#!/usr/bin/env python

header = 'A model of a diamond lattice comprising 2 x 2 x 2 unit cells by CMG Lee.'

import re, struct, math
def fmt(string): ## string.format(**vars()) using tags {expression!format} by CMG Lee
 def f(tag): i_sep = tag.rfind('!'); return (re.sub('\.0+$', '', str(eval(tag[1:-1])))
  if (i_sep < 0) else ('{:%s}' % tag[i_sep + 1:-1]).format(eval(tag[1:i_sep])))
 return (re.sub(r'(?<!{){[^{}]+}', lambda m:f(m.group()), string)
         .replace('{{', '{').replace('}}', '}'))
def append(obj, string): return obj.append(fmt(string))
def tabbify(cellss, separator='|'):
 cellpadss = [list(rows) + [''] * (len(max(cellss, key=len)) - len(rows)) for rows in cellss]
 fmts = ['%%%ds' % (max([len(str(cell)) for cell in cols])) for cols in zip(*cellpadss)]
 return '\n'.join([separator.join(fmts) % tuple(rows) for rows in cellpadss])
def hex_rgb(colour): ## convert [#]RGB to #RRGGBB and [#]RRGGBB to #RRGGBB
 return '#%s' % (colour if len(colour) > 4 else ''.join([c * 2 for c in colour])).lstrip('#')
def viscam_colour(colour):
 colour_hex      = hex_rgb(colour)
 colour_top5bits = [int(colour_hex[i:i+2], 16) >> 3 for i in range(1,7,2)]
 return (1 << 15) + (colour_top5bits[0] << 10) + (colour_top5bits[1] << 5) + colour_top5bits[2]
def roundm(x, multiple=1):
 if   (isinstance(x, tuple)): return tuple(roundm(list(x), multiple))
 elif (isinstance(x, list )): return [roundm(x_i, multiple) for x_i in x]
 else: return int(math.floor(float(x) / multiple + 0.5)) * multiple
def rotate(facetss, deg_x, deg_y, deg_z): ## around x then y then z axes
 (sin_x, cos_x) = (math.sin(math.radians(deg_x)), math.cos(math.radians(deg_x)))
 (sin_y, cos_y) = (math.sin(math.radians(deg_y)), math.cos(math.radians(deg_y)))
 (sin_z, cos_z) = (math.sin(math.radians(deg_z)), math.cos(math.radians(deg_z)))
 facet_rotatess = []
 for facets in facetss:
  facet_rotates = []
  for i_point in range(4):
   (x, y, z) = [facets[3 * i_point + i_xyz] for i_xyz in range(3)]
   if (x is None or y is None or z is None):
    facet_rotates += [x, y, z]
   else:
    (y, z) = (y * cos_x - z * sin_x,  y * sin_x + z * cos_x) ## rotate about x
    (x, z) = (x * cos_y + z * sin_y, -x * sin_y + z * cos_y) ## rotate about y
    (x, y) = (x * cos_z - y * sin_z,  x * sin_z + y * cos_z) ## rotate about z
    facet_rotates += [round(value, 9) for value in [x, y, z]]
  facet_rotatess.append(facet_rotates)
 return facet_rotatess
def translate(facetss, dx, dy, dz):
 ds = [dx, dy, dz]
 return [facets[:3] + [facets[3 * i_point + i_xyz] + ds[i_xyz]
                       for i_point in range(1,4) for i_xyz in range(3)]
         for facets in facetss]

## Add facets
facet_stickss          = [[None,0,0,  -2,10,10, -40,40,48, -10, 2,10],
                          [None,0,0, -10, 2,10, -48,40,40, -10,10, 2],
                          [None,0,0, -10,10, 2, -40,48,40,  -2,10,10]]
facet_stickss         += translate(rotate(translate(facet_stickss, 25,-25,-25),
                                          90,-90,90), -25,25,25)
facet_stickss         += rotate(facet_stickss,  0,  0,180)
facet_stickss         += rotate(facet_stickss,  0,180,  0)
facet_ball_triangless  = [[None,0,0, 12,12,0, 0,12,12, 12,0,12]]
facet_ball_triangless += rotate(facet_ball_triangless   ,  90,  0, 0)
facet_ball_triangless += rotate(facet_ball_triangless   , 180,  0, 0)
facet_ball_triangless += rotate(facet_ball_triangless   ,   0,180, 0)
facet_ball_diamondss   = [[None,0,0, 17,0,0, 12,12,0, 12,0,12]]
facet_ball_diamondss  += rotate(facet_ball_diamondss    , 180,  0, 0)
facet_ball_diamondss  += rotate(facet_ball_diamondss    ,  90,  0, 0)
facet_ball_diamondss  += rotate(facet_ball_diamondss    ,   0,180, 0)
facet_ball_diamondss  += rotate(facet_ball_diamondss    ,   0, 90, 0)
facet_ball_diamondss  += rotate(facet_ball_diamondss[:8],   0,  0,90)
facet_ballss           = facet_ball_diamondss + facet_ball_triangless
facet_stick_ballss     = facet_stickss + facet_ballss

