Geografic-Information-System/gui/wxpython/gui_core/ghelp.py

"""
@package gui_core.ghelp

@brief Help/about window, menu tree, search module tree

Classes:
 - ghelp::AboutWindow
 - ghelp::HelpFrame
 - ghelp::HelpWindow
 - ghelp::HelpPanel

(C) 2008-2019 by the GRASS Development Team

This program is free software under the GNU General Public License
(>=v2). Read the file COPYING that comes with GRASS for details.

@author Martin Landa <landa.martin gmail.com>
"""

import os
import codecs
import platform
import re
import textwrap
import sys
import six

if sys.version_info.major == 2:
    _unichr = unichr
else:
    _unichr = chr

import wx
from wx.html import HtmlWindow
try:
    from wx.lib.agw.hyperlink import HyperLinkCtrl
except ImportError:
    from wx.lib.hyperlink import HyperLinkCtrl
try:
    from wx.adv import AboutDialogInfo
    from wx.adv import AboutBox
except ImportError:
    from wx import AboutDialogInfo
    from wx import AboutBox

import grass.script as grass

# needed just for testing
if __name__ == '__main__':
    from grass.script.setup import set_gui_path
    set_gui_path()

from core import globalvar
from core.gcmd import GError, DecodeString
from gui_core.widgets import FormNotebook, ScrolledPanel
from gui_core.wrap import Button, StaticText, TextCtrl
from core.debug import Debug


class AboutWindow(wx.Frame):
    """Create custom About Window
    """

    def __init__(self, parent, size=(770, 460),
                 title=_('About GRASS GIS'), **kwargs):
        wx.Frame.__init__(
            self,
            parent=parent,
            id=wx.ID_ANY,
            title=title,
            size=size,
            **kwargs)

        self.panel = wx.Panel(parent=self, id=wx.ID_ANY)

        # icon
        self.SetIcon(
            wx.Icon(
                os.path.join(
                    globalvar.ICONDIR,
                    'grass.ico'),
                wx.BITMAP_TYPE_ICO))

        # notebook
        self.aboutNotebook = FormNotebook(self.panel, style=wx.BK_LEFT)

        for title, win in ((_("Info"), self._pageInfo()),
                           (_("Copyright"), self._pageCopyright()),
                           (_("License"), self._pageLicense()),
                           (_("Citation"), self._pageCitation()),
                           (_("Authors"), self._pageCredit()),
                           (_("Contributors"), self._pageContributors()),
                           (_("Extra contributors"), self._pageContributors(extra=True)),
                           (_("Translators"), self._pageTranslators()),
                           (_("Translation status"), self._pageStats())):
            self.aboutNotebook.AddPage(page=win, text=title)
        wx.CallAfter(self.aboutNotebook.SetSelection, 0)
        wx.CallAfter(self.aboutNotebook.Refresh)

        # buttons
        self.btnClose = Button(parent=self.panel, id=wx.ID_CLOSE)
        self.btnClose.Bind(wx.EVT_BUTTON, self.OnCloseWindow)

        self._doLayout()

    def _doLayout(self):
        btnSizer = wx.BoxSizer(wx.HORIZONTAL)
        btnSizer.Add(self.btnClose, proportion=0, flag=wx.ALL, border=5)

        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(self.aboutNotebook, proportion=1,
                  flag=wx.EXPAND | wx.ALL, border=1)
        sizer.Add(btnSizer, proportion=0,
                  flag=wx.ALL | wx.ALIGN_RIGHT, border=1)

        self.SetMinSize((400, 400))

        self.panel.SetSizer(sizer)
        sizer.Fit(self.panel)

        self.Layout()

    def _pageInfo(self):
        """Info page"""
        # get version and web site
        vInfo = grass.version()
        if not vInfo:
            sys.stderr.write(_("Unable to get GRASS version\n"))

