https://github.com/awilliams/RTanque

rtanque-lexun.rb

class Lexun < RTanque::Bot::Brain

  NAME = 'Lexun'
  include RTanque::Bot::BrainHelper

  Wall = Struct.new :name, :axis, :position, :opposite

  def tick!
    @tick = @tick.to_i.succ
    setup if @tick == 1

    manage_movement
    manage_aggression
  end

  def setup
    north_wall = Wall.new 'north_wall', 'y', self.arena.height, RTanque::Heading::S
    east_wall = Wall.new 'east_wall', 'x', self.arena.width, RTanque::Heading::W
    south_wall = Wall.new 'south_wall', 'y', 0, RTanque::Heading::N
    west_wall = Wall.new 'west_wall', 'x', 0, RTanque::Heading::E
    @walls = north_wall, east_wall, south_wall, west_wall
  end

  def manage_movement
    command.heading = desired_heading
    command.speed = desired_speed

    return if transitioning?
    @desired_speed = MAX_BOT_SPEED

    avoid_walls if near_wall?
    evade_attacker if taking_damage?
  end

  def manage_aggression
    if sensors.radar.any?
      if lock_on_target
        command.fire MAX_FIRE_POWER
      end
    else
      radar_scan
    end
  end

  def lock_on_target
    if sensors.radar.none?
      radar_scan
    else
      @target = sensors.radar.first.name != NAME ? sensors.radar.first : sensors.radar.to_a.last

      command.turret_heading = @target.heading
      command.radar_heading = @target.heading

      @target.heading.delta(sensors.turret_heading).abs < RTanque::Heading::ONE_DEGREE * 5.0
    end
  end

  def radar_scan
    command.radar_heading = sensors.radar_heading + MAX_RADAR_ROTATION
  end

  def avoid_walls
    @desired_heading = @nearby_walls[0].opposite + (rand(1..2) -1) * RTanque::Heading::EIGHTH_ANGLE
    transition 140
  end

  def evade_attacker
    maneuver = rand(1..4) > 1 ? 2 : 1
    case maneuver
    when 1
      @desired_speed = -2
      transition 100
    when 2
      @desired_heading = sensors.heading + RTanque::Heading::rand
      transition 40
    end
  end

  def taking_damage?
    @health ||= sensors.health

    sensors.health < @health ? @health = sensors.health : false
  end

  def near_wall?
    @nearby_walls = []
    discover_nearby_walls
    @nearby_walls.any?
  end

  def discover_nearby_walls
    @walls.each do |wall|
      wall_position = wall.position
      tank_position = sensors.position.send(wall.axis)

      if distance_between(wall_position, tank_position) < 135
        @nearby_walls << wall
      end
    end
    @nearby_walls
  end

  def desired_heading
    @desired_heading ||= RTanque::Heading::rand
  end

  def desired_speed
    @desired_speed ||= MAX_BOT_SPEED
  end

  def transition(steps)
    @transition_time = @tick + steps
  end

  def transitioning?
    @transition_time ||= 0
    @transition_time > @tick
  end

  def distance_between(x, y)
    case x <=> y
    when -1
      y - x
    when 0
      0
    when 1
      x - y
    end
  end
end