12 files changed, 306 insertions, 244 deletions

diff --git a/src/openvic-simulation/map/Map.cpp b/src/openvic-simulation/map/MapDefinition.cpp
index 11b940f..f3bb619 100644
--- a/src/openvic-simulation/map/Map.cpp
+++ b/src/openvic-simulation/map/MapDefinition.cpp
@@ -1,9 +1,7 @@
-#include "Map.hpp"
+#include "MapDefinition.hpp"
 
-#include <cstddef>
 #include <vector>
 
-#include "openvic-simulation/history/ProvinceHistory.hpp"
 #include "openvic-simulation/types/Colour.hpp"
 #include "openvic-simulation/types/OrderedContainers.hpp"
 #include "openvic-simulation/utility/BMP.hpp"
@@ -12,11 +10,9 @@
 using namespace OpenVic;
 using namespace OpenVic::NodeTools;
 
-Map::Map()
-  : dims { 0, 0 }, max_provinces { ProvinceDefinition::MAX_INDEX }, selected_province { nullptr },
-	highest_province_population { 0 }, total_map_population { 0 } {}
+MapDefinition::MapDefinition() : dims { 0, 0 }, max_provinces { ProvinceDefinition::MAX_INDEX } {}
 
-bool Map::add_province_definition(std::string_view identifier, colour_t colour) {
+bool MapDefinition::add_province_definition(std::string_view identifier, colour_t colour) {
 	if (province_definitions.size() >= max_provinces) {
 		Logger::error(
 			"The map's province list is full - maximum number of provinces is ", max_provinces, " (this can be at most ",
@@ -53,23 +49,7 @@ bool Map::add_province_definition(std::string_view identifier, colour_t colour)
 	return province_definitions.add_item(std::move(new_province));
 }
 
-ProvinceInstance* Map::get_province_instance_from_const(ProvinceDefinition const* province) {
-	if (province != nullptr) {
-		return get_province_instance_by_index(province->get_index());
-	} else {
-		return nullptr;
-	}
-}
-
-ProvinceInstance const* Map::get_province_instance_from_const(ProvinceDefinition const* province) const {
-	if (province != nullptr) {
-		return get_province_instance_by_index(province->get_index());
-	} else {
-		return nullptr;
-	}
-}
-
-ProvinceDefinition::distance_t Map::calculate_distance_between(
+ProvinceDefinition::distance_t MapDefinition::calculate_distance_between(
 	ProvinceDefinition const& from, ProvinceDefinition const& to
 ) const {
 	const fvec2_t to_pos = to.get_unit_position();
@@ -90,7 +70,7 @@ using adjacency_t = ProvinceDefinition::adjacency_t;
 
 /* This is called for all adjacent pixel pairs and returns whether or not a new adjacency was add,
  * hence the lack of error messages in the false return cases. */
-bool Map::add_standard_adjacency(ProvinceDefinition& from, ProvinceDefinition& to) const {
+bool MapDefinition::add_standard_adjacency(ProvinceDefinition& from, ProvinceDefinition& to) const {
 	if (from == to) {
 		return false;
 	}
@@ -129,7 +109,7 @@ bool Map::add_standard_adjacency(ProvinceDefinition& from, ProvinceDefinition& t
 	return true;
 }
 
-bool Map::add_special_adjacency(
+bool MapDefinition::add_special_adjacency(
 	ProvinceDefinition& from, ProvinceDefinition& to, adjacency_t::type_t type, ProvinceDefinition const* through,
 	adjacency_t::data_t data
 ) const {
@@ -257,7 +237,7 @@ bool Map::add_special_adjacency(
 	return add_adjacency(from, to) & add_adjacency(to, from);
 }
 
-bool Map::set_water_province(std::string_view identifier) {
+bool MapDefinition::set_water_province(std::string_view identifier) {
 	if (water_provinces.is_locked()) {
 		Logger::error("The map's water provinces have already been locked!");
 		return false;
@@ -285,7 +265,7 @@ bool Map::set_water_province(std::string_view identifier) {
 	return true;
 }
 
-bool Map::set_water_province_list(std::vector<std::string_view> const& list) {
+bool MapDefinition::set_water_province_list(std::vector<std::string_view> const& list) {
 	if (water_provinces.is_locked()) {
 		Logger::error("The map's water provinces have already been locked!");
 		return false;
@@ -299,12 +279,12 @@ bool Map::set_water_province_list(std::vector<std::string_view> const& list) {
 	return ret;
 }
 
-void Map::lock_water_provinces() {
+void MapDefinition::lock_water_provinces() {
 	water_provinces.lock();
 	Logger::info("Locked water provinces after registering ", water_provinces.size());
 }
 
-bool Map::add_region(std::string_view identifier, std::vector<ProvinceDefinition const*>&& provinces, colour_t colour) {
+bool MapDefinition::add_region(std::string_view identifier, std::vector<ProvinceDefinition const*>&& provinces, colour_t colour) {
 	if (identifier.empty()) {
 		Logger::error("Invalid region identifier - empty!");
 		return false;
@@ -345,7 +325,7 @@ bool Map::add_region(std::string_view identifier, std::vector<ProvinceDefinition
 	return ret;
 }
 
-ProvinceDefinition::index_t Map::get_index_from_colour(colour_t colour) const {
+ProvinceDefinition::index_t MapDefinition::get_index_from_colour(colour_t colour) const {
 	const colour_index_map_t::const_iterator it = colour_index_map.find(colour);
 	if (it != colour_index_map.end()) {
 		return it->second;
@@ -353,22 +333,22 @@ ProvinceDefinition::index_t Map::get_index_from_colour(colour_t colour) const {
 	return ProvinceDefinition::NULL_INDEX;
 }
 
-ProvinceDefinition::index_t Map::get_province_index_at(ivec2_t pos) const {
+ProvinceDefinition::index_t MapDefinition::get_province_index_at(ivec2_t pos) const {
 	if (pos.nonnegative() && pos.less_than(dims)) {
 		return province_shape_image[get_pixel_index_from_pos(pos)].index;
 	}
 	return ProvinceDefinition::NULL_INDEX;
 }
 
