extends Control
## #348: F3 debug overlay — real-time visualization of game state for dev use.
## Dev-only: disabled entirely in export builds (OS.is_debug_build() = false).
##
## Panels:
##   1. Stats text (top-left): tick, pos, fps, etc.
##   2. World overlays (over game): LOS rays, vision cone, NPC paths, info tags
##   3. Tick timing graph (bottom-left): last-30-tick delta sparkline

# ---------------------------------------------------------------------------
# Constants
# ---------------------------------------------------------------------------

const HEADER_COLOR := Color("#e8c547")
const LABEL_COLOR := Color("#8890a0")
const VALUE_COLOR := Color("#c8d0e0")
const BG_COLOR := Color(0.08, 0.08, 0.12, 0.85)
const FONT_SIZE := 12
const LINE_HEIGHT := 16
const PADDING := Vector2(10, 8)
const COL_GAP := 16

# World overlay colors
const LOS_COLOR := Color(0.27, 0.78, 0.65, 0.50)
const PLAYER_DOT_COLOR := Color(0.88, 0.77, 0.28, 0.85)
const CONE_FORWARD_COLOR := Color(0.27, 0.78, 0.65, 0.12)
const CONE_PERIPHERAL_COLOR := Color(0.20, 0.55, 0.80, 0.07)
const CONE_RING_COLOR := Color(0.27, 0.78, 0.65, 0.55)
const NPC_PATH_COLOR := Color(0.83, 0.48, 0.35, 0.75)
const NPC_DOT_COLOR := Color(0.83, 0.48, 0.35, 0.90)
const TAG_BG_COLOR := Color(0.05, 0.05, 0.10, 0.80)
const TAG_TEXT_COLOR := Color("#c8d0e0")
const GRAPH_BG_COLOR := Color(0.06, 0.06, 0.10, 0.82)
const GRAPH_LINE_COLOR := Color("#6bc9a6")
const GRAPH_WARN_COLOR := Color("#e8c547")

# Vision cone geometry (radians)
# Forward: ±60° around facing direction (120° total)
# Peripheral: ±60° to ±120° on each side (60° band each side)
const CONE_FORWARD_HALF: float = PI / 3.0  # 60°
const CONE_PERIPHERAL_HALF: float = PI * 2.0 / 3.0  # 120°
const CONE_ARC_STEPS: int = 20

# NPC path history
const NPC_HISTORY_LEN: int = 12
const NPC_DOT_RADIUS: float = 3.5
const PLAYER_DOT_RADIUS: float = 5.0

# Tick timing graph
const GRAPH_W: float = 160.0
const GRAPH_H: float = 48.0
const GRAPH_MARGIN: float = 10.0
const TICK_HISTORY_LEN: int = 30
const TICK_WARN_MS: float = 120.0

# ---------------------------------------------------------------------------
# State
# ---------------------------------------------------------------------------

var _cached_font: Font = null
var _dev_mode: bool = false

# NPC path history: entity_id (int) → Array of Vector2 (world positions)
var _npc_paths: Dictionary = {}
var _last_tick_processed: int = -1

# Tick timing ring
var _tick_times: Array = []  # Time.get_ticks_msec() on each snapshot
var _tick_deltas: Array = []  # ms between consecutive snapshots

# ---------------------------------------------------------------------------
# Lifecycle
# ---------------------------------------------------------------------------


func _ready() -> void:
	_dev_mode = OS.is_debug_build()
	visible = false
	# Position set in main.tscn: below merged HUD status panel (starts at y:16)
	_cached_font = ThemeDB.fallback_font
	# Clear NPC path history on session change to prevent entity ID collisions
	GameState.connect("game_id_changed", _on_game_id_changed)


func _on_game_id_changed(_new_id: String) -> void:
	_npc_paths.clear()
	_tick_deltas.clear()
	_tick_times.clear()
	_last_tick_processed = -1


func _unhandled_input(event: InputEvent) -> void:
	if not _dev_mode:
		return
	if event.is_action_pressed("debug_overlay"):
		visible = not visible
		if visible:
			queue_redraw()


