class_name LuneMap
extends RefCounted
## Map data in ground coordinates Vector2(x, z): Blau (team 0) in the south-west,
## Rot (team 1) in the north-east. Rot is the mirror image of Blau across x = z
## (mirror(v) = Vector2(v.y, v.x)); every lane is built from its Blau half and that
## half mirrored, so strecken, towers and spawns are functionally equal by construction.
## G1 layout: Top climbs the north-western highland, Mid crosses the Kluft over the
## central platform, Bottom winds through the south-eastern lowland and fords the river.
## Top and Bottom differ in shape but have exactly the same length (solved at load).

const LANES: Array[String] = ["top", "mid", "bot"]
const LANE_NAMES: Dictionary = {"top": "Top", "mid": "Mid", "bot": "Bottom"}
## Catmull-Rom control points of each Blau half, from the Blau base to the symmetry axis.
## The last point lies on x = z; the curve is sampled every ~2 m into the lane polyline.
const TOP_CONTROL: Array[Vector2] = [Vector2(-27.4, 21.0), Vector2(-26.4, 13.0), Vector2(-28.4, 4.0), Vector2(-26.2, -5.0),
	Vector2(-28.6, -13.5), Vector2(-28.4, -21.2), Vector2(-25.0, -25.0)]
const MID_CONTROL: Array[Vector2] = [Vector2(-21.6, 21.6), Vector2(-16.4, 17.2), Vector2(-10.9, 11.5), Vector2(-5.6, 5.9), Vector2(0, 0)]
const CORE_BLUE := Vector2(-30, 30)
## Two base towers in front of each Ancient, 6 m out and 40° either side of the Mid direction.
const BASE_TOWERS_BLUE: Array[Vector2] = [Vector2(-29.477, 24.023), Vector2(-24.023, 29.477)]
## Neutral boss grotto on the symmetry axis between Top and Mid, beside the Mid lane.
const GROTTO := Vector2(-13.5, -13.5)
const HALF_EXTENT: float = 36.0
## Direction of the symmetry axis (north-west to south-east) and its Blau-side normal.
const AXIS := Vector2(0.70710678, 0.70710678)
const BLUE_SIDE := Vector2(-0.70710678, 0.70710678)
const SAMPLE_SPACING: float = 2.0

var balance: LuneBalance
var lanes: Dictionary = {}
var buildings: Array[Dictionary] = []

class LanePath:
	extends RefCounted
	var points: PackedVector2Array
	var cumulative: PackedFloat32Array
	var length: float = 0.0

	func _init(source: Array[Vector2]) -> void:
		points = PackedVector2Array(source)
		cumulative.append(0.0)
		for i: int in range(1, points.size()):
			length += points[i].distance_to(points[i - 1])
			cumulative.append(length)

	## Index i of the segment [i - 1, i] that contains lane coordinate d (binary search).
	func _segment(d: float) -> int:
		var low: int = 1
		var high: int = points.size() - 1
		while low < high:
			var middle: int = (low + high) >> 1
			if d <= cumulative[middle]:
				high = middle
			else:
				low = middle + 1
		return low

	func point_at(s: float) -> Vector2:
		var d: float = clampf(s, 0.0, length)
		var i: int = _segment(d)
		var span: float = maxf(0.0001, cumulative[i] - cumulative[i - 1])
		return points[i - 1].lerp(points[i], clampf((d - cumulative[i - 1]) / span, 0.0, 1.0))

	func tangent_at(s: float) -> Vector2:
		var i: int = _segment(clampf(s, 0.0, length))
		return (points[i] - points[i - 1]).normalized()

