#!/usr/bin/env python

'''A module to draw a graph on the screen given a data file.

The code is written such that it may be run as a program or imported
and used as a module.
'''

import sys
import os.path
import types
import csv
import time
import getopt
import string
try:
    import cpickle as pickle
except:
    import pickle

try:
    import pylab
except ImportError:
    import tkinter_error
    msg = ('Sorry, you have to install matplotlib.\n'
           'Get it from either:\n'
           r'   N:\georisk\downloads\matplotlib, or' '\n'
           '   [http://matplotlib.sourceforge.net/].\n\n'
           'You will also need to have numpy installed:\n'
           r'   N:\georisk\downloads\numpy')
    tkinter_error.tkinter_error(msg)
    print msg
    sys.exit(1)

try:
    import wx
except ImportError:
    import tkinter_error
    msg = ('Sorry, you have to install WxPython.\n'
           'Get it from either:\n'
           r'   N:\georisk\downloads\event_selection, or' '\n'
           '   [http://www.wxpython.org/download.php#binaries].')
    tkinter_error.tkinter_error(msg)
    print msg
    sys.exit(1)

Imported_PyEmbeddedImage = True
try:
    from wx.lib.embeddedimage import PyEmbeddedImage
except ImportError:
    Imported_PyEmbeddedImage = False


# program name and version
APP_NAME = 'plotcsv'
APP_VERSION = '0.7'

# name of the configuration filename
# GUI values are saved in this file for next time
ConfigFilename = '%s.cfg' % APP_NAME

# GUI definitions
BUTTON_WIDTH = 100
BUTTON_HEIGHT = 30

MARGIN = 10

LAB_CTRL_OFFSET = 5

BOX_WIDTH = 400
BOX_HEIGHT = 360
BOX_CSV_WIDTH = 400
BOX_CSV_HEIGHT = 265
BOX_PLOT_WIDTH = 400
BOX_PLOT_HEIGHT = 140+25+25+30

TXT_CSVFILE_WIDTH = 390
TXT_CSVFILE_HEIGHT = 200

COLLAB_X_OFFSET = 25

CHBOX_HEIGHT = 30
CHBOX_WIDTH = 100

FORM_WIDTH = BOX_WIDTH + 15
FORM_HEIGHT = 450+25+25+30

START_YOFFSET = 7
OUT_TEXT_XOFFSET = 8
OUT_TEXT_YOFFSET = 11
OUTPUT_BOX_HEIGHT = 45

GEN_YOFFSET = 15
GEN_DELTAY = 15
GEN_LABELXOFFSET = 5
GEN_TEXTXOFFSET = BOX_WIDTH/2 + GEN_LABELXOFFSET + 10

TEXTLIST_WIDTH = BOX_WIDTH - 10
TEXTLIST_HEIGHT = 200

CTL_WIDTH = BOX_WIDTH / 2
CTL_HEIGHT = 22

DOUBLE_BUTTON_OFFSET = 8

COMBO_FUDGE = 2

# Copies of various parameters
Region = ''
GaugeNumber = ''
MinimumHeight = ''
MaximumHeight = ''

# Flag strings - keys in the 'options' dictionary
X_DATACOL = 'x_datacol'
Y_DATACOL = 'y_datacol'
X_RANGE = 'x_range'
Y_RANGE = 'y_range'
FILENAME = 'filename'
SIZE = 'size'
TITLE = 'title'
X_LABEL = 'x_label'
Y_LABEL = 'y_label'

CSVWildcard = 'CSV files (*.csv)|*.csv|All files (*.*)|*.*'

# Flag strings - keys in the 'options' dictionary
X_DATACOL = 'x_datacol'
Y_DATACOL = 'y_datacol'
X_RANGE = 'x_range'
Y_RANGE = 'y_range'
FILENAME = 'filename'
SIZE = 'size'
TITLE = 'title'
X_LABEL = 'x_label'
Y_LABEL = 'y_label'


