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

# Copyright (c) 2007 - 2018 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing an exporter for HTML.
"""

from __future__ import unicode_literals

try:  # Only for Py2
    import StringIO as io   # __IGNORE_EXCEPTION__
except (ImportError, NameError):
    import io       # __IGNORE_WARNING__

# This code is a port of the C++ code found in SciTE 1.74
# Original code: Copyright 1998-2006 by Neil Hodgson <neilh@scintilla.org>

import os
import sys

from PyQt5.QtCore import Qt
from PyQt5.QtGui import QCursor, QFontInfo
from PyQt5.QtWidgets import QApplication
from PyQt5.Qsci import QsciScintilla

from E5Gui import E5MessageBox

from .ExporterBase import ExporterBase

import Preferences
import Utilities


class HTMLGenerator(object):
    """
    Class implementing an HTML generator for exporting source code.
    """
    def __init__(self, editor):
        """
        Constructor
        
        @param editor reference to the editor object (QScintilla.Editor.Editor)
        """
        self.editor = editor
    
    def generate(self, tabSize=4, useTabs=False, wysiwyg=True, folding=False,
                 onlyStylesUsed=False, titleFullPath=False):
        """
        Public method to generate HTML for the source editor.
        
        @keyparam tabSize size of tabs (integer)
        @keyparam useTabs flag indicating the use of tab characters (boolean)
        @keyparam wysiwyg flag indicating colorization (boolean)
        @keyparam folding flag indicating usage of fold markers
        @keyparam onlyStylesUsed flag indicating to include only style
            definitions for styles used in the source (boolean)
        @keyparam titleFullPath flag indicating to include the full file path
            in the title tag (boolean)
        @return generated HTML text (string)
        """
        self.editor.recolor(0, -1)
        
        lengthDoc = self.editor.length()
        styleIsUsed = {}
        if onlyStylesUsed:
            for index in range(QsciScintilla.STYLE_MAX + 1):
                styleIsUsed[index] = False
            # check the used styles
            pos = 0
            while pos < lengthDoc:
                styleIsUsed[self.editor.styleAt(pos) & 0x7F] = True
                pos += 1
        else:
            for index in range(QsciScintilla.STYLE_MAX + 1):
                styleIsUsed[index] = True
        styleIsUsed[QsciScintilla.STYLE_DEFAULT] = True
        
        html = \
            '''<!DOCTYPE html PUBLIC "-//W3C//DTD''' \
            ''' XHTML 1.0 Transitional//EN"\n''' \
            ''' "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">''' \
            '''\n''' \
            '''<html xmlns="http://www.w3.org/1999/xhtml">\n''' \
            '''<head>\n'''
        if titleFullPath:
            html += '''<title>{0}</title>\n'''.format(
                self.editor.getFileName())
        else:
            html += '''<title>{0}</title>\n'''.format(
                os.path.basename(self.editor.getFileName()))
        html += '''<meta name="Generator" content="eric6" />\n''' \
            '''<meta http-equiv="Content-Type" ''' \
            '''content="text/html; charset=utf-8" />\n'''
        if folding:
            html += \
                '''<script language="JavaScript" type="text/javascript">\n''' \
                '''<!--\n''' \
                '''function symbol(id, sym) {\n''' \
                '''  if (id.textContent == undefined) {\n''' \
                '''    id.innerText = sym;\n''' \
                '''  } else {\n''' \
                '''    id.textContent = sym;\n''' \
                '''  }\n''' \
                '''}\n''' \
                '''function toggle(id) {\n''' \
                '''  var thislayer = document.getElementById('ln' + id);\n''' \
                '''  id -= 1;\n''' \
                '''  var togline = document.getElementById('hd' + id);\n''' \
                '''  var togsym = document.getElementById('bt' + id);\n''' \
                '''  if (thislayer.style.display == 'none') {\n''' \
                '''    thislayer.style.display = 'block';\n''' \
                '''    togline.style.textDecoration = 'none';\n''' \
                '''    symbol(togsym, '- ');\n''' \
                '''  } else {\n''' \
                '''    thislayer.style.display = 'none';\n''' \
                '''    togline.style.textDecoration = 'underline';\n''' \
                '''    symbol(togsym, '+ ');\n''' \
                '''  }\n''' \
                '''}\n''' \
                '''//-->\n''' \
                '''</script>\n'''
        