-ProvinceDefinition* Map::get_province_definition_at(ivec2_t pos) {
+ProvinceDefinition* MapDefinition::get_province_definition_at(ivec2_t pos) {
 	return get_province_definition_by_index(get_province_index_at(pos));
 }
 
-ProvinceDefinition const* Map::get_province_definition_at(ivec2_t pos) const {
+ProvinceDefinition const* MapDefinition::get_province_definition_at(ivec2_t pos) const {
 	return get_province_definition_by_index(get_province_index_at(pos));
 }
 
-bool Map::set_max_provinces(ProvinceDefinition::index_t new_max_provinces) {
+bool MapDefinition::set_max_provinces(ProvinceDefinition::index_t new_max_provinces) {
 	if (new_max_provinces <= ProvinceDefinition::NULL_INDEX) {
 		Logger::error(
 			"Trying to set max province count to an invalid value ", new_max_provinces, " (must be greater than ",
@@ -386,127 +366,6 @@ bool Map::set_max_provinces(ProvinceDefinition::index_t new_max_provinces) {
 	return true;
 }
 
-void Map::set_selected_province(ProvinceDefinition::index_t index) {
-	if (index == ProvinceDefinition::NULL_INDEX) {
-		selected_province = nullptr;
-	} else {
-		selected_province = get_province_instance_by_index(index);
-		if (selected_province == nullptr) {
-			Logger::error(
-				"Trying to set selected province to an invalid index ", index, " (max index is ",
-				get_province_instance_count(), ")"
-			);
-		}
-	}
-}
-
-ProvinceInstance* Map::get_selected_province() {
-	return selected_province;
-}
-
-ProvinceDefinition::index_t Map::get_selected_province_index() const {
-	return selected_province != nullptr ? selected_province->get_province_definition().get_index()
-		: ProvinceDefinition::NULL_INDEX;
-}
-
-bool Map::reset(BuildingTypeManager const& building_type_manager) {
-	if (!province_definitions_are_locked()) {
-		Logger::error("Cannot reset map - province consts are not locked!");
-		return false;
-	}
-
-	bool ret = true;
-
-	// TODO - ensure all references to old ProvinceInstances are safely cleared
-	state_manager.reset();
-	selected_province = nullptr;
-
-	province_instances.reset();
-
-	province_instances.reserve(province_definitions.size());
-
-	for (ProvinceDefinition const& province : province_definitions.get_items()) {
-		ret &= province_instances.add_item({ province });
-	}
-
-	province_instances.lock();
-
-	for (ProvinceInstance& province : province_instances.get_items()) {
-		ret &= province.reset(building_type_manager);
-	}
-
-	if (get_province_instance_count() != get_province_definition_count()) {
-		Logger::error(
-			"ProvinceInstance count (", get_province_instance_count(), ") does not match ProvinceDefinition count (",
-			get_province_definition_count(), ")!"
-		);
-		return false;
-	}
-
-	return ret;
-}
-
-bool Map::apply_history_to_provinces(
-	ProvinceHistoryManager const& history_manager, Date date, IdeologyManager const& ideology_manager,
-	IssueManager const& issue_manager, Country const& country
-) {
-	bool ret = true;
-
-	for (ProvinceInstance& province : province_instances.get_items()) {
-		ProvinceDefinition const& province_definition = province.get_province_definition();
-		if (!province_definition.is_water()) {
-			ProvinceHistoryMap const* history_map = history_manager.get_province_history(&province_definition);
-
-			if (history_map != nullptr) {
-				ProvinceHistoryEntry const* pop_history_entry = nullptr;
-
-				for (ProvinceHistoryEntry const* entry : history_map->get_entries_up_to(date)) {
-					province.apply_history_to_province(entry);
-
-					if (!entry->get_pops().empty()) {
-						pop_history_entry = entry;
-					}
-				}
-
-				if (pop_history_entry != nullptr) {
-					province.add_pop_vec(pop_history_entry->get_pops());
-
-					province.setup_pop_test_values(ideology_manager, issue_manager, country);
-				}
-			}
-		}
-	}
-
-	return ret;
-}
-
-void Map::update_gamestate(Date today) {
-	for (ProvinceInstance& province : province_instances.get_items()) {
-		province.update_gamestate(today);
-	}
-	state_manager.update_gamestate();
-
-	// Update population stats
-	highest_province_population = 0;
-	total_map_population = 0;
-
-	for (ProvinceInstance const& province : province_instances.get_items()) {
-		const Pop::pop_size_t province_population = province.get_total_population();
-
-		if (highest_province_population < province_population) {
-			highest_province_population = province_population;
-		}
-
-		total_map_population += province_population;
-	}
-}
-
-void Map::tick(Date today) {
-	for (ProvinceInstance& province : province_instances.get_items()) {
-		province.tick(today);
-	}
-}
-
 using namespace ovdl::csv;
 
 static bool _validate_province_definitions_header(LineObject const& header) {
@@ -541,7 +400,7 @@ static bool _parse_province_colour(colour_t& colour, std::array<std::string_view
 	return ret;
 }
 
-bool Map::load_province_definitions(std::vector<LineObject> const& lines) {
+bool MapDefinition::load_province_definitions(std::vector<LineObject> const& lines) {
 	if (lines.empty()) {
 		Logger::error("No header or entries in province definition file!");
 		return false;
@@ -581,7 +440,7 @@ bool Map::load_province_definitions(std::vector<LineObject> const& lines) {
 	return ret;
 }
 
-bool Map::load_province_positions(BuildingTypeManager const& building_type_manager, ast::NodeCPtr root) {
+bool MapDefinition::load_province_positions(BuildingTypeManager const& building_type_manager, ast::NodeCPtr root) {
 	return expect_province_definition_dictionary(
 		[this, &building_type_manager](ProvinceDefinition& province, ast::NodeCPtr node) -> bool {
 			return province.load_positions(*this, building_type_manager, node);
@@ -589,7 +448,7 @@ bool Map::load_province_positions(BuildingTypeManager const& building_type_manag
 	)(root);
 }
 