func update_from_state() -> void:
	if not _dev_mode or not visible:
		return

	# Record tick arrival time for timing graph
	var now_ms := Time.get_ticks_msec()
	if _last_tick_processed != GameState.current_tick:
		_last_tick_processed = GameState.current_tick
		if _tick_times.size() > 0:
			_tick_deltas.append(float(now_ms - _tick_times.back()))
			if _tick_deltas.size() > TICK_HISTORY_LEN:
				_tick_deltas.pop_front()
		_tick_times.append(now_ms)
		if _tick_times.size() > TICK_HISTORY_LEN + 1:
			_tick_times.pop_front()
		_update_npc_paths()

	queue_redraw()


func _update_npc_paths() -> void:
	var seen_ids: Dictionary = {}
	for entity in GameState.visible_entities:
		if not entity is Dictionary:
			continue
		var kind_variant: String = entity.get("kind", {}).get("variant", "")
		if kind_variant != "Npc":
			continue
		var eid: int = entity.get("entity_id", -1)
		if eid < 0:
			continue
		seen_ids[eid] = true
		var pos := Vector2(entity.get("x", 0.0), entity.get("y", 0.0))
		if not _npc_paths.has(eid):
			_npc_paths[eid] = []
		var path: Array = _npc_paths[eid]
		if path.size() == 0 or path.back() != pos:
			path.append(pos)
			if path.size() > NPC_HISTORY_LEN:
				path.pop_front()
	# Prune entities no longer visible
	for eid in _npc_paths.keys():
		if not seen_ids.has(eid):
			_npc_paths.erase(eid)


# ---------------------------------------------------------------------------
# Draw dispatch
# ---------------------------------------------------------------------------


func _draw() -> void:
	if not visible:
		return
	_draw_stats_panel()
	_draw_world_overlays()
	_draw_tick_graph()


# ---------------------------------------------------------------------------
# Panel 1: Stats text (top-left)
# ---------------------------------------------------------------------------


func _draw_stats_panel() -> void:
	var font: Font = _cached_font if _cached_font else ThemeDB.fallback_font

	var left_lines: Array = []
	var right_lines: Array = []

	left_lines.append(["tick", str(GameState.current_tick)])
	right_lines.append(["fps", str(Engine.get_frames_per_second())])

	var pos := GameState.player_position
	left_lines.append(["pos", "(%d, %d)" % [int(pos.x), int(pos.y)]])
	right_lines.append(["facing", GameState.player_facing])

	left_lines.append(["stance", GameState.player_stance])
	right_lines.append(
		["zone", GameState.current_zone_id if GameState.current_zone_id != "" else "-"]
	)

	left_lines.append(["entities", str(GameState.visible_entities.size())])
	right_lines.append(["tiles", str(GameState.visible_tiles.size())])

	left_lines.append(["interactions", str(GameState.nearby_interactions.size())])
	right_lines.append(["recognitions", str(GameState.pending_recognitions.size())])

	var mono_status := "active" if GameState.current_monologue != null else "idle"
	var dlg_status := "active" if GameState.dialogue_active else "idle"
	left_lines.append(["monologue", mono_status])
	right_lines.append(["dialogue", dlg_status])

	left_lines.append(["stationary", str(GameState.stationary_ticks)])
	right_lines.append(["insert", "ON" if GameState.insert_active else "OFF"])

	var gt := GameState.game_time
	var time_str := (
		"%s d%s" % [gt.get("day_phase", "-"), str(gt.get("day", "-"))] if gt.size() > 0 else "-"
	)
	var rate_str: String = gt.get("tick_rate", "-") if gt.size() > 0 else "-"
	left_lines.append(["time", time_str])
	right_lines.append(["tick_rate", rate_str])

	var mode_str := "test" if SimBridge.test_mode else "live"
	var gauntlet_str := "ON" if GameState.gauntlet_mode else "OFF"
	left_lines.append(["mode", mode_str])
	right_lines.append(["gauntlet", gauntlet_str])

	var gid := GameState.current_game_id
	left_lines.append(["game_id", gid if gid != "" else "-"])
	right_lines.append(["npc_paths", str(_npc_paths.size())])

	var left_label_w: float = 0.0
	var left_value_w: float = 0.0
	var right_label_w: float = 0.0
	var right_value_w: float = 0.0

	for line in left_lines:
		left_label_w = max(
			left_label_w,
			font.get_string_size(line[0] + ": ", HORIZONTAL_ALIGNMENT_LEFT, -1, FONT_SIZE).x
		)
		left_value_w = max(
			left_value_w, font.get_string_size(line[1], HORIZONTAL_ALIGNMENT_LEFT, -1, FONT_SIZE).x
		)
	for line in right_lines:
		right_label_w = max(
			right_label_w,
			font.get_string_size(line[0] + ": ", HORIZONTAL_ALIGNMENT_LEFT, -1, FONT_SIZE).x
		)
		right_value_w = max(
			right_value_w, font.get_string_size(line[1], HORIZONTAL_ALIGNMENT_LEFT, -1, FONT_SIZE).x
		)

