#! /usr/bin/python3 -t


PROG_DESC = "Outputs an SVG 'roadkill' diagram for said molecule"

import math; from math import sqrt,sin,cos,pi
import rn
import sys, os, re
import mformula
import mformula_oxocarbon
import mformula_svg



def image_name(style):
  fname = __file__
  imgname = re.sub(r'.*[/]', "", fname[0:-3]) + \
    "_style" + style
  return imgname

def image_descr(style):
  fname = __file__
  imgname = re.sub(r'.*[/]', "", fname[0:-3])
  descr = "Structural formula of " + re.sub(r'[_]', " ", imgname)
  descr += "\n" + \
    "\n" + \
    mformula_svg.style_descr(style)
  return descr

def build_formula(svg):
  fh = build_formula_half(svg) # The left half of the molecule.

  fm = mformula.obj()
  k0 = fm.add_subformula(fh, 0,   0, [0,0])
  k1 = fm.add_subformula(fh, 0, 180, [0,0])
  fm.add_bond(k0+4,k1+0,1.0)
  fm.add_bond(k1+4,k0+0,1.0)
  return fm

def image_name(style):
  fname = __file__
  imgname = re.sub(r'.*[/]', "", fname[0:-3]) + \
    "_style" + style
  return imgname

def image_descr(style):
  fname = __file__
  imgname = re.sub(r'.*[/]', "", fname[0:-3])
  descr = "Structural formula of " + re.sub(r'[_]', " ", imgname)
  descr += "\n" + \
    "\n" + \
    mformula_svg.style_descr(style)
  return descr

def build_formula_half(svg) :
  "Builds the left half of the molecule, assumed centered at [0,0]."
  fh = mformula.obj()

  c30 = cos(30*pi/180)
  s30 = sin(30*pi/180)
  db = svg.rel_bond_length(2.0) # Relative length of double bonds.
  p0 = [-c30, +s30]                           # Upper left carbon.
  p1 = rn.add(p0, rn.scale(db, [-c30, +s30])) # Upper left oxygen.
  p2 = [-c30, -s30]                           # Bottom oxygen.
  p3 = rn.add(p2, rn.scale(db, [-c30, -s30])) # Bottom oxygen.
  p4 = [0, -1]                                # Bottom oxygen.

  k0 = fh.add_atom("C", p0, 0,0)
  k1 = fh.add_atom("O", p1, 0,0)
  k2 = fh.add_atom("C", p2, 0,0)
  k3 = fh.add_atom("O", p3, 0,0)
  k4 = fh.add_atom("O", p4, 0,0)
  fh.add_bond(k0,k2,1.0)
  fh.add_bond(k2,k4,1.0)
  fh.add_bond(k0,k1,2.0)
  fh.add_bond(k2,k3,2.0)
  return fh