-bool Map::load_region_colours(ast::NodeCPtr root, std::vector<colour_t>& colours) {
+bool MapDefinition::load_region_colours(ast::NodeCPtr root, std::vector<colour_t>& colours) {
 	return expect_dictionary_reserve_length(
 		colours,
 		[&colours](std::string_view key, ast::NodeCPtr value) -> bool {
@@ -601,7 +460,7 @@ bool Map::load_region_colours(ast::NodeCPtr root, std::vector<colour_t>& colours
 	})(root);
 }
 
-bool Map::load_region_file(ast::NodeCPtr root, std::vector<colour_t> const& colours) {
+bool MapDefinition::load_region_file(ast::NodeCPtr root, std::vector<colour_t> const& colours) {
 	const bool ret = expect_dictionary_reserve_length(
 		regions,
 		[this, &colours](std::string_view region_identifier, ast::NodeCPtr region_node) -> bool {
@@ -631,7 +490,7 @@ static constexpr colour_t colour_at(uint8_t const* colour_data, int32_t idx) {
 	return { colour_data[idx + 2], colour_data[idx + 1], colour_data[idx] };
 }
 
-bool Map::load_map_images(fs::path const& province_path, fs::path const& terrain_path, bool detailed_errors) {
+bool MapDefinition::load_map_images(fs::path const& province_path, fs::path const& terrain_path, bool detailed_errors) {
 	if (!province_definitions_are_locked()) {
 		Logger::error("Province index image cannot be generated until after provinces are locked!");
 		return false;
@@ -784,7 +643,7 @@ bool Map::load_map_images(fs::path const& province_path, fs::path const& terrain
 /* REQUIREMENTS:
  * MAP-19, MAP-84
  */
-bool Map::_generate_standard_province_adjacencies() {
+bool MapDefinition::_generate_standard_province_adjacencies() {
 	bool changed = false;
 
 	const auto generate_adjacency = [this](ProvinceDefinition* current, ivec2_t pos) -> bool {
@@ -809,7 +668,7 @@ bool Map::_generate_standard_province_adjacencies() {
 	return changed;
 }
 
-bool Map::generate_and_load_province_adjacencies(std::vector<LineObject> const& additional_adjacencies) {
+bool MapDefinition::generate_and_load_province_adjacencies(std::vector<LineObject> const& additional_adjacencies) {
 	bool ret = _generate_standard_province_adjacencies();
 	if (!ret) {
 		Logger::error("Failed to generate standard province adjacencies!");
@@ -871,7 +730,7 @@ bool Map::generate_and_load_province_adjacencies(std::vector<LineObject> const&
 	return ret;
 }
 
-bool Map::load_climate_file(ModifierManager const& modifier_manager, ast::NodeCPtr root) {
+bool MapDefinition::load_climate_file(ModifierManager const& modifier_manager, ast::NodeCPtr root) {
 	bool ret = expect_dictionary_reserve_length(
 		climates,
 		[this, &modifier_manager](std::string_view identifier, ast::NodeCPtr node) -> bool {
@@ -924,7 +783,7 @@ bool Map::load_climate_file(ModifierManager const& modifier_manager, ast::NodeCP
 	return ret;
 }
 
-bool Map::load_continent_file(ModifierManager const& modifier_manager, ast::NodeCPtr root) {
+bool MapDefinition::load_continent_file(ModifierManager const& modifier_manager, ast::NodeCPtr root) {
 	bool ret = expect_dictionary_reserve_length(
 		continents,
 		[this, &modifier_manager](std::string_view identifier, ast::NodeCPtr node) -> bool {
diff --git a/src/openvic-simulation/map/Map.hpp b/src/openvic-simulation/map/MapDefinition.hpp
index 12c9de4..9ec4367 100644
--- a/src/openvic-simulation/map/Map.hpp
+++ b/src/openvic-simulation/map/MapDefinition.hpp
@@ -1,27 +1,30 @@
 #pragma once
 
 #include <filesystem>
+#include <string_view>
+#include <vector>
 
 #include <openvic-dataloader/csv/LineObject.hpp>
 
 #include "openvic-simulation/map/ProvinceDefinition.hpp"
-#include "openvic-simulation/map/ProvinceInstance.hpp"
 #include "openvic-simulation/map/Region.hpp"
-#include "openvic-simulation/map/State.hpp"
 #include "openvic-simulation/map/TerrainType.hpp"
 #include "openvic-simulation/types/Colour.hpp"
+#include "openvic-simulation/types/IdentifierRegistry.hpp"
 #include "openvic-simulation/types/OrderedContainers.hpp"
+#include "openvic-simulation/types/Vector.hpp"
 
 namespace OpenVic {
 	namespace fs = std::filesystem;
 
-	struct GoodManager;
-	struct ProvinceHistoryManager;
+	struct BuildingTypeManager;
+	struct ModifierManager;
 
 	/* REQUIREMENTS:
 	 * MAP-4
 	 */
-	struct Map {
+	struct MapDefinition {
+
 #pragma pack(push, 1)
 		/* Used to represent tightly packed 3-byte integer pixel information. */
 		struct shape_pixel_t {
@@ -29,11 +32,11 @@ namespace OpenVic {
 			TerrainTypeMapping::index_t terrain;
 		};
 #pragma pack(pop)
+
 	private:
 		using colour_index_map_t = ordered_map<colour_t, ProvinceDefinition::index_t>;
 
 		IdentifierRegistry<ProvinceDefinition> IDENTIFIER_REGISTRY_CUSTOM_INDEX_OFFSET(province_definition, 1);
-		IdentifierRegistry<ProvinceInstance> IDENTIFIER_REGISTRY_CUSTOM_INDEX_OFFSET(province_instance, 1);
 		IdentifierRegistry<Region> IDENTIFIER_REGISTRY(region);
 		IdentifierRegistry<Climate> IDENTIFIER_REGISTRY(climate);
 		IdentifierRegistry<Continent> IDENTIFIER_REGISTRY(continent);
@@ -45,36 +48,24 @@ namespace OpenVic {
 		colour_index_map_t colour_index_map;
 
