## Oscillator movement — perpendicular strafing relative to enemy bearing.
## Reverses direction every PERIOD ticks; wall proximity triggers one reversal
## then locks out further wall-reversals for WALL_LOCKOUT ticks to prevent
## sign-flip every tick (which would zero net movement and park the bot).

import std/math
import gun_harness/gun_interface
import movement_harness/movement_interface

const
  MaxSpeed*      = 8.0  ## Tank Royale max speed
  Period*        = 40   ## ticks between reversals; ponytail: fixed, tune if evasion feels predictable
  WallMargin*    = 80.0 ## px from wall to trigger early reversal
  WallLockout*   = 20   ## ticks to suppress further wall-reversals after one fires

type OscillatorModule* = object
  sign:           float  ## +1 or -1, forward/backward relative to perp heading
  elapsed:        int    ## ticks since last reversal
  wallLockout:    int    ## remaining ticks where wall-reversal is suppressed
  debugGraphics*: bool

proc initOscillator*(): OscillatorModule =
  OscillatorModule(sign: 1.0, elapsed: 0, wallLockout: 0, debugGraphics: false)

proc computeMove*(m: var OscillatorModule, ws: WorldState): MoveCommand =
  inc m.elapsed
  if m.wallLockout > 0: dec m.wallLockout

  # Perpendicular heading to enemy: enemy bearing + 90°
  let enemyBearing = arctan2(ws.enemyY - ws.selfY, ws.enemyX - ws.selfX) * (180.0 / PI)
  let perpHeading  = (enemyBearing + 90.0) mod 360.0

  let nearWall = ws.selfX < WallMargin or ws.selfX > ws.arenaWidth - WallMargin or
                 ws.selfY < WallMargin or ws.selfY > ws.arenaHeight - WallMargin

  if m.elapsed >= Period or (nearWall and m.wallLockout == 0):
    m.sign   *= -1.0
    m.elapsed = 0
    if nearWall: m.wallLockout = WallLockout

  # Turn rate = delta from current heading toward perpendicular
  var delta = perpHeading - ws.selfHeading
  while delta > 180.0:  delta -= 360.0
  while delta < -180.0: delta += 360.0

  # When moving backward, flip the turn to keep perpendicular
  var normDelta = if m.sign < 0: delta - 180.0 else: delta
  while normDelta > 180.0:  normDelta -= 360.0
  while normDelta < -180.0: normDelta += 360.0

  (speed: m.sign * MaxSpeed, turnRate: normDelta.clamp(-10.0, 10.0))