;; Copyright 2019 Edward L. Platt <elplatt@alum.mit.edu
;;
;; TODO: add comments

#lang racket

(require racket/draw)
(require racket/gui)
(require "sylvester.rkt")
(require "network.rkt")

(define (draw-sylvester m w h margin)
  (define target (make-bitmap w h))
  (define dc (new bitmap-dc% [bitmap target]))
  (let ([edges (sylvester-edges m)]
        [nodes (sylvester-nodes m)])
    (for ([e edges])
      (draw-edge m e dc (- (/ w 2) margin) margin))
    (for ([v nodes])
      (draw-node m v dc (- (/ w 2) margin) margin)))
  (make-object image-snip% target))

(define (draw-edge m edge dc r margin)
  (let* ([v (sylvester-radix-value (first edge))]
         [w (sylvester-radix-value (second edge))])
    (send dc set-pen "gray" 2 'solid)
    (send dc draw-line
      (node-x v m r margin) (node-y v m r margin)
      (node-x w m r margin) (node-y w m r margin))))

(define (draw-node m v dc r margin)
  (let ([v (sylvester-radix-value v)])
    (send dc set-pen "black" 2 'solid)
    (send dc draw-arc
          (- (node-x v m r margin) 4) (- (node-y v m r margin) 4)
          8 8 0 (* 2 pi))))

(define (node-x v m r margin)
  (let ([vtheta (* 2 pi (/ v (- (sylvester m) 1)))])
    (+ r margin (* r (cos vtheta)))))

(define (node-y v m r margin)
  (let ([vtheta (* 2 pi (/ v (- (sylvester m) 1)))])
    (+ r margin (* r (sin vtheta)))))

(draw-sylvester 3 320 320 10)