################################################################################
# This code was generated by img2py.py
# Embed the ICON image here, so we don't need an external *.ico file.
################################################################################

if Imported_PyEmbeddedImage:
    def getIcon():
        return PyEmbeddedImage(
    "iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAYAAABzenr0AAAABHNCSVQICAgIfAhkiAAAApxJ"
    "REFUWIXtlr9O40AQh2edWwsKJFAarGtcRaElJWkoo4TGZegocqLME6TOC6CtaWjCFXRUfgJE"
    "xStsiivuKiQ4ND8Kx/bu+k+cUKRhpC0ie+f7sjs7a0FEoB3GDyIiYDcOQgjydkI24lvgW2Bj"
    "gctLolaLaG+P6OiI6PCQSIh89HpEy+VmOdE0lAKI1o8oArSuycMKAQegVQ9qDJeymUCdhGIF"
    "yRLE1FzAhZ+dATc3wN0d8PiYg9z3XAkLbgl0u4DnAePxWvja5XXen0zK4RFHhoA5lNoabs4z"
    "Uw4finDN2hAIw/xtKQGltoanMZut5k4U6K0IB2AIaJ0QVrQPT+LaU1vD0xg+2PDuSwJXCggC"
    "UwAoSLyTxC9SpfAFLxBwAJ99THlavg1uwS0i0LHGcGiurHMKbucav0Uu8V9I/JsrK7FmjRM+"
    "yRL77CPmuBbefUngxeNqCKR7HpDGPUWFmkjhEUf5v1qNkMNMoqzaNWtMJsU+kQmMx/bDq4HG"
    "68CW0LdzC97iFtrctiSmPC2Fpzvc7yenvd9PfmcC+/s56/x8tedGTehjQnQvssSSJRQrxBwj"
    "5LCwIi68KqwV8LykHz0/mxuuoa8GiBZ5YvnhQXFeF2USTeCWQFVo1oheBzn8jaCuPatZpRId"
    "7sBnHyMeJXCtgaen2vNbK+AWnHwXUJNiYZZP1slylt1Sp6eZVKVAAc4S6u/c6hO1Em7JV1yV"
    "pQKl8HTPnWZVKpH14PX3dUGgFm4ub5WEewvNZvZc54KxBBrB6ySmU+DgoHgPu2FIZAIbwask"
    "zNHrrf9oCIxPMrO3N4LXSYQhEMeNpmcCKVywaA43JUYjwPeBTqcx3BIIOYTHHi74YjP4F4OI"
    "IIgI9JOI2kS0JKI/m33TfzU+ASG0bvT61fpzAAAAAElFTkSuQmCC")


################################################################################
# An object that behaves like a dictionary but is pickled/unpickled from a file.
# Used to save state in the application.
################################################################################

class Config(object):
    """An object that behaves like a dictionary but is persistent:

        cfg = Config('filename')
        cfg['save'] = 'A saved value'
        cfg[123] = 'value 123'
        print cfg['save']

    The values stored in the file 'filename' will be available to any
    application using that config file.
    """

    def __init__(self, configfile=None):
        """__init__(self, String filename=None) -> Config"""

        self.delconf = False
        self.cfgdict = {}
        self.changed = False
        if not configfile:
            self.delconf = True
            configfile =tempfile.mktemp()
        self.configfile = os.path.abspath(configfile)
        if os.path.exists(self.configfile):
            try:
                f = open(configfile, "r")
                u = pickle.Unpickler(f)
                self.cfgdict = u.load()
            except pickle.UnpicklingError, e:
                print e
            except:
                pass
            else:
                f.close()

    def __setitem__(self, key, value):
        """Override to allow: cfg[<key>] = <value>"""
        
        self.cfgdict[key] = value
        self.changed = True

    def get(self, key, default=None):
        """Override to allow: <var> = cfg.get(<key>, default=None)"""
        
        return self.cfgdict.get(key, default)
        
    def __getitem__(self, key):
        """Override to allow: <var> = cfg[<key>]"""
        
        return self.cfgdict.get(key, None)

    def __str__(self):
        """__str__(self) -> String"""
        
        return "<config object at %s>" % hex(id(self))

    def getfilename(self):
        """getfilename(self) -> String filename"""
        
        return self.configfile

    def setdeleted(self):
        """setdeleted(self)"""
        
        self.delconf = True

    def save(self):
        """save(self)"""
        
        try:
            f = open(self.configfile, "w")
            p = pickle.Pickler(f)
            p.dump(self.cfgdict)
        except pickle.PicklingError, e:
            print e
        else:
            f.close()
        self.changed = False

    def close(self):
        """close(self)"""
        
        if self.changed:
            self.save()
        if self.delconf:
            if os.path.exists(self.configfile):
                os.remove(self.configfile)

    def __del__(self):
        """__del__(self)"""
        
        self.close()
        