        lex = self.editor.getLexer()
        if lex:
            bgColour = lex.paper(QsciScintilla.STYLE_DEFAULT).name()
        else:
            bgColour = self.editor.paper().name()
        
        html += '''<style type="text/css">\n'''
        if lex:
            istyle = 0
            while istyle <= QsciScintilla.STYLE_MAX:
                if (istyle <= QsciScintilla.STYLE_DEFAULT or
                    istyle > QsciScintilla.STYLE_LASTPREDEFINED) and \
                   styleIsUsed[istyle]:
                    if lex.description(istyle) or \
                       istyle == QsciScintilla.STYLE_DEFAULT:
                        font = lex.font(istyle)
                        colour = lex.color(istyle)
                        paper = lex.paper(istyle)
                        if istyle == QsciScintilla.STYLE_DEFAULT:
                            html += '''span {\n'''
                        else:
                            html += '''.S{0:d} {{\n'''.format(istyle)
                        if font.italic():
                            html += '''    font-style: italic;\n'''
                        if font.bold():
                            html += '''    font-weight: bold;\n'''
                        if wysiwyg:
                            html += '''    font-family: '{0}';\n'''.format(
                                    font.family())
                        html += '''    color: {0};\n'''.format(colour.name())
                        if istyle != QsciScintilla.STYLE_DEFAULT and \
                           bgColour != paper.name():
                            html += '''    background: {0};\n'''.format(
                                    paper.name())
                            html += '''    text-decoration: inherit;\n'''
                        if wysiwyg:
                            html += '''    font-size: {0:d}pt;\n'''.format(
                                    QFontInfo(font).pointSize())
                        html += '''}\n'''
                    else:
                        styleIsUsed[istyle] = False
                istyle += 1
        else:
            colour = self.editor.color()
            paper = self.editor.paper()
            font = Preferences.getEditorOtherFonts("DefaultFont")
            html += '''.S0 {\n'''
            if font.italic():
                html += '''    font-style: italic;\n'''
            if font.bold():
                html += '''    font-weight: bold;\n'''
            if wysiwyg:
                html += '''    font-family: '{0}';\n'''.format(font.family())
            html += '''    color: {0};\n'''.format(colour.name())
            if bgColour != paper.name():
                html += '''    background: {0};\n'''.format(paper.name())
                html += '''    text-decoration: inherit;\n'''
            if wysiwyg:
                html += '''    font-size: {0:d}pt;\n'''.format(
                        QFontInfo(font).pointSize())
            html += '''}\n'''
        html += '''</style>\n'''
        html += '''</head>\n'''
        
        html += '''<body bgcolor="{0}">\n'''.format(bgColour)
        line = self.editor.lineAt(0)
        level = self.editor.foldLevelAt(line) - QsciScintilla.SC_FOLDLEVELBASE
        levelStack = [level]
        styleCurrent = self.editor.styleAt(0)
        inStyleSpan = False
        inFoldSpan = False
        # Global span for default attributes
        if wysiwyg:
            html += '''<span>'''
        else:
            html += '''<pre>'''
        
        if folding:
            if self.editor.foldFlagsAt(line) & \
               QsciScintilla.SC_FOLDLEVELHEADERFLAG:
                html += '''<span id="hd{0:d}" onclick="toggle('{1:d}')">'''\
                        .format(line, line + 1)
                html += '''<span id="bt{0:d}">- </span>'''.format(line)
                inFoldSpan = True
            else:
                html += '''&nbsp; '''
        
        if styleIsUsed[styleCurrent]:
            html += '''<span class="S{0:0d}">'''.format(styleCurrent)
            inStyleSpan = True
        
        column = 0
        pos = 0
        utf8 = self.editor.isUtf8()
        utf8Ch = b""
        utf8Len = 0
        
