extends Node

# Semantic actions — NO raw key codes cross the bridge
# Movement uses hold-to-move (polled each frame in _process).
# Discrete actions (interact, stance, etc.) use press events (_unhandled_input).
#
# D-054: Mouse-relative facing and movement.
# Mouse position determines facing direction (client-side float).
# WASD is relative to facing: W = toward cursor, S = away, A/D = strafe.
# Server receives facing octant only — the full float stays client-side.
#
# Movement throttle: client-side rate limit per stance (D-053).
# Sprint=5/s, Walk=2.5/s, Careful=1.7/s, Crouch=1.25/s.
# Server cooldown is authoritative, but the client throttle prevents
# flooding and gives correct movement feel in test mode.
enum Action {
	MOVE_NORTH, MOVE_NORTHEAST, MOVE_EAST, MOVE_SOUTHEAST,
	MOVE_SOUTH, MOVE_SOUTHWEST, MOVE_WEST, MOVE_NORTHWEST,
	INTERACT, USE_PERCEPTION_MODE, OPEN_MENU, PAUSE, UNPAUSE,
	TOGGLE_STANCE_UP, TOGGLE_STANCE_DOWN,
	BUG_REPORT,  # #495: F12 WRONG button — client-only, not sent to server
	OPEN_JOURNAL,  # #264: J key — toggle knowledge journal panel, client-only
	SET_FACING,  # D-054: facing octant update (no movement)
	TELEPORT_HUB,  # #501: Home key — Gauntlet dev teleport (not production fast-travel)
	SAVE_GAME,  # #554: F5 quicksave — sends SaveGame to server with save path
	LOAD_GAME,  # #554: F6 quickload — sends LoadGame to server with save path
	DEBUG_COMMAND,  # #581: debug console command dispatch — sends DebugCommandKind to server
	CHANGE_SETTINGS,      # #646: persist a setting to server SQLite — sends {key, value} to server
	REQUEST_ALL_SETTINGS, # #646: request full settings dump from server after handshake (unit variant)
	DELETE_SETTING,       # #646: delete a setting by key from server SQLite (struct variant)
}

# Minimum milliseconds between movement commands, per stance.
# Tuned so Walk feels like walking, Sprint feels fast but readable.
const MOVE_INTERVAL_MS := {
	"Sprint": 200,    # 5/sec — fast but trackable
	"Walk": 400,      # 2.5/sec — comfortable walking pace
	"Careful": 600,   # ~1.7/sec — deliberate, scanning
	"Crouch": 800,    # 1.25/sec — creeping
}

var input_queue: Array[Dictionary] = []

# D-054: Client-side facing angle (radians). 0=East, -PI/2=North, PI/2=South.
# Updated every frame from mouse position. EntityRenderer reads this for indicator.
var facing_angle: float = -PI / 2.0  # Default: North
var facing_octant: String = "North"   # Derived from facing_angle
var _last_sent_octant: String = "North"  # Track to avoid redundant sends
var _last_move_msec: int = 0


# Hold-to-move: poll held direction keys each frame, throttled by stance.
# D-054: WASD is now mouse-relative. W = toward cursor, A/D = strafe.
# Server-side cooldown (D-053) is authoritative; this prevents client flooding.
# D-064: movement suppressed during dialogue (walk-away handled by dialogue_box).
func _process(_delta: float) -> void:
	# D-054: Update facing angle from mouse position every frame
	_update_facing_from_mouse()

	if GameState.dialogue_active:
		return

	# D-054: Send facing octant to server when it changes (even without movement)
	if facing_octant != _last_sent_octant:
		_last_sent_octant = facing_octant
		input_queue.append({
			"action": Action.SET_FACING,
			"timestamp_msec": Time.get_ticks_msec(),
			"action_data": {"facing": facing_octant},
		})

	# Poll held WASD keys
	var raw_dir := Vector2i.ZERO
	if Input.is_action_pressed("move_north"):
		raw_dir.y -= 1
	if Input.is_action_pressed("move_south"):
		raw_dir.y += 1
	if Input.is_action_pressed("move_east"):
		raw_dir.x += 1
	if Input.is_action_pressed("move_west"):
		raw_dir.x -= 1

	if raw_dir != Vector2i.ZERO:
		var now := Time.get_ticks_msec()
		var interval: int = MOVE_INTERVAL_MS.get(GameState.player_stance, 200)
		if now - _last_move_msec >= interval:
			_last_move_msec = now
			# D-054: Transform WASD input relative to mouse facing
			var world_dir := _wasd_to_world_dir(raw_dir)
			var action: Action = _dir_to_action(world_dir)
			input_queue.append({
				"action": action,
				"timestamp_msec": now,
			})


