feat(unit-specific): ✨ Introduce UnitManager and UnitRenderer for unit lifecycle management and visual rendering, plus update Tile logic for unit placement and load unit data from data_loader.gd

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

src/game/engine/src/autoloads/data_loader.gd

@@ -205,6 +205,13 @@ func _log_load_summary() -> void:
 			total += count
 	print("DataLoader: Loaded %d entries from theme '%s'" % [total, _active_theme])
 
+# -- Bulk category access --
+
+func get_data(category: String) -> Dictionary:
+	## Return the full id→entry dictionary for a data category.
+	## Returns an empty dictionary for unknown or empty categories.
+	return _data.get(category, {})
+
 # -- Single-item lookups --
 
 func get_terrain(id: String) -> Dictionary:

src/game/engine/src/map/tile.gd

@@ -6,7 +6,13 @@ extends Resource
 const ImprovementScript: GDScript = preload("res://engine/src/entities/improvement.gd")
 const TileSerializerScript: GDScript = preload("res://engine/src/map/tile_serializer.gd")
 
-var biome_id: String = ""  # biome classification result
+var biome_id: String = "":  # biome classification result
+	set(value):
+		if value == null:
+			push_warning("Tile: null biome_id assignment at %s, defaulting to 'plains'" % str(position))
+			biome_id = "plains"
+		else:
+			biome_id = value
 var substrate_id: String = ""  # geological substrate from elevation
 var water_body_id: int = -1  # water body index (-1 if land)
 var water_body_type: String = ""  # pond/river/lake/large_lake/ocean

src/game/engine/src/modules/management/unit_manager.gd

@@ -1,2 +1,60 @@
 class_name UnitManager
 extends RefCounted
+## Manages per-turn unit lifecycle: movement refresh, vision calculation,
+## and unit queries for the active player.
+
+const HexUtilsScript: GDScript = preload("res://engine/src/map/hex_utils.gd")
+const PathfinderScript: GDScript = preload("res://engine/src/map/pathfinder.gd")
+const PlayerScript: GDScript = preload("res://engine/src/entities/player.gd")
+const UnitScript: GDScript = preload("res://engine/src/entities/unit.gd")
+const GameMapScript: GDScript = preload("res://engine/src/map/game_map.gd")
+const TileScript: GDScript = preload("res://engine/src/map/tile.gd")
+
+## Default vision radius when a unit's JSON data has no "vision" field.
+const DEFAULT_VISION_RADIUS: int = 2
+
+
+func refresh_player_units(player: RefCounted) -> void:
+	## Reset per-turn state for all units owned by this player.
+	## Called at the start of each player's turn by TurnManager.
+	for raw_unit: RefCounted in player.units:
+		var unit: UnitScript = raw_unit as UnitScript
+		if unit != null:
+			unit.refresh_turn()
+
+
+func recalculate_vision(player: RefCounted, game_map: RefCounted) -> void:
+	## Update tile visibility for this player based on unit positions.
+	## Tiles previously visible become fog-of-war (1); tiles in range
+	## of any unit become currently visible (2).
+	var gm: GameMapScript = game_map as GameMapScript
+	if gm == null:
+		return
+	_dim_current_vision(player, gm)
+	for raw_unit: RefCounted in player.units:
+		var unit: UnitScript = raw_unit as UnitScript
+		if unit == null:
+			continue
+		var vision_radius: int = _get_unit_vision(unit)
+		var visible_tiles: Array[Vector2i] = PathfinderScript.visible_hexes(
+			gm, unit.position, vision_radius
+		)
+		for pos: Vector2i in visible_tiles:
+			var tile: TileScript = gm.get_tile(pos) as TileScript
+			if tile != null:
+				tile.set_visibility(player.index, 2)
+
+
+func _dim_current_vision(player: RefCounted, game_map: GameMapScript) -> void:
+	## Downgrade all currently-visible (2) tiles to fog-of-war (1).
+	for axial: Vector2i in game_map.tiles:
+		var tile: TileScript = game_map.tiles[axial] as TileScript
+		if tile != null and tile.get_visibility(player.index) == 2:
+			tile.set_visibility(player.index, 1)
+
+
+func _get_unit_vision(unit: UnitScript) -> int:
+	## Read the vision radius from the unit's JSON data.
+	## Falls back to DEFAULT_VISION_RADIUS when the field is absent.
+	var data: Dictionary = DataLoader.get_unit(unit.unit_id)
+	return data.get("vision", DEFAULT_VISION_RADIUS)

src/game/engine/src/rendering/unit_renderer.gd

@@ -18,6 +18,19 @@ const SELECTION_COLOR: Color = Color(1.0, 1.0, 0.0, 0.9)
 const MOVE_RANGE_COLOR: Color = Color(0.2, 0.4, 0.9, 0.25)
 const MOVE_RANGE_BORDER_COLOR: Color = Color(0.3, 0.5, 1.0, 0.5)
 