        while pos < lengthDoc:
            ch = self.editor.byteAt(pos)
            style = self.editor.styleAt(pos)
            if style != styleCurrent:
                if inStyleSpan:
                    html += '''</span>'''
                    inStyleSpan = False
                if ch not in [b'\r', b'\n']:  # no need of a span for the EOL
                    if styleIsUsed[style]:
                        html += '''<span class="S{0:d}">'''.format(style)
                        inStyleSpan = True
                    styleCurrent = style
            
            if ch == b' ':
                if wysiwyg:
                    prevCh = b''
                    if column == 0:
                        # at start of line, must put a &nbsp;
                        # because regular space will be collapsed
                        prevCh = b' '
                    while pos < lengthDoc and self.editor.byteAt(pos) == b' ':
                        if prevCh != b' ':
                            html += ' '
                        else:
                            html += '''&nbsp;'''
                        prevCh = self.editor.byteAt(pos)
                        pos += 1
                        column += 1
                    pos -= 1
                    # the last incrementation will be done by the outer loop
                else:
                    html += ' '
                    column += 1
            elif ch == b'\t':
                ts = tabSize - (column % tabSize)
                if wysiwyg:
                    html += '''&nbsp;''' * ts
                    column += ts
                else:
                    if useTabs:
                        html += '\t'
                        column += 1
                    else:
                        html += ' ' * ts
                        column += ts
            elif ch in [b'\r', b'\n']:
                if inStyleSpan:
                    html += '''</span>'''
                    inStyleSpan = False
                if inFoldSpan:
                    html += '''</span>'''
                    inFoldSpan = False
                if ch == b'\r' and self.editor.byteAt(pos + 1) == b'\n':
                    pos += 1  # CR+LF line ending, skip the "extra" EOL char
                column = 0
                if wysiwyg:
                    html += '''<br />'''
                
                styleCurrent = self.editor.styleAt(pos + 1)
                if folding:
                    line = self.editor.lineAt(pos + 1)
                    newLevel = self.editor.foldLevelAt(line)
                    
                    if newLevel < level:
                        while levelStack[-1] > newLevel:
                            html += '''</span>'''
                            levelStack.pop()
                    html += '\n'  # here to get clean code
                    if newLevel > level:
                        html += '''<span id="ln{0:d}">'''.format(line)
                        levelStack.append(newLevel)
                    if self.editor.foldFlagsAt(line) & \
                       QsciScintilla.SC_FOLDLEVELHEADERFLAG:
                        html += \
                            '''<span id="hd{0:d}"''' \
                            ''' onclick="toggle('{1:d}')">''' \
                            .format(line, line + 1)
                        html += '''<span id="bt{0:d}">- </span>'''.format(line)
                        inFoldSpan = True
                    else:
                        html += '''&nbsp; '''
                    level = newLevel
                else:
                    html += '\n'
                
                if styleIsUsed[styleCurrent] and \
                   self.editor.byteAt(pos + 1) not in [b'\r', b'\n']:
                    # We know it's the correct next style,
                    # but no (empty) span for an empty line
                    html += '''<span class="S{0:0d}">'''.format(styleCurrent)
                    inStyleSpan = True
            else:
                if ch == b'<':
                    html += '''&lt;'''
                elif ch == b'>':
                    html += '''&gt'''
                elif ch == b'&':
                    html += '''&amp;'''
                else:
                    if ord(ch) > 127 and utf8:
                        utf8Ch += ch
                        if utf8Len == 0:
                            if (utf8Ch[0] & 0xF0) == 0xF0:
                                utf8Len = 4
                            elif (utf8Ch[0] & 0xE0) == 0xE0:
                                utf8Len = 3
                            elif (utf8Ch[0] & 0xC0) == 0xC0:
                                utf8Len = 2
                            column -= 1  # will be incremented again later
                        elif len(utf8Ch) == utf8Len:
                            ch = utf8Ch.decode('utf8')
                            html += Utilities.html_encode(ch)
                            utf8Ch = b""
                            utf8Len = 0
                        else:
                            column -= 1  # will be incremented again later
                    else:
                        html += ch.decode()
                column += 1
            
            pos += 1
        
        if inStyleSpan:
            html += '''</span>'''
        
        if folding:
            while levelStack:
                html += '''</span>'''
                levelStack.pop()
        
        if wysiwyg:
            html += '''</span>'''
        else:
            html += '''</pre>'''
        
        html += '''</body>\n</html>\n'''
        
        return html


class ExporterHTML(ExporterBase):
    """
    Class implementing an exporter for HTML.
    """
    def __init__(self, editor, parent=None):
        """
        Constructor
        
