Added resources subtracting while building

cardinal/system/create_building.go

@@ -1,6 +1,7 @@
 package system
 
 import (
+	"errors"
 	"fmt"
 
 	"pkg.world.dev/world-engine/cardinal"
@@ -29,6 +30,10 @@ func CreateBuildingSystem(world cardinal.WorldContext) error {
 				return msg.CreateBuildingResult{Success: false}, fmt.Errorf("index of tiles out of range")
 			}
 
+			if err := SubtractResourcesToBuild(world, building, request.Tx.PersonaTag); err != nil {
+				return msg.CreateBuildingResult{Success: false}, err
+			}
+
 			tile := &(*playerMap.Tiles)[request.Msg.TileIndex]
 			if tile.Building == nil {
 				tile.Building = &building
@@ -76,3 +81,50 @@ func CreateBuildingSystem(world cardinal.WorldContext) error {
 			return msg.CreateBuildingResult{Success: true}, nil
 		})
 }
+
+func SubtractResourcesToBuild(world cardinal.WorldContext, building comp.Building, personaTag string) error {
+	playerResourcesEntityID, playerResources, _ := QueryComponent[comp.PlayerResources](
+		world,
+		personaTag,
+		filter.Component[comp.Player](),
+		filter.Component[comp.PlayerResources](),
+	)
+
+	resourcesToBuild := comp.BuildingConfigs[building.Type].Resources
+	for _, resource := range resourcesToBuild {
+		var playerResource *comp.Resource
+		var err error
+		if playerResource, err = GetResourceByType(playerResources, resource.Type); err != nil {
+			return fmt.Errorf("can't get player resource %s: %w", resource.Type, err)
+		}
+		if playerResource.Amount < resource.Amount {
+			return fmt.Errorf("not enough resource %s", resource.Type)
+		}
+
+		playerResource.Amount -= resource.Amount
+		SetResourceByType(playerResources, *playerResource)
+
+		if err := cardinal.SetComponent(world, playerResourcesEntityID, playerResources); err != nil {
+			return fmt.Errorf("failed to update player resource: %w", err)
+		}
+	}
+
+	return nil
+}
+
+func GetResourceByType(playerResources *comp.PlayerResources, resourceType comp.ResourceType) (*comp.Resource, error) {
+	for i := range playerResources.Resources {
+		if playerResources.Resources[i].Type == resourceType {
+			return &playerResources.Resources[i], nil
+		}
+	}
+	return nil, errors.New("resource not found")
+}
+
+func SetResourceByType(playerResources *comp.PlayerResources, newResource comp.Resource) {
+	for i := range playerResources.Resources {
+		if playerResources.Resources[i].Type == newResource.Type {
+			playerResources.Resources[i] = newResource
+		}
+	}
+}