################################################################################
# Plot routines
################################################################################

##
# @brief Get CSV data from a file.
# @param filename Path to the data file to plot.
# @param x_hdr The X axis title string.
# @param y_hdr The Y axis title string.
def getCSVData(filename, x_hdr, y_hdr):
    # get contents of data file
    # after this, 'header' is list of column header strings
    #             'data' is a list of lists of data
    fd = open(filename)
    c = csv.reader(fd)
    data = []
    for row in c:
        data.append(row)
    fd.close()
    header = data[0]
    del data[0]         # get rid of header in dataset

    # ensure header strings don't have leading/trailing spaces
    header = map(string.strip, header)

    # get int index values for column headers
    try:
        x_index = header.index(x_hdr)
    except ValueError:
        TheFrame.error("Sorry, X column header '%s' isn't in data file '%s'."
                     % (x_hdr, filename))
        return None

    try:
        y_index = header.index(y_hdr)
    except ValueError:
        TheFrame.error("Sorry, Y column header '%s' isn't in data file '%s'."
                       % (y_hdr, filename))
        return None

    # get appropriate columns from data[]
    x_data = map(lambda x: float(x[x_index]), data)
    if x_hdr == 'time':
        x_data = map(lambda x: float(x)/3600., x_data)
    y_data = map(lambda x: float(x[y_index]), data)

    return (x_data, y_data)


##
# @brief Plot data files.
# @param filenames List of full pathnames to plot.
# @param x_hdr The X axis data header string.
# @param y_hdr The Y axis data header string.
# @param title The string used to title the graph.
# @param legend True if a legend is to be displayed.
# @param legend_path True if legend is to contain full file paths.
# @param grid True if grid is to be displayed.
# @param fontsize Point size of font.
# @param plot_width Width of plot lines.
# @param x_label Override X axis label.
# @param y_label Override Y axis label.
def plot_files(filenames, x_hdr, y_hdr, title='', legend=False,
               legend_path=False, grid=False, fontsize=10,
               plot_width=2, x_label=None, y_label=None):
    if x_label is None:
        x_label = x_hdr
    if y_label is None:
        y_label = y_hdr
        
    pylab.rc('axes', linewidth=2)
    pylab.rc('lines', linewidth=float(plot_width))
    pylab.rc(('xtick', 'ytick'), labelsize=float(fontsize)*0.75,)
    pylab.rc(('xtick.major', 'ytick.major'), size=5, pad=5)
    pylab.rc('axes', labelsize=float(fontsize))
    pylab.xlabel(x_label)
    pylab.ylabel(y_label)

    pylab.grid(grid)

    for f in filenames:
        result = getCSVData(f, x_hdr, y_hdr)
        if result is None:          # some sort of error
            pylab.close()
            return

        (x_data, y_data) = result
        pylab.plot(x_data, y_data)

    if title:
        pylab.title(title, fontsize=float(fontsize)*1.5)
        
    if legend:
        pylab.rc('legend', fancybox=True)
        (min_y, max_y) = pylab.ylim()
        range_y = max_y - min_y
        add_y = float(range_y) / 5
        pylab.ylim((min_y, max_y+add_y))
        legend_names = filenames
        if not legend_path:
            legend_names = [os.path.basename(x) for x in filenames]
        pylab.legend(legend_names, 'upper right')

    pylab.show()
    pylab.close()


