class_name Wolf extends Node2D
## Wolf entity — hostile animal with a 4-state AI state machine.
##
## Player-facing copy renames this entity to "hyena" (see strings.gd, event_catalog.gd
## labels). Internal class + registry identifiers remain "wolf"/"Wolf" for save
## compatibility — class_id: &"wolf" in saves, World.wolves registry, EventBus.wolf_spawned.
##
## State machine (docs/architecture.md "Wolf AI"):
##   APPROACH → walk toward nearest non-downed pawn within sight radius.
##   ENGAGE   → attack adjacent pawn; 70% hit chance; 50% chance to apply Bleeding.
##   FLEE     → Phase 10 simplification: wolves never flee (fight to the death).
##              Phase 17 may add flee-when-low-hp behaviour.
##   DEAD     → HP reached 0; renders an X marker.
##
## Combat tunables are Phase 10 placeholders; Phase 20 will tune them against
## real pawn stats. Hit math matches docs/architecture.md "Hit / damage resolution"
## (simplified — no weapon/armor/cover modifiers until Phase 17).
##
## Registration follows the same pattern as Tree and Rock: _ready() calls
## World.register_wolf(), _exit_tree() calls World.unregister_wolf().
## Pawns are referenced by duck typing only (no `Pawn` class_name) so the
## autoload-ordering window from Phase 2/3 cannot bite here.

const TILE_SIZE_PX: int = 16
## Wolves move slightly faster than pawns (pawn STEP_TICKS = 10).
const STEP_TICKS: int = 8

const _HYENA_SPRITE_FRAMES = preload("res://scenes/entities/hyena_sprite_frames.gd")

# ── combat tunables (Phase 10 placeholders; tune Phase 20) ──────────────────
const ATTACK_DAMAGE: float = 12.0
## 1.5 in-game seconds between attacks at 1× (30 ticks × 50 ms).
const ATTACK_COOLDOWN_TICKS: int = 30
## How many tiles away a wolf can "see" a pawn.
const SIGHT_RADIUS: int = 12
const HP_MAX: float = 40.0
## Probability (0–1) that a successful hit also inflicts Bleeding status.
const BLEEDING_CHANCE: float = 0.5

# ── state machine ────────────────────────────────────────────────────────────
enum State { APPROACH, ENGAGE, FLEE, DEAD }

@export var tile: Vector2i = Vector2i.ZERO

var state: State = State.APPROACH
var hp: float = HP_MAX
## Current pawn target; duck-typed (exposes .tile, .pawn_name, .is_downed(), .take_damage(), .add_status()).
var target_pawn = null
var _path: Array[Vector2i] = []
var _step_progress: float = 0.0
var _attack_cooldown: int = 0
var _sprite: AnimatedSprite2D = null

## Transient: set by from_dict() to the saved target's pawn_name string.
## SaveSystem._post_load_resolve_references() walks World.pawns, matches by
## pawn_name, assigns target_pawn, then clears this field.
## If the named pawn no longer exists the field stays "" and target_pawn stays
## null — the AI will pick a new target on the next sim tick.
var _pending_target_name: String = ""


# ── lifecycle ────────────────────────────────────────────────────────────────

func _ready() -> void:
	position = _tile_to_world(tile)
	World.register_wolf(self)
	EventBus.sim_tick.connect(_on_sim_tick)


func _exit_tree() -> void:
	World.unregister_wolf(self)