        @param editor reference to the editor object (QScintilla.Editor.Editor)
        @param parent parent object of the exporter (QObject)
        """
        ExporterBase.__init__(self, editor, parent)
    
    def exportSource(self):
        """
        Public method performing the export.
        """
        filename = self._getFileName(self.tr("HTML Files (*.html)"))
        if not filename:
            return
        
        try:
            QApplication.setOverrideCursor(QCursor(Qt.WaitCursor))
            QApplication.processEvents()
            
            fn = self.editor.getFileName()
            if fn:
                extension = os.path.normcase(os.path.splitext(fn)[1][1:])
            else:
                extension = ""
            
            if extension in \
                Preferences.getEditor("PreviewMarkdownFileNameExtensions") or \
                    self.editor.getLanguage().lower() == "markdown":
                # export markdown to HTML
                html = self.__generateFromMarkdown()
            elif extension in \
                Preferences.getEditor("PreviewRestFileNameExtensions") or \
                    self.editor.getLanguage().lower() == "restructuredtext":
                # export ReST to HTML
                html = self.__generateFromReSTDocutils()
            else:
                tabSize = Preferences.getEditor("TabWidth")
                if tabSize == 0:
                    tabSize = 4
                wysiwyg = Preferences.getEditorExporter("HTML/WYSIWYG")
                folding = Preferences.getEditorExporter("HTML/Folding")
                onlyStylesUsed = Preferences.getEditorExporter(
                    "HTML/OnlyStylesUsed")
                titleFullPath = Preferences.getEditorExporter(
                    "HTML/FullPathAsTitle")
                tabs = Preferences.getEditorExporter("HTML/UseTabs")
                
                generator = HTMLGenerator(self.editor)
                html = generator.generate(
                    tabSize=tabSize,
                    useTabs=tabs,
                    wysiwyg=wysiwyg,
                    folding=folding,
                    onlyStylesUsed=onlyStylesUsed,
                    titleFullPath=titleFullPath
                )
            
            if html:
                try:
                    f = open(filename, "w", encoding="utf-8")
                    f.write(html)
                    f.close()
                except IOError as err:
                    QApplication.restoreOverrideCursor()
                    E5MessageBox.critical(
                        self.editor,
                        self.tr("Export source"),
                        self.tr(
                            """<p>The source could not be exported to"""
                            """ <b>{0}</b>.</p><p>Reason: {1}</p>""")
                        .format(filename, str(err)))
            else:
                QApplication.restoreOverrideCursor()
                E5MessageBox.critical(
                    self.editor,
                    self.tr("Export source"),
                    self.tr(
                        """<p>The source could not be exported to"""
                        """ <b>{0}</b>.</p><p>Reason: No HTML code"""
                        """ generated.</p>""")
                    .format(filename))
        finally:
            QApplication.restoreOverrideCursor()
    
    def __generateFromReSTDocutils(self):
        """
        Private method to convert ReST text into HTML using 'docutils'.
        
        @return processed HTML (string)
        """
        if 'sphinx' in sys.modules:
            # Make sure any Sphinx polution of docutils has been removed.
            unloadKeys = [k for k in sys.modules.keys()
                          if k.startswith(('docutils', 'sphinx'))]
            for key in unloadKeys:
                sys.modules.pop(key)
        
        try:
            import docutils.core    # __IGNORE_EXCEPTION__
        except ImportError:
            E5MessageBox.critical(
                self.editor,
                self.tr("Export source"),
                self.tr(
                    """<p>ReStructuredText export requires the"""
                    """ <b>python-docutils</b> package.<br/>Install it with"""
                    """ your package manager, 'pip install docutils' or see"""
                    """ <a href="http://pypi.python.org/pypi/docutils">"""
                    """this page.</a></p>""")
            )
            return ""
        
        htmlFormat = Preferences.getEditor(
            "PreviewRestDocutilsHTMLFormat").lower()
        # redirect sys.stderr because we are not interested in it here
        origStderr = sys.stderr
        sys.stderr = io.StringIO()
        html = docutils.core.publish_string(
            self.editor.text(), writer_name=htmlFormat).decode("utf-8")
        sys.stderr = origStderr
        return html
    
    def __generateFromMarkdown(self):
        """
        Private method to convert Markdown text into HTML.
        