	## Point and unit tangent at s in one pass.
	func sample(s: float) -> Array:
		var d: float = clampf(s, 0.0, length)
		var i: int = _segment(d)
		var a: Vector2 = points[i - 1]
		var b: Vector2 = points[i]
		var span: float = maxf(0.0001, cumulative[i] - cumulative[i - 1])
		return [a.lerp(b, clampf((d - cumulative[i - 1]) / span, 0.0, 1.0)), (b - a) / span]

	func project(position: Vector2) -> float:
		var best: float = INF
		var best_s: float = 0.0
		for i: int in range(1, points.size()):
			var a: Vector2 = points[i - 1]
			var b: Vector2 = points[i]
			var ab: Vector2 = b - a
			var t: float = clampf((position - a).dot(ab) / maxf(0.0001, ab.length_squared()), 0.0, 1.0)
			var d: float = position.distance_squared_to(a + ab * t)
			if d < best:
				best = d
				best_s = cumulative[i - 1] + ab.length() * t
		return best_s

static func mirror(v: Vector2) -> Vector2:
	return Vector2(v.y, v.x)

static func mirror_mid(v: Vector2) -> Vector2:
	return Vector2(-v.y, -v.x)

static func full_lane(half: Array[Vector2]) -> Array[Vector2]:
	var result: Array[Vector2] = half.duplicate()
	for i: int in range(half.size() - 2, -1, -1):
		result.append(mirror(half[i]))
	return result

## Samples the Catmull-Rom curve through the control points of a Blau half. The phantom
## point after the axis point is the mirror of the one before it, so the joined lane has
## no kink on the axis (its tangent there is perpendicular to x = z).
static func sample_half(control: Array[Vector2]) -> Array[Vector2]:
	var ext: Array[Vector2] = [control[0] * 2.0 - control[1]]
	ext.append_array(control)
	ext.append(mirror(control[control.size() - 2]))
	var result: Array[Vector2] = []
	for i: int in range(1, ext.size() - 2):
		var p0: Vector2 = ext[i - 1]
		var p1: Vector2 = ext[i]
		var p2: Vector2 = ext[i + 1]
		var p3: Vector2 = ext[i + 2]
		var steps: int = maxi(2, ceili(p1.distance_to(p2) / SAMPLE_SPACING))
		for k: int in range(steps):
			var t: float = float(k) / steps
			var t2: float = t * t
			var t3: float = t2 * t
			result.append(0.5 * (2.0 * p1 + (p2 - p0) * t + (2.0 * p0 - 5.0 * p1 + 4.0 * p2 - p3) * t2 + (3.0 * p1 - p0 - 3.0 * p2 + p3) * t3))
	result.append(control[control.size() - 1])
	return result

## Bottom half through the south-eastern lowland; `bend` pulls the valley meander inwards.
static func bottom_control(bend: float) -> Array[Vector2]:
	return [Vector2(-21.0, 27.4), Vector2(-12.5, 27.0), Vector2(-4.0, 27.6), Vector2(4.0, 27.0 - bend),
		Vector2(12.0, 27.4 - 0.6 * bend), Vector2(19.5, 27.0), Vector2(22.2, 27.8), Vector2(25.0, 25.0)]

## Bisection on the meander so that Bottom is exactly as long as Top (fair lane roles).
static func solve_bottom(target_length: float) -> Array[Vector2]:
	var low: float = 0.0
	var high: float = 8.0
	for i: int in range(60):
		var bend: float = (low + high) * 0.5
		if LanePath.new(full_lane(sample_half(bottom_control(bend)))).length < target_length:
			low = bend
		else:
			high = bend
	return full_lane(sample_half(bottom_control((low + high) * 0.5)))

func _init(config: LuneBalance = null) -> void:
	balance = config if config != null else LuneBalance.default_balance()
	lanes["top"] = LanePath.new(full_lane(sample_half(TOP_CONTROL)))
	lanes["mid"] = LanePath.new(full_lane(sample_half(MID_CONTROL)))
	lanes["bot"] = LanePath.new(solve_bottom(lanes["top"].length))
	_build_buildings()

## Lane coordinate s for a team's own marching progress p (0 at its own base).
func s_for(team: int, lane: String, progress: float) -> float:
	var path: LanePath = lanes[lane]
	return progress if team == 0 else path.length - progress

func progress_for(team: int, lane: String, s: float) -> float:
	var path: LanePath = lanes[lane]
	return s if team == 0 else path.length - s

