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

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

"""
Module implementing an exporter for TeX.
"""

from __future__ import unicode_literals

# 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

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

from E5Gui import E5MessageBox

from .ExporterBase import ExporterBase

import Preferences


class ExporterTEX(ExporterBase):
    """
    Class implementing an exporter for TeX.
    """
    CHARZ = ord('z') - ord('a') + 1
    
    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 __getTexRGB(self, color):
        """
        Private method to convert a color object to a TeX color string.
        
        @param color color object to convert (QColor)
        @return TeX color string (string)
        """
        # texcolor[rgb]{0,0.5,0}{....}
        rf = color.red() / 256.0
        gf = color.green() / 256.0
        bf = color.blue() / 256.0
        
        # avoid breakage due to locale setting
        r = int(rf * 10 + 0.5)
        g = int(gf * 10 + 0.5)
        b = int(bf * 10 + 0.5)
        
        return "{0:d}.{1:d}, {2:d}.{3:d}, {4:d}.{5:d}".format(
               r // 10, r % 10, g // 10, g % 10, b // 10, b % 10)
    
    def __texStyle(self, style):
        """
        Private method to calculate a style name string for a given style
        number.
        
        @param style style number (integer)
        @return style name string (string)
        """
        buf = ""
        if style == 0:
            buf = "a"
        else:
            while style > 0:
                buf += chr(ord('a') + (style % self.CHARZ))
                style //= self.CHARZ
        return buf
    
    def __defineTexStyle(self, font, color, paper, file, istyle):
        """
        Private method to define a new TeX style.
        
        @param font the font to be used (QFont)
        @param color the foreground color to be used (QColor)
        @param paper the background color to be used (QColor)
        @param file reference to the open file to write to (file object)
        @param istyle style number (integer)
        """
        closing_brackets = 3
        file.write(
            "\\newcommand{{\\eric{0}}}[1]{{\\noindent{{\\ttfamily{{".format(
                self.__texStyle(istyle)))
        if font.italic():
            file.write("\\textit{")
            closing_brackets += 1
        if font.bold():
            file.write("\\textbf{")
            closing_brackets += 1
        if color != self.defaultColor:
            file.write(
                "\\textcolor[rgb]{{{0}}}{{".format(self.__getTexRGB(color)))
            closing_brackets += 1
        if paper != self.defaultPaper:
            file.write(
                "\\colorbox[rgb]{{{0}}}{{".format(self.__getTexRGB(paper)))
            closing_brackets += 1
        file.write("#1{0}\n".format('}' * closing_brackets))
    
    def exportSource(self):
        """
        Public method performing the export.
        """
        filename = self._getFileName(self.tr("TeX Files (*.tex)"))
        if not filename:
            return
        
        try:
            QApplication.setOverrideCursor(QCursor(Qt.WaitCursor))
            QApplication.processEvents()
            
            self.editor.recolor(0, -1)
            
            tabSize = Preferences.getEditor("TabWidth")
            if tabSize == 0:
                tabSize = 4
            
            onlyStylesUsed = Preferences.getEditorExporter(
                "TeX/OnlyStylesUsed")
            titleFullPath = Preferences.getEditorExporter(
                "TeX/FullPathAsTitle")
            
            lex = self.editor.getLexer()
            self.defaultPaper = lex and \
                lex.paper(QsciScintilla.STYLE_DEFAULT) or \
                self.editor.paper().name()
            self.defaultColor = lex and \
                lex.color(QsciScintilla.STYLE_DEFAULT) or \
                self.editor.color().name()
            self.defaultFont = lex and \
                lex.color(QsciScintilla.STYLE_DEFAULT) or \
                Preferences.getEditorOtherFonts("DefaultFont")
            
            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
            
            try:
                f = open(filename, "w", encoding="utf-8")
                
                f.write("\\documentclass[a4paper]{article}\n")
                f.write("\\usepackage[a4paper,margin=1.5cm]{geometry}\n")
                f.write("\\usepackage[T1]{fontenc}\n")
                f.write("\\usepackage{color}\n")
                f.write("\\usepackage{alltt}\n")
                f.write("\\usepackage{times}\n")
                if self.editor.isUtf8():
                    f.write("\\usepackage[utf8]{inputenc}\n")
                else:
                    f.write("\\usepackage[latin1]{inputenc}\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)
                                
                                self.__defineTexStyle(font, colour, paper, f,
                                                      istyle)
                        istyle += 1
                else:
                    colour = self.editor.color()
                    paper = self.editor.paper()
                    font = Preferences.getEditorOtherFonts("DefaultFont")
                    
                    self.__defineTexStyle(font, colour, paper, f, 0)
                    self.__defineTexStyle(font, colour, paper, f,
                                          QsciScintilla.STYLE_DEFAULT)
                
                f.write("\\begin{document}\n\n")
                if titleFullPath:
                    title = self.editor.getFileName()
                else:
                    title = os.path.basename(self.editor.getFileName())
                f.write(
                    "Source File: {0}\n\n\\noindent\n\\tiny{{\n".format(title))
                
                styleCurrent = self.editor.styleAt(0)
                f.write("\\eric{0}{{".format(self.__texStyle(styleCurrent)))
                
                lineIdx = 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:
                        # new style
                        f.write(
                            "}}\n\\eric{0}{{".format(self.__texStyle(style)))
                        styleCurrent = style
                    
                    if ch == b'\t':
                        ts = tabSize - (lineIdx % tabSize)
                        lineIdx += ts - 1
                        f.write("\\hspace*{{{0:d}em}}".format(ts))
                    elif ch == b'\\':
                        f.write("{\\textbackslash}")
                    elif ch in [b'>', b'<', b'@']:
                        f.write("${0}$".format(ch[0]))
                    elif ch in [b'{', b'}', b'^', b'_', b'&', b'$', b'#',
                                b'%', b'~']:
                        f.write("\\{0}".format(ch[0]))
                    elif ch in [b'\r', b'\n']:
                        lineIdx = -1    # because incremented below
                        if ch == b'\r' and \
                                self.editor.byteAt(pos + 1) == b'\n':
                            pos += 1    # skip the LF
                        styleCurrent = self.editor.styleAt(pos + 1)
                        f.write("}} \\\\\n\\eric{0}{{".format(
                                self.__texStyle(styleCurrent)))
                    elif ch == b' ':
                        if self.editor.byteAt(pos + 1) == b' ':
                            f.write("{\\hspace*{1em}}")
                        else:
                            f.write(' ')
                    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
                            elif len(utf8Ch) == utf8Len:
                                ch = utf8Ch.decode('utf8')
                                f.write(ch)
                                utf8Ch = b""
                                utf8Len = 0
                        else:
                            f.write(ch.decode())
                    lineIdx += 1
                    pos += 1
                
                # close last empty style macros and document too
                f.write("}\n} %end tiny\n\n\\end{document}\n")
                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)))
        finally:
            QApplication.restoreOverrideCursor()