	var header_text := "F3 DEBUG"
	var header_w := (
		font.get_string_size(header_text, HORIZONTAL_ALIGNMENT_LEFT, -1, FONT_SIZE + 1).x
	)
	var content_w := left_label_w + left_value_w + COL_GAP + right_label_w + right_value_w
	var box_w: float = max(header_w, content_w) + PADDING.x * 2
	var line_count: int = maxi(left_lines.size(), right_lines.size())
	var box_h: float = PADDING.y * 2 + LINE_HEIGHT + LINE_HEIGHT * line_count

	draw_rect(Rect2(Vector2.ZERO, Vector2(box_w, box_h)), BG_COLOR)

	var y: float = PADDING.y + FONT_SIZE
	draw_string(
		font,
		Vector2(PADDING.x, y),
		header_text,
		HORIZONTAL_ALIGNMENT_LEFT,
		-1,
		FONT_SIZE + 1,
		HEADER_COLOR
	)
	y += LINE_HEIGHT

	var right_x: float = PADDING.x + left_label_w + left_value_w + COL_GAP
	for i in range(line_count):
		if i < left_lines.size():
			draw_string(
				font,
				Vector2(PADDING.x, y),
				left_lines[i][0] + ": ",
				HORIZONTAL_ALIGNMENT_LEFT,
				-1,
				FONT_SIZE,
				LABEL_COLOR
			)
			draw_string(
				font,
				Vector2(PADDING.x + left_label_w, y),
				left_lines[i][1],
				HORIZONTAL_ALIGNMENT_LEFT,
				-1,
				FONT_SIZE,
				VALUE_COLOR
			)
		if i < right_lines.size():
			draw_string(
				font,
				Vector2(right_x, y),
				right_lines[i][0] + ": ",
				HORIZONTAL_ALIGNMENT_LEFT,
				-1,
				FONT_SIZE,
				LABEL_COLOR
			)
			draw_string(
				font,
				Vector2(right_x + right_label_w, y),
				right_lines[i][1],
				HORIZONTAL_ALIGNMENT_LEFT,
				-1,
				FONT_SIZE,
				VALUE_COLOR
			)
		y += LINE_HEIGHT


# ---------------------------------------------------------------------------
# Panel 2: World overlays
# ---------------------------------------------------------------------------


func _draw_world_overlays() -> void:
	var vp := get_viewport()
	if vp == null:
		return
	# get_canvas_transform() applies Camera2D — valid for CanvasLayer 0 content.
	# The DebugOverlay is on UILayer (layer 20) so its own draw space IS screen space.
	# Using this transform converts world coords → screen pixel coords for the overlays.
	var canvas_xf := vp.get_canvas_transform()
	var player_screen := _w2s(GameState.player_position, canvas_xf)

	_draw_vision_cone(player_screen, canvas_xf)
	_draw_los_rays(player_screen, canvas_xf)
	_draw_npc_paths(canvas_xf)
	_draw_info_tags(canvas_xf)


# Convert world tile position → screen pixel position
func _w2s(world_pos: Vector2, canvas_xf: Transform2D) -> Vector2:
	return canvas_xf * (world_pos * Constants.TILE_SIZE)


# Vision cone: filled forward sector + peripheral bands.
# Uses player facing direction and visibility sector distance.
func _draw_vision_cone(player_screen: Vector2, canvas_xf: Transform2D) -> void:
	var facing_angle := _facing_to_angle(GameState.player_facing)

	# Estimate visible radius from furthest visibility sector tile
	var max_d: float = 4.0
	for vpos in GameState.visibility_sectors.keys():
		var d := Vector2(vpos.x, vpos.y).distance_to(GameState.player_position)
		if d > max_d:
			max_d = d
	var scale_x := canvas_xf.x.length()
	var r: float = clampf(max_d * Constants.TILE_SIZE * scale_x, 40.0, 280.0)

