## Linear gun: predict enemy continues at current velocity and heading.
## Coordinate system: 0° = East, CCW positive (Tank Royale standard).

import std/math
import gun_harness/gun_interface
import guns/lead_forecast

type LinearGun* = object
  debugGraphics*: bool

proc predict*(g: var LinearGun, state: WorldState, bulletSpeed: float): GunPrediction =
  # Self-consistent constant-velocity forecast: iterate the flight time until the
  # predicted point sits at the distance the virtual bullet actually travels.
  # Without the iteration the bullet resolves early/late whenever the target
  # moves radially, which is why this gun scored 87% (p3.0 = 63/100) on the
  # constant-velocity fixture where a self-consistent forecast scores 100%.
  let f = forecastLinear(state, bulletSpeed)
  GunPrediction(x: clamp(f.x, 0.0, state.arenaWidth),
                y: clamp(f.y, 0.0, state.arenaHeight))

proc onResult*(g: var LinearGun, e: FeedbackEvent) =
  discard  # analytical gun — no learning