        infoTxt = ScrolledPanel(self.aboutNotebook)
        infoTxt.SetBackgroundColour('WHITE')
        infoTxt.SetupScrolling()
        infoSizer = wx.BoxSizer(wx.VERTICAL)
        infoGridSizer = wx.GridBagSizer(vgap=5, hgap=5)
        logo = os.path.join(globalvar.ICONDIR, "grass-64x64.png")
        logoBitmap = wx.StaticBitmap(infoTxt, wx.ID_ANY,
                                     wx.Bitmap(name=logo, type=wx.BITMAP_TYPE_PNG))
        infoSizer.Add(logoBitmap, proportion=0,
                      flag=wx.ALL | wx.ALIGN_CENTER, border=20)

        infoLabel = 'GRASS GIS %s' % vInfo.get('version', _('unknown version'))
        if 'x86_64' in vInfo.get('build_platform', ''):
            infoLabel += ' (64bit)'
        info = StaticText(parent=infoTxt, id=wx.ID_ANY,
                          label=infoLabel + os.linesep)
        info.SetFont(wx.Font(13, wx.DEFAULT, wx.NORMAL, wx.BOLD, 0, ""))
        info.SetForegroundColour(wx.Colour(35, 142, 35))
        infoSizer.Add(info, proportion=0,
                      flag=wx.BOTTOM | wx.ALIGN_CENTER, border=1)

        team = StaticText(parent=infoTxt, label=_grassDevTeam(1999) + '\n')
        infoSizer.Add(team, proportion=0,
                      flag=wx.BOTTOM | wx.ALIGN_CENTER, border=1)

        row = 0
        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label=_('Official GRASS site:')),
                          pos=(row, 0),
                          flag=wx.ALIGN_RIGHT)

        infoGridSizer.Add(HyperLinkCtrl(parent=infoTxt, id=wx.ID_ANY,
                                        label='https://grass.osgeo.org'),
                          pos=(row, 1),
                          flag=wx.ALIGN_LEFT)

        row += 2
        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label='%s:' % _('Code Revision')),
                          pos=(row, 0),
                          flag=wx.ALIGN_RIGHT)

        infoGridSizer.Add(HyperLinkCtrl(parent=infoTxt, id=wx.ID_ANY,
                                        label=vInfo.get('revision', '?'),
                                        URL='https://github.com/OSGeo/grass.git'),
                          pos=(row, 1),
                          flag=wx.ALIGN_LEFT)

        row += 1
        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label='%s:' % _('Build Date')),
                          pos=(row, 0),
                          flag=wx.ALIGN_RIGHT)

        infoGridSizer.Add(
            StaticText(
                parent=infoTxt, id=wx.ID_ANY, label=vInfo.get(
                    'build_date', '?')), pos=(
                row, 1), flag=wx.ALIGN_LEFT)

        # show only basic info
        # row += 1
        # infoGridSizer.Add(item = wx.StaticText(parent = infoTxt, id = wx.ID_ANY,
        #                                        label = '%s:' % _('GIS Library Revision')),
        #                   pos = (row, 0),
        #                   flag = wx.ALIGN_RIGHT)

        # infoGridSizer.Add(item = wx.StaticText(parent = infoTxt, id = wx.ID_ANY,
        #                                        label = vInfo['libgis_revision'] + ' (' +
        #                                        vInfo['libgis_date'].split(' ')[0] + ')'),
        #                   pos = (row, 1),
        #                   flag = wx.ALIGN_LEFT)

        row += 2
        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label='Python:'),
                          pos=(row, 0),
                          flag=wx.ALIGN_RIGHT)

        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label=platform.python_version()),
                          pos=(row, 1),
                          flag=wx.ALIGN_LEFT)

        row += 1
        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label='wxPython:'),
                          pos=(row, 0),
                          flag=wx.ALIGN_RIGHT)