################################################################################
# GUI routines
################################################################################

class MyFrame(wx.Frame):
    def __init__(self, parent, id, title, pos=wx.DefaultPosition,
                    size=wx.DefaultSize, style=wx.DEFAULT_FRAME_STYLE):
        '''Lay out the GUI form'''
        
        # Make the frame
        wx.Frame.__init__(self, parent, id, title, pos=(50, 50),
                          size=(FORM_WIDTH, FORM_HEIGHT),
                          style=(wx.DEFAULT_FRAME_STYLE &
                                 ~ (wx.RESIZE_BOX | wx.MAXIMIZE_BOX |
                                    wx.RESIZE_BORDER)))

        p = self.panel = wx.Panel(self, -1)

        if Imported_PyEmbeddedImage:
            tsunami = getIcon()
            icon = tsunami.GetIcon()
            self.SetIcon(icon)
        
        self.Center()
        self.Show(True)

        # start laying out controls
        Y_OFFSET = START_YOFFSET
        wx.StaticBox(p, -1, 'CSV files', (3, Y_OFFSET),
                     size=(BOX_CSV_WIDTH, BOX_CSV_HEIGHT))
        Y_OFFSET += GEN_DELTAY 
        self.txtCSVFiles = wx.ListBox(p, -1, pos=(8, Y_OFFSET),
                                      size=(TXT_CSVFILE_WIDTH,
                                            TXT_CSVFILE_HEIGHT))
        self.CSVFiles = []
        Y_OFFSET += TXT_CSVFILE_HEIGHT + MARGIN 
        x = FORM_WIDTH/2 - BUTTON_WIDTH - DOUBLE_BUTTON_OFFSET
        self.btnAddCSVFile = wx.Button(p, label="Add", pos=(x, Y_OFFSET),
                                     size=(100, BUTTON_HEIGHT))
        x = FORM_WIDTH/2 + DOUBLE_BUTTON_OFFSET
        self.btnDelCSVFile = wx.Button(p, label="Delete All", pos=(x, Y_OFFSET),
                                     size=(100, BUTTON_HEIGHT))
        Y_OFFSET += BUTTON_HEIGHT + MARGIN 

        wx.StaticBox(p, -1, 'Plot files', (3, Y_OFFSET),
                     size=(BOX_PLOT_WIDTH, BOX_PLOT_HEIGHT))
        Y_OFFSET += GEN_DELTAY

        wx.StaticText(p, -1, 'X-Column',
                      pos=(COLLAB_X_OFFSET, Y_OFFSET+LAB_CTRL_OFFSET), style=wx.ALIGN_LEFT)
        self.cbXColHdr = wx.Choice(p, -1, pos=(COLLAB_X_OFFSET+50, Y_OFFSET),
                                   size=(80, -1))
        self.XColHdr = []
        wx.StaticText(p, -1, 'Y-Column',
                      pos=(FORM_WIDTH/2,
                           Y_OFFSET+LAB_CTRL_OFFSET), style=wx.ALIGN_LEFT)
        x = FORM_WIDTH/2+50
        self.cbYColHdr = wx.Choice(p, -1, pos=(x, Y_OFFSET), size=(80, -1))
        self.YColHdr = []
        Y_OFFSET += GEN_DELTAY*1.5

        wx.StaticText(p, -1, 'X-Label',
                      pos=(COLLAB_X_OFFSET, Y_OFFSET+LAB_CTRL_OFFSET), style=wx.ALIGN_LEFT)
        self.txtXLabel = wx.TextCtrl(p, -1, "", size=(100, -1),
                                     pos=(COLLAB_X_OFFSET+50,
                                          Y_OFFSET+LAB_CTRL_OFFSET),
                                     style=wx.ALIGN_LEFT)
        wx.StaticText(p, -1, 'Y-Label',
                      pos=(FORM_WIDTH/2,
                           Y_OFFSET+LAB_CTRL_OFFSET), style=wx.ALIGN_LEFT)
        x = FORM_WIDTH/2 + 50
        self.txtYLabel = wx.TextCtrl(p, -1, "", size=(100, -1),
                                     pos=(x,
                                          Y_OFFSET+LAB_CTRL_OFFSET),
                                     style=wx.ALIGN_LEFT)
        Y_OFFSET += GEN_DELTAY*2.5