## One-shot initialiser. Call after add_child() so _ready() has already fired.
func setup(p_tile: Vector2i) -> void:
	tile = p_tile
	position = _tile_to_world(tile)
	_mount_sprite()
	Audit.log("wolf", "spawned at %s" % tile)


func take_damage(amount: float) -> void:
	hp = maxf(0.0, hp - amount)
	if hp <= 0.0 and state != State.DEAD:
		state = State.DEAD
		Audit.log("wolf", "wolf at %s killed" % tile)
		# Hide sprite; dead X marker is drawn by _draw() on the Node2D.
		if _sprite != null:
			_sprite.visible = false
		queue_redraw()


func is_dead() -> bool:
	return state == State.DEAD


## Creates (or re-creates) the AnimatedSprite2D child.  Idempotent — frees any
## prior sprite so setup() and from_dict() can both call it safely.
func _mount_sprite() -> void:
	if _sprite != null:
		_sprite.queue_free()
		_sprite = null
	_sprite = AnimatedSprite2D.new()
	_sprite.sprite_frames = _HYENA_SPRITE_FRAMES.build()
	# 48×48 sprite centred on the tile origin: shift up so the feet land at the
	# tile bottom edge (tile bottom = +8 px from centre → feet need to be at +8
	# → sprite centre at +8 − 24 = −16 px).
	_sprite.offset = Vector2(0.0, -16.0)
	# Y-sort: sit on the same plane as pawns (z_index 0, use y_sort_enabled on
	# the parent World node). Slightly behind pawns so they occlude the hyena
	# when occupying the same tile.
	_sprite.z_index = -1
	_sprite.play(&"idle")
	add_child(_sprite)


# ── state machine tick ──────────────────────────────────────────────────────

func _on_sim_tick(_n: int) -> void:
	if state == State.DEAD:
		return
	if _attack_cooldown > 0:
		_attack_cooldown -= 1

	match state:
		State.APPROACH: _tick_approach()
		State.ENGAGE:   _tick_engage()
		State.FLEE:     _tick_flee()


func _tick_approach() -> void:
	# Find nearest non-downed pawn within sight radius.
	if target_pawn == null or target_pawn.is_downed():
		target_pawn = _find_target()
		if target_pawn == null:
			return  # No eligible target; wolf stands still.
		# (Re-)plan path whenever we acquire a new target.
		if World.pathfinder != null:
			_path = World.pathfinder.find_path(tile, target_pawn.tile)

	_advance_walk()

	# Switch to ENGAGE when adjacent to the target.
	if target_pawn != null and _manhattan(tile, target_pawn.tile) <= 1:
		state = State.ENGAGE


func _tick_engage() -> void:
	# Re-acquire if current target was downed or lost.
	if target_pawn == null or target_pawn.is_downed():
		target_pawn = _find_target()
		if target_pawn == null:
			return
		state = State.APPROACH
		return

	# Move toward target if it has drifted more than 1 tile away.
	if _manhattan(tile, target_pawn.tile) > 1:
		state = State.APPROACH
		return

	# Attack if off cooldown.
	if _attack_cooldown == 0:
		_attack(target_pawn)
		_attack_cooldown = ATTACK_COOLDOWN_TICKS


func _tick_flee() -> void:
	# Phase 10 simplification: wolves fight to the death — FLEE is a no-op.
	# Phase 17 may add flee-when-low-hp via: if hp < HP_MAX * 0.30 → flee logic.
	pass


func _attack(target) -> void:
	# Simple two-outcome hit roll (70% base hit chance per docs/architecture.md
	# "Hit / damage resolution"). Phase 17 will add weapon/armor/cover modifiers.
	var hit_roll := randf()
	if hit_roll < 0.7:
		target.take_damage(ATTACK_DAMAGE, "wolf")
		Audit.log("wolf", "wolf hit %s for %.1f" % [target.pawn_name, ATTACK_DAMAGE])
		# 50% chance to inflict Bleeding status (design.md "Combat" + Phase 9 StatusCatalog).
		if randf() < BLEEDING_CHANCE:
			target.add_status(StatusCatalog.bleeding(1))
			Audit.log("wolf", "wolf applied Bleeding to %s" % target.pawn_name)
	else:
		Audit.log("wolf", "wolf missed %s" % target.pawn_name)


func _find_target():
	## Returns the nearest non-downed pawn within SIGHT_RADIUS tiles (Manhattan),
	## or null if none exists. Duck-typed — no Pawn class_name dependency.
	var best = null
	var best_dist: int = SIGHT_RADIUS + 1   # exclusive upper bound
	for p in World.pawns:
		if p.is_downed():
			continue
		var d := _manhattan(tile, p.tile)
		if d > SIGHT_RADIUS:
			continue
		if d < best_dist:
			best_dist = d
			best = p
	return best


func _advance_walk() -> void:
	if _path.is_empty():
		return
	_step_progress += 1.0 / float(STEP_TICKS)
	if _step_progress >= 1.0:
		tile = _path[0]
		_path.remove_at(0)
		_step_progress = 0.0


