riversong-code-showcase/Source/Riversong/Game/EditTools/Validation/EditToolValidatorSystem.cs

using Unity.Mathematics;

namespace DanieleMarotta.RiversongCodeShowcase
{
    [Service(typeof(IEditToolValidatorService))]
    public class EditToolValidatorSystem : GameSystem, IEditToolValidatorService
    {
        [InjectService]
        private GameConfig _config;

        [InjectService]
        private World _world;

        public EditToolValidatorSystem(IServiceLocator serviceLocator) : base(serviceLocator)
        {
        }

        public EditToolValidationResult DoCommonValidation(TileRect rect, BlockReason blockReason)
        {
            foreach (var tile in TileRange.From(rect))
                if (!DoCommonTileValidation(tile, blockReason))
                    return EditToolValidationResult.BlockedTile;

            return EditToolValidationResult.Success;
        }

        private bool DoCommonTileValidation(int2 tile, BlockReason blockReason)
        {
            return _world.Contains(tile) && !_world.BlockMap.IsBlocked(tile, blockReason);
        }

        public EditToolValidationResult ValidateBuildingPlacementRules(TileRect rect, BuildingDefinition buildingDefinition)
        {
            if (buildingDefinition.NearWater)
            {
                var waterMap = _world.WaterMap;
                foreach (var tile in TileRange.From(rect))
                    if (!waterMap.IsNearWater(tile))
                        return EditToolValidationResult.CanOnlyBePlacedNearWater;
            }

            if (buildingDefinition.RequiresFertileTile)
            {
                foreach (var tile in TileRange.From(rect))
                {
                    var fertility = _world.Fertility.GetValue(tile);
                    if (fertility.MaxFertility > 0) return EditToolValidationResult.Success;
                }

                return EditToolValidationResult.CanOnlyBePlacedOnFertileGround;
            }

            return EditToolValidationResult.Success;
        }
    }
}