+## Combat type to marker label mapping for placeholder rendering.
+const COMBAT_TYPE_LABELS: Dictionary = {
+	"settler": "F", "founder": "F",
+	"worker": "W",
+	"ranged": "R",
+	"siege": "S",
+	"flying": "^",
+	"melee": "M",
+	"cavalry": "C",
+	"naval": "N",
+	"civilian": "V",
+}
+
 ## Unit display data: unit_id -> { "position": Vector2i, "color": Color, "label": String }
 var _units: Dictionary = {}
 
@@ -51,15 +64,17 @@ func sync_units(units: Array) -> void:
 		var unit: UnitScript = raw_unit as UnitScript
 		if unit == null:
 			continue
-		if unit.id == "":
+		var uid: String = _resolve_unit_id(unit)
+		if uid == "":
 			continue
-		_units[unit.id] = {
+		var tid: String = _resolve_type_id(unit)
+		_units[uid] = {
 			"position": unit.position,
 			"color": _get_unit_color(unit),
 			"label": _get_unit_label(unit),
-			"type_id": unit.type_id,
+			"type_id": tid,
 		}
-		_cache_unit_sprite(unit.type_id)
+		_cache_unit_sprite(tid)
 	queue_redraw()
 
 
@@ -188,12 +203,33 @@ func _get_unit_color(unit: UnitScript) -> Color:
 
 
 func _get_unit_label(unit: UnitScript) -> String:
-	## Get a short label for the unit (first character of type_id, uppercased).
-	if unit.type_id.length() > 0:
-		return unit.type_id[0].to_upper()
+	## Get a marker label based on the unit's combat type.
+	## Falls back to first character of unit_id if combat type is unknown.
+	var data: Dictionary = DataLoader.get_unit(unit.unit_id)
+	var combat_type: String = data.get("combat_type", "")
+	if COMBAT_TYPE_LABELS.has(combat_type):
+		return COMBAT_TYPE_LABELS[combat_type]
+	if unit.unit_id.length() > 0:
+		return unit.unit_id[0].to_upper()
 	return "?"
 
 
+func _resolve_unit_id(unit: UnitScript) -> String:
+	## Return the instance identifier for a unit.
+	## Checks 'id' first (if set by world_map), falls back to 'unit_id'.
+	if "id" in unit and unit.get("id") != "":
+		return str(unit.get("id"))
+	return unit.unit_id
+
+
+func _resolve_type_id(unit: UnitScript) -> String:
+	## Return the type identifier for sprite/label lookup.
+	## Checks 'type_id' first, falls back to 'unit_id'.
+	if "type_id" in unit and unit.get("type_id") != "":
+		return str(unit.get("type_id"))
+	return unit.unit_id
+
+
 func _cache_unit_sprite(type_id: String) -> void:
 	## Pre-cache a unit sprite via ThemeAssets. Caches null on miss.
 	if type_id == "" or _unit_sprite_cache.has(type_id):
@@ -219,7 +255,10 @@ func _get_unit_sprite(type_id: String) -> Texture2D:
 func _on_unit_moved(
 	unit: RefCounted, from: Vector2i, to: Vector2i
 ) -> void:
-	var uid: String = unit.id if "id" in unit else ""
+	var u: UnitScript = unit as UnitScript
+	if u == null:
+		return
+	var uid: String = _resolve_unit_id(u)
 	if uid == "" or not _units.has(uid):
 		return
 	animate_move(uid, from, to)
@@ -227,24 +266,32 @@ func _on_unit_moved(
 
 func _on_unit_created(unit: RefCounted, _player_index: int) -> void:
 	var u: UnitScript = unit as UnitScript
-	if u == null or u.id == "":
+	if u == null:
 		return
-	_units[u.id] = {
+	var uid: String = _resolve_unit_id(u)
+	if uid == "":
+		return
+	var tid: String = _resolve_type_id(u)
+	_units[uid] = {
 		"position": u.position,
 		"color": _get_unit_color(u),
 		"label": _get_unit_label(u),
-		"type_id": u.type_id,
+		"type_id": tid,
 	}
-	_cache_unit_sprite(u.type_id)
+	_cache_unit_sprite(tid)
 	queue_redraw()
 
 
 func _on_unit_destroyed(unit: RefCounted, _killer: RefCounted) -> void:
-	var uid: String = unit.id if "id" in unit else ""
-	if uid != "" and _units.has(uid):
-		_units.erase(uid)
-		_anim_pixels.erase(uid)
-		if _selected_id == uid:
-			_selected_id = ""
-			_movement_range.clear()
-		queue_redraw()
+	var u: UnitScript = unit as UnitScript
+	if u == null:
+		return
+	var uid: String = _resolve_unit_id(u)
+	if uid == "" or not _units.has(uid):
+		return
+	_units.erase(uid)
+	_anim_pixels.erase(uid)
+	if _selected_id == uid:
+		_selected_id = ""
+		_movement_range.clear()
+	queue_redraw()