#!/usr/bin/env python3

'''
Application for splitting groups from one SVG file into separate files

Usage:
python3 vector_layer_split.py infile format outdir

Usage Example:
python3 vector_layer_split.py vector_source.svg tw ../src/art/vector/layers/
'''

import lxml.etree as etree
import sys
import os
import copy
import re
import normalize_svg
import argparse

parser = argparse.ArgumentParser(
	description='Application for splitting groups from one SVG file into separate files.')
parser.add_argument('-o', '--output', dest='output_dir', required=True,
					help='output directory')
parser.add_argument('-f', '--format', dest='output_format',
					choices=['svg', 'tw'], default='svg', help='output format.')
parser.add_argument('-p', '--prefix', dest='prefix', default='',
					help='Prepend this string to result file names')
parser.add_argument('input_file', metavar='FILENAME', nargs='+',
					help='Input SVG file with layers')

args = parser.parse_args()
output_format = args.output_format
output_directory = args.output_dir


def splitFile(inputFile):
	tree = etree.parse(inputFile)
	normalize_svg.fix(tree)

	# prepare output template
	template = copy.deepcopy(tree)
	root = template.getroot()

	# remove all svg root attributes except document size
	for a in root.attrib:
		if (a != "viewBox"):
			del root.attrib[a]

	# add placeholder for CSS class (needed for workaround for non HTML 5.1 compliant browser)
	# if output_format == 'tw':
		# root.attrib["class"] = "'+_art_display_class+'"
	ns = {
		'svg': 'http://www.w3.org/2000/svg',
		'inkscape': 'http://www.inkscape.org/namespaces/inkscape',
		'sodipodi': "http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd",
	}

	# remove all content, including metadata
	# for twine output, style definitions are removed, too
	defs = None
	for e in root:
		if (e.tag == etree.QName(ns['svg'], 'defs')):
			defs = e
		if (e.tag == etree.QName(ns['svg'], 'g') or
			e.tag == etree.QName(ns['svg'], 'metadata') or
			e.tag == etree.QName(ns['svg'], 'defs') or
			e.tag == etree.QName(ns['sodipodi'], 'namedview') or
			(output_format == 'tw' and e.tag == etree.QName(ns['svg'], 'style'))
			):
			root.remove(e)
	# template preparation finished

	# prepare regex for later use
	regex_xmlns = re.compile(' xmlns[^ ]+')
	regex_space = re.compile(r'[>]\s+[<]')

	# find all groups
	layers = tree.xpath('//svg:g', namespaces=ns)
	for layer in layers:
		i = layer.get('id')
		if (  # disregard non-content groups
			i.endswith("_") or  # manually suppressed with underscore
			i.startswith("XMLID") or  # Illustrator generated group
			i.startswith("g")  # Inkscape generated group
		):
			continue
	# create new canvas
		output = copy.deepcopy(template)
	# copy all shapes into template
		canvas = output.getroot()
		for e in layer:
			canvas.append(e)
		# represent template as SVG (binary string)
		svg = etree.tostring(output, pretty_print=False)
		# poor man's conditional defs insertion
		# TODO: extract only referenced defs (filters, gradients, ...)
		# TODO: detect necessity by traversing the elements. do not stupidly search in the string representation
		if ("filter:" in svg.decode('utf-8')):
			# it seems there is a filter referenced in the generated SVG, re-insert defs from main document
			canvas.insert(0, defs)
			# re-generate output
			svg = etree.tostring(output, pretty_print=False)

		if (output_format == 'tw'):
			# remove unnecessary attributes
			# TODO: never generate unnecessary attributes in the first place
			svg = svg.decode('utf-8')
			svg = regex_xmlns.sub('', svg)
			svg = svg.replace(' inkscape:connector-curvature="0"', '')  # this just saves space
			svg = svg.replace('\n', '').replace('\r', '')  # print cannot be multi-line
			svg = regex_space.sub('><', svg)  # remove indentation
			svg = svg.replace('svg:', '')  # svg namespace was removed
			if ("Boob" in i):  # internal groups are used for scaling
				svg = svg.replace('<g ', '<g data-transform="boob" ')  # boob art uses the boob scaling
			elif ("Belly" in i):
				svg = svg.replace('<g ', '<g data-transform="belly" ')  # belly art uses the belly scaling
			elif ("Balls" in i):
				svg = svg.replace('<g ', '<g data-transform="balls" ')  # balls art uses the balls scaling
			else:
				svg = svg.replace('<g ', '<g data-transform="art" ')  # otherwise use default scaling
		if (not svg.endswith('\n')):
			svg += '\n'
		svg = svg.encode('utf-8')

		# save SVG string to file
		i = layer.get('id')
		output_path = os.path.join(output_directory, "{0}{1}.svg".format(args.prefix, i))
		with open(output_path, 'wb') as f:
			if (output_format == 'svg'):
				# Header for normal SVG (XML)
				f.write('<?xml version="1.0" encoding="UTF-8" standalone="no"?>\n'.encode("utf-8"))
				f.write(svg)
			elif (output_format == 'tw'):
				f.write(svg)


if not os.path.exists(output_directory):
	os.makedirs(output_directory)

for f in args.input_file:
	splitFile(f)