class_name SnapshotHandler
## Applies ObserverSnapshot data to GameState fields (D-020).
##
## Extracted from game_state.gd to separate snapshot parsing from state storage.
## All methods are static — no instance state required.
## Called via GameState.apply_snapshot() which delegates here.

# DEPRECATED: Client-side stationary_ticks fallback. Remove when server sends
# "stationary_ticks" in ObserverSnapshot (D-020 violation).
static var _prev_player_position: Vector2 = Vector2(-1e9, -1e9)


static func apply(snapshot: Dictionary) -> void:
	GameState.current_snapshot = snapshot

	if snapshot.has("tick"):
		GameState.current_tick = snapshot.tick

	if snapshot.has("entities"):
		GameState.visible_entities = snapshot.entities
		var found_player := false
		for entity in GameState.visible_entities:
			if (
				entity.has("kind")
				and entity.kind is Dictionary
				and entity.kind.get("variant") == "Player"
			):
				GameState.player_position = Vector2(entity.x, entity.y)
				if entity.has("entity_id"):
					GameState.player_entity_id = entity.entity_id
				found_player = true
				break
		if not found_player and GameState.visible_entities.size() > 0:
			push_warning(
				(
					"GameState: no Player entity found in %d entities"
					% [GameState.visible_entities.size()]
				)
			)

	# D-020/D-071 (#530): Server-authoritative stationary_ticks for ListeningFocus boost.
	if snapshot.has("stationary_ticks") and snapshot.stationary_ticks is int:
		GameState.stationary_ticks = snapshot.stationary_ticks
	else:
		# DEPRECATED fallback — client-side accumulation. Remove when server sends field.
		if GameState.player_position == _prev_player_position:
			GameState.stationary_ticks += 1
		else:
			GameState.stationary_ticks = 0
	_prev_player_position = GameState.player_position

	# Tiles for rendering: test mode sends "tiles", live server sends "visible_tiles"
	if snapshot.has("tiles"):
		GameState.visible_tiles = snapshot.tiles
	elif (
		snapshot.has("visible_tiles")
		and snapshot.visible_tiles is Array
		and snapshot.visible_tiles.size() > 0
	):
		var has_type := false
		if snapshot.visible_tiles.size() > 0 and snapshot.visible_tiles[0] is Dictionary:
			has_type = snapshot.visible_tiles[0].has("type")
		if has_type:
			GameState.visible_tiles = snapshot.visible_tiles

	if snapshot.has("visible_positions"):
		GameState.visible_positions.clear()
		for pos in snapshot.visible_positions:
			GameState.visible_positions[Vector2i(pos.x, pos.y)] = true

	# v2: game_time (D-031)
	if snapshot.has("game_time") and snapshot.game_time is Dictionary:
		GameState.game_time = snapshot.game_time

	# v2: player_facing (D-015)
	if snapshot.has("player_facing") and snapshot.player_facing is String:
		GameState.player_facing = snapshot.player_facing

	# v4: nearby_interactions (#404/#405)
	if snapshot.has("nearby_interactions") and snapshot.nearby_interactions is Array:
		GameState.nearby_interactions = snapshot.nearby_interactions
	else:
		GameState.nearby_interactions = []

	# v5: current_monologue (#414)
	if snapshot.has("current_monologue") and snapshot.current_monologue is Dictionary:
		GameState.current_monologue = snapshot.current_monologue
	else:
		GameState.current_monologue = null

	# #122: lattice_profile
	if snapshot.has("lattice_profile") and snapshot.lattice_profile is String:
		GameState.lattice_profile = snapshot.lattice_profile

	# v6: player_stance (#449, D-053)
	if snapshot.has("player_stance") and snapshot.player_stance is String:
		GameState.player_stance = snapshot.player_stance

	# v6: player_inventory (#449, D-065)
	if snapshot.has("player_inventory") and snapshot.player_inventory is Array:
		GameState.player_inventory = snapshot.player_inventory
	else:
		GameState.player_inventory = []

	# v7: current_dialogue (#434, D-061)
	if snapshot.has("current_dialogue") and snapshot.current_dialogue is Dictionary:
		GameState.current_dialogue = snapshot.current_dialogue
	else:
		GameState.current_dialogue = null

	# v7: pending_recognitions (#431, D-059/D-060)
	if snapshot.has("pending_recognitions") and snapshot.pending_recognitions is Array:
		GameState.pending_recognitions = snapshot.pending_recognitions
	else:
		GameState.pending_recognitions = []

	# v9: conversation_events (#535, D-078)
	if snapshot.has("conversation_events") and snapshot.conversation_events is Array:
		GameState.conversation_events = snapshot.conversation_events
	else:
		GameState.conversation_events = []

	# v9: conversation_ended (#535, D-078)
	if snapshot.has("conversation_ended") and snapshot.conversation_ended is Array:
		GameState.conversation_ended = snapshot.conversation_ended
	else:
		GameState.conversation_ended = []

	# v8: dialogue_response (#305, D-028)
	if snapshot.has("dialogue_response") and snapshot.dialogue_response is Dictionary:
		GameState.dialogue_response = snapshot.dialogue_response
	else:
		GameState.dialogue_response = null

	# v8: gauntlet mode (#496)
	if snapshot.has("gauntlet_mode") and snapshot.gauntlet_mode == true:
		GameState.gauntlet_mode = true
	else:
		GameState.gauntlet_mode = false
	if snapshot.has("room_id") and snapshot.room_id is String:
		GameState.room_id = snapshot.room_id
	else:
		GameState.room_id = null

