class_name CursorRenderer
extends Node2D

## Cursor state machine — 4 geometric states, 150ms linear transitions (D-056).
## Insert-styled cursor on z-layer 7 (UILayer CanvasLayer).
## Detects entity hover via world-space proximity to visible entities.

enum State { DEFAULT, ENTITY_HOVER, OBJECT_HOVER, WEAPON_AIM }

# --- Public ---
var current_state: State = State.DEFAULT
var hovered_entity_id: int = -1
var weapon_mode_active: bool = false
# OQ-07 (#522): when false, verb labels are suppressed (should_show_interactions → false).
# Cursor shape transitions still fire — the character's body still orients to targets.
var insert_active: bool = true

signal state_changed(new_state: State)
signal hovered_entity_changed(entity_id: int)

# D-056 colors
const COLOR_DEFAULT := Color("#c8d0e0")
const COLOR_OBJECT := Color("#8b8ba0")
const COLOR_OBJECT_FLAGGED := Color("#e8c547")
const COLOR_WEAPON := Color("#f0e8d8")

const TRANSITION_SEC := 0.15  # 150ms linear (D-056)
const HOVER_RADIUS_PX := 16.0  # World pixels — ~half a tile

# Bracket geometry (screen pixels — sized for 24px entity at 2x zoom)
const BRACKET_HALF := 26.0
const BRACKET_ARM := 8.0

# --- Transition state ---
var _target: State = State.DEFAULT
var _t: float = 1.0
var _from: Dictionary = {}
var _time: float = 0.0
var _mouse_inside: bool = true
var _shift_held: bool = false

# Hover tracking
var _hover_color: Color = COLOR_DEFAULT
var _hover_offset: Vector2 = Vector2.ZERO

# Interpolated draw params
var _gap: float = 4.0
var _len: float = 6.0
var _rot: float = 0.0
var _thick: float = 1.0
var _color: Color = COLOR_DEFAULT
var _bloom: float = 0.4
var _bracket_a: float = 0.0
var _alpha: float = 0.45


func _ready() -> void:
	Input.set_mouse_mode(Input.MOUSE_MODE_HIDDEN)
	_from = _snapshot()


func _notification(what: int) -> void:
	if what == NOTIFICATION_WM_MOUSE_EXIT:
		_mouse_inside = false
		visible = false
	elif what == NOTIFICATION_WM_MOUSE_ENTER:
		_mouse_inside = true
		visible = true


func _process(delta: float) -> void:
	if not _mouse_inside:
		return
	_time += delta
	position = get_viewport().get_mouse_position()
	_detect_hover()
	if _t < 1.0:
		_t = minf(_t + delta / TRANSITION_SEC, 1.0)
		_interpolate()
		if _t >= 1.0:
			current_state = _target
	queue_redraw()


# --- Hover detection (automatic, from GameState.visible_entities) ---

func _detect_hover() -> void:
	var prev_id := hovered_entity_id

	if weapon_mode_active:
		var found := _find_nearest_entity()
		hovered_entity_id = found.id
		_hover_color = found.color
		_hover_offset = found.offset
		_set_target(State.WEAPON_AIM)
		if hovered_entity_id != prev_id:
			hovered_entity_changed.emit(hovered_entity_id)
		return

	var found := _find_nearest_entity()
	hovered_entity_id = found.id
	_hover_color = found.color
	_hover_offset = found.offset
	var new_state := State.DEFAULT
	if found.id >= 0:
		new_state = State.ENTITY_HOVER if found.kind == "Npc" else State.OBJECT_HOVER
	_set_target(new_state)
	if hovered_entity_id != prev_id:
		hovered_entity_changed.emit(hovered_entity_id)


func _find_nearest_entity() -> Dictionary:
	var xform := get_viewport().get_canvas_transform()
	var mouse_screen := get_viewport().get_mouse_position()
	var mouse_world: Vector2 = xform.affine_inverse() * mouse_screen

	var best_dist := INF
	var result := { id = -1, kind = "", color = COLOR_DEFAULT, offset = Vector2.ZERO }