        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label=wx.__version__),
                          pos=(row, 1),
                          flag=wx.ALIGN_LEFT)

        infoGridSizer.AddGrowableCol(0)
        infoGridSizer.AddGrowableCol(1)
        infoSizer.Add(infoGridSizer, proportion=1, flag=wx.EXPAND)

        row += 2
        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label="%s:" % _('Language')),
                          pos=(row, 0),
                          flag=wx.ALIGN_RIGHT)
        self.langUsed = grass.gisenv().get('LANG', None)
        if not self.langUsed:
            import locale
            loc = locale.getdefaultlocale()
            if loc == (None, None):
                self.langUsed = _('unknown')
            else:
                self.langUsed = u'%s.%s' % (loc[0], loc[1])
        infoGridSizer.Add(StaticText(parent=infoTxt, id=wx.ID_ANY,
                                     label=self.langUsed),
                          pos=(row, 1),
                          flag=wx.ALIGN_LEFT)

        infoTxt.SetSizer(infoSizer)
        infoSizer.Fit(infoTxt)

        return infoTxt

    def _pageCopyright(self):
        """Copyright information"""
        copyfile = os.path.join(os.getenv("GISBASE"), "COPYING")
        if os.path.exists(copyfile):
            copyrightFile = open(copyfile, 'r')
            copytext = copyrightFile.read()
            copyrightFile.close()
        else:
            copytext = _('%s file missing') % 'COPYING'

        # put text into a scrolling panel
        copyrightwin = ScrolledPanel(self.aboutNotebook)
        copyrighttxt = TextCtrl(
            copyrightwin, id=wx.ID_ANY, value=copytext,
        style=wx.TE_MULTILINE | wx.TE_READONLY)
        copyrightwin.SetAutoLayout(True)
        copyrightwin.sizer = wx.BoxSizer(wx.VERTICAL)
        copyrightwin.sizer.Add(copyrighttxt, proportion=1,
                               flag=wx.EXPAND | wx.ALL, border=3)
        copyrightwin.SetSizer(copyrightwin.sizer)
        copyrightwin.Layout()
        copyrightwin.SetupScrolling()

        return copyrightwin

    def _pageLicense(self):
        """Licence about"""
        licfile = os.path.join(os.getenv("GISBASE"), "GPL.TXT")
        if os.path.exists(licfile):
            licenceFile = open(licfile, 'r')
            license = ''.join(licenceFile.readlines())
            licenceFile.close()
        else:
            license = _('%s file missing') % 'GPL.TXT'
        # put text into a scrolling panel
        licensewin = ScrolledPanel(self.aboutNotebook)
        licensetxt = TextCtrl(
            licensewin, id=wx.ID_ANY, value=license,
        style=wx.TE_MULTILINE | wx.TE_READONLY)
        licensewin.SetAutoLayout(True)
        licensewin.sizer = wx.BoxSizer(wx.VERTICAL)
        licensewin.sizer.Add(licensetxt, proportion=1,
                             flag=wx.EXPAND | wx.ALL, border=3)
        licensewin.SetSizer(licensewin.sizer)
        licensewin.Layout()
        licensewin.SetupScrolling()

        return licensewin

    def _pageCitation(self):
        """Citation information"""
        try:
            # import only when needed
            import grass.script as gscript
            text = gscript.read_command('g.version', flags='x')
        except CalledModuleError as error:
            text = _("Unable to provide citation suggestion,"
                     " see GRASS GIS website instead."
                     " The error was: {0}").format(error)

        # put text into a scrolling panel
        window = ScrolledPanel(self.aboutNotebook)
        stat_text = TextCtrl(
            window, id=wx.ID_ANY, value=text,
        style=wx.TE_MULTILINE | wx.TE_READONLY)
        window.SetAutoLayout(True)
        window.sizer = wx.BoxSizer(wx.VERTICAL)
        window.sizer.Add(stat_text, proportion=1,
                         flag=wx.EXPAND | wx.ALL, border=3)
        window.SetSizer(window.sizer)
        window.Layout()
        window.SetupScrolling()

        return window

    def _pageCredit(self):
        """Credit about"""
        # credits
        authfile = os.path.join(os.getenv("GISBASE"), "AUTHORS")
        if os.path.exists(authfile):
            with codecs.open(authfile, encoding='utf-8', mode='r') as authorsFile:
                authors = ''.join(authorsFile.readlines())
        else:
            authors = _('%s file missing') % 'AUTHORS'
        authorwin = ScrolledPanel(self.aboutNotebook)
        authortxt = TextCtrl(
            authorwin, id=wx.ID_ANY, value=authors,
        style=wx.TE_MULTILINE | wx.TE_READONLY)
        authorwin.SetAutoLayout(True)
        authorwin.SetupScrolling()
        authorwin.sizer = wx.BoxSizer(wx.VERTICAL)
        authorwin.sizer.Add(authortxt, proportion=1,
                            flag=wx.EXPAND | wx.ALL, border=3)
        authorwin.SetSizer(authorwin.sizer)
        authorwin.Layout()

