"rules"
{
	//-----------------------------------------------------------------------------
	// Cap a level with 'Border' pieces.
	//-----------------------------------------------------------------------------
	"rule"
	{
		"name"	"BorderCapLevel"
		"friendly_name"	"Border Cap Level"
		"description"	"Attempts to form a seamless edge around a level using room tiles tagged with 'Border'. Several conditions must be met for this to work properly; e.g. exits in the core of the level must be tagged with [Exit Tag to Cap] (default: 'center'), there must be sufficient variety of 'Border' pieces to create a seamless edge, tiles in the center should all be the same size, etc.."
		"type"	"state"
		"hidden"	"0"
		
		"param"
		{
			"name"	"$ExitTagToCap"
			"friendly_name"	"Exit Tag to Cap"
			"description"	"The exit tag which interfaces between the inside of the level and the border cap (default: 'center')."
			"type"	"string"
			"default"	"center"
			"source"	"literal"
		}
		
		"param"
		{
			"name"	"$RoomCandidateFilters"
			"friendly_name"	"Room Candidate Filters"
			"description"	"Additional room candidate filter criteria for placing border tiles."
			"type"	"room_candidate_filter"
			"source"	"expression"
			"array"	"unordered"
			"element_container"	"param"
			"default"
			{
				"param"
				{
					"rule_instance"
					{
						"name"	"DisallowNewCenterExits"
						"$DisallowedTag"	"center"
					}
				}
			}
		}
		
		"substitute"
		{
			// Phase 1: fill in any gaps in the existing level by placing
			// tiles in any place where they would create only 1 new exit (applies
			// only if the room template has at least 4 exits).
			// This my cause an infinite loop if the tile set is not built properly.
			"state"
			{
				"name"		"FillInGaps_%Unique"
				"action"
				{
					"class"		"CTilegenAction_AddRoomCandidates"					
					"Theme"
					{
						"rule_instance"
						{
							"name"	"GlobalTheme"
						}
					}					
					"room_template_filter"
					{
						"class"	"&&"
						"param"
						{
							"class"	"CTilegenExpression_CanPlaceRandomly"
							"room_template"
							{
								"class"		"var_room_template"
								"variable"		"RoomTemplate"
							}
						}
						"param"
						{
							"class"	"!"
							"param"
							{
								"class"	"CTilegenExpression_HasTag"
								"tag"	"Border"
								"room_template"
								{
									"class"		"var_room_template"
									"variable"		"RoomTemplate"
								}
							}
						}
						"param"
						{
							"rule_instance"
							{
								"name"	"UniqueRooms"
							}
						}
					}
					"room_candidate_filter"
					{
						"class"		">"
						"param0"
						{
							"rule_instance"
							{
								"name"		"CountClosedExits"
							}
						}
						"param1"
						{
							"rule_instance"
							{
								"name"		"CountNewOpenExits"
							}
						}
					}
					"exclude_global_filters"	"1"
				}
				"rule_instance"
				{
					"name"	"ChooseRandomCandidate"
					"$StopProcessing"	"1"
				}
				"action"
				{
					"class"		"CTilegenAction_SwitchState"
				}
			}
			
			// Phase 2: cap off any corners where a 'Border' piece would close 2 inner exits.
			"state"
			{
				"name"		"BorderTiles_InnerCorner_%Unique"
				"action"
				{
					"class"		"CTilegenAction_AddRoomCandidates"					
					"Theme"
					{
						"rule_instance"
						{
							"name"	"GlobalTheme"
						}
					}					
					"exit_filter"
					{
						"rule_instance"
						{
							"name"		"GrowFromCenter"
							"$GrowFromTag"	"$ExitTagToCap"
						}
					}
					"room_template_filter"
					{
						"class"	"&&"
						"param"
						{
							"rule_instance"
							{
								"name"		"AllowBorderNonTransitionRoomTemplates"
							}
						}
						"param"
						{
							"rule_instance"
							{
								"name"	"UniqueRooms"
							}
						}
					}
					"room_candidate_filter"
					{
						"class"		"&&"
						"_elide"	"$RoomCandidateFilters"
						"param"
						{
							"rule_instance"
							{
								"name"		"CloseAtLeastNExits"
								"$N"		"2"
								"$ExitTag"		"$ExitTagToCap"
							}
						}
					}
					"exclude_global_filters"	"1"
				}
				"rule_instance"
				{
					"name"	"ChooseRandomCandidate"
					"$StopProcessing"	"1"
				}
				"action"
				{
					"class"		"CTilegenAction_SwitchState"
				}
			}
			
			// Phase 3: grow from the edge of the map, placing 'Border' pieces 
			"state"
			{
				"name"		"BorderTiles_Edge_%Unique"
				"action"
				{
					"class"		"CTilegenAction_AddRoomCandidates"					
					"Theme"
					{
						"rule_instance"
						{
							"name"	"GlobalTheme"
						}
					}					
					"exit_filter"
					{
						"rule_instance"
						{
							"name"		"GrowFromCenter"
							"$GrowFromTag"	"$ExitTagToCap"
						}
					}
					"room_template_filter"
					{
						"class"	"&&"
						"param"
						{
							"rule_instance"
							{
								"name"		"AllowBorderNonTransitionRoomTemplates"
							}
						}
						"param"
						{
							"rule_instance"
							{
								"name"	"UniqueRooms"
							}
						}
					}
					"room_candidate_filter"
					{
						"class"	"&&"
						"_elide"	"$RoomCandidateFilters"
					}
					"exclude_global_filters"	"1"
				}
				"rule_instance"
				{
					"name"	"ChooseRandomCandidate"
					"$StopProcessing"	"1"
				}
				"action"
				{
					"class"		"CTilegenAction_SwitchState"
				}
			}
			