 		ProvinceDefinition::index_t PROPERTY(max_provinces);
-		ProvinceInstance* PROPERTY(selected_province); // is it right for this to be mutable? how about using an index instead?
-		Pop::pop_size_t PROPERTY(highest_province_population);
-		Pop::pop_size_t PROPERTY(total_map_population);
 
 		ProvinceDefinition::index_t get_index_from_colour(colour_t colour) const;
 		bool _generate_standard_province_adjacencies();
 
-		StateManager PROPERTY_REF(state_manager);
-
 		inline constexpr int32_t get_pixel_index_from_pos(ivec2_t pos) const {
 			return pos.x + pos.y * dims.x;
 		}
 
+		IDENTIFIER_REGISTRY_NON_CONST_ACCESSORS_CUSTOM_INDEX_OFFSET(province_definition, 1);
+
 	public:
-		Map();
+		MapDefinition();
 
 		inline constexpr int32_t get_width() const { return dims.x; }
 		inline constexpr int32_t get_height() const { return dims.y; }
 
 		bool add_province_definition(std::string_view identifier, colour_t colour);
 
-	private:
-		IDENTIFIER_REGISTRY_NON_CONST_ACCESSORS_CUSTOM_INDEX_OFFSET(province_definition, 1);
-
-	public:
-		IDENTIFIER_REGISTRY_NON_CONST_ACCESSORS_CUSTOM_INDEX_OFFSET(province_instance, 1);
-
-		ProvinceInstance* get_province_instance_from_const(ProvinceDefinition const* province);
-		ProvinceInstance const* get_province_instance_from_const(ProvinceDefinition const* province) const;
-
 		ProvinceDefinition::distance_t calculate_distance_between(
 			ProvinceDefinition const& from, ProvinceDefinition const& to
 		) const;
@@ -105,21 +96,9 @@ namespace OpenVic {
 	public:
 		ProvinceDefinition const* get_province_definition_at(ivec2_t pos) const;
 		bool set_max_provinces(ProvinceDefinition::index_t new_max_provinces);
-		void set_selected_province(ProvinceDefinition::index_t index);
-		ProvinceInstance* get_selected_province();
-		ProvinceDefinition::index_t get_selected_province_index() const;
 
 		bool add_region(std::string_view identifier, std::vector<ProvinceDefinition const*>&& provinces, colour_t colour);
 