        return authorwin

    def _pageContributors(self, extra=False):
        """Contributors info"""
        if extra:
            contribfile = os.path.join(
                os.getenv("GISBASE"),
                "contributors_extra.csv")
        else:
            contribfile = os.path.join(
                os.getenv("GISBASE"),
                "contributors.csv")
        if os.path.exists(contribfile):
            contribFile = codecs.open(contribfile, encoding='utf-8', mode='r')
            contribs = list()
            errLines = list()
            for line in contribFile.readlines()[1:]:
                line = line.rstrip('\n')
                try:
                    if extra:
                        name, email, country, rfc2_agreed = line.split(',')
                    else:
                        cvs_id, name, email, country, osgeo_id, rfc2_agreed = line.split(
                            ',')
                except ValueError:
                    errLines.append(line)
                    continue
                if extra:
                    contribs.append((name, email, country))
                else:
                    contribs.append((name, email, country, osgeo_id))

            contribFile.close()

            if errLines:
                GError(parent=self, message=_("Error when reading file '%s'.") %
                       contribfile + "\n\n" + _("Lines:") + " %s" %
                       os.linesep.join(map(DecodeString, errLines)))
        else:
            contribs = None

        contribwin = ScrolledPanel(self.aboutNotebook)
        contribwin.SetAutoLayout(True)
        contribwin.SetupScrolling()
        contribwin.sizer = wx.BoxSizer(wx.VERTICAL)

        if not contribs:
            contribtxt = StaticText(
                contribwin,
                id=wx.ID_ANY,
                label=_('%s file missing') %
                contribfile)
            contribwin.sizer.Add(contribtxt, proportion=1,
                                 flag=wx.EXPAND | wx.ALL, border=3)
        else:
            if extra:
                items = (_('Name'), _('E-mail'), _('Country'))
            else:
                items = (_('Name'), _('E-mail'), _('Country'), _('OSGeo_ID'))
            contribBox = wx.FlexGridSizer(cols=len(items), vgap=5, hgap=5)
            for item in items:
                text = StaticText(parent=contribwin, id=wx.ID_ANY,
                                  label=item)
                text.SetFont(
                    wx.Font(
                        10,
                        wx.DEFAULT,
                        wx.NORMAL,
                        wx.BOLD,
                        0,
                        ""))
                contribBox.Add(text)
            for vals in sorted(contribs, key=lambda x: x[0]):
                for item in vals:
                    contribBox.Add(
                        StaticText(
                            parent=contribwin,
                            id=wx.ID_ANY,
                            label=item))
            contribwin.sizer.Add(contribBox, proportion=1,
                                 flag=wx.EXPAND | wx.ALL, border=3)

        contribwin.SetSizer(contribwin.sizer)
        contribwin.Layout()

        return contribwin

    def _pageTranslators(self):
        """Translators info"""
        translatorsfile = os.path.join(os.getenv("GISBASE"), "translators.csv")
        if os.path.exists(translatorsfile):
            translatorsFile = codecs.open(translatorsfile, encoding='utf-8', mode='r')
            translators = dict()
            errLines = list()
            for line in translatorsFile.readlines()[1:]:
                line = line.rstrip('\n')
                try:
                    name, email, languages = line.split(',')
                except ValueError:
                    errLines.append(line)
                    continue
                for language in languages.split(' '):
                    if language not in translators:
                        translators[language] = list()
                    translators[language].append((name, email))
            translatorsFile.close()

            if errLines:
                GError(parent=self, message=_("Error when reading file '%s'.") %
                       translatorsfile + "\n\n" + _("Lines:") + " %s" %
                       os.linesep.join(map(DecodeString, errLines)))
        else:
            translators = None

