class_name NpcService
extends RefCounted
## The client /npc/speak loop (§6). Posts persona-free request (npc_id +
## disposition + client-computed available_moves + utterance) through an injected
## transport, degrades to an authored NPC fallback on ANY failure, extracts tags
## with TagExtractor, validates moves against available_moves (MoveValidator),
## and returns an NpcResult. It applies NO state — the caller runs MoveApplier,
## keeping state writes explicit (§2).

const ENDING_MOVES := ["end_conversation", "become_hostile"]

var _transport: DmTransport
var _fallback: FallbackLibrary


func _init(transport: DmTransport, fallback: FallbackLibrary) -> void:
	_transport = transport
	_fallback = fallback


func speak(npc_id: String, utterance: String, canon_log: CanonLog,
		disposition: int, available_moves: Array) -> NpcResult:
	var resp: DmResponse = await _transport.post_json("/npc/speak", {
		"canon_log": canon_log.to_dict(),
		"npc_id": npc_id,
		"disposition": disposition,
		"available_moves": available_moves,
		"utterance": utterance,
	})
	if not resp.transport_ok or resp.status != 200 \
			or typeof(resp.body) != TYPE_DICTIONARY or not resp.body.has("prose"):
		return NpcResult.fallback(_fallback.npc_line())

	var extracted := TagExtractor.extract(str(resp.body["prose"]))
	var moves: Array = extracted["moves"].duplicate()
	# Fold the [ADJUST_DISPOSITION:n] alias into the move stream so the validator
	# sees one uniform shape (§ tag convention).
	for delta in extracted["dispositions"]:
		moves.append({"name": "adjust_disposition", "args": [str(delta)]})

	var checked := MoveValidator.validate(moves, available_moves)
	var ends := false
	for m in checked["valid"]:
		if m["name"] in ENDING_MOVES:
			ends = true
	return NpcResult.new(
		extracted["clean_text"], extracted["facts"],
		checked["valid"], checked["dropped"], ends, false)