// Can a client shoot now
bool Util_CanClientShoot(int client)
{
	// Get active weapon
	int weapon = GetEntPropEnt(client, Prop_Send, "m_hActiveWeapon");
	if (weapon == INVALID_ENT_REFERENCE)
	{
		return false;
	}

	float nextAttack = GetEntPropFloat(weapon, Prop_Send, "m_flNextPrimaryAttack");

	return GetGameTime() >= nextAttack;
}

public Action OnPlayerRunCmd(int client, int& buttons, int& impulse, float vel[3], float angles[3], int& weapon, int& subtype, int& cmdnum, int& tickcount, int& seed, int mouse[2])
{
	// ...
	if (buttons & IN_ATTACK && Util_CanClientShoot(client))
	{
		angles[0] = -89.0;
		PrintToChat(client, "You just shot your gun");
	}
	return Plugin_Continue;
}