# -*- coding: utf-8 -*-
"""
/***************************************************************************
 NBNDialog
                                 A QGIS plugin
 FSC Tomorrow's Biodiversity productivity tools for biological recorders
                             -------------------
        begin                : 2014-02-17
        copyright            : (C) 2014 by Rich Burkmar, Field Studies Council
        email                : richardb@field-studies-council.org
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
"""

from ui_nbn import Ui_nbn
import os.path
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyQt4.QtNetwork import *
from qgis.core import *
from qgis.gui import *
from qgis.utils import *
from filedialog import FileDialog
import urllib, urllib2
import cookielib
import json 
import hashlib, uuid
import shutil
from osgr import *
from envmanager import *
import threading
import csv

#import requests

class NBNDialog(QWidget, Ui_nbn):

    displayNBNCSVFile = pyqtSignal(basestring)

    def __init__(self, iface, dockwidget):
        QWidget.__init__(self)
        Ui_nbn.__init__(self)
        self.setupUi(self)
        self.canvas = iface.mapCanvas()
        self.iface = iface
    
        self.pathPlugin = "%s%s%%s" % ( os.path.dirname( __file__ ), os.path.sep )
        
        # Get a reference to an osgr object and an osgrLayer object
        self.osgr = osgr()
        
        # Load the environment stuff
        self.env = envManager()
        
        # WMS
        self.pbSpeciesWMS.clicked.connect(self.WMSFetchSpecies)
        self.pbDatasetWMS.clicked.connect(self.WMSFetchDataset)
        self.pbDesignationWMS.clicked.connect(self.WMSFetchDesignation)
        self.butTaxonSearch.clicked.connect(self.TaxonSearch)
        self.butClearLast.clicked.connect(self.removeMap)
        self.butClear.clicked.connect(self.removeMaps)
        self.pbLogin.clicked.connect(self.loginNBN)
        self.pbLogout.clicked.connect(self.logoutNBN)
        self.butHelp.clicked.connect(self.helpFile)
        self.pbRefreshDatasets.clicked.connect(self.refreshDatasets)
        self.pbRefreshDesignations.clicked.connect(self.refreshDesignations)
        self.pbRefreshGroups.clicked.connect(self.refreshGroups)
        self.pbRefreshAreas.clicked.connect(self.refreshBothAreas)
        self.pbUncheckAll.clicked.connect(self.uncheckAll)
        self.twDatasets.itemClicked.connect(self.datasetTwClick)
        self.twDesignations.itemClicked.connect(self.designationTwClick)
        self.twGroups.itemClicked.connect(self.groupTwClick)
        self.twAreas.itemClicked.connect(self.siteTwClick)
        self.twTaxa.itemClicked.connect(self.taxaTwClick)
        self.cbStartYear.stateChanged.connect(self.checkFilters)
        self.cbEndYear.stateChanged.connect(self.checkFilters)
        self.rbAbsence.toggled.connect(self.checkFilters)
        self.leGridRef.textChanged.connect(self.checkFilters)
        self.twAreaCategories.itemDoubleClicked.connect(self.readAreaFile)
        self.pbBuffer.clicked.connect(self.generateBuffer)
        self.pbClearLastBuffer.clicked.connect(self.removeBuffer)
        self.rbGR.toggled.connect(self.bufferEnableDisable)
        
        self.pbDownloadGridRef.clicked.connect(self.downloadNBNObservations)
        self.pbSendToBiorec.clicked.connect(self.displayCSV)
        #self.butOS.clicked.connect(self.osBackdrop)
        
        # Map canvas events
        self.canvas.extentsChanged.connect(self.mapExtentsChanged)
        self.canvas.selectionChanged.connect(self.checkMapSelectionFilter)
        self.iface.currentLayerChanged.connect(self.checkMapSelectionFilter)
        
        # Make a coordinate translator. Also need global references to OSGB and canvas CRSs since
        # they cannot be retrieved from a translator object.
        self.canvasCrs = self.canvas.mapRenderer().destinationCrs()
        self.osgbCrs = QgsCoordinateReferenceSystem("EPSG:27700")
        self.transformCrs = QgsCoordinateTransform(self.canvas.mapRenderer().destinationCrs(), QgsCoordinateReferenceSystem("EPSG:27700"))
        
        # Inits
        self.nbnOSLayerName = "NBN OS Backdrop"
        self.layers = []
        self.buffers = []
        self.tvks = {} #Initialise tvk dictionary
        self.pbSendToBiorec.setIcon(QIcon( self.pathPlugin % "images/maptaxa.png" ))
        self.butClearLast.setIcon(QIcon( self.pathPlugin % "images/removelayer.png" ))
        self.butClear.setIcon(QIcon( self.pathPlugin % "images/removelayers.png" ))
        self.pbSpeciesWMS.setIcon(QIcon( self.pathPlugin % "images/nbngridmap.png" ))
        self.pbDatasetWMS.setIcon(QIcon( self.pathPlugin % "images/nbngridmap.png" ))
        self.pbDesignationWMS.setIcon(QIcon( self.pathPlugin % "images/nbngridmap.png" ))
        self.pbDownloadGridRef.setIcon(QIcon( self.pathPlugin % "images/nbndownload.png" ))
        self.butTaxonSearch.setIcon(QIcon( self.pathPlugin % "images/speciesinventory.png" ))
        self.pbBuffer.setIcon(QIcon( self.pathPlugin % "images/buffer.png" ))
        self.pbClearLastBuffer.setIcon(QIcon( self.pathPlugin % "images/bufferclear.png" ))
        #self.butOS.setIcon(QIcon( self.pathPlugin % "images/os.png" ))
        self.butHelp.setIcon(QIcon( self.pathPlugin % "images/bang.png" ))
        self.twTaxa.setHeaderLabel("Matching taxa")
        self.noLoginText = "Not logged in to NBN. Default NBN access will apply."
        self.lblLoginStatus.setText (self.noLoginText)
        self.currentNBNUser = ""
        self.nbnAthenticationCookie = None
        self.guiFile = None
        self.infoFile = os.path.join(os.path.dirname( __file__ ), "infoNBNTool.txt")
        self.readDatasetFile()
        self.readDesignationFile()
        self.readGroupFile()
        self.readAreaCategoriesFile()
        self.datasetSelectionChanged()
        self.checkFilters()
        self.lblSiteDataset.setText("")
        self.bufferEnableDisable()
        