        translatorswin = ScrolledPanel(self.aboutNotebook)
        translatorswin.SetBackgroundColour('WHITE')
        translatorswin.SetAutoLayout(True)
        translatorswin.SetupScrolling()
        translatorswin.sizer = wx.BoxSizer(wx.VERTICAL)

        if not translators:
            translatorstxt = StaticText(
                translatorswin,
                id=wx.ID_ANY,
                label=_('%s file missing') %
                'translators.csv')
            translatorswin.sizer.Add(translatorstxt, proportion=1,
                                     flag=wx.EXPAND | wx.ALL, border=3)
        else:
            translatorsBox = wx.FlexGridSizer(cols=4, vgap=5, hgap=5)
            languages = sorted(translators.keys())
            tname = StaticText(parent=translatorswin, id=wx.ID_ANY,
                               label=_('Name'))
            tname.SetFont(wx.Font(10, wx.DEFAULT, wx.NORMAL, wx.BOLD, 0, ""))
            translatorsBox.Add(tname)
            temail = StaticText(parent=translatorswin, id=wx.ID_ANY,
                                label=_('E-mail'))
            temail.SetFont(wx.Font(10, wx.DEFAULT, wx.NORMAL, wx.BOLD, 0, ""))
            translatorsBox.Add(temail)
            tlang = StaticText(parent=translatorswin, id=wx.ID_ANY,
                               label=_('Language'))
            tlang.SetFont(wx.Font(10, wx.DEFAULT, wx.NORMAL, wx.BOLD, 0, ""))
            translatorsBox.Add(tlang)
            tnat = StaticText(parent=translatorswin, id=wx.ID_ANY,
                              label=_('Nation'))
            tnat.SetFont(wx.Font(10, wx.DEFAULT, wx.NORMAL, wx.BOLD, 0, ""))
            translatorsBox.Add(tnat)
            for lang in languages:
                for translator in translators[lang]:
                    name, email = translator
                    translatorsBox.Add(
                        StaticText(
                            parent=translatorswin,
                            id=wx.ID_ANY,
                            label=name))
                    translatorsBox.Add(
                        StaticText(
                            parent=translatorswin,
                            id=wx.ID_ANY,
                            label=email))
                    translatorsBox.Add(
                        StaticText(
                            parent=translatorswin,
                            id=wx.ID_ANY,
                            label=lang))
                    flag = os.path.join(
                        globalvar.ICONDIR, "flags", "%s.png" %
                        lang.lower())
                    if os.path.exists(flag):
                        flagBitmap = wx.StaticBitmap(translatorswin, wx.ID_ANY, wx.Bitmap(
                                                     name=flag, type=wx.BITMAP_TYPE_PNG))
                        translatorsBox.Add(flagBitmap)
                    else:
                        translatorsBox.Add(
                            StaticText(
                                parent=translatorswin,
                                id=wx.ID_ANY,
                                label=lang))

            translatorswin.sizer.Add(translatorsBox, proportion=1,
                                     flag=wx.EXPAND | wx.ALL, border=3)

        translatorswin.SetSizer(translatorswin.sizer)
        translatorswin.Layout()

        return translatorswin

    def _langString(self, k, v):
        """Return string for the status of translation"""
        allStr = "%s :" % k.upper()
        try:
            allStr += _("   %d translated" % v['good'])
        except:
            pass
        try:
            allStr += _("   %d fuzzy" % v['fuzzy'])
        except:
            pass
        try:
            allStr += _("   %d untranslated" % v['bad'])
        except:
            pass
        return allStr