	# OQ-07 (#522): insert_active
	if snapshot.has("insert_active") and snapshot.insert_active is bool:
		GameState.insert_active = snapshot.insert_active
	else:
		GameState.insert_active = true

	# #507: rng_seed
	if snapshot.has("rng_seed"):
		GameState.rng_seed = snapshot.rng_seed
	else:
		GameState.rng_seed = null

	# D-018: Sound events — partition by range_category.
	if snapshot.has("sound_events") and snapshot.sound_events is Array:
		GameState.medium_sound_events = []
		GameState.close_sound_events = []
		for se in snapshot.sound_events:
			if not se is Dictionary:
				continue
			var rc: String = se.get("range_category", "")
			if rc == "Medium":
				GameState.medium_sound_events.append(se)
			elif rc == "Close":
				GameState.close_sound_events.append(se)
	else:
		GameState.medium_sound_events = []
		GameState.close_sound_events = []

	# v10: discovered_pois (#151, D-013)
	if snapshot.has("discovered_pois") and snapshot.discovered_pois is Array:
		GameState.discovered_pois = snapshot.discovered_pois
	elif snapshot.has("poi_list") and snapshot.poi_list is Array:
		GameState.discovered_pois = snapshot.poi_list

	# v14: examine_result (#174, #242)
	if snapshot.has("examine_result") and snapshot.examine_result is Dictionary:
		GameState.current_examine_result = snapshot.examine_result
	else:
		GameState.current_examine_result = null

	# v15: save_result (#554, D-085)
	if snapshot.has("save_result") and snapshot.save_result is Dictionary:
		GameState.save_result = snapshot.save_result
	else:
		GameState.save_result = null

	# v18: debug_response (#580)
	if snapshot.has("debug_response") and snapshot.debug_response is Dictionary:
		GameState.debug_response = snapshot.debug_response
	else:
		GameState.debug_response = null

	# v20: settings_response (#627, D-138)
	if snapshot.has("settings_response") and snapshot.settings_response is Dictionary:
		GameState.settings_response = snapshot.settings_response
		var sr: Dictionary = snapshot.settings_response
		if sr.get("kind") == "full":
			var sr_settings: Variant = sr.get("settings")
			if sr_settings is Array:
				for entry in sr_settings:
					if not entry is Dictionary:
						continue
					if entry.get("key") == "ai_dialogue.enabled":
						var val: Variant = entry.get("value")
						if val != null:
							GameState.ai_enhanced_dialogue_enabled = _extract_bool_setting(
								"ai_dialogue.enabled", val
							)
	else:
		GameState.settings_response = null

	# v21: economy_snapshot (#824, D-181)
	if snapshot.has("economy_snapshot") and snapshot.economy_snapshot is Dictionary:
		GameState.economy_snapshot = snapshot.economy_snapshot
	else:
		GameState.economy_snapshot = null

	# #718: character_visual_descriptor — restored from server snapshot on save/load.
	if (
		snapshot.has("character_visual_descriptor")
		and snapshot.character_visual_descriptor is Dictionary
	):
		var CVD := load("res://scripts/rendering/character_visual_descriptor.gd")
		if CVD != null:
			var restored = CVD.from_dict(snapshot.character_visual_descriptor)
			if restored != null:
				GameState.character_visual_descriptor = restored

	# v14: player_knowledge (#264, D-041)
	if snapshot.has("player_knowledge") and snapshot.player_knowledge is Dictionary:
		GameState.player_knowledge = snapshot.player_knowledge

	# D-020/D-073 (#529): Server-authoritative zone_id for zone ambient crossfade.
	if snapshot.has("zone_id") and snapshot.zone_id is String:
		GameState.current_zone_id = snapshot.zone_id
	else:
		# DEPRECATED fallback — client-side tile lookup. Remove when server sends top-level "zone_id".
		var tile_by_coord: Dictionary = {}
		for vtile in GameState.visible_tiles:
			if vtile is Dictionary and vtile.has("x") and vtile.has("y"):
				tile_by_coord[Vector2i(vtile.x, vtile.y)] = vtile
		var player_pos_key := Vector2i(
			int(GameState.player_position.x), int(GameState.player_position.y)
		)
		var player_tile = tile_by_coord.get(player_pos_key, null)
		GameState.current_zone_id = player_tile.get("zone_id", "") if player_tile else ""

	# v2: visible_tiles with visibility sectors
	if (
		snapshot.has("visible_tiles")
		and snapshot.visible_tiles is Array
		and snapshot.visible_tiles.size() > 0
	):
		GameState.visibility_sectors.clear()
		var has_explicit_positions := snapshot.has("visible_positions")
		if not has_explicit_positions:
			GameState.visible_positions.clear()
		GameState.boundary_positions.clear()
		for vtile in snapshot.visible_tiles:
			if not vtile is Dictionary or not vtile.has("x") or not vtile.has("y"):
				continue
			var pos := Vector2i(vtile.x, vtile.y)
			var vis_sector: String = vtile.get("visibility", "")
			if vtile.has("visibility"):
				GameState.visibility_sectors[pos] = vis_sector
			if vis_sector == "BoundaryWall":
				GameState.boundary_positions[pos] = true
			elif not has_explicit_positions:
				GameState.visible_positions[pos] = true


## Extract a bool from a tagged-union {"Bool": true} or plain bool value.
static func _extract_bool_setting(key: String, val: Variant) -> bool:
	if val is bool:
		return val
	if val is Dictionary and val.has("Bool"):
		return bool(val["Bool"])
	push_warning("GameState: unexpected type for setting '%s': %s" % [key, str(val)])
	return false