class_name IconButton
extends Control

# Square neon-outlined button, hand-drawn to match the game's existing
# no-texture glowing look (same NeonDraw technique as ships/enemies) -
# no icon image assets, just a glyph drawn inside the frame.

signal pressed

# Scenes store `icon` as a plain int, so NEW ENTRIES MUST BE APPENDED -
# inserting one would silently repoint every button after it.
enum Icon {
	MAP, CLOSE, SHIP, DOWN_ARROW, UP_ARROW, BUILD, ROTATE_CW, ROTATE_CCW,
	# One per building, each a miniature of what actually gets placed. The
	# build menu used to pick from the generic set, which left the mothership
	# and the command centre sharing a folded-map glyph and neither of them
	# looking anything like the structure they build.
	MOTHERSHIP, CRAFTER, COMMAND_CENTER, EXTRACTOR,
}

# Size the glyphs were originally drawn against. Every glyph dimension is
# scaled by (actual size / this), so the button can be resized in the scene
# without the icon inside it staying small.
const REFERENCE_SIZE: float = 56.0

@export var icon: int = Icon.MAP
@export var glow_color: Color = Color(0.25, 0.85, 1.0)
# Colour of the bright core stroke. Defaults to near-white, which reads well
# on the dark space background; scenes drawing over a bright backdrop (the
# lunar surface) override this with a dark colour so the button doesn't wash
# out. See NeonDraw.
@export var core_color: Color = Color(1.0, 1.0, 1.0)
# When false the button is drawn greyed out, but STILL emits `pressed` -
# the caller decides what to do, which is what lets an unavailable option
# explain itself instead of silently doing nothing.
@export var enabled: bool = true: set = set_enabled
@export var disabled_color: Color = Color(0.42, 0.45, 0.5)

var pressed_down: bool = false


func set_enabled(value: bool) -> void:
	if enabled == value:
		return
	enabled = value
	queue_redraw()


func _ready() -> void:
	queue_redraw()


func _gui_input(event: InputEvent) -> void:
	if event is InputEventScreenTouch:
		_handle_press(event.pressed, event.position)
		accept_event()
	elif event is InputEventMouseButton and event.button_index == MOUSE_BUTTON_LEFT:
		_handle_press(event.pressed, event.position)
		accept_event()


func _handle_press(is_pressed: bool, at_position: Vector2) -> void:
	if is_pressed:
		pressed_down = true
		queue_redraw()
	elif pressed_down:
		pressed_down = false
		queue_redraw()
		# Only counts as a real press if the finger/cursor is still over
		# the button when it lifts - dragging off before releasing (a
		# common way to "cancel" a touch) must not still trigger it.
		if Rect2(Vector2.ZERO, size).has_point(at_position):
			pressed.emit()


func _active_color() -> Color:
	return glow_color if enabled else disabled_color


func _draw() -> void:
	var rect_size: Vector2 = size
	var s: float = min(rect_size.x, rect_size.y) / REFERENCE_SIZE
	# Constant glow, brighter while held. Only the press state changes it,
	# so the button redraws on press/release instead of every frame.
	var pulse: float = 1.0 if pressed_down else 0.85

	var margin: float = 4.0 * s
	var square: PackedVector2Array = PackedVector2Array([
		Vector2(margin, margin),
		Vector2(rect_size.x - margin, margin),
		Vector2(rect_size.x - margin, rect_size.y - margin),
		Vector2(margin, rect_size.y - margin),
	])
	NeonDraw.draw_glowing_polygon(self, square, _active_color(), pulse, core_color)

	var center: Vector2 = rect_size / 2.0
	match icon:
		Icon.CLOSE:
			_draw_close(center, pulse, s)
		Icon.SHIP:
			_draw_ship(center, pulse, s)
		Icon.MAP:
			_draw_map(center, pulse, s)
		Icon.DOWN_ARROW:
			_draw_arrow(center, pulse, 1.0, s)
		Icon.UP_ARROW:
			_draw_arrow(center, pulse, -1.0, s)
		Icon.BUILD:
			_draw_build(center, pulse, s)
		Icon.ROTATE_CW:
			_draw_rotate(center, pulse, s, 1.0)
		Icon.ROTATE_CCW:
			_draw_rotate(center, pulse, s, -1.0)
		Icon.MOTHERSHIP:
			_draw_mothership_icon(center, pulse, s)
		Icon.CRAFTER:
			_draw_crafter_icon(center, pulse, s)
		Icon.COMMAND_CENTER:
			_draw_command_icon(center, pulse, s)
		Icon.EXTRACTOR:
			_draw_extractor_icon(center, pulse, s)


func _draw_close(center: Vector2, pulse: float, s: float) -> void:
	var r: float = 10.0 * s
	NeonDraw.draw_glowing_line(self, center + Vector2(-r, -r), center + Vector2(r, r), _active_color(), pulse, 0.5 * s, core_color)
	NeonDraw.draw_glowing_line(self, center + Vector2(-r, r), center + Vector2(r, -r), _active_color(), pulse, 0.5 * s, core_color)