	# Helper: build a polygon fan from center outward over arc [angle_from, angle_to]
	var forward_from := facing_angle - CONE_FORWARD_HALF
	var forward_to := facing_angle + CONE_FORWARD_HALF
	var perip_l_from := facing_angle - CONE_PERIPHERAL_HALF
	var perip_l_to := facing_angle - CONE_FORWARD_HALF
	var perip_r_from := facing_angle + CONE_FORWARD_HALF
	var perip_r_to := facing_angle + CONE_PERIPHERAL_HALF

	draw_colored_polygon(
		_arc_polygon(player_screen, r, forward_from, forward_to), CONE_FORWARD_COLOR
	)
	draw_colored_polygon(
		_arc_polygon(player_screen, r, perip_l_from, perip_l_to), CONE_PERIPHERAL_COLOR
	)
	draw_colored_polygon(
		_arc_polygon(player_screen, r, perip_r_from, perip_r_to), CONE_PERIPHERAL_COLOR
	)

	# Forward arc boundary ring
	draw_arc(player_screen, r, forward_from, forward_to, CONE_ARC_STEPS, CONE_RING_COLOR, 1.0)

	# Player dot
	draw_circle(player_screen, PLAYER_DOT_RADIUS, PLAYER_DOT_COLOR)


# Build a filled polygon fan from center through an arc
func _arc_polygon(
	center: Vector2, radius: float, angle_from: float, angle_to: float
) -> PackedVector2Array:
	var pts := PackedVector2Array()
	pts.append(center)
	for i in range(CONE_ARC_STEPS + 1):
		var t := float(i) / float(CONE_ARC_STEPS)
		var a := angle_from + t * (angle_to - angle_from)
		pts.append(center + Vector2(cos(a), sin(a)) * radius)
	return pts


# Dashed LOS lines from player to each visible non-player entity
func _draw_los_rays(player_screen: Vector2, canvas_xf: Transform2D) -> void:
	for entity in GameState.visible_entities:
		if not entity is Dictionary:
			continue
		if entity.get("kind", {}).get("variant", "") == "Player":
			continue
		var entity_world := Vector2(entity.get("x", 0.0), entity.get("y", 0.0))
		var entity_screen := _w2s(entity_world, canvas_xf)
		var rel: String = entity.get("relationship", "Unknown")
		var color := Constants.color_for_relationship(rel)
		color.a = 0.45
		draw_dashed_line(player_screen, entity_screen, color, 1.0, 6.0)
		draw_circle(entity_screen, NPC_DOT_RADIUS, Color(color.r, color.g, color.b, 0.7))


# Fading NPC movement path trails from position history
func _draw_npc_paths(canvas_xf: Transform2D) -> void:
	for eid in _npc_paths.keys():
		var path: Array = _npc_paths[eid]
		if path.size() < 2:
			continue
		for i in range(1, path.size()):
			var a_screen := _w2s(path[i - 1], canvas_xf)
			var b_screen := _w2s(path[i], canvas_xf)
			var alpha := float(i) / float(path.size())
			draw_line(
				a_screen,
				b_screen,
				Color(
					NPC_PATH_COLOR.r, NPC_PATH_COLOR.g, NPC_PATH_COLOR.b, NPC_PATH_COLOR.a * alpha
				),
				1.5
			)
		draw_circle(_w2s(path.back(), canvas_xf), NPC_DOT_RADIUS, NPC_DOT_COLOR)


# Information state tags above visible NPCs from player_knowledge
func _draw_info_tags(canvas_xf: Transform2D) -> void:
	if GameState.player_knowledge == null:
		return
	var font: Font = _cached_font if _cached_font else ThemeDB.fallback_font
	var knowledge: Dictionary = GameState.player_knowledge

	# Build entity_id → knowledge entry lookup
	var kg_by_id: Dictionary = {}
	for entry in knowledge.get("entities", []):
		if entry is Dictionary and entry.has("entity_id"):
			kg_by_id[entry.entity_id] = entry

	for entity in GameState.visible_entities:
		if not entity is Dictionary:
			continue
		if entity.get("kind", {}).get("variant", "") != "Npc":
			continue
		var eid: int = entity.get("entity_id", -1)
		if not kg_by_id.has(eid):
			continue
		var kg_entry: Dictionary = kg_by_id[eid]
		var confidence: String = kg_entry.get("confidence", "Unknown")
		var name_str: String = kg_entry.get("name", "?")
		var label := "%s [%s]" % [name_str, confidence]

