4 files changed, 81 insertions, 0 deletions
diff --git a/src/openvic-simulation/map/MapInstance.cpp b/src/openvic-simulation/map/MapInstance.cpp
index 0ce8cea..d8ec2fb 100644
--- a/src/openvic-simulation/map/MapInstance.cpp
+++ b/src/openvic-simulation/map/MapInstance.cpp
@@ -118,6 +118,12 @@ bool MapInstance::apply_history_to_provinces(
 	return ret;
 }
 
+void MapInstance::update_modifier_sums(Date today, StaticModifierCache const& static_modifier_cache) {
+	for (ProvinceInstance& province : province_instances.get_items()) {
+		province.update_modifier_sum(today, static_modifier_cache);
+	}
+}
+
 void MapInstance::update_gamestate(Date today, DefineManager const& define_manager) {
 	for (ProvinceInstance& province : province_instances.get_items()) {
 		province.update_gamestate(today, define_manager);
diff --git a/src/openvic-simulation/map/MapInstance.hpp b/src/openvic-simulation/map/MapInstance.hpp
index 99c13d3..e7c623e 100644
--- a/src/openvic-simulation/map/MapInstance.hpp
+++ b/src/openvic-simulation/map/MapInstance.hpp
@@ -52,6 +52,7 @@ namespace OpenVic {
 			IssueManager const& issue_manager
 		);
 
+		void update_modifier_sums(Date today, StaticModifierCache const& static_modifier_cache);
 		void update_gamestate(Date today, DefineManager const& define_manager);
 		void tick(Date today);
 	};
diff --git a/src/openvic-simulation/map/ProvinceInstance.cpp b/src/openvic-simulation/map/ProvinceInstance.cpp
index 06b3f1e..e85c576 100644
--- a/src/openvic-simulation/map/ProvinceInstance.cpp
+++ b/src/openvic-simulation/map/ProvinceInstance.cpp
@@ -2,7 +2,10 @@
 
 #include "openvic-simulation/country/CountryInstance.hpp"
 #include "openvic-simulation/history/ProvinceHistory.hpp"
+#include "openvic-simulation/map/Crime.hpp"
 #include "openvic-simulation/map/ProvinceDefinition.hpp"
+#include "openvic-simulation/map/Region.hpp"
+#include "openvic-simulation/map/TerrainType.hpp"
 #include "openvic-simulation/military/UnitInstanceGroup.hpp"
 #include "openvic-simulation/misc/Define.hpp"
 #include "openvic-simulation/politics/Ideology.hpp"
@@ -21,6 +24,8 @@ ProvinceInstance::ProvinceInstance(
 	owner { nullptr },
 	controller { nullptr },
 	cores {},
+	modifier_sum {},
+	event_modifiers {},
 	slave { false },
 	crime { nullptr },
 	rgo { nullptr },
@@ -185,6 +190,65 @@ void ProvinceInstance::_update_pops(DefineManager const& define_manager) {
 	}
 }
 