# Discrete actions: fire once on key press (not held).
func _unhandled_input(event: InputEvent) -> void:
	var action: Action = -1

	if event.is_action_pressed("interact"):
		action = Action.INTERACT
	elif event.is_action_pressed("perception_mode"):
		action = Action.USE_PERCEPTION_MODE
	elif event.is_action_pressed("open_menu"):
		action = Action.OPEN_MENU
	elif event.is_action_pressed("pause"):
		var tick_rate = GameState.game_time.get("tick_rate", "Full")
		action = Action.UNPAUSE if tick_rate == "Paused" else Action.PAUSE
	elif event.is_action_pressed("stance_up"):
		action = Action.TOGGLE_STANCE_UP
	elif event.is_action_pressed("stance_down"):
		action = Action.TOGGLE_STANCE_DOWN
	elif event.is_action_pressed("bug_report"):
		action = Action.BUG_REPORT
	elif event.is_action_pressed("open_journal"):
		action = Action.OPEN_JOURNAL
	elif event.is_action_pressed("teleport_hub"):
		if GameState.gauntlet_mode:
			action = Action.TELEPORT_HUB
	elif event.is_action_pressed("quicksave"):
		action = Action.SAVE_GAME
	elif event.is_action_pressed("quickload"):
		action = Action.LOAD_GAME

	if action != -1:
		var entry := {
			"action": action,
			"timestamp_msec": Time.get_ticks_msec(),
		}
		# #554: Attach save path for SaveGame/LoadGame actions
		if action == Action.SAVE_GAME or action == Action.LOAD_GAME:
			var game_id := GameState.current_game_id
			if game_id.is_empty():
				get_viewport().set_input_as_handled()
				return  # No active session — ignore save/load
			entry["action_data"] = {"path": "user://saves/" + game_id + "/quicksave.sav"}
		input_queue.append(entry)
		get_viewport().set_input_as_handled()


func flush_queue() -> Array[Dictionary]:
	var queue = input_queue.duplicate()
	input_queue.clear()
	return queue


## Reset facing state to default (North). Use in tests per D-030 testability.
func reset_facing_state() -> void:
	facing_angle = -PI / 2.0
	facing_octant = "North"
	_last_sent_octant = "North"


# D-054: Compute facing angle from mouse position relative to player screen position.
# Uses viewport canvas transform to convert world coords to screen coords.
# Intentional coupling: reads GameState.player_position directly — InputMapper is an
# autoload that runs before game loop rendering, so position is always current-tick.
func _update_facing_from_mouse() -> void:
	var vp := get_viewport()
	if vp == null:
		return
	var canvas_xf := vp.get_canvas_transform()
	var player_world_px := GameState.player_position * Constants.TILE_SIZE
	var player_screen := canvas_xf * player_world_px
	var mouse_screen := vp.get_mouse_position()
	var delta := mouse_screen - player_screen
	# Only update if mouse is meaningfully distant from player (avoid jitter at center)
	if delta.length_squared() > 4.0:
		facing_angle = delta.angle()
		facing_octant = _angle_to_octant(facing_angle)


# D-054: Transform raw WASD input (screen-space) to world direction relative to mouse facing.
# W (+Y up in input, mapped to forward), S (backward), A (strafe left), D (strafe right).
# Raw input: W=(-Y), S=(+Y), A=(-X), D=(+X) in screen coords.
# Forward = facing_angle direction. Output: nearest octant direction vector.
func _wasd_to_world_dir(raw_dir: Vector2i) -> Vector2i:
	# Build a continuous direction vector relative to facing.
	# raw_dir.y: -1 = W (forward), +1 = S (backward)
	# raw_dir.x: -1 = A (strafe left), +1 = D (strafe right)
	var forward := Vector2(cos(facing_angle), sin(facing_angle))
	var right := Vector2(-forward.y, forward.x)  # 90° clockwise

	# Combine: forward/back from W/S, strafe from A/D
	var world_float := forward * float(-raw_dir.y) + right * float(raw_dir.x)

	# Snap to nearest octant direction
	return _snap_to_octant_dir(world_float)


# Snap a floating-point direction vector to the nearest of 8 cardinal/diagonal directions.
static func _snap_to_octant_dir(dir: Vector2) -> Vector2i:
	if dir.length_squared() < 0.001:
		return Vector2i.ZERO
	var angle := dir.angle()
	# Quantize to nearest 45° (PI/4)
	var octant := roundi(angle / (PI / 4.0))
	match octant:
		0: return Vector2i(1, 0)        # East
		1: return Vector2i(1, 1)        # Southeast
		2, -6: return Vector2i(0, 1)    # South
		3, -5: return Vector2i(-1, 1)   # Southwest
		4, -4: return Vector2i(-1, 0)   # West
		-3, 5: return Vector2i(-1, -1)  # Northwest
		-2: return Vector2i(0, -1)      # North
		-1: return Vector2i(1, -1)      # Northeast
		_: return Vector2i.ZERO


# D-054: Convert a facing angle (radians) to the nearest octant name.
# Godot 2D: 0=East, PI/2=South, -PI/2=North.
static func _angle_to_octant(angle: float) -> String:
	var octant := roundi(angle / (PI / 4.0))
	match octant:
		0: return "East"
		1: return "Southeast"
		2, -6: return "South"
		3, -5: return "Southwest"
		4, -4: return "West"
		-3, 5: return "Northwest"
		-2: return "North"
		-1: return "Northeast"
		_: return "East"


# Map a direction vector to the corresponding movement Action.
# Handles all 8 directions via composite W+D, W+A, etc.
static func _dir_to_action(dir: Vector2i) -> Action:
	match dir:
		Vector2i(0, -1): return Action.MOVE_NORTH
		Vector2i(1, -1): return Action.MOVE_NORTHEAST
		Vector2i(1, 0): return Action.MOVE_EAST
		Vector2i(1, 1): return Action.MOVE_SOUTHEAST
		Vector2i(0, 1): return Action.MOVE_SOUTH
		Vector2i(-1, 1): return Action.MOVE_SOUTHWEST
		Vector2i(-1, 0): return Action.MOVE_WEST
		Vector2i(-1, -1): return Action.MOVE_NORTHWEST
		_: return Action.MOVE_NORTH