func _draw_ship(center: Vector2, pulse: float, s: float) -> void:
	var nose: Vector2 = center + Vector2(0, -11) * s
	var left: Vector2 = center + Vector2(-7, 8) * s
	var right: Vector2 = center + Vector2(7, 8) * s
	var points: PackedVector2Array = PackedVector2Array([nose, left, right])
	NeonDraw.draw_glowing_polygon(self, points, _active_color(), pulse, core_color)


func _draw_arrow(center: Vector2, pulse: float, direction: float, s: float) -> void:
	var r: float = 9.0 * s
	var tip: Vector2 = center + Vector2(0, r * direction)
	var shaft_top: Vector2 = center + Vector2(0, -r * direction)
	NeonDraw.draw_glowing_line(self, shaft_top, tip, _active_color(), pulse, 0.5 * s, core_color)
	NeonDraw.draw_glowing_line(self, tip, tip + Vector2(-r * 0.7, -r * 0.8 * direction), _active_color(), pulse, 0.5 * s, core_color)
	NeonDraw.draw_glowing_line(self, tip, tip + Vector2(r * 0.7, -r * 0.8 * direction), _active_color(), pulse, 0.5 * s, core_color)


func _draw_build(center: Vector2, pulse: float, s: float) -> void:
	# A plus inside a frame - "add a structure".
	var r: float = 11.0 * s
	var frame: PackedVector2Array = PackedVector2Array([
		center + Vector2(-r, -r), center + Vector2(r, -r),
		center + Vector2(r, r), center + Vector2(-r, r),
	])
	NeonDraw.draw_glowing_polygon(self, frame, _active_color(), pulse, core_color)
	var arm: float = r * 0.55
	NeonDraw.draw_glowing_line(self, center + Vector2(-arm, 0), center + Vector2(arm, 0), _active_color(), pulse, 0.4 * s, core_color)
	NeonDraw.draw_glowing_line(self, center + Vector2(0, -arm), center + Vector2(0, arm), _active_color(), pulse, 0.4 * s, core_color)


func _draw_rotate(center: Vector2, pulse: float, s: float, direction: float) -> void:
	# Three-quarter arc with an arrowhead on the leading end, mirrored for
	# the counter-clockwise variant.
	var r: float = 11.0 * s
	var segments: int = 14
	var sweep: float = TAU * 0.75
	var start: float = -PI * 0.5
	var arc: PackedVector2Array = PackedVector2Array()
	for i in range(segments + 1):
		var t: float = float(i) / segments
		var a: float = start + sweep * t * direction
		arc.append(center + Vector2(cos(a), sin(a)) * r)
	for i in range(segments):
		NeonDraw.draw_glowing_line(self, arc[i], arc[i + 1], _active_color(), pulse, 0.34 * s, core_color)

	var tip: Vector2 = arc[arc.size() - 1]
	var tangent: Vector2 = (tip - arc[arc.size() - 2]).normalized()
	var normal: Vector2 = Vector2(-tangent.y, tangent.x)
	var head: float = 5.0 * s
	NeonDraw.draw_glowing_line(self, tip, tip - tangent * head + normal * head, _active_color(), pulse, 0.34 * s, core_color)
	NeonDraw.draw_glowing_line(self, tip, tip - tangent * head - normal * head, _active_color(), pulse, 0.34 * s, core_color)


# --- building glyphs, each echoing the placed structure's silhouette ------

func _draw_mothership_icon(center: Vector2, pulse: float, s: float) -> void:
	# Radial flagship: a reactor core with six swept talons around it, the
	# same silhouette as the placed structure.
	for i in range(6):
		var base: float = (float(i) / 6.0) * TAU
		var talon: PackedVector2Array = PackedVector2Array()
		for step in [0.0, 0.5, 1.0]:
			var a: float = base + 0.72 * pow(step, 1.3)
			talon.append(center + Vector2(cos(a), sin(a)) * lerpf(7.0, 16.0, step) * s)
		for step in [1.0, 0.5, 0.0]:
			var a: float = base + 0.72 * pow(step, 1.3) - (0.34 * (1.0 - step) + 0.05)
			talon.append(center + Vector2(cos(a), sin(a)) * lerpf(7.0, 16.0, step) * s)
		NeonDraw.draw_glowing_polygon(self, talon, _active_color(), pulse, core_color)

	for radius in [6.5, 3.0]:
		var ring: PackedVector2Array = PackedVector2Array()
		for i in range(6):
			var a: float = (float(i) / 6.0) * TAU + PI / 6.0
			ring.append(center + Vector2(cos(a), sin(a)) * radius * s)
		NeonDraw.draw_glowing_polygon(self, ring, _active_color(), pulse, core_color)


