function boss_showerhead_ai()
{
    facing_x   = sign(global.player.x - x);
    image_xscale = facing_x;
    
    switch(state)
    {
        case "SPAWN":
			state = "IDLE";
            idle_timer = 60;
            break;
        
        case "IDLE":
            if --idle_timer <= 0
            {
                var _next = attack_queue[attack_index];
                attack_index = (attack_index + 1) % array_length(attack_queue);
                
                switch(_next)
                {
                    case 1:
                        state = "WINDUP";
                        set_sprite(sBossShowerheadWindup);
                        break;
                    case 2:
                        state = "SLAM";
                        set_sprite(sBossShowerheadSlam);
                        break;
                    case 3:
                        state = "RETREAT";
                        x_spd = -boss_side * retreat_spd;
                        set_sprite(sBossShowerheadRetreat);
                        break;
                }
            }
            break;
        
        case "WINDUP":
            if animation_end()
            {
                shoot_count = 0;
                state = "SHOOT";
                set_sprite(sBossShowerheadShoot);
            }
            break;
        
        case "SHOOT":
            if animation_end()
            {
                var _bomb = icl(oShowerheadBomb);
                _bomb.x_spd = facing_x * (8 + shoot_count * 2);
                _bomb.y_spd = -10;
                
                shoot_count++;
                if shoot_count >= 3
                {
                    state = "IDLE";
                    idle_timer = 60;
                    set_sprite(sBossShowerheadIdle);
                }
            }
            break;
        
        case "SLAM":
            if animation_end()
            {
                // 生成预警线控制器
                var _warn = icl(oBossWarning);
                _warn.phase = phase;
                
                state = "IDLE";
                idle_timer = 60;
                set_sprite(sBossShowerheadIdle);
            }
            break;
        
        case "RETREAT":
            var _target = (boss_side == 1) ? anchor_l : anchor_r;
            if abs(x - _target) < abs(x_spd)
            {
                x     = _target;
                x_spd = 0;
                state = "CHARGE";
                x_spd = boss_side * charge_spd;
                set_sprite(sBossShowerheadCharge);
            }
            break;
        
        case "CHARGE":
            var _target = (boss_side == 1) ? anchor_r : anchor_l;
            if abs(x - _target) < abs(x_spd)
            {
                x        = _target;
                x_spd    = 0;
                boss_side *= -1; // 换边
                state      = "IDLE";
                idle_timer = 60;
                set_sprite(sBossShowerheadIdle);
            }
            break;
    }
}