#include <amxmodx>
#include <engine>


#define PLUGIN "Pump Knockback (when shot by one)"
#define VERSION "1.0"
#define AUTHOR "v3x & Chronic"


new cvar_pump_active , cvar_pump_force;


public plugin_init()
{
 register_plugin(PLUGIN , VERSION , AUTHOR);


 register_event("Damage" , "event_Damage" , "b" , "2>0");


 cvar_pump_active   = register_cvar("pump_knockback" , "1");
 cvar_pump_force    = register_cvar("pump_force"     , "10");
}


public event_Damage(id)
{
 if(!get_pcvar_num(cvar_pump_active))
 return PLUGIN_CONTINUE;


 if(!is_user_alive(id))
 return PLUGIN_CONTINUE;


 new weapon , attacker = get_user_attacker(id , weapon);


 if(!is_user_alive(attacker))
 return PLUGIN_CONTINUE;


 if(weapon == CSW_M3)
 {
 new Float:vec[3];
 new Float:oldvelo[3];
 get_user_velocity(id, oldvelo);
 create_velocity_vector(id , attacker , vec);
 vec[0] += oldvelo[0];
 vec[1] += oldvelo[1];
 set_user_velocity(id , vec);
 }


 return PLUGIN_CONTINUE;
}


// Stock by the one and only, Chronic :P
stock create_velocity_vector(victim,attacker,Float:velocity[3])
{
 if(!is_user_alive(victim) || !is_user_alive(attacker))
 return 0;


 new Float:vicorigin[3];
 new Float:attorigin[3];
 entity_get_vector(victim   , EV_VEC_origin , vicorigin);
 entity_get_vector(attacker , EV_VEC_origin , attorigin);


 new Float:origin2[3]
 origin2[0] = vicorigin[0] - attorigin[0];
 origin2[1] = vicorigin[1] - attorigin[1];


 new Float:largestnum = 0.0;


 if(floatabs(origin2[0])>largestnum) largestnum = floatabs(origin2[0]);
 if(floatabs(origin2[1])>largestnum) largestnum = floatabs(origin2[1]);


 origin2[0] /= largestnum;
 origin2[1] /= largestnum;


 velocity[0] = ( origin2[0] * (get_pcvar_float(cvar_pump_force) * 3000) ) / get_entity_distance(victim , attacker);
 velocity[1] = ( origin2[1] * (get_pcvar_float(cvar_pump_force) * 3000) ) / get_entity_distance(victim , attacker);
 if(velocity[0] <= 20.0 || velocity[1] <= 20.0)
 velocity[2] = random_float(200.0 , 275.0);


 return 1;
}