facet_cell_1ss  = (translate(facet_ballss,100,100,0)
                 + translate(facet_stick_ballss, 50,50,50))
facet_cell_1ss += translate(facet_cell_1ss, 100,100,0)
facet_cell_2ss  = (translate(facet_ballss,200,100,100)
                 + translate(facet_stick_ballss, 150,50,150))
facet_cell_2ss += translate(facet_cell_2ss, -100,100,0)
facet_cellss    = facet_cell_1ss + facet_cell_2ss

facetss  = facet_cellss
facetss += translate(facetss, 200,  0,  0)
facetss += translate(facetss,   0,200,  0)
facetss += translate(facetss,   0,  0,200)
facetss += (facet_ballss
           + translate(facet_ballss,   0,200,  0)
           + translate(facet_ballss,   0,100,100)
           + translate(facet_ballss,   0,300,100)
           + translate(facet_ballss,   0,  0,200)
           + translate(facet_ballss,   0,200,200)
           + translate(facet_ballss,   0,400,200)
           + translate(facet_ballss,   0,100,300)
           + translate(facet_ballss,   0,300,300)
           + translate(facet_ballss,   0,200,400)
           + translate(facet_ballss,   0,400,400)
           + translate(facet_ballss, 200,  0,  0)
           + translate(facet_ballss, 100,  0,100)
           + translate(facet_ballss, 300,  0,100)
           + translate(facet_ballss,   0,  0,200)
           + translate(facet_ballss, 200,  0,200)
           + translate(facet_ballss, 400,  0,200)
           + translate(facet_ballss, 100,  0,300)
           + translate(facet_ballss, 300,  0,300)
           + translate(facet_ballss, 200,  0,400)
           + translate(facet_ballss, 400,  0,400)
           + translate(facet_ballss, 100,100,400)
           + translate(facet_ballss, 100,300,400)
           + translate(facet_ballss, 200,200,400)
           + translate(facet_ballss, 300,100,400)
           + translate(facet_ballss, 400,200,400)
           + translate(facet_ballss, 300,300,400)
           + translate(facet_ballss, 200,400,400)
           )

## Calculate normals
for facets in facetss:
 if (facets[0] is None or facets[1] is None or facets[2] is None):
  us      = [facets[i_xyz + 9] - facets[i_xyz + 6] for i_xyz in range(3)]
  vs      = [facets[i_xyz + 6] - facets[i_xyz + 3] for i_xyz in range(3)]
  normals = [us[1]*vs[2] - us[2]*vs[1], us[2]*vs[0] - us[0]*vs[2], us[0]*vs[1] - us[1]*vs[0]]
  normal_length = sum([component * component for component in normals]) ** 0.5
  facets[:3] = [round(component / normal_length, 10) for component in normals]

# print(tabbify([['%s%d' % (xyz, n) for n in range(3) for xyz in list('XYZ')] +
#                ['N%s'  % (xyz) for xyz in list('xyz')] + ['s0f']] + facetss))
## Compile STL
outss = ([['STL\n\n%-73s\n\n' % (header[:73]), struct.pack('<L', len(facetss))]] +
         [[struct.pack('<f', float(value)) for value in facets[:12]] +
          [struct.pack('<H', 0 if (len(facets) <= 12) else
                             viscam_colour(facets[12]))] for facets in facetss])
out   = ''.join([out for outs in outss for out in outs])
print('# bytes:%d\t# facets:%d\ttitle: %s' % (len(out), len(facetss), header[:73]))
with open(__file__[:__file__.rfind('.')] + '.stl', 'wb') as f_out: f_out.write(out)
 # f_out.write('%s\n## Python script to generate STL\n%s\n' % (''.join(outs), open(__file__).read()))