			// Phase 4: plug any border gaps with transition pieces.
			"state"
			{
				"name"		"BorderTiles_Transition_%Unique"
				"action"
				{
					"class"		"CTilegenAction_AddRoomCandidates"					
					"Theme"
					{
						"rule_instance"
						{
							"name"	"GlobalTheme"
						}
					}					
					"exit_filter"
					{
						"rule_instance"
						{
							"name"		"GrowFromCenter"
							"$GrowFromTag"	"$ExitTagToCap"
						}
					}
					"room_template_filter"
					{
						"class"	"&&"
						"param"
						{
							"class"		"CTilegenExpression_HasTag"
							"tag"	"border"
							"room_template"
							{
								"class"		"var_room_template"
								"variable"		"RoomTemplate"
							}
						}
						"param"
						{
							"rule_instance"
							{
								"name"	"UniqueRooms"
							}
						}
					}
					"room_candidate_filter"
					{
						"class"	"&&"
						"_elide"	"$RoomCandidateFilters"
					}
					"exclude_global_filters"	"1"
				}
				"rule_instance"
				{
					"name"	"ChooseRandomCandidate"
					"$StopProcessing"	"1"
				}
				"action"
				{
					"class"		"CTilegenAction_SwitchState"
				}
			}
			
			// Phase 5: fill in outer corners so you can't see off the edge of the world.
			// The only places where you can connect outer-corner pieces are other 'Border' pieces.
			"state"
			{
				"name"		"BorderTiles_OuterCorner_%Unique"
				"action"
				{
					"class"		"CTilegenAction_AddRoomCandidates"
					"Theme"
					{
						"rule_instance"
						{
							"name"	"GlobalTheme"
						}
					}
					"room_template_filter"
					{
						"class"	"&&"
						"param"
						{
							"class"		"CTilegenExpression_HasTag"
							"tag"	"border"
							"room_template"
							{
								"class"		"var_room_template"
								"variable"		"RoomTemplate"
							}
						}
						"param"
						{
							"rule_instance"
							{
								"name"	"UniqueRooms"
							}
						}
					}
					"room_candidate_filter"
					{
						"class"		"=="
						"param0"		"0"
						"param1"
						{
							"rule_instance"
							{
								"name"		"CountNewOpenExits"
							}
						}
					}
					"exclude_global_filters"	"1"
				}
				"rule_instance"
				{
					"name"	"ChooseRandomCandidate"
					"$StopProcessing"	"1"
				}
				"action"
				{
					"class"		"CTilegenAction_SwitchState"
				}
			}
		}
	}
	
	//-----------------------------------------------------------------------------
	// Allow room templates with the 'Border' tag but without the 'Transition' tag.
	//-----------------------------------------------------------------------------
	"rule"
	{
		"name"		"AllowBorderNonTransitionRoomTemplates"
		"friendly_name"	"Allow Border, Non-Transition Rooms"
		"description"	"Allow rooms with the 'Border' tag but without the 'Transition' tag."
		"type"	"room_template_filter"
		
		"substitute"
		{
			"class"		"&&"
			"param"
			{
				"class"		"CTilegenExpression_HasTag"
				"tag"		"Border"
				"room_template"
				{
					"class"		"var_room_template"
					"variable"		"RoomTemplate"
				}
			}
			"param"
			{
				"class"		"!"
				"param"
				{
					"class"		"CTilegenExpression_HasTag"
					"tag"		"Transition"
					"room_template"
					{
						"class"		"var_room_template"
						"variable"		"RoomTemplate"
					}
				}
			}
		}
	}
	
	//-----------------------------------------------------------------------------
	// Disallow exits from rooms with the 'Border' tag.
	//-----------------------------------------------------------------------------
	"rule"
	{
		"name"	"GrowFromCenter"
		"type"	"exit_filter"
		
		"param"
		{
			"name"	"$GrowFromTag"
		}
		
		"substitute"
		{
			"class"	"streq"
			"param0"
			{
				"class"	"CTilegenExpression_ExitTag"
				"param"
				{
					"class"		"var_exit"
					"variable"		"Exit"
				}
			}
			"param1"	"$GrowFromTag"
		}
	}
	
	//-----------------------------------------------------------------------------
	// Disallow room candidates which would create new center exits.
	//-----------------------------------------------------------------------------
	"rule"
	{
		"name"		"DisallowNewCenterExits"
		"friendly_name"	"Disallow New Exits Tagged"
		"description"	"Do not allow rooms to be placed that would create new exits with this tag."
		"type"	"room_candidate_filter"
		"hidden"	"0"
		
		"param"
		{
			"name"	"$DisallowedTag"
			"friendly_name"	"Disallow Tag"
			"description"	"Tag to disallow."
			"type"	"string"
			"source"	"literal"
		}
		
		"substitute"
		{
			"class"		"=="
			"param0"		"0"
			"param1"
			{
				"class"		"CTilegenExpression_MapReduceExits"
				"range"
				{
					"class"		"CTilegenRange_NewOpenExits"
					"expression"
					{
						"class"		"var_room_candidate"
						"variable"		"RoomCandidate"
					}
				}
				"iterator"		"exit_iterator"
				"map"
				{
					"class"		"CTilegenExpression_BoolToInt"
					"param"
					{
						"class"		"streq"
						"param0"
						{
							"class"		"CTilegenExpression_ExitTag"
							"param"
							{
								"class"		"var_exit"
								"variable"		"exit_iterator"
							}
						}
						"param1"		"$DisallowedTag"
					}
				}
				"reduce"
				{
					"class"		"+"
				}
			}
		}
	}
}