Added Delete building query

cardinal/main.go

@@ -48,6 +48,7 @@ func MustInitWorld(w *cardinal.World) {
 		cardinal.RegisterMessage[msg.CreatePlayerMsg, msg.CreatePlayerResult](w, "create-player"),
 		cardinal.RegisterMessage[msg.AttackPlayerMsg, msg.AttackPlayerMsgReply](w, "attack-player"),
 		cardinal.RegisterMessage[msg.CreateBuildingMsg, msg.CreateBuildingResult](w, "create-building"),
+		cardinal.RegisterMessage[msg.DeleteBuildingMsg, msg.DeleteBuildingResult](w, "delete-building"),
 	)
 
 	// Register queries
@@ -80,6 +81,7 @@ func MustInitWorld(w *cardinal.World) {
 		system.FarmingSystem,
 		system.PlayerSpawnerSystem,
 		system.CreateBuildingSystem,
+		system.DeleteBuildingSystem,
 	))
 }
 

cardinal/msg/delete_building.go

@@ -0,0 +1,9 @@
+package msg
+
+type DeleteBuildingMsg struct {
+	TileIndex int `json:"tileID"`
+}
+
+type DeleteBuildingResult struct {
+	Success bool `json:"success"`
+}

cardinal/system/delete_building.go

@@ -0,0 +1,68 @@
+package system
+
+import (
+	"fmt"
+
+	"pkg.world.dev/world-engine/cardinal"
+	"pkg.world.dev/world-engine/cardinal/search/filter"
+
+	comp "oceanus-shard/component"
+	"oceanus-shard/msg"
+)
+
+// DeleteBuildingSystem removes buildings.
+func DeleteBuildingSystem(world cardinal.WorldContext) error {
+	return cardinal.EachMessage[msg.DeleteBuildingMsg, msg.DeleteBuildingResult](
+		world,
+		func(request cardinal.TxData[msg.DeleteBuildingMsg]) (msg.DeleteBuildingResult, error) {
+			mapEntityID, playerMap, _ := QueryComponent[comp.TileMap](
+				world,
+				request.Tx.PersonaTag,
+				filter.Component[comp.Player](),
+				filter.Component[comp.TileMap](),
+			)
+
+			buildingsEntityIDs, buildingComponents, _ := QueryAllComponents[comp.Building](
+				world,
+				request.Tx.PersonaTag,
+				filter.Component[comp.Player](),
+				filter.Component[comp.Building](),
+			)
+
+			if playerMap == nil {
+				return msg.DeleteBuildingResult{Success: false},
+					fmt.Errorf("failed to delete building, this player did not have tilemap")
+			}
+
+			tileMapPlayer, _ := cardinal.GetComponent[comp.Player](world, mapEntityID)
+			if tileMapPlayer.Nickname != request.Tx.PersonaTag {
+				return msg.DeleteBuildingResult{Success: false}, fmt.Errorf("can't delete another player building")
+			}
+
+			tiles := *playerMap.Tiles
+
+			if request.Msg.TileIndex < 0 || request.Msg.TileIndex >= len(tiles) {
+				return msg.DeleteBuildingResult{Success: false}, fmt.Errorf("index of tiles out of range")
+			}
+
+			tile := &(*playerMap.Tiles)[request.Msg.TileIndex]
+			if tile.Building == nil {
+				return msg.DeleteBuildingResult{Success: false},
+					fmt.Errorf("failed to delete building, this tile didn't have buildings")
+			}
+			for i, building := range buildingComponents {
+				if building.Type == tile.Building.Type {
+					if err := cardinal.Remove(world, buildingsEntityIDs[i]); err != nil {
+						return msg.DeleteBuildingResult{Success: false}, fmt.Errorf("failed to delete building entity: %w", err)
+					}
+				}
+			}
+			tile.Building = nil
+
+			if err := cardinal.SetComponent(world, mapEntityID, playerMap); err != nil {
+				return msg.DeleteBuildingResult{Success: false}, fmt.Errorf("failed to delete building from tile: %w", err)
+			}
+
+			return msg.DeleteBuildingResult{Success: true}, nil
+		})
+}

cardinal/system/query_utils.go

@@ -57,8 +57,8 @@ func QueryAllComponents[T types.Component](
 	world cardinal.WorldContext,
 	targetNickname string,
 	components ...filter.ComponentWrapper,
-) (types.EntityID, []*T, error) {
-	var entityID types.EntityID
+) ([]types.EntityID, []*T, error) {
+	var entityIDs []types.EntityID
 	var targetComponents []*T
 	var err error
 
@@ -72,18 +72,18 @@ func QueryAllComponents[T types.Component](
 			}
 
 			if player.Nickname == targetNickname {
-				entityID = id
+				entityIDs = append(entityIDs, id)
 				targetComponent, _ := cardinal.GetComponent[T](world, id)
 				targetComponents = append(targetComponents, targetComponent)
 			}
 
 			return true
 		})
 	if searchErr != nil {
-		return 0, nil, err
+		return nil, nil, err
 	}
 	if err != nil {
-		return 0, nil, err
+		return nil, nil, err
 	}
-	return entityID, targetComponents, err
+	return entityIDs, targetComponents, err
 }