-		bool reset(BuildingTypeManager const& building_type_manager);
-		bool apply_history_to_provinces(
-			ProvinceHistoryManager const& history_manager, Date date, IdeologyManager const& ideology_manager,
-			IssueManager const& issue_manager, Country const& country
-		);
-
-		void update_gamestate(Date today);
-		void tick(Date today);
-
 		bool load_province_definitions(std::vector<ovdl::csv::LineObject> const& lines);
 		/* Must be loaded after adjacencies so we know what provinces are coastal, and so can have a port */
 		bool load_province_positions(BuildingTypeManager const& building_type_manager, ast::NodeCPtr root);
diff --git a/src/openvic-simulation/map/MapInstance.cpp b/src/openvic-simulation/map/MapInstance.cpp
new file mode 100644
index 0000000..23fe6a3
--- /dev/null
+++ b/src/openvic-simulation/map/MapInstance.cpp
@@ -0,0 +1,148 @@
+#include "MapInstance.hpp"
+
+#include "openvic-simulation/history/ProvinceHistory.hpp"
+#include "openvic-simulation/map/MapDefinition.hpp"
+#include "openvic-simulation/utility/Logger.hpp"
+
+using namespace OpenVic;
+
+MapInstance::MapInstance(MapDefinition const& new_map_definition)
+  : map_definition { new_map_definition }, selected_province { nullptr }, highest_province_population { 0 },
+	total_map_population { 0 } {}
+
+ProvinceInstance* MapInstance::get_province_instance_from_const(ProvinceDefinition const* province) {
+	if (province != nullptr) {
+		return get_province_instance_by_index(province->get_index());
+	} else {
+		return nullptr;
+	}
+}
+
+ProvinceInstance const* MapInstance::get_province_instance_from_const(ProvinceDefinition const* province) const {
+	if (province != nullptr) {
+		return get_province_instance_by_index(province->get_index());
+	} else {
+		return nullptr;
+	}
+}
+
+void MapInstance::set_selected_province(ProvinceDefinition::index_t index) {
+	if (index == ProvinceDefinition::NULL_INDEX) {
+		selected_province = nullptr;
+	} else {
+		selected_province = get_province_instance_by_index(index);
+		if (selected_province == nullptr) {
+			Logger::error(
+				"Trying to set selected province to an invalid index ", index, " (max index is ",
+				get_province_instance_count(), ")"
+			);
+		}
+	}
+}
+
+ProvinceInstance* MapInstance::get_selected_province() {
+	return selected_province;
+}
+
+ProvinceDefinition::index_t MapInstance::get_selected_province_index() const {
+	return selected_province != nullptr ? selected_province->get_province_definition().get_index()
+		: ProvinceDefinition::NULL_INDEX;
+}
+
+bool MapInstance::reset(BuildingTypeManager const& building_type_manager) {
+	if (!map_definition.province_definitions_are_locked()) {
+		Logger::error("Cannot reset map - province consts are not locked!");
+		return false;
+	}
+
+	bool ret = true;
+
+	// TODO - ensure all references to old ProvinceInstances are safely cleared
+	state_manager.reset();
+	selected_province = nullptr;
+
+	province_instances.reset();
+
+	province_instances.reserve(map_definition.get_province_definition_count());
+
+	for (ProvinceDefinition const& province : map_definition.get_province_definitions()) {
+		ret &= province_instances.add_item({ province });
+	}
+
+	province_instances.lock();
+
+	for (ProvinceInstance& province : province_instances.get_items()) {
+		ret &= province.reset(building_type_manager);
+	}
+
+	if (get_province_instance_count() != map_definition.get_province_definition_count()) {
+		Logger::error(
+			"ProvinceInstance count (", get_province_instance_count(), ") does not match ProvinceDefinition count (",
+			map_definition.get_province_definition_count(), ")!"
+		);
+		return false;
+	}
+
+	return ret;
+}
+
+bool MapInstance::apply_history_to_provinces(
+	ProvinceHistoryManager const& history_manager, Date date, IdeologyManager const& ideology_manager,
+	IssueManager const& issue_manager, Country const& country
+) {
+	bool ret = true;
+
+	for (ProvinceInstance& province : province_instances.get_items()) {
+		ProvinceDefinition const& province_definition = province.get_province_definition();
+		if (!province_definition.is_water()) {
+			ProvinceHistoryMap const* history_map = history_manager.get_province_history(&province_definition);
+
+			if (history_map != nullptr) {
+				ProvinceHistoryEntry const* pop_history_entry = nullptr;
+
+				for (ProvinceHistoryEntry const* entry : history_map->get_entries_up_to(date)) {
+					province.apply_history_to_province(entry);
+
+					if (!entry->get_pops().empty()) {
+						pop_history_entry = entry;
+					}
+				}
+
+				if (pop_history_entry != nullptr) {
+					province.add_pop_vec(pop_history_entry->get_pops());
+
+					province.setup_pop_test_values(ideology_manager, issue_manager, country);
+				}
+			}
+		}
+	}
+
+	return ret;
+}
+
+void MapInstance::update_gamestate(Date today) {
+	for (ProvinceInstance& province : province_instances.get_items()) {
+		province.update_gamestate(today);
+	}
+	state_manager.update_gamestate();
+
+	// Update population stats
+	highest_province_population = 0;
+	total_map_population = 0;
+
+	for (ProvinceInstance const& province : province_instances.get_items()) {
+		const Pop::pop_size_t province_population = province.get_total_population();
+
+		if (highest_province_population < province_population) {
+			highest_province_population = province_population;
+		}
+
+		total_map_population += province_population;
+	}
+}
+
+void MapInstance::tick(Date today) {
+	for (ProvinceInstance& province : province_instances.get_items()) {
+		province.tick(today);
+	}
+}
diff --git a/src/openvic-simulation/map/MapInstance.hpp b/src/openvic-simulation/map/MapInstance.hpp
new file mode 100644
index 0000000..1f87326
--- /dev/null
+++ b/src/openvic-simulation/map/MapInstance.hpp
@@ -0,0 +1,56 @@
+#pragma once
+
+#include "openvic-simulation/map/ProvinceDefinition.hpp"
+#include "openvic-simulation/map/ProvinceInstance.hpp"
+#include "openvic-simulation/map/State.hpp"
+#include "openvic-simulation/types/Date.hpp"
+#include "openvic-simulation/types/IdentifierRegistry.hpp"
+
+namespace OpenVic {
+	struct MapDefinition;
+	struct BuildingTypeManager;
+	struct ProvinceHistoryManager;
+	struct IdeologyManager;
+	struct IssueManager;
+	struct Country;
+
+	/* REQUIREMENTS:
+	 * MAP-4
+	 */
+	struct MapInstance {
+		MapDefinition const& PROPERTY(map_definition);
+
+		IdentifierRegistry<ProvinceInstance> IDENTIFIER_REGISTRY_CUSTOM_INDEX_OFFSET(province_instance, 1);
+
+		ProvinceInstance* PROPERTY(selected_province); // is it right for this to be mutable? how about using an index instead?
+		Pop::pop_size_t PROPERTY(highest_province_population);
+		Pop::pop_size_t PROPERTY(total_map_population);
+
+		StateManager PROPERTY_REF(state_manager);
+
+	public:
+		MapInstance(MapDefinition const& new_map_definition);
+
+		inline explicit constexpr operator MapDefinition const&() const {
+			return map_definition;
+		}
+
+		IDENTIFIER_REGISTRY_NON_CONST_ACCESSORS_CUSTOM_INDEX_OFFSET(province_instance, 1);
+
+		ProvinceInstance* get_province_instance_from_const(ProvinceDefinition const* province);
+		ProvinceInstance const* get_province_instance_from_const(ProvinceDefinition const* province) const;
+
+		void set_selected_province(ProvinceDefinition::index_t index);
+		ProvinceInstance* get_selected_province();
+		ProvinceDefinition::index_t get_selected_province_index() const;
+
+		bool reset(BuildingTypeManager const& building_type_manager);
+		bool apply_history_to_provinces(
+			ProvinceHistoryManager const& history_manager, Date date, IdeologyManager const& ideology_manager,
+			IssueManager const& issue_manager, Country const& country
+		);
+
+		void update_gamestate(Date today);
+		void tick(Date today);
+	};
+}
diff --git a/src/openvic-simulation/map/Mapmode.cpp b/src/openvic-simulation/map/Mapmode.cpp
index d2acd84..6f8e606 100644
--- a/src/openvic-simulation/map/Mapmode.cpp
+++ b/src/openvic-simulation/map/Mapmode.cpp
@@ -3,7 +3,10 @@
 #include <cassert>
 
 #include "openvic-simulation/country/Country.hpp"
-#include "openvic-simulation/map/Map.hpp"
+#include "openvic-simulation/map/MapDefinition.hpp"
+#include "openvic-simulation/map/MapInstance.hpp"
+#include "openvic-simulation/map/ProvinceDefinition.hpp"
+#include "openvic-simulation/map/ProvinceInstance.hpp"
 #include "openvic-simulation/utility/Utility.hpp"
 
 using namespace OpenVic;
@@ -16,13 +19,15 @@ Mapmode::Mapmode(
 }
 
 const Mapmode Mapmode::ERROR_MAPMODE {
-	"mapmode_error", 0, [](Map const& map, ProvinceInstance const& province) -> base_stripe_t {
+	"mapmode_error", 0, [](MapInstance const&, ProvinceInstance const& province) -> base_stripe_t {
 		return { 0xFFFF0000_argb, colour_argb_t::null() };
 	}
 };
 
