifierEffect const* effect, bool* successful) const {
 	const effect_map_t::const_iterator it = values.find(effect);
 	if (it != values.end()) {
 		if (successful != nullptr) {
@@ -67,6 +67,14 @@ bool ModifierValue::has_effect(ModifierEffect const* effect) const {
 	return values.contains(effect);
 }
 
+void ModifierValue::set_effect(ModifierEffect const* effect, fixed_point_t value) {
+	if (effect != nullptr) {
+		values[effect] = value;
+	} else {
+		Logger::error("Tried to set null modifier effect on ModifierValue!");
+	}
+}
+
 ModifierValue& ModifierValue::operator+=(ModifierValue const& right) {
 	for (effect_map_t::value_type const& value : right.values) {
 		values[value.first] += value.second;
@@ -99,6 +107,32 @@ ModifierValue ModifierValue::operator-(ModifierValue const& right) const {
 	return ret -= right;
 }
 
+ModifierValue& ModifierValue::operator*=(fixed_point_t const& right) {
+	for (auto value : mutable_iterator(values)) {
+		value.second *= right;
+	}
+	return *this;
+}
+
+ModifierValue ModifierValue::operator*(fixed_point_t const& right) const {
+	ModifierValue ret = *this;
+	return ret *= right;
+}
+
+fixed_point_t& ModifierValue::operator[](ModifierEffect const* effect) {
+	return values[effect];
+}
+
+void ModifierValue::multiply_add(ModifierValue const& other, fixed_point_t multiplier) {
+	if (multiplier == fixed_point_t::_1()) {
+		*this += other;
+	} else if (multiplier != fixed_point_t::_0()) {
+		for (effect_map_t::value_type const& value : other.values) {
+			values[value.first] += value.second * multiplier;
+		}
+	}
+}
+
 Modifier::Modifier(std::string_view new_identifier, ModifierValue&& new_values, icon_t new_icon)
 	: HasIdentifier { new_identifier }, ModifierValue { std::move(new_values) }, icon { new_icon } {}
 
@@ -110,8 +144,63 @@ bool TriggeredModifier::parse_scripts(DefinitionManager const& definition_manage
 	return trigger.parse_script(false, definition_manager);
 }
 
-ModifierInstance::ModifierInstance(Modifier const& modifier, Date expiry_date)
-	: modifier { modifier }, expiry_date { expiry_date } {}
+ModifierInstance::ModifierInstance(Modifier const& new_modifier, Date new_expiry_date)
+	: modifier { &new_modifier }, expiry_date { new_expiry_date } {}
+
+void ModifierSum::clear() {
+	modifiers.clear();
+	value_sum.clear();
+}
+
+bool ModifierSum::empty() {
+	return modifiers.empty();
+}
+
+fixed_point_t ModifierSum::get_effect(ModifierEffect const* effect, bool* successful) const {
+	return value_sum.get_effect(effect, successful);
+}
+
+bool ModifierSum::has_effect(ModifierEffect const* effect) const {
+	return value_sum.has_effect(effect);
+}
+
+void ModifierSum::add_modifier(Modifier const& modifier, fixed_point_t multiplier) {
+	modifiers[&modifier] += multiplier;
+	value_sum.multiply_add(modifier, multiplier);
+}
+
+void ModifierSum::add_modifier_sum(ModifierSum const& modifier_sum) {
+	modifiers += modifier_sum.modifiers;
+	value_sum += modifier_sum.value_sum;
+}
+
+ModifierSum& ModifierSum::operator+=(Modifier const& modifier) {
+	add_modifier(modifier);
+	return *this;
+}
+
+ModifierSum& ModifierSum::operator+=(ModifierSum const& modifier_sum) {
+	add_modifier_sum(modifier_sum);
+	return *this;
+}
+
+// TODO - include value_sum[effect] in result? Early return if lookup in value_sum fails?
+std::vector<std::pair<Modifier const*, fixed_point_t>> ModifierSum::get_contributing_modifiers(
+	ModifierEffect const* effect
+) const {
+	std::vector<std::pair<Modifier const*, fixed_point_t>> ret;
+
+	for (auto const& [modifier, multiplier] : modifiers) {
+		bool successful = false;
+		const fixed_point_t value = modifier->get_effect(effect, &successful);
+
+		if (successful) {
+			ret.emplace_back(modifier, value * multiplier);
+		}
+	}
+
+	return ret;
+}
 
 bool ModifierManager::add_modifier_effect(
 	std::string_view identifier, bool positive_good, ModifierEffect::format_t format, std::string_view localisation_key
diff --git a/src/openvic-simulation/misc/Modifier.hpp b/src/openvic-simulation/misc/Modifier.hpp
index f3cc0f6..c36585f 100644
--- a/src/openvic-simulation/misc/Modifier.hpp
+++ b/src/openvic-simulation/misc/Modifier.hpp
@@ -57,14 +57,21 @@ namespace OpenVic {
 		void clear();
 		bool empty() const;
 
-		fixed_point_t get_effect(ModifierEffect const* effect, bool* successful = nullptr);
+		fixed_point_t get_effect(ModifierEffect const* effect, bool* successful = nullptr) const;
 		bool has_effect(ModifierEffect const* effect) const;
+		void set_effect(ModifierEffect const* effect, fixed_point_t value);
 
 		ModifierValue& operator+=(ModifierValue const& right);
 		ModifierValue operator+(ModifierValue const& right) const;
 		ModifierValue operator-() const;
 		ModifierValue& operator-=(ModifierValue const& right);
 		ModifierValue operator-(ModifierValue const& right) const;
+		ModifierValue& operator*=(fixed_point_t const& right);
+		ModifierValue operator*(fixed_point_t const& right) const;
+
+		fixed_point_t& operator[](ModifierEffect const* effect);
+
+		void multiply_add(ModifierValue const& other, fixed_point_t multiplier);
 
 		friend std::ostream& operator<<(std::ostream& stream, ModifierValue const& value);
 	};
@@ -105,10 +112,35 @@ namespace OpenVic {
 	struct ModifierInstance {
 
 	private:
-		Modifier const& PROPERTY(modifier);
+		Modifier const* PROPERTY(modifier); // We can assume this is never null
 		Date PROPERTY(expiry_date);
 
-		ModifierInstance(Modifier const& modifier, Date expiry_date);
+	public:
+		ModifierInstance(Modifier const& new_modifier, Date new_expiry_date);
+	};
+
+	struct ModifierSum {
+	private:
+		fixed_point_map_t<Modifier const*> PROPERTY(modifiers);
+		ModifierValue PROPERTY(value_sum);
+
+	public:
+		ModifierSum() = default;
+		ModifierSum(ModifierSum&&) = default;
+
+		void clear();
+		bool empty();
+
+		fixed_point_t get_effect(ModifierEffect const* effect, bool* successful = nullptr) const;
+		bool has_effect(ModifierEffect const* effect) const;
+
+		void add_modifier(Modifier const& modifier, fixed_point_t multiplier = fixed_point_t::_1());
+		void add_modifier_sum(ModifierSum const& modifier_sum);
+
+		ModifierSum& operator+=(Modifier const& modifier);
+		ModifierSum& operator+=(ModifierSum const& modifier_sum);
+
+		std::vector<std::pair<Modifier const*, fixed_point_t>> get_contributing_modifiers(ModifierEffect const* effect) const;
 	};
 
 	template<typename Fn>