extends Node

## Fog texture state — visibility/exploration/zone tint images updated from GameState.
## Read by fog_shader.gd for shader uniforms. Not a renderer — pure data.
## Architecture: docs/architecture/fog-shader-spec.md | D-059

# Fog texture byte values — visibility and exploration layers.
# Used by fog shader to distinguish visual treatment per tile.
# Test assertions reference these: assert_that(byte).is_equal(FogState.VIS_FORWARD)
const VIS_HIDDEN: int = 0  # Not in LOS — fully fogged
const VIS_PERIPHERAL: int = 180  # DEPRECATED: peripheral sector removed in Sprint 22 (#569).
# Retained — tests still reference it.
const VIS_FORWARD: int = 255  # In LOS, forward sector — clear vision

const EXP_UNEXPLORED: int = 0  # Never seen — total darkness
const EXP_EXPLORED: int = 128  # Previously seen, now out of LOS — deep fog
const EXP_VISIBLE: int = 255  # Currently in LOS — clear (written each frame)

# Zone temperature tints (D-059 + D-046, Sprint 22) — keyed by zone_id string from server.
# Matches audio_manager.gd ZONE_ASSETS zone_id strings for consistent zone semantics.
# Low saturation is intentional (D-046): tints are subtle — distinguishable as warm/cool/neutral
# in side-by-side comparison, not garish. The "Hopper test" validates this.
# Colors are dark tints used as the fog overlay in the deep fog zone:
#   hub/workplace: #1a1f2e (cool blue-dark — terminal, institutional)
#   bar:           #2a1f15 (warm amber-dark — social, inhabited)
#   corridor:      #1a1a1a (neutral dark — transitional, maintenance)
const ZONE_TINTS: Dictionary = {
	"hub": Color(0.102, 0.122, 0.180),  # #1a1f2e — cool blue-dark
	"workplace": Color(0.102, 0.122, 0.180),  # same as hub
	"bar": Color(0.165, 0.122, 0.082),  # #2a1f15 — warm amber-dark
	"corridor": Color(0.102, 0.102, 0.102),  # #1a1a1a — neutral dark
}
const ZONE_TINT_DEFAULT: Color = Color(0.102, 0.102, 0.102)  # #1a1a1a neutral

var map_bounds: Rect2i = Rect2i(0, 0, 1, 1)
var visibility_texture: ImageTexture
var exploration_texture: ImageTexture
var zone_tint_texture: ImageTexture
## Debug flag — when true, fog.gdshader renders raw exploration texture
## as colored overlay (green=visible, blue=explored, red=unexplored).
## Toggle via FogState.debug_exploration = true in the console.
var debug_exploration: bool = false
## Deterministic shader time for visual test captures.
## When >= 0, fog_shader.gd uses this instead of Time.get_ticks_msec().
## Set before settle frames so noise phase is reproducible across runs.
var override_time: float = -1.0

var _vis_bytes: PackedByteArray
var _exp_bytes: PackedByteArray
var _vis_image: Image
var _exp_image: Image
var _tint_image: Image
# Zone tint stored as 3-channel RGB bytes (R, G, B per pixel) for preservation across resizes
var _tint_bytes: PackedByteArray
var _width: int = 1
var _height: int = 1
var _prev_visible: Dictionary = {}  # Tiles visible last frame (for incremental decay)


func _ready() -> void:
	_resize(Rect2i(0, 0, 64, 64))


func _resize(bounds: Rect2i) -> void:
	var old_bounds := map_bounds
	var old_exp := _exp_bytes
	var old_tint := _tint_bytes  # empty on first call (_ready); guard at line 104 skips copy
	var old_w := _width
	var old_h := _height

	map_bounds = bounds
	_width = maxi(bounds.size.x, 1)
	_height = maxi(bounds.size.y, 1)
	var sz := _width * _height

	_vis_bytes = PackedByteArray()
	_vis_bytes.resize(sz)
	_vis_bytes.fill(VIS_HIDDEN)
	_vis_image = Image.create_from_data(_width, _height, false, Image.FORMAT_R8, _vis_bytes)
	visibility_texture = ImageTexture.create_from_image(_vis_image)

