ProjectWeb/Html5ToCss3Converter.py

# -*- coding: utf-8 -*-

# Copyright (c) 2014 - 2020 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing the HTML5 to CSS3 converter.
"""

import os
import datetime
import getpass
import random

from PyQt5.QtCore import QObject
from PyQt5.QtWidgets import QDialog

from .Html5ToCss3ConverterParameterDialog import (
    Html5ToCss3ConverterParameterDialog
)


class Html5ToCss3Converter(QObject):
    """
    Class implementing the HTML5 to CSS3 converter.
    """
    CssTemplate7 = "{0}{1}{2}{3}{4}{5}{6}"
    CssTemplate8 = "{0}{1}{2}{3}{4}{5}{6}{7}"
    Placeholders = ('margin:0', 'padding:0', 'border:0', 'font-size:100%',
                    'font:inherit', 'vertical-align:baseline', 'line-height:1',
                    'outline:0', 'font-weight:inherit', 'font-style:inherit',
                    'font-family:inherit', 'vertical-align:baseline')
    TagsToIgnore = ('head', 'meta', 'noscript', 'script', 'style', 'link',
                    'no-js', 'title', 'object', 'col', 'colgroup', 'option',
                    'param', 'audio', 'basefont', 'isindex', 'svg', 'area',
                    'embed', 'br')
    
    def __init__(self, html, parent=None):
        """
        Constructor
        
        @param html HTML text to be converted (string)
        @param parent reference to the parent object (QObject)
        """
        super(Html5ToCss3Converter, self).__init__(parent)
        
        self.__html = html
    
    def getCss3(self):
        """
        Public method to get the converted CSS3 text.
        
        @return CSS3 text (string)
        """
        dlg = Html5ToCss3ConverterParameterDialog()
        if dlg.exec_() == QDialog.Accepted:
            indentation, placeholders = dlg.getData()
            
            self.__createSoup()
            
            alreadyDone = list(self.TagsToIgnore)
            
            css = '@charset "utf-8";{0}'.format(os.linesep)
            css += "/* {0} by {1}*/{2}".format(
                datetime.datetime.now().isoformat().split(".")[0],
                getpass.getuser(),
                2 * os.linesep
            )
            
            # step 1: tags
            for tag in self.__getTags():
                if tag not in alreadyDone:
                    css += self.CssTemplate7.format(
                        tag,
                        "{",
                        os.linesep,
                        indentation,
                        random.choice(self.Placeholders) + os.linesep   # secok
                        if placeholders else os.linesep,
                        "}",
                        os.linesep
                    )
                    alreadyDone.append(tag)
            css += "/*{0}*/{1}".format(
                "-" * 75,
                os.linesep
            )
            
            # step 2: IDs
            for id_ in self.__getIds():
                if id_ not in alreadyDone:
                    css += "/* {0} */{1}".format(
                        "_".join(id_).lower(),
                        os.linesep
                    )
                    css += self.CssTemplate8.format(
                        "#",
                        id_[1],
                        "{",
                        os.linesep,
                        indentation,
                        random.choice(self.Placeholders) + os.linesep   # secok
                        if placeholders else os.linesep,
                        "}",
                        os.linesep
                    )
                    alreadyDone.append(id_)
            css += "/*{0}*/{1}".format(
                "-" * 75,
                os.linesep
            )
            
            # step 3: classes
            for class_ in self.__getClasses():
                if class_ not in alreadyDone:
                    css += "/* {0} */{1}".format(
                        "_".join(class_).lower(),
                        os.linesep
                    )
                    css += self.CssTemplate8.format(
                        ".",
                        ", .".join(class_[1].split()),
                        "{",
                        os.linesep,
                        indentation,
                        random.choice(self.Placeholders) + os.linesep   # secok
                        if placeholders else os.linesep,
                        "}",
                        os.linesep
                    )
                    alreadyDone.append(class_)
        else:
            css = ""
        return css.strip()
    
    def __createSoup(self):
        """
        Private method to get a BeaitifulSoup object with our HTML text.
        """
        from bs4 import BeautifulSoup
        self.__soup = BeautifulSoup(BeautifulSoup(self.__html).prettify())
    
    def __getTags(self):
        """
        Private method to extract all tags of the HTML text.
        
        @return list of all tags (list of strings)
        """
        tags = [t.name for t in self.__soup.find_all(True)]
        return list(set(tags))
    
    def __getClasses(self):
        """
        Private method to extract all classes of the HTML text.
        
        @return list of tuples containing the tag name and its classes
            as a blank separated string (list of tuples of two strings)
        """
        classes = [(t.name, " ".join(t["class"])) for t in
                   self.__soup.find_all(True, {"class": True})]
        return sorted(list(set(classes)))
    
    def __getIds(self):
        """
        Private method to extract all IDs of the HTML text.
        
        @return list of tuples containing the tag name and its ID
            (list of tuples of two strings)
        """
        ids = [(t.name, t["id"]) for t in
               self.__soup.find_all(True, {"id": True})]
        return sorted(list(set(ids)))