	for entity in GameState.visible_entities:
		if not entity.has("entity_id") or not entity.has("x") or not entity.has("y"):
			continue
		if entity.entity_id == GameState.player_entity_id:
			continue
		var center := Vector2(
			floorf(entity.x) * Constants.TILE_SIZE + Constants.TILE_SIZE * 0.5,
			floorf(entity.y) * Constants.TILE_SIZE + Constants.TILE_SIZE * 0.5
		)
		var dist := mouse_world.distance_to(center)
		if dist < HOVER_RADIUS_PX and dist < best_dist:
			best_dist = dist
			result.id = entity.entity_id
			result.kind = entity.get("kind", {}).get("variant", "")
			result.color = Constants.color_for_entity_kind(entity)
			result.offset = (xform * center) - mouse_screen
	return result


# --- State transitions ---

func _set_target(new_state: State) -> void:
	if new_state == _target:
		return
	_target = new_state
	_from = _snapshot()
	# D-056: weapon aim is "hard transition" — skip interpolation
	if new_state == State.WEAPON_AIM:
		_t = 1.0
		_apply_params(_params_for(State.WEAPON_AIM))
		current_state = State.WEAPON_AIM
	else:
		_t = 0.0
	state_changed.emit(new_state)


func _snapshot() -> Dictionary:
	return { gap = _gap, len = _len, rot = _rot, thick = _thick,
		color = _color, bloom = _bloom, bracket_a = _bracket_a, alpha = _alpha }


func _params_for(state: State) -> Dictionary:
	match state:
		State.ENTITY_HOVER:
			return { gap = 10.0, len = 6.0, rot = 0.0, thick = 1.0,
				color = _hover_color, bloom = 0.5, bracket_a = 1.0, alpha = 1.0 }
		State.OBJECT_HOVER:
			return { gap = 4.0, len = 6.0, rot = PI / 4.0, thick = 1.0,
				color = _hover_color, bloom = 0.3, bracket_a = 0.0, alpha = 0.8 }
		State.WEAPON_AIM:
			return { gap = 12.0, len = 9.0, rot = 0.0, thick = 2.0,
				color = COLOR_WEAPON, bloom = 0.0, bracket_a = 0.0, alpha = 1.0 }
		_:
			return { gap = 4.0, len = 6.0, rot = 0.0, thick = 1.0,
				color = COLOR_DEFAULT, bloom = 0.4, bracket_a = 0.0, alpha = 0.45 }


func _apply_params(p: Dictionary) -> void:
	_gap = p.gap; _len = p.len; _rot = p.rot; _thick = p.thick
	_color = p.color; _bloom = p.bloom; _bracket_a = p.bracket_a; _alpha = p.alpha


func _interpolate() -> void:
	var p := _params_for(_target)
	_gap = lerpf(_from.gap, p.gap, _t)
	_len = lerpf(_from.len, p.len, _t)
	_rot = lerp_angle(_from.rot, p.rot, _t)
	_thick = lerpf(_from.thick, p.thick, _t)
	_color = _from.color.lerp(p.color, _t)
	_bloom = lerpf(_from.bloom, p.bloom, _t)
	_bracket_a = lerpf(_from.bracket_a, p.bracket_a, _t)
	_alpha = lerpf(_from.alpha, p.alpha, _t)


# --- Drawing ---

func _draw() -> void:
	# _hover_offset is computed in _detect_hover() during _process(), not recalculated
	# here. This is safe because Camera2D (tree sibling, earlier in scene order) applies
	# its smoothing transform before CursorRenderer._process() reads canvas_transform.
	# Nothing modifies the canvas transform between _process() and _draw().