        @return processed HTML
        @rtype str
        """
        try:
            import markdown     # __IGNORE_EXCEPTION__
        except ImportError:
            E5MessageBox.critical(
                self.editor,
                self.tr("Export source"),
                self.tr(
                    """<p>Markdown export requires the <b>python-markdown"""
                    """</b> package.<br/>Install it with your package"""
                    """ manager, 'pip install docutils' or see """
                    """<a href="http://pythonhosted.org/Markdown/install"""
                    """.html"> installation instructions.</a></p>""")
            )
            return ""
        
        try:
            import mdx_mathjax  # __IGNORE_EXCEPTION__ __IGNORE_WARNING__
        except ImportError:
            # mathjax doesn't require import statement if installed as
            # extension
            pass
        
        if Preferences.getEditor("PreviewMarkdownNLtoBR"):
            extensions = ['fenced_code', 'nl2br', 'extra']
        else:
            extensions = ['fenced_code', 'extra']
        
        # version 2.0 supports only extension names, not instances
        if markdown.version_info[0] > 2 or \
                (markdown.version_info[0] == 2 and
                 markdown.version_info[1] > 0):
            class _StrikeThroughExtension(markdown.Extension):
                """
                Class is placed here, because it depends on imported markdown,
                and markdown import is lazy.
                
                (see http://achinghead.com/
                python-markdown-adding-insert-delete.html this page for
                details)
                """
                DEL_RE = r'(~~)(.*?)~~'

                def extendMarkdown(self, md, md_globals):
                    # Create the del pattern
                    del_tag = markdown.inlinepatterns.SimpleTagPattern(
                        self.DEL_RE, 'del')
                    # Insert del pattern into markdown parser
                    md.inlinePatterns.add('del', del_tag, '>not_strong')
            
            extensions.append(_StrikeThroughExtension())
        
        htmlFormat = Preferences.getEditor("PreviewMarkdownHTMLFormat").lower()
        try:
            body = markdown.markdown(self.editor.text(),
                                     extensions=extensions + ['mathjax'],
                                     output_format=htmlFormat)
        except (ImportError, ValueError):
            # markdown raises ValueError or ImportError, depends on version
            # It is not clear, how to distinguish missing mathjax from other
            # errors. So keep going without mathjax.
            body = markdown.markdown(self.editor.text(),
                                     extensions=extensions,
                                     output_format=htmlFormat)
        
        if htmlFormat == "xhtml1":
            head = \
                '''<!DOCTYPE html PUBLIC "-//W3C//DTD''' \
                ''' XHTML 1.0 Transitional//EN"\n''' \
                ''' "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional''' \
                '''.dtd">\n''' \
                '''<html xmlns="http://www.w3.org/1999/xhtml">\n'''
        elif htmlFormat == "html5":
            head = \
                '''<!DOCTYPE html>\n''' \
                '''<html lang="EN">\n'''
        else:
            head = '<html lang="EN">\n'
        head += '''<head>\n'''
        if Preferences.getEditorExporter("HTML/FullPathAsTitle"):
            head += '''<title>{0}</title>\n'''.format(
                self.editor.getFileName())
        else:
            head += '''<title>{0}</title>\n'''.format(
                os.path.basename(self.editor.getFileName()))
        head += '''<meta name="Generator" content="eric6" />\n''' \
            '''<meta http-equiv="Content-Type" ''' \
            '''content="text/html; charset=utf-8" />\n''' \
            '''</head>\n''' \
            '''<body>\n'''
        
        foot = '''\n</body>\n</html>\n'''
        
        return head + body + foot