# ── save / load ──────────────────────────────────────────────────────────────

func to_dict() -> Dictionary:
	# target_pawn is stored as a name string so the loader can re-resolve it
	# against World.pawns without a live Node reference.
	var target_name: String = ""
	if target_pawn != null and target_pawn.get("pawn_name") != null:
		target_name = str(target_pawn.pawn_name)
	var path_data: Array = []
	for v in _path:
		path_data.append([v.x, v.y])
	return {
		"class_id": &"wolf",
		"tile_x": tile.x,
		"tile_y": tile.y,
		"hp": hp,
		"state": int(state),
		"step_progress": _step_progress,
		"attack_cooldown": _attack_cooldown,
		"target_pawn_name": target_name,
		"path": path_data,
	}


func from_dict(d: Dictionary) -> void:
	tile = Vector2i(int(d.get("tile_x", 0)), int(d.get("tile_y", 0)))
	hp = clampf(float(d.get("hp", HP_MAX)), 0.0, HP_MAX)
	state = int(d.get("state", State.APPROACH)) as State
	_step_progress = float(d.get("step_progress", 0.0))
	_attack_cooldown = int(d.get("attack_cooldown", 0))
	# target_pawn is re-wired by SaveSystem._post_load_resolve_references() after
	# all pawns are spawned. Store the name for that pass; if the pawn no longer
	# exists target_pawn stays null and the AI picks a new target next tick.
	target_pawn = null
	_pending_target_name = str(d.get("target_pawn_name", ""))
	_path.clear()
	for entry in d.get("path", []):
		if entry is Array and entry.size() == 2:
			_path.append(Vector2i(int(entry[0]), int(entry[1])))
	position = _tile_to_world(tile)
	_mount_sprite()
	# If dead on load, hide sprite immediately (X marker drawn by _draw()).
	if state == State.DEAD and _sprite != null:
		_sprite.visible = false
		queue_redraw()


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

func _process(_delta: float) -> void:
	if state == State.DEAD:
		return
	# Lerp render position between current tile and next tile in the path.
	var from_w := _tile_to_world(tile)
	var to_t := _path[0] if not _path.is_empty() else tile
	var to_w := _tile_to_world(to_t)
	position = from_w.lerp(to_w, _step_progress)

	# Anim switching — avoid restarting the same anim each frame.
	if _sprite == null:
		return
	var moving: bool = not _path.is_empty()
	var target_anim := &"walk" if moving else &"idle"
	if _sprite.animation != target_anim:
		_sprite.play(target_anim)

	# Facing — 2-direction horizontal flip; preserve last facing on pure vertical.
	if not _path.is_empty():
		var delta_x: int = _path[0].x - tile.x
		if delta_x > 0:
			_sprite.flip_h = false   # moving right → face right (default)
		elif delta_x < 0:
			_sprite.flip_h = true    # moving left  → face left


func _draw() -> void:
	if state == State.DEAD:
		# X marker — dark red crosshatch so the corpse is visible but subdued.
		var x_color := Color(0.30, 0.10, 0.10, 0.8)
		draw_line(Vector2(-6, -6), Vector2(6, 6), x_color, 2.0)
		draw_line(Vector2(6, -6), Vector2(-6, 6), x_color, 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
	)


func _manhattan(a: Vector2i, b: Vector2i) -> int:
	return abs(a.x - b.x) + abs(a.y - b.y)