#!/usr/bin/env python3

import math
import sys
import argparse
import svgturtle

parser = argparse.ArgumentParser(description='Generate a hexagonal battery case')
parser.add_argument('--dimension', default=5, type=int, help='Grid dimension')
parser.add_argument('--height', type=float, help='Height of battery')
parser.add_argument('--hole', default='AA', help='Hole diameter (mm or A, AA, AAA)')
parser.add_argument('--kerf', default=.1, type=float, help='Kerf')
parser.add_argument('--horizontal-finger', default=10.0, type=float, help='Width of horizontal fingers')
parser.add_argument('--vertical-finger', default=5.0, type=float, help='Width of vertical fingers')
parser.add_argument('--padding', default=1.5, type=float, help='Padding around holes')
parser.add_argument('--outside-padding', default=2, type=float, help='Extra padding between holes and wall')
parser.add_argument('--thickness', default=3.0, type=float, help='Thickness of material')
parser.add_argument('--lid', default=0.2, type=float, help='How much extra play to give the lid')

args = parser.parse_args()
assert (args.dimension % 2) == 1

BATTERY = {
    'AAA': [10.5, 44.5],
    'AA':  [14.5, 50.5],
    'C':   [26.2, 50.0],
    'D':   [34.2, 61.5],
}

if args.hole in BATTERY:
    dim = BATTERY[args.hole]
    args.hole = dim[0]
    if args.height == None:
        args.height = dim[1]
else:
    args.hole = float(args.hole)
    assert(args.height != None)

GRID   = args.hole+args.padding
RADIUS = args.hole/2
DIMX   = 2*(args.dimension+1)*GRID
DIMY   = 2*(args.dimension+1)*GRID
PI3    = math.pi/3

def draw_grid(cx, cy):
    for row in range(-int(args.dimension/2), int((args.dimension+1)/2)):
        cyr = cy+GRID*row*math.sin(PI3)
        num_col = args.dimension-abs(row)
        cxr = cx-.5*GRID*(num_col-1.0)
        for col in range(num_col):
            print('<circle cx="%.2f" cy="%.2f" r="%.2f" stroke="black" fill="none"/>' % (cxr+col*GRID, cyr, RADIUS))

def draw_plane(cx, cy, interior=False):
    radius = GRID*args.dimension*0.5+args.outside_padding
    if not interior:
        radius += args.thickness
    turtle       = svgturtle.SvgTurtle(cx, cy)
    turtle.penup()
    turtle.forward(radius)
    turtle.right(120)
    turtle.pendown()
    if interior:
        leg = (radius-args.horizontal_finger-args.kerf)/2
        for side in range(6):
            turtle.forward(leg)
            turtle.left(90)
            turtle.forward(args.thickness)
            turtle.right(90)
            turtle.forward(args.horizontal_finger+args.kerf)
            turtle.right(90)
            turtle.forward(args.thickness)
            turtle.left(90)
            turtle.forward(leg)
            turtle.right(60)
    else:
        num_fingers = int(radius/args.horizontal_finger/2)
        leg = (radius-(2*num_fingers-1)*args.horizontal_finger-args.kerf)/2
        for side in range(6):
            turtle.forward(leg)
            for finger in range(num_fingers):
                turtle.right(90)
                turtle.forward(args.thickness)
                turtle.left(90)
                turtle.forward(args.horizontal_finger+args.kerf)
                turtle.left(90)
                turtle.forward(args.thickness)
                turtle.right(90)
                turtle.forward(leg if finger == num_fingers-1 else args.horizontal_finger-args.kerf)
            turtle.right(60)
    print('<path d="%s" fill="none" stroke="black"/>' % turtle.to_s())

print('<svg viewBox="0 0 %.2f %.2f" width="%.2fmm" height="%.2fmm" stroke-width="0.1" xmlns="http://www.w3.org/2000/svg">' % (DIMX, DIMY, DIMX, DIMY))
draw_grid(GRID*(0.5*args.dimension+0.5), GRID*(0.5*args.dimension+1))
draw_grid(GRID*(1.5*args.dimension+1.5), GRID*(0.5*args.dimension+1))
draw_plane(GRID*(0.5*args.dimension+0.5), GRID*(0.5*args.dimension+1), True)
draw_plane(GRID*(1.5*args.dimension+1.5), GRID*(0.5*args.dimension+1), True)
draw_plane(GRID*(0.5*args.dimension+0.5), GRID*(1.5*args.dimension+1))
draw_plane(GRID*(1.5*args.dimension+1.5), GRID*(1.5*args.dimension+1))
print('</svg>')