extends Node2D
## Pawn entity — grid-snapped, sim-tick-driven movement with smooth render lerp.
##
## Movement model (docs/architecture.md "Pawn movement"):
##   At 1× speed, crossing one tile costs STEP_TICKS sim ticks (10 ticks = 0.5 s
##   at 20 Hz). Each sim tick advances _step_progress by 1/STEP_TICKS. When
##   progress reaches 1.0 the pawn snaps to the next waypoint.
##
## Speed scaling is free: Pause → no ticks → pawn frozen; Ultra → 12× ticks/s →
## pawn crosses the map in ~7 s real time. No per-pawn speed handling needed.
##
## Render: _process() lerps world-position between current and next tile every
## render frame at 60 Hz — motion is smooth even at low sim Hz.

class_name Pawn

const STEP_TICKS: int = 10
const TILE_SIZE_PX: int = 16  # Mirrors World.TILE_SIZE_PX; standalone so Pawn needs no World reference.

signal walk_started
signal walk_completed
signal arrived_at_destination(tile: Vector2i)

@export var pawn_name: String = ""

var tile: Vector2i = Vector2i.ZERO

var _path: Array[Vector2i] = []
var _step_progress: float = 0.0
var _selected: bool = false

@onready var _name_label: Label = $NameLabel
@onready var _state_label: Label = $StateLabel


func _ready() -> void:
	EventBus.sim_tick.connect(_on_sim_tick)
	_state_label.text = Strings.t(&"pawn.state.idle")


func setup(p_name: String, start_tile: Vector2i) -> void:
	pawn_name = p_name
	tile = start_tile
	position = _tile_to_world(tile)
	_name_label.text = pawn_name
	_state_label.text = Strings.t(&"pawn.state.idle")
	Audit.log("pawn", "%s spawned at %s" % [pawn_name, start_tile])


# ── public API ──────────────────────────────────────────────────────────────

func walk_along_path(new_path: Array[Vector2i]) -> void:
	if new_path.is_empty():
		return
	var was_walking := is_walking()
	_path = new_path.duplicate()
	# _step_progress carries over; when it hits 1.0 the pawn snaps to
	# the first tile of the new path and picks up the new direction.
	if not was_walking:
		walk_started.emit()
		_state_label.text = Strings.t(&"pawn.state.walking")
	Audit.log("pawn", "%s walk path len %d → %s" % [pawn_name, new_path.size(), new_path[-1]])


func is_walking() -> bool:
	return not _path.is_empty()


func set_selected(value: bool) -> void:
	if _selected == value:
		return
	_selected = value
	queue_redraw()


func is_selected() -> bool:
	return _selected


# ── sim tick ────────────────────────────────────────────────────────────────

func _on_sim_tick(_tick_number: int) -> void:
	if not is_walking():
		return
	_step_progress += 1.0 / float(STEP_TICKS)
	if _step_progress >= 1.0:
		tile = _path[0]
		_path.remove_at(0)
		_step_progress = 0.0
		if _path.is_empty():
			_state_label.text = Strings.t(&"pawn.state.idle")
			walk_completed.emit()
			arrived_at_destination.emit(tile)
			Audit.log("pawn", "%s arrived at %s" % [pawn_name, tile])


# ── render ──────────────────────────────────────────────────────────────────

func _process(_delta: float) -> void:
	var from_world := _tile_to_world(tile)
	var next := _path[0] if is_walking() else tile
	var to_world := _tile_to_world(next)
	position = from_world.lerp(to_world, _step_progress)


func _draw() -> void:
	# Body disc — colour derived deterministically from pawn name so each pawn
	# is visually distinct without any art dependency.
	var hue := float(pawn_name.hash() % 360) / 360.0
	var body_colour := Color.from_hsv(hue, 0.7, 0.85)

	draw_circle(Vector2.ZERO, 6.0, body_colour)

	# Dark outline ring.
	draw_arc(Vector2.ZERO, 7.0, 0.0, TAU, 24, Color(0.0, 0.0, 0.0, 0.6), 1.0)

	# Selection ring.
	if _selected:
		draw_arc(Vector2.ZERO, 10.0, 0.0, TAU, 32, Color(1.0, 0.9, 0.2, 0.85), 2.0)


# ── helpers ─────────────────────────────────────────────────────────────────

func _tile_to_world(t: Vector2i) -> Vector2:
	return Vector2(
		t.x * TILE_SIZE_PX + TILE_SIZE_PX / 2.0,
		t.y * TILE_SIZE_PX + TILE_SIZE_PX / 2.0
	)