    def _langBox(self, par, k, v):
        """Return box"""
        langBox = wx.FlexGridSizer(cols=4, vgap=5, hgap=5)
        tkey = StaticText(parent=par, id=wx.ID_ANY,
                          label=k.upper())
        langBox.Add(tkey)
        try:
            tgood = StaticText(parent=par, id=wx.ID_ANY,
                               label=_("%d translated" % v['good']))
            tgood.SetForegroundColour(wx.Colour(35, 142, 35))
            langBox.Add(tgood)
        except:
            tgood = StaticText(parent=par, id=wx.ID_ANY,
                               label="")
            langBox.Add(tgood)
        try:
            tfuzzy = StaticText(parent=par, id=wx.ID_ANY,
                                label=_("   %d fuzzy" % v['fuzzy']))
            tfuzzy.SetForegroundColour(wx.Colour(255, 142, 0))
            langBox.Add(tfuzzy)
        except:
            tfuzzy = StaticText(parent=par, id=wx.ID_ANY,
                                label="")
            langBox.Add(tfuzzy)
        try:
            tbad = StaticText(parent=par, id=wx.ID_ANY,
                              label=_("   %d untranslated" % v['bad']))
            tbad.SetForegroundColour(wx.Colour(255, 0, 0))
            langBox.Add(tbad)
        except:
            tbad = StaticText(parent=par, id=wx.ID_ANY,
                              label="")
            langBox.Add(tbad)
        return langBox

    def _langPanel(self, lang, js):
        """Create panel for each languages"""
        text = self._langString(lang, js['total'])
        panel = wx.CollapsiblePane(
            self.statswin, -1, label=text, style=wx.CP_DEFAULT_STYLE | wx.CP_NO_TLW_RESIZE)
        panel.Bind(wx.EVT_COLLAPSIBLEPANE_CHANGED, self.OnPaneChanged)
        win = panel.GetPane()
        # TODO IT DOESN'T WORK
        # TO ADD ONLY WHEN TAB IS OPENED
        # if lang == self.langUsed.split('_')[0]:
        # panel.Collapse(False)
        # else:
        # panel.Collapse(True)
        pageSizer = wx.BoxSizer(wx.VERTICAL)
        for k, v in six.iteritems(js):
            if k != 'total' and k != 'name':
                box = self._langBox(win, k, v)
                pageSizer.Add(box, proportion=1,
                              flag=wx.EXPAND | wx.ALL, border=3)

        win.SetSizer(pageSizer)
        pageSizer.SetSizeHints(win)

        return panel

    def OnPaneChanged(self, evt):
        """Redo the layout"""
        # TODO better to test on Windows
        self.statswin.SetupScrolling(scrollToTop=False)

    def _pageStats(self):
        """Translation statistics info"""
        fname = "translation_status.json"
        statsfile = os.path.join(os.getenv("GISBASE"), fname)
        if os.path.exists(statsfile):
            statsFile = open(statsfile)
            import json
            jsStats = json.load(statsFile)
        else:
            jsStats = None
        self.statswin = ScrolledPanel(self.aboutNotebook)
        self.statswin.SetBackgroundColour('WHITE')
        self.statswin.SetAutoLayout(True)

        if not jsStats:
            Debug.msg(5, _("File <%s> not found") % fname)
            statsSizer = wx.BoxSizer(wx.VERTICAL)
            statstext = StaticText(self.statswin, id=wx.ID_ANY,
                                   label=_('%s file missing') % fname)
            statsSizer.Add(statstext, proportion=1,
                           flag=wx.EXPAND | wx.ALL, border=3)
        else:
            languages = sorted(jsStats['langs'].keys())

            statsSizer = wx.BoxSizer(wx.VERTICAL)
            for lang in languages:
                v = jsStats['langs'][lang]
                panel = self._langPanel(lang, v)
                statsSizer.Add(panel)

        self.statswin.SetSizer(statsSizer)
        self.statswin.SetupScrolling(scroll_x=False, scroll_y=True)
        self.statswin.Layout()
        self.statswin.Fit()
        return self.statswin

    def OnCloseWindow(self, event):
        """Close window"""
        self.Close()


class HelpFrame(wx.Dialog):
    """GRASS Quickstart help window

    As a base class wx.Dialog is used, because of not working
    close button with wx.Frame when dialog is called from wizard.
    If parent is None, application TopLevelWindow is used (wxPython
    standard behaviour).

