#!/usr/bin/python3

# Thanks to the GNOME theme nerds for the original source of this script

import os
import sys
import xml.sax
import subprocess

INKSCAPE = '/usr/bin/inkscape'
OPTIPNG = '/usr/bin/optipng'
MAINDIR = '../Paper'
SRC = os.path.join('.', 'wm')

inkscape_process = None


def optimize_png(png_file):
    if os.path.exists(OPTIPNG):
        process = subprocess.Popen([OPTIPNG, '-quiet', '-o7', png_file])
        process.wait()


def wait_for_prompt(process, command=None):
    if command is not None:
        process.stdin.write((command+'\n').encode('utf-8'))

    # This is kinda ugly ...
    # Wait for just a '>', or '\n>' if some other char appearead first
    output = process.stdout.read(1)
    if output == b'>':
        return

    output += process.stdout.read(1)
    while output != b'\n>':
        output += process.stdout.read(1)
        output = output[1:]


def start_inkscape():
    process = subprocess.Popen(
        [INKSCAPE, '--shell'],
        bufsize=0, stdin=subprocess.PIPE, stdout=subprocess.PIPE
        )
    wait_for_prompt(process)
    return process


def inkscape_render_rect(icon_file, rect, output_file):
    global inkscape_process
    if inkscape_process is None:
        inkscape_process = start_inkscape()
    wait_for_prompt(inkscape_process,
                    '--export-dpi=180 %s -i %s -e %s' % (icon_file, rect, output_file)
                    )
    optimize_png(output_file)


class ContentHandler(xml.sax.ContentHandler):
    ROOT = 0
    SVG = 1
    LAYER = 2
    OTHER = 3
    TEXT = 4

    def __init__(self, path, force=False, filter=None):
        self.stack = [self.ROOT]
        self.inside = [self.ROOT]
        self.path = path
        self.rects = []
        self.state = self.ROOT
        self.chars = ""
        self.force = force
        self.filter = filter

    def endDocument(self):
        pass

    def startElement(self, name, attrs):
        if self.inside[-1] == self.ROOT:
            if name == "svg":
                self.stack.append(self.SVG)
                self.inside.append(self.SVG)
                return
        elif self.inside[-1] == self.SVG:
            if (name == "g" and ('inkscape:groupmode' in attrs) and ('inkscape:label' in attrs)
               and attrs['inkscape:groupmode'] == 'layer' and attrs['inkscape:label'].startswith('Baseplate')):
                self.stack.append(self.LAYER)
                self.inside.append(self.LAYER)
                self.context = None
                self.icon_name = None
                self.rects = []
                return
        elif self.inside[-1] == self.LAYER:
            if name == "text" and ('inkscape:label' in attrs) and attrs['inkscape:label'] == 'context':
                self.stack.append(self.TEXT)
                self.inside.append(self.TEXT)
                self.text='context'
                self.chars = ""
                return
            elif name == "text" and ('inkscape:label' in attrs) and attrs['inkscape:label'] == 'icon-name':
                self.stack.append(self.TEXT)
                self.inside.append(self.TEXT)
                self.text = 'icon-name'
                self.chars = ""
                return
            elif name == "rect":
                self.rects.append(attrs)

        self.stack.append(self.OTHER)

    def endElement(self, name):
        stacked = self.stack.pop()
        if self.inside[-1] == stacked:
            self.inside.pop()

        if stacked == self.TEXT and self.text is not None:
            assert self.text in ['context', 'icon-name']
            if self.text == 'context':
                self.context = self.chars
            elif self.text == 'icon-name':
                self.icon_name = self.chars
            self.text = None
        elif stacked == self.LAYER:
            assert self.icon_name
            assert self.context

            if self.filter is not None and not self.icon_name in self.filter:
                return

            print (self.context, self.icon_name)
            for rect in self.rects:
                width = rect['width']
                height = rect['height']
                id = rect['id']

                dir = os.path.join(MAINDIR, self.context)
                outfile = os.path.join(dir, self.icon_name+'.png')
                if not os.path.exists(dir):
                    os.makedirs(dir)
                # Do a time based check!
                if self.force or not os.path.exists(outfile):
                    inkscape_render_rect(self.path, id, outfile)
                    sys.stdout.write('.')
                else:
                    stat_in = os.stat(self.path)
                    stat_out = os.stat(outfile)
                    if stat_in.st_mtime > stat_out.st_mtime:
                        inkscape_render_rect(self.path, id, outfile)
                        sys.stdout.write('.')
                    else:
                        sys.stdout.write('-')
                sys.stdout.flush()
            sys.stdout.write('\n')
            sys.stdout.flush()

    def characters(self, chars):
        self.chars += chars.strip()

if len(sys.argv) == 1:
    if not os.path.exists(MAINDIR):
        os.mkdir(MAINDIR)
    print ('Rendering from SVGs in', SRC)
    for file in os.listdir(SRC):
        if file[-4:] == '.svg':
            file = os.path.join(SRC, file)
            handler = ContentHandler(file)
            xml.sax.parse(open(file), handler)
else:
    file = os.path.join(SRC, sys.argv[1] + '.svg')
    if len(sys.argv) > 2:
        icons = sys.argv[2:]
    else:
        icons = None
    if os.path.exists(os.path.join(file)):
        handler = ContentHandler(file, True, filter=icons)
        xml.sax.parse(open(file), handler)
    else:
        print ("Error: No such file", file)
        sys.exit(1)