## Tree entity — choppable by a pawn with a Chop job. Drops wood Item nodes
## when felled.
##
## Chopping model (docs/implementation.md Phase 4):
##   A ChopProvider creates a Job whose INTERACT toil calls on_chop_tick() once
##   per sim tick via JobRunner. After CHOP_TICKS ticks the tree is felled.
##
## World registration (World.register_tree / World.unregister_tree) is called
## here but the methods land in World during Opus integration.

class_name HarvestableTree extends Node2D
## NOTE: class_name is HarvestableTree because Godot 4 ships a built-in `Tree`
## Control node — using "Tree" would shadow that. Filename / scene name stay
## as `tree` because the game-side concept is still just "tree".

const TILE_SIZE_PX: int = 16

## Sim ticks to fell a tree at 1× speed (80 ticks = ~4 sim seconds at 20 Hz).
const CHOP_TICKS: int = 80
## Number of separate wood Item nodes dropped on fell.
const WOOD_DROPS_ON_FELL: int = 3
## Stack size per dropped Item (Phase 4 simplicity: 3 items of stack 1 each).
const STACK_SIZE_PER_DROP: int = 1

# ── state ─────────────────────────────────────────────────────────────────────

var tile: Vector2i = Vector2i.ZERO
## 0..CHOP_TICKS. Advanced by on_chop_tick(); tree is felled when equal to CHOP_TICKS.
var chop_progress: int = 0

# Preloaded scene for spawned wood items.
const ITEM_SCENE: PackedScene = preload("res://scenes/entities/item.tscn")

## ElvGames Grasslands tree pack — 4 variants laid out left-to-right.
## Each variant is 64×80 px; trunk base sits in the bottom ~10 rows. We anchor
## the sprite center 32 px above tile origin so the trunk bottom lands at the
## tile's bottom edge and the canopy rises into the cells above.
const _TREE_TEX: Texture2D = preload("res://art/sprites/FG_Tree_Spring.png")
const _TREE_VARIANT_W: int = 64
const _TREE_VARIANT_H: int = 80
const _TREE_VARIANT_COUNT: int = 4


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

func _ready() -> void:
	position = _tile_to_world(tile)
	_build_sprite()
	# Y-sort so the canopy draws behind walls/pawns that are visually south of
	# the trunk base. Position.y is the trunk-base row.
	y_sort_enabled = true
	World.register_tree(self)


## Adds a Sprite2D child painted with one of the 4 ElvGames tree variants.
## Variant chosen deterministically from the tile coord so the same tile always
## gets the same tree silhouette across boots and load/save.
func _build_sprite() -> void:
	var sprite := Sprite2D.new()
	sprite.name = "Sprite"
	sprite.texture = _TREE_TEX
	sprite.region_enabled = true
	var variant: int = (tile.x * 31 + tile.y * 17) % _TREE_VARIANT_COUNT
	sprite.region_rect = Rect2(variant * _TREE_VARIANT_W, 0, _TREE_VARIANT_W, _TREE_VARIANT_H)
	sprite.centered = true
	# Lift the sprite up so its bottom edge sits at the tile's bottom row.
	# Sprite center is at offset.y; sprite half-height is _TREE_VARIANT_H/2 = 40.
	# We want bottom edge at +8 (tile bottom) → center at 8 - 40 = -32.
	sprite.offset = Vector2(0, -32)
	# Render behind pawns/items that are at higher z_index; trees live at z=0.
	sprite.z_index = 0
	add_child(sprite)


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


# ── public API ────────────────────────────────────────────────────────────────

## One-shot initialiser. Call after add_child() so _ready() already fired.
func setup(start_tile: Vector2i) -> void:
	tile = start_tile
	chop_progress = 0
	position = _tile_to_world(tile)
	queue_redraw()
	Audit.log("tree", "spawned at %s" % tile)


## True when the tree hasn't been fully chopped yet.
func is_choppable() -> bool:
	return chop_progress < CHOP_TICKS


## Called by the INTERACT toil in JobRunner once per sim tick while the pawn
## works this tree. Advances chop_progress and fells the tree when complete.
func on_chop_tick() -> void:
	if not is_choppable():
		return
	chop_progress += 1
	queue_redraw()
	if chop_progress >= CHOP_TICKS:
		fell()


## Drop wood Items and free this node. Called by on_chop_tick() automatically,
## but also accessible for scripted felling (debug, storyteller events).
func fell() -> void:
	var drop_tiles := _pick_drop_tiles()
	var drops_count := 0
	for drop_tile in drop_tiles:
		var item: Item = ITEM_SCENE.instantiate()
		get_parent().add_child(item)
		item.setup(Item.TYPE_WOOD, STACK_SIZE_PER_DROP, drop_tile)
		drops_count += 1
	Audit.log("tree", "felled at %s; %d wood drops" % [tile, drops_count])
	queue_free()


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

func to_dict() -> Dictionary:
	return {
		"class_id": &"tree",
		"tile_x": tile.x,
		"tile_y": tile.y,
		"chop_progress": chop_progress,
	}


static func from_dict(d: Dictionary) -> Dictionary:
	return {
		"tile_x": int(d.get("tile_x", 0)),
		"tile_y": int(d.get("tile_y", 0)),
		"chop_progress": int(d.get("chop_progress", 0)),
	}


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

func _draw() -> void:
	# Canopy + trunk now come from the Sprite2D child (see _build_sprite).
	# This _draw renders only the chop-progress notch overlaid on the trunk.
	if chop_progress > 0:
		var ratio := float(chop_progress) / float(CHOP_TICKS)
		var notch_depth := ratio * 3.0
		draw_line(
			Vector2(-2.0, 2.0 + notch_depth),
			Vector2(2.0, 2.0),
			Color(0.15, 0.08, 0.02, 0.9),
			1.5
		)


# ── helpers ───────────────────────────────────────────────────────────────────

## Returns up to WOOD_DROPS_ON_FELL tile positions for wood drops.
## Prefers the tree's own tile then walkable 4-neighbours; falls back to the
## tree tile for any remaining drops when neighbours are scarce.
func _pick_drop_tiles() -> Array[Vector2i]:
	var chosen: Array[Vector2i] = []

	# First drop always goes on the tree's tile itself.
	chosen.append(tile)

	# Remaining drops prefer walkable neighbours.
	var offsets: Array[Vector2i] = [Vector2i(1, 0), Vector2i(-1, 0), Vector2i(0, 1), Vector2i(0, -1)]
	for offset in offsets:
		if chosen.size() >= WOOD_DROPS_ON_FELL:
			break
		var candidate: Vector2i = tile + offset
		if World.pathfinder != null and World.pathfinder.is_walkable(candidate):
			chosen.append(candidate)

	# Fill any remaining slots with the tree tile (all 3 land there if boxed in).
	while chosen.size() < WOOD_DROPS_ON_FELL:
		chosen.append(tile)

	return chosen


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
	)