		var entity_screen := _w2s(Vector2(entity.get("x", 0.0), entity.get("y", 0.0)), canvas_xf)
		var tag_baseline := entity_screen.y - 18.0
		var text_w := font.get_string_size(label, HORIZONTAL_ALIGNMENT_LEFT, -1, FONT_SIZE - 1).x
		var tag_rect := Rect2(
			entity_screen.x - text_w / 2.0 - 3.0,
			tag_baseline - FONT_SIZE + 2.0,
			text_w + 6.0,
			FONT_SIZE
		)
		draw_rect(tag_rect, TAG_BG_COLOR)
		draw_string(
			font,
			Vector2(entity_screen.x - text_w / 2.0, tag_baseline),
			label,
			HORIZONTAL_ALIGNMENT_LEFT,
			-1,
			FONT_SIZE - 1,
			TAG_TEXT_COLOR
		)


# ---------------------------------------------------------------------------
# Panel 3: Tick timing sparkline (bottom-left)
# ---------------------------------------------------------------------------


func _draw_tick_graph() -> void:
	if _tick_deltas.size() < 2:
		return
	var font: Font = _cached_font if _cached_font else ThemeDB.fallback_font
	var vp_size := get_viewport_rect().size
	var box_x := GRAPH_MARGIN
	var label_h := LINE_HEIGHT
	var box_y := vp_size.y - GRAPH_H - label_h - GRAPH_MARGIN

	draw_rect(Rect2(box_x, box_y, GRAPH_W, GRAPH_H + label_h), GRAPH_BG_COLOR)
	draw_string(
		font,
		Vector2(box_x + 4, box_y + FONT_SIZE + 1),
		"tick ms (n=%d)" % _tick_deltas.size(),
		HORIZONTAL_ALIGNMENT_LEFT,
		-1,
		FONT_SIZE - 1,
		LABEL_COLOR
	)

	var chart_top := box_y + label_h
	var chart_left := box_x + 4.0
	var chart_w := GRAPH_W - 8.0
	var chart_h := GRAPH_H - 4.0

	# Max value for scale
	var max_ms: float = TICK_WARN_MS
	for d in _tick_deltas:
		if float(d) > max_ms:
			max_ms = float(d)
	max_ms *= 1.1

	# Warn threshold dashed line
	var warn_y := chart_top + chart_h * (1.0 - TICK_WARN_MS / max_ms)
	draw_dashed_line(
		Vector2(chart_left, warn_y),
		Vector2(chart_left + chart_w, warn_y),
		Color(GRAPH_WARN_COLOR.r, GRAPH_WARN_COLOR.g, GRAPH_WARN_COLOR.b, 0.3),
		1.0,
		4.0
	)

	# Sparkline
	var n := _tick_deltas.size()
	var prev_pt := Vector2.ZERO
	for i in range(n):
		var x := chart_left + chart_w * (float(i) / float(n - 1))
		var clamped := clampf(float(_tick_deltas[i]), 0.0, max_ms)
		var y := chart_top + chart_h * (1.0 - clamped / max_ms)
		var pt := Vector2(x, y)
		var color := GRAPH_WARN_COLOR if float(_tick_deltas[i]) > TICK_WARN_MS else GRAPH_LINE_COLOR
		if i > 0:
			draw_line(prev_pt, pt, color, 1.5)
		draw_circle(pt, 2.0, color)
		prev_pt = pt

	# Average label
	var avg_ms := 0.0
	for d in _tick_deltas:
		avg_ms += float(d)
	avg_ms /= float(_tick_deltas.size())
	draw_string(
		font,
		Vector2(chart_left + chart_w - 54.0, chart_top + chart_h + FONT_SIZE - 2),
		"avg %.0fms" % avg_ms,
		HORIZONTAL_ALIGNMENT_LEFT,
		-1,
		FONT_SIZE - 1,
		LABEL_COLOR
	)


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------


# Convert facing string to angle in radians (Godot 2D: 0=East, -PI/2=North)
static func _facing_to_angle(facing: String) -> float:
	match facing:
		"North":
			return -PI / 2.0
		"Northeast":
			return -PI / 4.0
		"East":
			return 0.0
		"Southeast":
			return PI / 4.0
		"South":
			return PI / 2.0
		"Southwest":
			return PI * 3.0 / 4.0
		"West":
			return PI
		"Northwest":
			return -PI * 3.0 / 4.0
		_:
			return -PI / 2.0