-Mapmode::base_stripe_t Mapmode::get_base_stripe_colours(Map const& map, ProvinceInstance const& province) const {
-	return colour_func ? colour_func(map, province) : colour_argb_t::null();
+Mapmode::base_stripe_t Mapmode::get_base_stripe_colours(
+	MapInstance const& map_instance, ProvinceInstance const& province
+) const {
+	return colour_func ? colour_func(map_instance, province) : colour_argb_t::null();
 }
 
 bool MapmodeManager::add_mapmode(std::string_view identifier, Mapmode::colour_func_t colour_func) {
@@ -37,7 +42,7 @@ bool MapmodeManager::add_mapmode(std::string_view identifier, Mapmode::colour_fu
 	return mapmodes.add_item({ identifier, mapmodes.size(), colour_func });
 }
 
-bool MapmodeManager::generate_mapmode_colours(Map const& map, Mapmode::index_t index, uint8_t* target) const {
+bool MapmodeManager::generate_mapmode_colours(MapInstance const& map_instance, Mapmode::index_t index, uint8_t* target) const {
 	if (target == nullptr) {
 		Logger::error("Mapmode colour target pointer is null!");
 		return false;
@@ -60,12 +65,17 @@ bool MapmodeManager::generate_mapmode_colours(Map const& map, Mapmode::index_t i
 
 	target_stripes[ProvinceDefinition::NULL_INDEX] = colour_argb_t::null();
 
-	if (map.province_instances_are_locked()) {
-		for (ProvinceInstance const& province : map.get_province_instances()) {
-			target_stripes[province.get_province_definition().get_index()] = mapmode->get_base_stripe_colours(map, province);
+	if (map_instance.province_instances_are_locked()) {
+		for (ProvinceInstance const& province : map_instance.get_province_instances()) {
+			target_stripes[province.get_province_definition().get_index()] =
+				mapmode->get_base_stripe_colours(map_instance, province);
 		}
 	} else {
-		for (size_t index = ProvinceDefinition::NULL_INDEX + 1; index <= map.get_province_definition_count(); ++index) {
+		for (
+			size_t index = ProvinceDefinition::NULL_INDEX + 1;
+			index <= map_instance.get_map_definition().get_province_definition_count();
+			++index
+		) {
 			target_stripes[index] = colour_argb_t::null();
 		}
 	}
@@ -83,7 +93,7 @@ static constexpr colour_argb_t DEFAULT_COLOUR_GREY = (0x7F7F7F_argb).with_alpha(
 template<utility::is_derived_from_specialization_of<_HasColour> T, typename P>
 requires(std::same_as<P, ProvinceDefinition> || std::same_as<P, ProvinceInstance>)
 static constexpr auto get_colour_mapmode(T const*(P::*get_item)() const) {
-	return [get_item](Map const& map, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+	return [get_item](MapInstance const&, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
 		ProvinceDefinition const& province_definition = province.get_province_definition();
 
 		T const* item = ([&province, &province_definition]() -> P const& {
@@ -124,7 +134,7 @@ static constexpr Mapmode::base_stripe_t shaded_mapmode(fixed_point_map_t<T const
 
 template<utility::is_derived_from_specialization_of<_HasColour> T>
 static constexpr auto shaded_mapmode(fixed_point_map_t<T const*> const&(ProvinceInstance::*get_map)() const) {
-	return [get_map](Map const& map, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+	return [get_map](MapInstance const&, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
 		return shaded_mapmode((province.*get_map)());
 	};
 }
@@ -136,7 +146,7 @@ bool MapmodeManager::setup_mapmodes() {
 	const std::vector<mapmode_t> mapmodes {
 		{
 			"mapmode_terrain",
-			[](Map const&, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+			[](MapInstance const&, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
 				return colour_argb_t::null();
 			}
 		},
@@ -146,7 +156,7 @@ bool MapmodeManager::setup_mapmodes() {
 		{
 			/* TEST MAPMODE, TO BE REMOVED */
 			"mapmode_province",
-			[](Map const&, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+			[](MapInstance const&, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
 				return colour_argb_t { province.get_province_definition().get_colour(), ALPHA_VALUE };
 			}
 		},
@@ -156,9 +166,10 @@ bool MapmodeManager::setup_mapmodes() {
 		{
 			/* TEST MAPMODE, TO BE REMOVED */
 			"mapmode_index",
-			[](Map const& map, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+			[](MapInstance const& map_instance, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
 				const colour_argb_t::value_type f = colour_argb_t::colour_traits::component_from_fraction(
-					province.get_province_definition().get_index(), map.get_province_definition_count() + 1
+					province.get_province_definition().get_index(),
+					map_instance.get_map_definition().get_province_definition_count() + 1
 				);
 				return colour_argb_t::fill_as(f).with_alpha(ALPHA_VALUE);
 			}
@@ -172,7 +183,7 @@ bool MapmodeManager::setup_mapmodes() {
 		},
 		{
 			"mapmode_infrastructure",
-			[](Map const& map, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+			[](MapInstance const&, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
 				BuildingInstance const* railroad = province.get_building_by_identifier("railroad");
 				if (railroad != nullptr) {
 					const colour_argb_t::value_type val = colour_argb_t::colour_traits::component_from_fraction(
@@ -192,13 +203,13 @@ bool MapmodeManager::setup_mapmodes() {
 		},
 		{
 			"mapmode_population",
-			[](Map const& map, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+			[](MapInstance const& map_instance, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
 				// TODO - explore non-linear scaling to have more variation among non-massive provinces
 				// TODO - when selecting a province, only show the population of provinces controlled (or owned?)
 				// by the same country, relative to the most populous province in that set of provinces
 				if (!province.get_province_definition().is_water()) {
 					const colour_argb_t::value_type val = colour_argb_t::colour_traits::component_from_fraction(
-						province.get_total_population(), map.get_highest_province_population() + 1, 0.1f, 1.0f
+						province.get_total_population(), map_instance.get_highest_province_population() + 1, 0.1f, 1.0f
 					);
 					return colour_argb_t { 0, val, 0, ALPHA_VALUE };
 				} else {
@@ -215,8 +226,9 @@ bool MapmodeManager::setup_mapmodes() {
 		},
 		{
 			/* TEST MAPMODE, TO BE REMOVED */
-			"mapmode_adjacencies", [](Map const& map, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
-				ProvinceInstance const* selected_province = map.get_selected_province();
+			"mapmode_adjacencies",
+			[](MapInstance const& map_instance, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+				ProvinceInstance const* selected_province = map_instance.get_selected_province();
 