	_exp_bytes = PackedByteArray()
	_exp_bytes.resize(sz)
	_exp_bytes.fill(EXP_UNEXPLORED)
	# Preserve exploration data from old bounds into new bounds
	if old_exp.size() > 0 and old_w > 0 and old_h > 0:
		var dx: int = old_bounds.position.x - bounds.position.x
		var dy: int = old_bounds.position.y - bounds.position.y
		for oy in range(old_h):
			var ny: int = oy + dy
			if ny < 0 or ny >= _height:
				continue
			for ox in range(old_w):
				var nx: int = ox + dx
				if nx < 0 or nx >= _width:
					continue
				var old_val: int = old_exp[oy * old_w + ox]
				if old_val > EXP_UNEXPLORED:
					_exp_bytes[ny * _width + nx] = old_val
	_exp_image = Image.create_from_data(_width, _height, false, Image.FORMAT_R8, _exp_bytes)
	exploration_texture = ImageTexture.create_from_image(_exp_image)

	# Zone tint — 3 bytes per pixel (RGB), default neutral dark
	var tint_sz := sz * 3
	_tint_bytes = PackedByteArray()
	_tint_bytes.resize(tint_sz)
	var default_r := int(ZONE_TINT_DEFAULT.r * 255.0)
	var default_g := int(ZONE_TINT_DEFAULT.g * 255.0)
	var default_b := int(ZONE_TINT_DEFAULT.b * 255.0)
	for i in range(sz):
		_tint_bytes[i * 3 + 0] = default_r
		_tint_bytes[i * 3 + 1] = default_g
		_tint_bytes[i * 3 + 2] = default_b
	# Preserve zone tint data from old bounds (zone tints are stable — tile zone never changes)
	if old_tint.size() > 0 and old_w > 0 and old_h > 0:
		var dx: int = old_bounds.position.x - bounds.position.x
		var dy: int = old_bounds.position.y - bounds.position.y
		for oy in range(old_h):
			var ny: int = oy + dy
			if ny < 0 or ny >= _height:
				continue
			for ox in range(old_w):
				var nx: int = ox + dx
				if nx < 0 or nx >= _width:
					continue
				var old_idx := (oy * old_w + ox) * 3
				var new_idx := (ny * _width + nx) * 3
				_tint_bytes[new_idx + 0] = old_tint[old_idx + 0]
				_tint_bytes[new_idx + 1] = old_tint[old_idx + 1]
				_tint_bytes[new_idx + 2] = old_tint[old_idx + 2]
	_tint_image = Image.create_from_data(_width, _height, false, Image.FORMAT_RGB8, _tint_bytes)
	zone_tint_texture = ImageTexture.create_from_image(_tint_image)

	_prev_visible.clear()


func update_from_state() -> void:
	# Grow bounds to include newly visible tiles — never shrink, so explored
	# tiles behind the player stay in the texture and render as deep fog
	# instead of black. Exploration data is preserved across resizes.
	# Use visible_positions (always populated from server snapshots) instead of
	# visible_tiles, which stays empty in live server mode because the server
	# sends tile_kind but game_state.gd's population check expects "type".
	var positions: Dictionary = GameState.visible_positions
	if positions.size() > 0:
		var new_bounds := _grow_bounds_from_positions(positions)
		if new_bounds != map_bounds:
			_resize(new_bounds)

	var ox: int = map_bounds.position.x
	var oy: int = map_bounds.position.y

	# TODO(v0.2): gradual decay over game-time instead of immediate EXP_VISIBLE→EXP_EXPLORED

	# 1. Clear visibility, then write current LOS (all tiles are Forward)
	_vis_bytes.fill(VIS_HIDDEN)
	for pos in positions:
		var px: int = pos.x - ox
		var py: int = pos.y - oy
		if px < 0 or py < 0 or px >= _width or py >= _height:
			continue
		_vis_bytes[py * _width + px] = VIS_FORWARD
	# #585: BoundaryWall margin tiles — fog lifts so wall content composites correctly,
	# but NOT in visible_positions so they don't persist as explored memory.
	for pos in GameState.boundary_positions:
		var px: int = pos.x - ox
		var py: int = pos.y - oy
		if px < 0 or py < 0 or px >= _width or py >= _height:
			continue
		_vis_bytes[py * _width + px] = VIS_FORWARD
	_vis_image.set_data(_width, _height, false, Image.FORMAT_R8, _vis_bytes)
	visibility_texture.update(_vis_image)

