class_name WeaponFireHelper extends Node


## Compute bullet properties for a standard shot.
## Returns a Dictionary with: position, angle, fire_time, time_offset, index_from_center, animation_offset
func compute_standard_props(weapon_data: WeaponShot, projectile_index: int, spawn_position: Vector2, current_time: float) -> Dictionary:
	var total_projectiles: int = weapon_data.projectiles
	var center_index: float = (total_projectiles - 1) / 2.0

	var index_from_center: float = projectile_index - center_index

	# Horizontal offset (symmetrical: left=-ve, right=+ve)
	var bullet_horizontal_offset: float = index_from_center * weapon_data.horizontal_offset

	# Timing: center-first, pairs outward
	var time_offset: float = abs(index_from_center) * weapon_data.stagger_offset

	# Vertical spacing creates the ^ (inverted-V) geometry: outer projectiles fire lower
	# (higher Y values, further from the player) than the center projectile, which sits
	# higher on screen (lower Y values). This creates a ^ pattern relative to the origin.
	var vertical_offset: float = (abs(index_from_center) * weapon_data.projectile_vertical_spacing) / 2.0
	var position: Vector2 = spawn_position + Vector2(bullet_horizontal_offset, +vertical_offset)

	# Angle (only when projectiles >= 3, division-by-zero guard)
	var bullet_angle: float = 0.0
	if total_projectiles >= 3:
		bullet_angle = (index_from_center / center_index) * (weapon_data.spread_angle / 2.0)

	# Fire time
	var fire_time: float = current_time + time_offset

	# Animation offset (if staggered animation is enabled)
	var animation_offset: float = index_from_center * weapon_data.stagger_offset

	return {
		"position": position,
		"angle": bullet_angle,
		"fire_time": fire_time,
		"time_offset": time_offset,
		"index_from_center": index_from_center,
		"animation_offset": animation_offset,
	}


## Compute bullet properties for a grouped shot, with optional mirroring.
## Returns a Dictionary with: position, angle, fire_time, time_offset, index_from_center, animation_offset
func compute_grouped_props(group: WeaponProjectileGroup, weapon_data: WeaponShot,
						   bullet_index: int, spawn_position: Vector2, current_time: float,
						   mirror: bool = false) -> Dictionary:
	var center_index: float = (group.bullet_count - 1) / 2.0
	var index_from_center: float = bullet_index - center_index

	# Horizontal offset: group offset + within-group spread
	var bullet_horizontal_offset: float = group.horizontal_offset + index_from_center * group.horizontal_spacing
	if mirror:
		bullet_horizontal_offset = -bullet_horizontal_offset

	# Base angle: group angle (negated when mirrored) + within-group spread
	var bullet_angle: float = group.angle_offset
	if mirror:
		bullet_angle = -group.angle_offset

	# Symmetrical spread (guard against < 3 bullets)
	if group.bullet_count >= 3:
		var spread_contribution = (index_from_center / center_index) * (group.spread_angle / 2.0)
		if mirror:
			bullet_angle -= spread_contribution
		else:
			bullet_angle += spread_contribution

	# Vertical spacing creates the ^ (inverted-V) geometry: outer projectiles fire lower
	# (higher Y values, further from the player) than the center projectile, which sits
	# higher on screen (lower Y values). This creates a ^ pattern relative to the origin.
	var vertical_offset: float = (abs(index_from_center) * weapon_data.projectile_vertical_spacing) / 2.0
	var position: Vector2 = spawn_position + Vector2(bullet_horizontal_offset, +vertical_offset)

	# Timing: group delay + within-group stagger
	var time_offset: float = group.group_delay + abs(index_from_center) * group.stagger_offset

	# Fire time
	var fire_time: float = current_time + time_offset

	# Animation offset (if staggered animation is enabled)
	var animation_offset: float = index_from_center * weapon_data.stagger_offset

	return {
		"position": position,
		"angle": bullet_angle,
		"fire_time": fire_time,
		"time_offset": time_offset,
		"index_from_center": index_from_center,
		"animation_offset": animation_offset,
	}