 				if (selected_province != nullptr) {
 					ProvinceDefinition const& selected_province_definition = selected_province->get_province_definition();
@@ -258,7 +270,7 @@ bool MapmodeManager::setup_mapmodes() {
 			}
 		},
 		{
-			"mapmode_port", [](Map const& map, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
+			"mapmode_port", [](MapInstance const&, ProvinceInstance const& province) -> Mapmode::base_stripe_t {
 				ProvinceDefinition const& province_definition = province.get_province_definition();
 
 				if (province_definition.has_port()) {
diff --git a/src/openvic-simulation/map/Mapmode.hpp b/src/openvic-simulation/map/Mapmode.hpp
index fa306e9..d514f7a 100644
--- a/src/openvic-simulation/map/Mapmode.hpp
+++ b/src/openvic-simulation/map/Mapmode.hpp
@@ -8,7 +8,7 @@
 
 namespace OpenVic {
 	struct MapmodeManager;
-	struct Map;
+	struct MapInstance;
 	struct ProvinceInstance;
 
 	struct Mapmode : HasIdentifier {
@@ -23,7 +23,7 @@ namespace OpenVic {
 				: base_colour { base }, stripe_colour { stripe } {}
 			constexpr base_stripe_t(colour_argb_t both) : base_stripe_t { both, both } {}
 		};
-		using colour_func_t = std::function<base_stripe_t(Map const&, ProvinceInstance const&)>;
+		using colour_func_t = std::function<base_stripe_t(MapInstance const&, ProvinceInstance const&)>;
 		using index_t = size_t;
 
 	private:
@@ -37,7 +37,7 @@ namespace OpenVic {
 
 		Mapmode(Mapmode&&) = default;
 
-		base_stripe_t get_base_stripe_colours(Map const& map, ProvinceInstance const& province) const;
+		base_stripe_t get_base_stripe_colours(MapInstance const& map_instance, ProvinceInstance const& province) const;
 	};
 
 	struct MapmodeManager {
@@ -54,7 +54,7 @@ namespace OpenVic {
 		 * and A = 255 is fully the RGB colour packaged with A. The base and stripe colours for each province are packed
 		 * together adjacently, so each province's entry is 8 bytes long. The list contains ProvinceDefinition::MAX_INDEX + 1
 		 * entries, that is the maximum allowed number of provinces plus one for the index-zero "null province". */
-		bool generate_mapmode_colours(Map const& map, Mapmode::index_t index, uint8_t* target) const;
+		bool generate_mapmode_colours(MapInstance const& map_instance, Mapmode::index_t index, uint8_t* target) const;
 
 		bool setup_mapmodes();
 	};
diff --git a/src/openvic-simulation/map/ProvinceDefinition.cpp b/src/openvic-simulation/map/ProvinceDefinition.cpp
index bb8ad59..c40f8f0 100644
--- a/src/openvic-simulation/map/ProvinceDefinition.cpp
+++ b/src/openvic-simulation/map/ProvinceDefinition.cpp
@@ -2,7 +2,7 @@
 
 #include "openvic-simulation/dataloader/NodeTools.hpp"
 #include "openvic-simulation/economy/BuildingType.hpp"
-#include "openvic-simulation/map/Map.hpp"
+#include "openvic-simulation/map/MapDefinition.hpp"
 
 using namespace OpenVic;
 using namespace OpenVic::NodeTools;
@@ -26,8 +26,10 @@ std::string ProvinceDefinition::to_string() const {
 	return stream.str();
 }
 
-bool ProvinceDefinition::load_positions(Map const& map, BuildingTypeManager const& building_type_manager, ast::NodeCPtr root) {
-	const fixed_point_t map_height = map.get_height();
+bool ProvinceDefinition::load_positions(
+	MapDefinition const& map_definition, BuildingTypeManager const& building_type_manager, ast::NodeCPtr root
+) {
+	const fixed_point_t map_height = map_definition.get_height();
 
 	const bool ret = expect_dictionary_keys(
 		"text_position", ZERO_OR_ONE,
@@ -70,7 +72,7 @@ bool ProvinceDefinition::load_positions(Map const& map, BuildingTypeManager cons
 			const fvec2_t port_dir { -rotation.cos(), rotation.sin() };
 			const ivec2_t port_facing_position = static_cast<ivec2_t>(*port_position + port_dir / 4);
 
-			ProvinceDefinition const* province = map.get_province_definition_at(port_facing_position);
+			ProvinceDefinition const* province = map_definition.get_province_definition_at(port_facing_position);
 
 			if (province != nullptr) {
 				if (province->is_water() && is_adjacent_to(province)) {
diff --git a/src/openvic-simulation/map/ProvinceDefinition.hpp b/src/openvic-simulation/map/ProvinceDefinition.hpp
index a4076fe..c66323c 100644
--- a/src/openvic-simulation/map/ProvinceDefinition.hpp
+++ b/src/openvic-simulation/map/ProvinceDefinition.hpp
@@ -11,7 +11,7 @@
 
 namespace OpenVic {
 
-	struct Map;
+	struct MapDefinition;
 	struct Region;
 	struct TerrainType;
 	struct ProvinceSetModifier;
@@ -25,7 +25,7 @@ namespace OpenVic {
 	 * POP-22
 	 */
 	struct ProvinceDefinition : HasIdentifierAndColour {
-		friend struct Map;
+		friend struct MapDefinition;
 
 		using index_t = uint16_t;
 		using distance_t = fixed_point_t; // should this go inside adjacency_t?
@@ -114,7 +114,9 @@ namespace OpenVic {
 		}
 