    Currently not used (was in location wizard before)
    due to unsolved problems - window sometimes does not respond.
    """

    def __init__(self, parent, id, title, size, file):
        wx.Dialog.__init__(
            self, parent=parent, id=id, title=title, size=size,
            style=wx.DEFAULT_DIALOG_STYLE | wx.RESIZE_BORDER | wx.MINIMIZE_BOX)

        sizer = wx.BoxSizer(wx.VERTICAL)

        # text
        content = HelpPanel(parent=self)
        content.LoadPage(file)

        sizer.Add(content, proportion=1, flag=wx.EXPAND)

        self.SetAutoLayout(True)
        self.SetSizer(sizer)
        self.Layout()


class HelpWindow(HtmlWindow):
    """This panel holds the text from GRASS docs.

    GISBASE must be set in the environment to find the html docs dir.
    The SYNOPSIS section is skipped, since this Panel is supposed to
    be integrated into the cmdPanel and options are obvious there.
    """

    def __init__(self, parent, command, text, skipDescription,
                 **kwargs):
        """If command is given, the corresponding HTML help
        file will be presented, with all links pointing to absolute
        paths of local files.

        If 'skipDescription' is True, the HTML corresponding to
        SYNOPSIS will be skipped, thus only presenting the help file
        from the DESCRIPTION section onwards.

        If 'text' is given, it must be the HTML text to be presented
        in the Panel.
        """
        self.parent = parent
        HtmlWindow.__init__(self, parent=parent, **kwargs)

        self.loaded = False
        self.history = list()
        self.historyIdx = 0
        self.fspath = os.path.join(os.getenv("GISBASE"), "docs", "html")

        self.SetStandardFonts(size=10)
        self.SetBorders(10)

        if text is None:
            if skipDescription:
                url = os.path.join(self.fspath, command + ".html")
                self.fillContentsFromFile(url,
                                          skipDescription=skipDescription)
                self.history.append(url)
                self.loaded = True
            else:
                # FIXME: calling LoadPage() is strangely time-consuming (only first call)
                # self.LoadPage(self.fspath + command + ".html")
                self.loaded = False
        else:
            self.SetPage(text)
            self.loaded = True

    def OnLinkClicked(self, linkinfo):
        url = linkinfo.GetHref()
        if url[:4] != 'http':
            url = os.path.join(self.fspath, url)
        self.history.append(url)
        self.historyIdx += 1
        self.parent.OnHistory()

        super(HelpWindow, self).OnLinkClicked(linkinfo)

    def LoadPage(self, path):
        super(HelpWindow, self).LoadPage(path)
        self.loaded = True

    def fillContentsFromFile(self, htmlFile, skipDescription=True):
        """Load content from file.

        Currently not used.
        """
        aLink = re.compile(r'(<a href="?)(.+\.html?["\s]*>)', re.IGNORECASE)
        imgLink = re.compile(r'(<img src="?)(.+\.[png|gif])', re.IGNORECASE)
        try:
            contents = []
            skip = False
            for l in open(htmlFile, "rb").readlines():
                if "DESCRIPTION" in l:
                    skip = False
                if not skip:
                    # do skip the options description if requested
                    if "SYNOPSIS" in l:
                        skip = skipDescription
                    else:
                        # FIXME: find only first item
                        findALink = aLink.search(l)
                        if findALink is not None:
                            contents.append(
                                aLink.sub(
                                    findALink.group(1) +
                                    self.fspath +
                                    findALink.group(2),
                                    l))
                        findImgLink = imgLink.search(l)
                        if findImgLink is not None:
                            contents.append(
                                imgLink.sub(
                                    findImgLink.group(1) +
                                    self.fspath +
                                    findImgLink.group(2),
                                    l))