        self.chkLegend = wx.CheckBox(p, -1, " Show graph legend",
                                     pos=(COLLAB_X_OFFSET+20, Y_OFFSET))        
        self.chkLegendPath = wx.CheckBox(p, -1, " Full file path in legend",
                                         pos=(COLLAB_X_OFFSET+180, Y_OFFSET))        
        Y_OFFSET += GEN_DELTAY*2

        font_sizes = ['10', '12', '14', '16', '18', '20',
                      '22', '24', '26', '28', '30', '32']
        self.cbLabFontSize = wx.ComboBox(p, -1, "10",
                                         (COLLAB_X_OFFSET+20, Y_OFFSET-5), 
                                         (47, -1), font_sizes,
                                        wx.CB_DROPDOWN)
        wx.StaticText(p, -1, 'Label fontsize',
                      pos=(COLLAB_X_OFFSET+72, Y_OFFSET),
                      style=wx.ALIGN_LEFT)

        self.chkShowGrid = wx.CheckBox(p, -1, " Show grid",
                                       pos=(COLLAB_X_OFFSET+180, Y_OFFSET))        
        
        Y_OFFSET += GEN_DELTAY*2

        plot_widths = ['1', '2', '3', '4', '5', '6', '7', '8', '9', '10']
        self.cbPlotWidth = wx.ComboBox(p, -1, "2",
                                       (COLLAB_X_OFFSET+20, Y_OFFSET-5), 
                                       (47, -1), plot_widths,
                                       wx.CB_DROPDOWN)
        wx.StaticText(p, -1, 'Plot width',
                      pos=(COLLAB_X_OFFSET+72, Y_OFFSET),
                      style=wx.ALIGN_LEFT)
        Y_OFFSET += GEN_DELTAY + 3
        
        wx.StaticText(p, -1, 'Title',
                      pos=(18, Y_OFFSET+LAB_CTRL_OFFSET+2), style=wx.ALIGN_LEFT)
        self.txtTitle = wx.TextCtrl(p, -1, "", size=(350, -1),
                                    pos=(COLLAB_X_OFFSET+20,
                                         Y_OFFSET+LAB_CTRL_OFFSET),
                                    style=wx.ALIGN_LEFT)
        Y_OFFSET += BUTTON_HEIGHT # + MARGIN
        x = FORM_WIDTH/2 - BUTTON_WIDTH/2
        self.btnPlot = wx.Button(p, label="Plot", pos=(x, Y_OFFSET),
                                     size=(100, BUTTON_HEIGHT))

        # bind controls/events to handlers
        self.Bind(wx.EVT_BUTTON, self.AddCSVFile, self.btnAddCSVFile)
        self.Bind(wx.EVT_BUTTON, self.DelCSVFile, self.btnDelCSVFile)
        self.Bind(wx.EVT_BUTTON, self.PlotFiles, self.btnPlot)
        self.Bind(wx.EVT_CHECKBOX, self.ChangeLegend, self.chkLegend)
        self.Bind(wx.EVT_CHOICE, self.ChangeXLabel, self.cbXColHdr)
        self.Bind(wx.EVT_CHOICE, self.ChangeYLabel, self.cbYColHdr)
        
        self.Bind(wx.EVT_CLOSE, self.doStateSave)

        # restore saved values
        self.common_headers = None
        self.cfg = Config(ConfigFilename)
        self.doStateRestore()
        self.updateHdrChoices()

    def ChangeXLabel(self, event):
        sel = self.cbXColHdr.GetCurrentSelection()
        self.txtXLabel.SetValue(self.cbXColHdr.GetItems()[sel].title())
    
    def ChangeYLabel(self, event):
        sel = self.cbYColHdr.GetCurrentSelection()
        self.txtYLabel.SetValue(self.cbYColHdr.GetItems()[sel].title())
    
    def AddCSVFile(self, event):
        """Add a CSV file to the listbox"""