+void ProvinceInstance::update_modifier_sum(Date today, StaticModifierCache const& static_modifier_cache) {
+	// Update sum of direct province modifiers
+	modifier_sum.clear();
+
+	const ModifierSum::modifier_source_t province_source { this };
+
+	// Erase expired event modifiers and add non-expired ones to the sum
+	std::erase_if(event_modifiers, [this, today, &province_source](ModifierInstance const& modifier) -> bool {
+		if (today <= modifier.get_expiry_date()) {
+			modifier_sum.add_modifier(*modifier.get_modifier(), province_source);
+			return false;
+		} else {
+			return true;
+		}
+	});
+
+	// Add static modifiers
+	if (is_owner_core()) {
+		modifier_sum.add_modifier_nullcheck(static_modifier_cache.get_core(), province_source);
+	}
+	if (province_definition.is_water()) {
+		modifier_sum.add_modifier_nullcheck(static_modifier_cache.get_sea_zone(), province_source);
+	} else {
+		modifier_sum.add_modifier_nullcheck(static_modifier_cache.get_land_province(), province_source);
+
+		if (province_definition.is_coastal()) {
+			modifier_sum.add_modifier_nullcheck(static_modifier_cache.get_coastal(), province_source);
+		} else {
+			modifier_sum.add_modifier_nullcheck(static_modifier_cache.get_non_coastal(), province_source);
+		}
+
+		// TODO - overseas, blockaded, no_adjacent_controlled, has_siege, occupied, nationalism, infrastructure
+	}
+
+	for (BuildingInstance const& building : buildings.get_items()) {
+		modifier_sum.add_modifier(building.get_building_type(), province_source);
+	}
+
+	modifier_sum.add_modifier_nullcheck(crime, province_source);
+
+	modifier_sum.add_modifier_nullcheck(province_definition.get_continent(), province_source);
+
+	modifier_sum.add_modifier_nullcheck(province_definition.get_climate(), province_source);
+
+	modifier_sum.add_modifier_nullcheck(terrain_type, province_source);
+}
+
+void ProvinceInstance::contribute_country_modifier_sum(ModifierSum const& owner_modifier_sum) {
+	modifier_sum.add_modifier_sum_exclude_source(owner_modifier_sum, this);
+}
+
+fixed_point_t ProvinceInstance::get_modifier_effect_value(ModifierEffect const& effect) const {
+	return modifier_sum.get_effect(effect);
+}
+
+fixed_point_t ProvinceInstance::get_modifier_effect_value_nullcheck(ModifierEffect const* effect) const {
+	return modifier_sum.get_effect_nullcheck(effect);
+}
+
 void ProvinceInstance::update_gamestate(Date today, DefineManager const& define_manager) {
 	for (BuildingInstance& building : buildings.get_items()) {
 		building.update_gamestate(today);
diff --git a/src/openvic-simulation/map/ProvinceInstance.hpp b/src/openvic-simulation/map/ProvinceInstance.hpp
index fa0be98..0b02c41 100644
--- a/src/openvic-simulation/map/ProvinceInstance.hpp
+++ b/src/openvic-simulation/map/ProvinceInstance.hpp
@@ -5,6 +5,7 @@
 #include "openvic-simulation/economy/BuildingInstance.hpp"
 #include "openvic-simulation/military/UnitInstance.hpp"
 #include "openvic-simulation/military/UnitType.hpp"
+#include "openvic-simulation/modifier/ModifierSum.hpp"
 #include "openvic-simulation/pop/Pop.hpp"
 #include "openvic-simulation/types/fixed_point/FixedPointMap.hpp"
 #include "openvic-simulation/types/HasIdentifier.hpp"
@@ -68,6 +69,10 @@ namespace OpenVic {
 		CountryInstance* PROPERTY(controller);
 		ordered_set<CountryInstance*> PROPERTY(cores);
 
+		// The total/resultant modifier affecting this province, including owner country contributions.
+		ModifierSum PROPERTY(modifier_sum);
+		std::vector<ModifierInstance> PROPERTY(event_modifiers);
+
 		bool PROPERTY(slave);
 		Crime const* PROPERTY_RW(crime);
 		// TODO - change this into a factory-like structure
@@ -124,6 +129,11 @@ namespace OpenVic {
 		bool add_pop_vec(std::vector<PopBase> const& pop_vec);
 		size_t get_pop_count() const;
 
+		void update_modifier_sum(Date today, StaticModifierCache const& static_modifier_cache);
+		void contribute_country_modifier_sum(ModifierSum const& owner_modifier_sum);
+		fixed_point_t get_modifier_effect_value(ModifierEffect const& effect) const;
+		fixed_point_t get_modifier_effect_value_nullcheck(ModifierEffect const* effect) const;
+
 		void update_gamestate(Date today, DefineManager const& define_manager);
 		void tick(Date today);