func _draw_crafter_icon(center: Vector2, pulse: float, s: float) -> void:
	# Reactor core, truss spine, and an open cradle holding a hull.
	var core_centre: Vector2 = center + Vector2(-11, 0) * s
	var core: PackedVector2Array = PackedVector2Array()
	for i in range(6):
		var a: float = (float(i) / 6.0) * TAU + PI / 6.0
		core.append(core_centre + Vector2(cos(a), sin(a)) * 5.0 * s)
	NeonDraw.draw_glowing_polygon(self, core, _active_color(), pulse, core_color)
	NeonDraw.draw_glowing_line(self, center + Vector2(-6, 0) * s,
		center + Vector2(-2, 0) * s, _active_color(), pulse, 0.35 * s, core_color)

	var bay: Vector2 = center + Vector2(6, 0) * s
	var cradle: PackedVector2Array = PackedVector2Array()
	for i in range(13):
		var a: float = lerpf(-0.25 * PI, 1.25 * PI, float(i) / 12.0)
		cradle.append(bay + Vector2(cos(a), sin(a)) * 10.0 * s)
	NeonDraw.draw_glowing_path(self, cradle, _active_color(), pulse, 0.4 * s, core_color)
	NeonDraw.draw_glowing_polygon(self, PackedVector2Array([
		bay + Vector2(0, -6) * s, bay + Vector2(-5, 4) * s, bay + Vector2(5, 4) * s,
	]), _active_color(), pulse, core_color)


func _draw_command_icon(center: Vector2, pulse: float, s: float) -> void:
	# Diamond with three formation pips - "arrangement".
	var d: float = 14.0 * s
	NeonDraw.draw_glowing_polygon(self, PackedVector2Array([
		center + Vector2(0, -d), center + Vector2(d, 0),
		center + Vector2(0, d), center + Vector2(-d, 0),
	]), _active_color(), pulse, core_color)
	for p in [Vector2(0, -5), Vector2(-5, 4), Vector2(5, 4)]:
		NeonDraw.draw_glowing_polygon(self, PackedVector2Array([
			center + (p + Vector2(0, -3)) * s,
			center + (p + Vector2(-2.6, 2.4)) * s,
			center + (p + Vector2(2.6, 2.4)) * s,
		]), _active_color(), pulse, core_color)


func _draw_extractor_icon(center: Vector2, pulse: float, s: float) -> void:
	# A derrick standing on a planet's limb, with ore lifting off it - the
	# one building that only works over a planet, so the planet is the point.
	var limb: PackedVector2Array = PackedVector2Array()
	for i in range(11):
		var a: float = lerpf(-0.82 * PI, -0.18 * PI, float(i) / 10.0)
		limb.append(center + (Vector2(0, 22) + Vector2(cos(a), sin(a)) * 17.0) * s)
	NeonDraw.draw_glowing_path(self, limb, _active_color(), pulse, 0.45 * s, core_color)

	NeonDraw.draw_glowing_line(self, center + Vector2(-6, 5) * s, center + Vector2(0, -9) * s, _active_color(), pulse, 0.4 * s, core_color)
	NeonDraw.draw_glowing_line(self, center + Vector2(6, 5) * s, center + Vector2(0, -9) * s, _active_color(), pulse, 0.4 * s, core_color)
	NeonDraw.draw_glowing_line(self, center + Vector2(-3.5, -1) * s, center + Vector2(3.5, -1) * s, _active_color(), pulse, 0.35 * s, core_color)
	# Shaft driven down through the limb - without it the derrick reads as a
	# tower standing on a hill rather than as something mining the planet.
	NeonDraw.draw_glowing_line(self, center + Vector2(0, -1) * s, center + Vector2(0, 14) * s, _active_color(), pulse, 0.3 * s, core_color)

	var ore_centre: Vector2 = center + Vector2(0, -15) * s
	var ore: PackedVector2Array = PackedVector2Array()
	for i in range(6):
		var a: float = (float(i) / 6.0) * TAU + PI / 6.0
		ore.append(ore_centre + Vector2(cos(a), sin(a)) * 4.0 * s)
	NeonDraw.draw_glowing_polygon(self, ore, _active_color(), pulse, core_color)


func _draw_map(center: Vector2, pulse: float, s: float) -> void:
	var w: float = 11.0 * s
	var h: float = 9.0 * s
	var outline: PackedVector2Array = PackedVector2Array([
		center + Vector2(-w, -h), center + Vector2(w, -h * 0.7),
		center + Vector2(w, h), center + Vector2(-w, h * 0.7),
	])
	NeonDraw.draw_glowing_polygon(self, outline, _active_color(), pulse, core_color)
	NeonDraw.draw_glowing_line(self, center + Vector2(-w * 0.34, -h * 0.9), center + Vector2(-w * 0.34, h * 0.77), _active_color(), pulse, 0.4 * s, core_color)
	NeonDraw.draw_glowing_line(self, center + Vector2(w * 0.34, -h * 0.77), center + Vector2(w * 0.34, h * 0.9), _active_color(), pulse, 0.4 * s, core_color)