        dlg = wx.FileDialog(self, message='Choose a CSV file',
                            defaultDir=self.file_dir, 
                            defaultFile='',
                            wildcard=CSVWildcard,
                            style=wx.OPEN | wx.MULTIPLE | wx.CHANGE_DIR)

        if dlg.ShowModal() == wx.ID_OK:
            # This returns a list of  files that were selected.
            files = dlg.GetFilenames()
            self.file_dir = dlg.GetDirectory()
            dlg.Destroy()
            for f in files:
                path = os.path.join(self.file_dir, f)
                if path not in self.CSVFiles:
                    headers = self.getHeaders(path)
                    if headers:
                        common_headers = self.orHeaders(headers)
                        if not common_headers or len(common_headers) < 2:
                            self.error("Sorry, file '%s' doesn't have enough headers in common with current files" % path)
                        else:
                            self.headers.append(headers)
                            self.common_headers = common_headers
                            self.CSVFiles.append(path)
                            self.txtCSVFiles.Append(path)
                    else:
                        self.error("Sorry, file '%s' doesn't appear to be a CSV file" % path)
                    self.updateHdrChoices()

    def DelCSVFile(self, event):
        """Delete all CSV files from the listbox"""
        
        self.txtCSVFiles.Clear()
        self.CSVFiles = []
        self.common_headers = None
        self.updateHdrChoices()
        
    def ChangeLegend(self, event):
        if self.chkLegend.GetValue():
            self.chkLegendPath.Enable()
        else:
            self.chkLegendPath.Disable()

    def doStateSave(self, event):
        """Save state from 'self' variables & controls."""

        self.cfg['CSVFiles'] = self.CSVFiles
        self.cfg['XColHdr'] = self.XColHdr
        self.cfg['XColHdrSelection'] = self.cbXColHdr.GetSelection()
        self.cfg['YColHdr'] = self.YColHdr
        self.cfg['YColHdrSelection'] = self.cbYColHdr.GetSelection()
        self.cfg['file_dir'] = self.file_dir
        self.cfg['GraphTitle'] = self.txtTitle.GetValue()
        self.cfg['GraphLegend'] = self.chkLegend.GetValue()
        self.cfg['LegendPath'] = self.chkLegendPath.GetValue()
        self.cfg['ShowGrid'] = self.chkShowGrid.GetValue()
        self.cfg['FontSize'] = self.cbLabFontSize.GetValue()
        self.cfg['PlotWidth'] = self.cbPlotWidth.GetValue()
        self.cfg['XLabel'] = self.txtXLabel.GetValue()
        self.cfg['YLabel'] = self.txtYLabel.GetValue()

        self.cfg.save()
        event.Skip(True)

    def doStateRestore(self):
        """Restore state to 'self' variables."""

        self.CSVFiles = self.cfg['CSVFiles']
        if self.CSVFiles is None:
            self.CSVFiles = []
        self.XColHdr = self.cfg['XColHdr']
        if self.XColHdr is None:
            self.XColHdr = []
        self.XColHdrSelection = self.cfg['XColHdrSelection']
        self.YColHdr = self.cfg['YColHdr']
        if self.YColHdr is None:
            self.YColHdr = []
        self.YColHdrSelection = self.cfg['YColHdrSelection']
        self.file_dir = self.cfg['file_dir']
        if self.file_dir is None:
            self.file_dir = os.getcwd()

        # put data into controls
        self.headers = []
        for (i, f) in enumerate(self.CSVFiles):
            headers = self.getHeaders(f)
            self.headers.append(headers)
            self.txtCSVFiles.Insert(f, i)
        self.common_headers = self.GenCommonHeaders(self.headers)
        self.updateHdrChoices()

        if self.XColHdrSelection >= 0:
            self.cbXColHdr.SetSelection(self.XColHdrSelection)
        if self.YColHdrSelection >= 0:
            self.cbYColHdr.SetSelection(self.YColHdrSelection)
        self.txtTitle.SetValue(self.cfg.get('GraphTitle', ''))
        self.chkLegend.SetValue(self.cfg.get('GraphLegend', False))
        self.chkLegendPath.SetValue(self.cfg.get('LegendPath', False))
        self.cbLabFontSize.SetValue(self.cfg.get('FontSize', '14'))
        self.cbPlotWidth.SetValue(self.cfg.get('PlotWidth', '1'))
        self.chkShowGrid.SetValue(self.cfg.get('ShowGrid', True))
        self.txtXLabel.SetValue(self.cfg.get('XLabel', ''))
        self.txtYLabel.SetValue(self.cfg.get('YLabel', ''))
        self.ChangeLegend(None)
        