 		/* The positions' y coordinates need to be inverted. */
-		bool load_positions(Map const& map, BuildingTypeManager const& building_type_manager, ast::NodeCPtr root);
+		bool load_positions(
+			MapDefinition const& map_definition, BuildingTypeManager const& building_type_manager, ast::NodeCPtr root
+		);
 
 		fvec2_t get_text_position() const;
 		fixed_point_t get_text_rotation() const;
diff --git a/src/openvic-simulation/map/ProvinceInstance.hpp b/src/openvic-simulation/map/ProvinceInstance.hpp
index 2dbc4e3..3292575 100644
--- a/src/openvic-simulation/map/ProvinceInstance.hpp
+++ b/src/openvic-simulation/map/ProvinceInstance.hpp
@@ -7,6 +7,7 @@
 #include "openvic-simulation/types/OrderedContainers.hpp"
 
 namespace OpenVic {
+	struct MapInstance;
 	struct ProvinceDefinition;
 	struct TerrainType;
 	struct State;
@@ -24,7 +25,7 @@ namespace OpenVic {
 	struct IssueManager;
 
 	struct ProvinceInstance : HasIdentifier {
-		friend struct Map;
+		friend struct MapInstance;
 
 		using life_rating_t = int8_t;
 
@@ -63,7 +64,7 @@ namespace OpenVic {
 	public:
 		ProvinceInstance(ProvinceInstance&&) = default;
 
-		inline constexpr operator ProvinceDefinition const&() const {
+		inline explicit constexpr operator ProvinceDefinition const&() const {
 			return province_definition;
 		}
 
diff --git a/src/openvic-simulation/map/Region.hpp b/src/openvic-simulation/map/Region.hpp
index f532400..1152dab 100644
--- a/src/openvic-simulation/map/Region.hpp
+++ b/src/openvic-simulation/map/Region.hpp
@@ -46,7 +46,7 @@ namespace OpenVic {
 	};
 
 	struct ProvinceSetModifier : Modifier, ProvinceSet {
-		friend struct Map;
+		friend struct MapDefinition;
 	private:
 		ProvinceSetModifier(std::string_view new_identifier, ModifierValue&& new_values);
 	public:
@@ -57,7 +57,7 @@ namespace OpenVic {
 	 * MAP-6, MAP-44, MAP-48
 	 */
 	struct Region : HasIdentifierAndColour, ProvinceSet {
-		friend struct Map;
+		friend struct MapDefinition;
 
 	private:
 		/* A meta region cannot be the template for a state.
diff --git a/src/openvic-simulation/map/State.cpp b/src/openvic-simulation/map/State.cpp
index 1c49ed7..46ff11d 100644
--- a/src/openvic-simulation/map/State.cpp
+++ b/src/openvic-simulation/map/State.cpp
@@ -1,7 +1,8 @@
 #include "State.hpp"
 
 #include "openvic-simulation/country/Country.hpp"
-#include "openvic-simulation/map/Map.hpp"
+#include "openvic-simulation/map/MapDefinition.hpp"
+#include "openvic-simulation/map/MapInstance.hpp"
 #include "openvic-simulation/map/ProvinceInstance.hpp"
 #include "openvic-simulation/map/Region.hpp"
 
@@ -39,7 +40,7 @@ void StateSet::update_gamestate() {
 	}
 }
 
-bool StateManager::add_state_set(Map& map, Region const& region) {
+bool StateManager::add_state_set(MapInstance& map_instance, Region const& region) {
 	if (region.get_meta()) {
 		Logger::error("Cannot use meta region \"", region.get_identifier(), "\" as state template!");
 		return false;
@@ -54,7 +55,7 @@ bool StateManager::add_state_set(Map& map, Region const& region) {
 
 	for (ProvinceDefinition const* province : region.get_provinces()) {
 
-		ProvinceInstance* province_instance = map.get_province_instance_from_const(province);
+		ProvinceInstance* province_instance = map_instance.get_province_instance_from_const(province);
 
 		// add to existing state if shared owner & status...
 		for (std::vector<ProvinceInstance*>& provinces : temp_provinces) {
@@ -98,16 +99,18 @@ bool StateManager::add_state_set(Map& map, Region const& region) {
 	return true;
 }
 
-bool StateManager::generate_states(Map& map) {
+bool StateManager::generate_states(MapInstance& map_instance) {
+	MapDefinition const& map_definition = map_instance.get_map_definition();
+
 	state_sets.clear();
-	state_sets.reserve(map.get_region_count());
+	state_sets.reserve(map_definition.get_region_count());
 
 	bool ret = true;
 	size_t state_count = 0;
 
-	for (Region const& region : map.get_regions()) {
+	for (Region const& region : map_definition.get_regions()) {
 		if (!region.get_meta()) {
-			if (add_state_set(map, region)) {
+			if (add_state_set(map_instance, region)) {
 				state_count += state_sets.back().get_state_count();
 			} else {
 				ret = false;
diff --git a/src/openvic-simulation/map/State.hpp b/src/openvic-simulation/map/State.hpp
index e030a0b..ff8acfa 100644
--- a/src/openvic-simulation/map/State.hpp
+++ b/src/openvic-simulation/map/State.hpp
@@ -53,20 +53,20 @@ namespace OpenVic {
 		void update_gamestate();
 	};
 
-	struct Map;
+	struct MapInstance;
 
 	/* Contains all current states.*/
 	struct StateManager {
 	private:
 		std::vector<StateSet> PROPERTY(state_sets);
 
-		bool add_state_set(Map& map, Region const& region);
+		bool add_state_set(MapInstance& map_instance, Region const& region);
 
 	public:
 		/* Creates states from current province gamestate & regions, sets province state value.
 		 * After this function, the `regions` property is unmanaged and must be carefully updated and
 		 * validated by functions that modify it. */
-		bool generate_states(Map& map);
+		bool generate_states(MapInstance& map_instance);
 
 		void reset();