	# 2. Exploration: tiles leaving LOS decay to EXP_EXPLORED, visible tiles stay EXP_VISIBLE
	#    Only touch tiles that changed (O(visible) not O(map_size))
	for pos in _prev_visible:
		if not positions.has(pos):
			var px: int = pos.x - ox
			var py: int = pos.y - oy
			if px >= 0 and py >= 0 and px < _width and py < _height:
				var idx: int = py * _width + px
				if _exp_bytes[idx] > EXP_EXPLORED:
					_exp_bytes[idx] = EXP_EXPLORED

	for pos in positions:
		var px: int = pos.x - ox
		var py: int = pos.y - oy
		if px >= 0 and py >= 0 and px < _width and py < _height:
			_exp_bytes[py * _width + px] = EXP_VISIBLE
	_exp_image.set_data(_width, _height, false, Image.FORMAT_R8, _exp_bytes)
	exploration_texture.update(_exp_image)

	# 3. Zone tint: write zone temperature color for currently visible tiles.
	#    Zone data is stable (tile zone never changes) so we only write on first sight.
	#    Data persists in _tint_bytes across frames and across resizes.
	#    visible_tiles carries zone_id per tile (populated from snapshot "tiles" or
	#    "visible_tiles" with type field — see game_state.gd apply_snapshot).
	var tiles := GameState.visible_tiles
	var tint_dirty := false
	for tile in tiles:
		if not tile is Dictionary or not tile.has("x") or not tile.has("y"):
			continue
		var zone_id: String = str(tile.get("zone_id", ""))
		if zone_id.is_empty():
			continue
		var tint_color: Color = ZONE_TINTS.get(zone_id, ZONE_TINT_DEFAULT)
		var px: int = int(tile.x) - ox
		var py: int = int(tile.y) - oy
		if px < 0 or py < 0 or px >= _width or py >= _height:
			continue
		var tint_idx := (py * _width + px) * 3
		var new_r := int(tint_color.r * 255.0)
		var new_g := int(tint_color.g * 255.0)
		var new_b := int(tint_color.b * 255.0)
		# Only update if different from current (avoid spurious texture uploads)
		if (
			_tint_bytes[tint_idx] != new_r
			or _tint_bytes[tint_idx + 1] != new_g
			or _tint_bytes[tint_idx + 2] != new_b
		):
			_tint_bytes[tint_idx + 0] = new_r
			_tint_bytes[tint_idx + 1] = new_g
			_tint_bytes[tint_idx + 2] = new_b
			tint_dirty = true
	if tint_dirty:
		_tint_image.set_data(_width, _height, false, Image.FORMAT_RGB8, _tint_bytes)
		zone_tint_texture.update(_tint_image)

	# Shallow copy — correct for Dictionary<Vector2i, bool/String> values
	_prev_visible = positions.duplicate()


func _grow_bounds_from_positions(positions: Dictionary) -> Rect2i:
	## Compute bounds from visible_positions (Dictionary[Vector2i, bool]).
	var min_x := 999999
	var min_y := 999999
	var max_x := -999999
	var max_y := -999999
	for pos in positions:
		min_x = mini(min_x, pos.x)
		min_y = mini(min_y, pos.y)
		max_x = maxi(max_x, pos.x)
		max_y = maxi(max_y, pos.y)
	if min_x > max_x:
		return map_bounds
	var tile_bounds := Rect2i(min_x - 8, min_y - 8, max_x - min_x + 17, max_y - min_y + 17)
	if map_bounds.size.x <= 1 and map_bounds.size.y <= 1:
		return tile_bounds
	return map_bounds.merge(tile_bounds)