    def getHeaders(self, filename):
        '''Get header list from a file'''

        try:
            fd = open(filename, 'r')
            hdr = fd.readline()
            fd.close()
        except:
            return None

        hdr = hdr.split(',')
        hdr = [x.strip() for x in hdr]

        return hdr
        
    def updateHdrChoices(self):
        '''Update choice controls with header lists.

        Disable controls if no CSV files (ie, no headers).
        Keep selections visible afterwards, if possible.
        '''

        # get current selections, if any
        selected_x = self.cbXColHdr.GetStringSelection()
        selected_y = self.cbYColHdr.GetStringSelection()
        
        self.cbXColHdr.Clear()
        self.cbYColHdr.Clear()

        if self.common_headers:
            self.cbXColHdr.Enable()
            self.cbYColHdr.Enable()
            self.btnPlot.Enable()
            for h in self.common_headers:
                self.cbXColHdr.Append(h)
                self.cbYColHdr.Append(h)
            if selected_x in self.common_headers:
                index = self.common_headers.index(selected_x)
                self.cbXColHdr.SetSelection(index)
            if selected_y in self.common_headers:
                index = self.common_headers.index(selected_y)
                self.cbYColHdr.SetSelection(index)
            self.txtXLabel.Enable()
            self.txtYLabel.Enable()
        else:
            self.cbXColHdr.Disable()
            self.cbYColHdr.Disable()
            self.txtXLabel.Disable()
            self.txtYLabel.Disable()
            self.btnPlot.Disable()

    def orHeaders(self, new_header):
        '''Update X & Y column header choices.

        Return new 'common headers' list from current
        self.common_headers and the supplied new_header list.
        '''

        if self.common_headers:
            result = [x for x in new_header if x in self.common_headers]
        else:
            result = new_header
        return result

    def GenCommonHeaders(self, headers):
        '''Get new set of common headers.

        Return a new 'common header' list given a
        list of header lists.
        '''

        result = []
        for header in headers:
            if result:
                result = [x for x in result if x in header]
            else:
                result = header
        return result

    def PlotFiles(self, event):
        '''Plot files in the CSV file listbox.'''
        
        selected_x = self.cbXColHdr.GetStringSelection()
        selected_y = self.cbYColHdr.GetStringSelection()

        x_label = self.txtXLabel.GetValue()
        y_label = self.txtYLabel.GetValue()

        if selected_x and selected_y:
            grid_on = self.chkShowGrid.GetValue()
            fontsize = self.cbLabFontSize.GetValue()
            plot_width = self.cbPlotWidth.GetValue()
            plot_files(self.CSVFiles, selected_x, selected_y,
                       x_label=x_label, y_label=y_label,
                       title=self.txtTitle.GetValue(),
                       legend=self.chkLegend.GetValue(),
                       legend_path=self.chkLegendPath.GetValue(),
                       grid=grid_on, fontsize=fontsize,
                       plot_width = plot_width)

            # hide problem with wxPython and matplotlib - close app!
            self.Close(True)
        else:
            self.error('Sorry, you must select X- and Y-column data values')
            
    def error(self, msg):
        '''Issue xwPython error message.'''
        
        wx.MessageBox(msg, 'Error')

        
################################################################################
# Mainline code - start the application.
################################################################################

if __name__ == '__main__':
    global TheFrame

    # The frame reference
    TheFrame = None

    app = wx.App()
    TheFrame = MyFrame(None, -1, '%s %s' % (APP_NAME, APP_VERSION),
                       size=(FORM_WIDTH, FORM_HEIGHT))
    app.SetTopWindow(TheFrame)
    app.MainLoop()