                        if findALink is None and findImgLink is None:
                            contents.append(l)
            self.SetPage("".join(contents))
            self.loaded = True
        except:  # The Manual file was not found
            self.loaded = False


class HelpPanel(wx.Panel):

    def __init__(self, parent, command="index", text=None,
                 skipDescription=False, **kwargs):
        self.command = command
        wx.Panel.__init__(self, parent=parent, id=wx.ID_ANY)

        self.content = HelpWindow(self, command, text, skipDescription)

        self.btnNext = Button(parent=self, id=wx.ID_ANY,
                                 label=_("&Next"))
        self.btnNext.Enable(False)
        self.btnPrev = Button(parent=self, id=wx.ID_ANY,
                                 label=_("&Previous"))
        self.btnPrev.Enable(False)

        self.btnNext.Bind(wx.EVT_BUTTON, self.OnNext)
        self.btnPrev.Bind(wx.EVT_BUTTON, self.OnPrev)

        self._layout()

    def _layout(self):
        """Do layout"""
        sizer = wx.BoxSizer(wx.VERTICAL)
        btnSizer = wx.BoxSizer(wx.HORIZONTAL)

        btnSizer.Add(self.btnPrev, proportion=0,
                     flag=wx.ALL, border=5)
        btnSizer.Add(wx.Size(1, 1), proportion=1)
        btnSizer.Add(self.btnNext, proportion=0,
                     flag=wx.ALL, border=5)

        sizer.Add(self.content, proportion=1,
                  flag=wx.EXPAND)
        sizer.Add(btnSizer, proportion=0,
                  flag=wx.EXPAND)

        self.SetSizer(sizer)
        sizer.Fit(self)

    def LoadPage(self, path=None):
        """Load page"""
        if not path:
            path = self.GetFile()
        self.content.history.append(path)
        self.content.LoadPage(path)

    def GetFile(self):
        """Get HTML file"""
        fMan = os.path.join(self.content.fspath, self.command + ".html")
        if os.path.isfile(fMan):
            return fMan

        # check also addons
        faMan = os.path.join(os.getenv('GRASS_ADDON_BASE'), "docs", "html",
                             self.command + ".html")
        if os.getenv('GRASS_ADDON_BASE') and \
                os.path.isfile(faMan):
            return faMan

        return None

    def IsLoaded(self):
        return self.content.loaded

    def OnHistory(self):
        """Update buttons"""
        nH = len(self.content.history)
        iH = self.content.historyIdx
        if iH == nH - 1:
            self.btnNext.Enable(False)
        elif iH > -1:
            self.btnNext.Enable(True)
        if iH < 1:
            self.btnPrev.Enable(False)
        else:
            self.btnPrev.Enable(True)

    def OnNext(self, event):
        """Load next page"""
        self.content.historyIdx += 1
        idx = self.content.historyIdx
        path = self.content.history[idx]
        self.content.LoadPage(path)
        self.OnHistory()

        event.Skip()

    def OnPrev(self, event):
        """Load previous page"""
        self.content.historyIdx -= 1
        idx = self.content.historyIdx
        path = self.content.history[idx]
        self.content.LoadPage(path)
        self.OnHistory()

        event.Skip()


def ShowAboutDialog(prgName, startYear):
    """Displays About window.

    :param prgName: name of the program
    :param startYear: the first year of existence of the program
    """
    info = AboutDialogInfo()

    info.SetIcon(
        wx.Icon(
            os.path.join(
                globalvar.ICONDIR,
                'grass.ico'),
            wx.BITMAP_TYPE_ICO))
    info.SetName(prgName)
    info.SetWebSite('https://grass.osgeo.org')
    info.SetDescription(
        _grassDevTeam(startYear) +
        '\n\n' +
        '\n'.join(
            textwrap.wrap(
                'This program is free software under the GNU General Public License'
                '(>=v2). Read the file COPYING that comes with GRASS for details.',
                75)))

    AboutBox(info)


def _grassDevTeam(start):
    try:
        end = grass.version()['date']
    except KeyError:
        sys.stderr.write(_("Unable to get GRASS version\n"))

        from datetime import date
        end = date.today().year

    return '%(c)s %(start)s-%(end)s by the GRASS Development Team' % {
        'c': _unichr(169), 'start': start, 'end': end}


def main():
    """Test application (potentially useful as g.gui.gmanual)"""
    app = wx.App()
    frame = HelpFrame(parent=None, id=wx.ID_ANY,
                      title="Test help application",
                      size=(600, 800), file=sys.argv[1])
    frame.Show()
    app.MainLoop()


if __name__ == '__main__':
    main()