	# Bloom pass — wider, semi-transparent glow
	if _bloom > 0.01:
		var bloom_mod := 1.0
		# D-056: ~10% bloom pulse during entity hover
		if current_state == State.ENTITY_HOVER:
			bloom_mod += sin(_time * 4.0) * 0.1
		var bloom_a := _alpha * _bloom * 0.6 * bloom_mod
		_draw_ticks(Color(_color, bloom_a), _thick + 3.0)
		if _bracket_a > 0.01:
			_draw_brackets(_hover_offset, Color(_color, _bracket_a * _bloom * 0.4))

	# Crisp pass
	_draw_ticks(Color(_color, _alpha), _thick)
	if _bracket_a > 0.01:
		_draw_brackets(_hover_offset, Color(_color, _bracket_a * _alpha))


func _draw_ticks(color: Color, thickness: float) -> void:
	var dirs: Array[Vector2] = [Vector2.UP, Vector2.RIGHT, Vector2.DOWN, Vector2.LEFT]
	for dir: Vector2 in dirs:
		var d := dir.rotated(_rot)
		draw_line(d * _gap, d * (_gap + _len), color, thickness, true)


func _draw_brackets(offset: Vector2, color: Color) -> void:
	for sx in [-1.0, 1.0]:
		for sy in [-1.0, 1.0]:
			var corner := offset + Vector2(sx * BRACKET_HALF, sy * BRACKET_HALF)
			draw_line(corner, corner + Vector2(-sx * BRACKET_ARM, 0), color, 1.0, true)
			draw_line(corner, corner + Vector2(0, -sy * BRACKET_ARM), color, 1.0, true)


# --- Test-friendly API (expected by test_cursor_states.gd) ---

func get_state() -> String:
	match current_state:
		State.DEFAULT: return "Default"
		State.ENTITY_HOVER: return "EntityHover"
		State.OBJECT_HOVER: return "ObjectHover"
		State.WEAPON_AIM: return "WeaponAim"
		_: return "Default"


func set_hover_target(data: Dictionary) -> void:
	var kind: String = data.get("kind", "")
	# D-056: cursor changes require LOS
	if not data.get("in_los", true):
		return

	hovered_entity_id = data.get("entity_id", -1)
	if kind == "Npc":
		var rel: String = data.get("relationship", "Unknown")
		match rel:
			"Friendly": _hover_color = Constants.ENTITY_COLOR_FRIENDLY
			"PersonOfInterest": _hover_color = Constants.ENTITY_COLOR_POI
			"Hostile": _hover_color = Constants.ENTITY_COLOR_HOSTILE
			_: _hover_color = Constants.ENTITY_COLOR_UNKNOWN
		_target = State.ENTITY_HOVER
		_t = 1.0
		_apply_params(_params_for(State.ENTITY_HOVER))
		current_state = State.ENTITY_HOVER
	elif kind == "Object" or kind == "Terrain":
		_hover_color = COLOR_OBJECT_FLAGGED if data.get("flagged", false) else COLOR_OBJECT
		_target = State.OBJECT_HOVER
		_t = 1.0
		_apply_params(_params_for(State.OBJECT_HOVER))
		current_state = State.OBJECT_HOVER


func clear_hover_target() -> void:
	hovered_entity_id = -1
	_hover_color = COLOR_DEFAULT
	_target = State.DEFAULT
	_t = 1.0
	_apply_params(_params_for(State.DEFAULT))
	current_state = State.DEFAULT


func set_weapon_mode(active: bool) -> void:
	weapon_mode_active = active
	if active:
		_target = State.WEAPON_AIM
		_t = 1.0
		_apply_params(_params_for(State.WEAPON_AIM))
		current_state = State.WEAPON_AIM
	else:
		_target = State.DEFAULT
		_t = 1.0
		_apply_params(_params_for(State.DEFAULT))
		current_state = State.DEFAULT


func set_shift_held(held: bool) -> void:
	_shift_held = held


func get_transition_duration() -> float:
	return TRANSITION_SEC


func get_cursor_color() -> Color:
	return _color


func get_z_layer() -> int:
	return Constants.CANVAS_UI  # D-049/D-056


func should_show_interactions() -> bool:
	# OQ-07: insert off suppresses verb labels even though cursor shape still changes
	if not insert_active:
		return false
	return not weapon_mode_active or _shift_held


func set_insert_active(active: bool) -> void:
	insert_active = active


func get_interaction_range() -> int:
	return 2  # D-056: ~2 sim tiles