## Blau frame point, mirrored for Rot so both sides are exact images.
func lane_point(team: int, lane: String, progress: float, lateral: float = 0.0) -> Vector2:
	var path: LanePath = lanes[lane]
	var sampled: Array = path.sample(progress)
	var tangent: Vector2 = sampled[1]
	var blue: Vector2 = sampled[0] + Vector2(-tangent.y, tangent.x) * lateral
	return blue if team == 0 else Vector2(blue.y, blue.x)

func lane_forward(team: int, lane: String, progress: float) -> Vector2:
	var path: LanePath = lanes[lane]
	var tangent: Vector2 = path.tangent_at(clampf(progress, 0.0, path.length))
	return tangent if team == 0 else mirror(tangent)

## Grotto deployment points: one mirrored entrance per team, boss slightly inside.
## The offsets from GROTTO are unchanged since M2, so expedition fights are unchanged.
func grotto_entry(team: int) -> Vector2:
	var blue: Vector2 = GROTTO + Vector2(1.2, 4.6)
	return blue if team == 0 else mirror(blue)

func grotto_boss_point() -> Vector2:
	return GROTTO + Vector2(-1.5, -1.5)

func grotto_center() -> Vector2:
	return GROTTO

## Army formation area of a team on a lane (lane progress from/to and lateral half width).
## Matches the spawn rows in LuneMatch._spawn_armies: rows of four, 1.2 m apart.
func deployment_span() -> Dictionary:
	return {"from": 0.4, "to": 7.2, "half_width": 2.4}

func core_position(team: int) -> Vector2:
	return CORE_BLUE if team == 0 else mirror(CORE_BLUE)

func _build_buildings() -> void:
	buildings.clear()
	for team: int in range(2):
		for lane: String in LANES:
			var path: LanePath = lanes[lane]
			for tier: String in ["inner", "outer"]:
				var fraction: float = balance.inner_tower_fraction if tier == "inner" else balance.outer_tower_fraction
				var progress: float = path.length * fraction
				buildings.append({"id": "%s_%s_%s" % ["blau" if team == 0 else "rot", lane, tier], "team": team, "lane": lane,
					"tier": tier, "progress": progress, "position": lane_point(team, lane, progress, balance.tower_side_offset),
					"max_hp": balance.tower_inner_hp if tier == "inner" else balance.tower_outer_hp,
					"damage": balance.tower_damage, "range": balance.tower_range,
					"bounty": balance.bounty_inner_tower if tier == "inner" else balance.bounty_outer_tower})
		for index: int in range(2):
			var point: Vector2 = BASE_TOWERS_BLUE[index]
			buildings.append({"id": "%s_base_%d" % ["blau" if team == 0 else "rot", index + 1], "team": team, "lane": "base",
				"tier": "base", "progress": -1.0, "position": point if team == 0 else mirror(point),
				"max_hp": balance.base_tower_hp, "damage": balance.base_tower_damage, "range": balance.tower_range,
				"bounty": balance.bounty_base_tower})
		buildings.append({"id": "%s_ancient" % ("blau" if team == 0 else "rot"), "team": team, "lane": "base", "tier": "core",
			"progress": -1.0, "position": core_position(team), "max_hp": balance.core_hp, "damage": 0.0, "range": 0.0, "bounty": 0})

var _index: Dictionary = {}

func building_def(id: String) -> Dictionary:
	if _index.is_empty():
		for entry: Dictionary in buildings:
			_index[entry.id] = entry
	return _index.get(id, {})

## Gate rule shared by every damage source. alive maps building id -> bool.
static func is_attackable(definition: Dictionary, alive: Dictionary) -> bool:
	var prefix: String = "blau" if int(definition.team) == 0 else "rot"
	match str(definition.tier):
		"outer":
			return true
		"inner":
			return not alive.get("%s_%s_outer" % [prefix, definition.lane], false)
		"base":
			for lane: String in LANES:
				if not alive.get("%s_%s_outer" % [prefix, lane], false) and not alive.get("%s_%s_inner" % [prefix, lane], false):
					return true
			return false
		"core":
			return not alive.get(prefix + "_base_1", false) and not alive.get(prefix + "_base_2", false)
	return false