Electric field of point image charge

This is a figure I used for my homework at drexel. I drew it with very little knowledge of tikz at the time.

%%A 2021-01-12
\usetikzlibrary{calc,patterns,angles,quotes}
\begin{tikzpicture}[
    thick,
    >=stealth,
    dot/.style = {
      draw,
      fill = white,
      circle,
      inner sep = 0pt,
      minimum size = 4pt
    }
  ]
  \coordinate (O) at (0,0);
  \coordinate (X)  at (5,0);
  \coordinate (Y) at (0,4) ;
  \coordinate (A) at (-4,0);
  \coordinate (L) at (0,-1);
  \coordinate (U) at (0,4);
  \coordinate[label=above:P] (P) at (2,3);
  \coordinate (B) at (4,0) {};
  \draw [dotted] (O) to node [below] {$d$} (A);
  \draw [dotted] (O) to node [below] {$d$} (B);
  \draw [-] (O) to node [below, sloped] {$r $} (P);
  \draw [dashed] (A) to node [sloped, above] {$r_2$} (P);
  \draw [dashed] (B) to node [sloped, above] {$r_1$} (P);
  % mirror 
  \draw [-] (L) --  (U);
  \fill[black] (A) circle (0.13) node [circle,above,left, label=$-q$] {};
  \fill [black] (B) circle(0.13) node [circle, above,right, label=$q$] {};
  %\fill [gray] (O) circle(0.19) node [circle, above,left,  label=$2q$] {};
  \pic [draw, -, "$\theta$", angle eccentricity=1.5] {angle = B--O--P};
\end{tikzpicture}