        self.WMSType = self.enum(species=1, dataset=2, designation=3)
            
    def showEvent(self, ev):
        # Load the environment stuff
        self.env = envManager()
        self.leUsername.setText(self.env.getEnvValue("nbn.username"))
        self.lePassword.setText(self.env.getEnvValue("nbn.password"))
        return QWidget.showEvent(self, ev)        
        
    def enum(self, **enums):
        return type('Enum', (), enums)
    
    def infoMessage(self, strMessage):
        self.iface.messageBar().pushMessage("Info", strMessage, level=QgsMessageBar.INFO)
        
    def warningMessage(self, strMessage):
        self.iface.messageBar().pushMessage("Warning", strMessage, level=QgsMessageBar.WARNING)
        
    def errorMessage(self, strMessage):
        self.iface.messageBar().pushMessage("Error", strMessage, level=QgsMessageBar.CRITICAL)
        
    def bugTest(self):
        url = ("url=https://gis.nbn.org.uk/SingleSpecies/NHMSYS0000530739&" +
        "layers=Grid-100m&layers=Grid-1km&layers=Grid-2km&layers=Grid-10km" +
        "&styles=&styles=&styles=&styles=" +
        "&format=image/png&crs=EPSG:27700")
        
        rlayer = QgsRasterLayer(url, 'NBN WMS layer', 'wms')
        QgsMapLayerRegistry.instance().addMapLayer(rlayer)
        
        rlayer.setSubLayerVisibility("Grid-10km", False)
        rlayer.setSubLayerVisibility("Grid-2km", True)
        rlayer.setSubLayerVisibility("Grid-1km", False)
        rlayer.setSubLayerVisibility("Grid-100m", False)
        
    def uncheckAll(self):
              
        for iProvider in range(self.twDatasets.topLevelItemCount()):
            twiProvider = self.twDatasets.topLevelItem(iProvider)
            twiProvider.setCheckState(0, Qt.Unchecked)
            for iDataset in range(twiProvider.childCount()):
                twiDataset = twiProvider.child(iDataset)
                twiDataset.setCheckState(0, Qt.Unchecked)
            
        self.datasetSelectionChanged()
        
    def bufferEnableDisable(self):
        if self.rbGR.isChecked():
            self.sbEasting.setEnabled(False)
            self.sbNorthing.setEnabled(False)
            self.lePointBufferGR.setEnabled(True)
        else:
            self.sbEasting.setEnabled(True)
            self.sbNorthing.setEnabled(True)
            self.lePointBufferGR.setEnabled(False)
           
    def generateBuffer(self):
    
        if self.rbGR.isChecked():
            #Get grid mid point of GR
            gridRef = self.lePointBufferGR.text().strip()
            ret = self.osgr.enFromGR(gridRef)
            if ret[0] == 0:
                self.warningMessage(ret[3])
                return
                
            sName = gridRef
            
            easting = ret[0]
            northing = ret[1]
        else:
            easting = self.sbEasting.value()
            northing = self.sbNorthing.value()
            
            sName = str(easting) + "/" + str(northing)
            
        sName = sName + " " + str(self.sbBuffer.value()) + "m"
        
        geom = self.osgr.circleGeom(easting, northing, self.sbBuffer.value())
        
        # Create layer 
        self.vl = QgsVectorLayer("Polygon?crs=epsg:27700", sName, "memory")
        self.pr = self.vl.dataProvider()
        self.buffers.append(self.vl.id())

        # Symbology
        props = { 'color' : '255,0,0,100', 'color_border' : '0,0,0,200', 'style' : 'solid', 'style_border' : 'solid' }
        s = QgsFillSymbolV2.createSimple(props)
        self.vl.setRendererV2( QgsSingleSymbolRendererV2( s ) )

        # Add to map layer registry
        QgsMapLayerRegistry.instance().addMapLayer(self.vl)    
        
        # Add geometry to layer
        fet = QgsFeature()
        fet.setGeometry(geom)
        self.vl.startEditing()
        self.vl.addFeatures([fet])
        self.vl.commitChanges()
        self.vl.updateExtents()

        # Zoom to buffer extent
        self.iface.actionZoomToLayer().trigger()
        
        self.checkMapSelectionFilter()
        
    def datasetTwClick(self, twItem, iCol):
              
        for iDataset in range(twItem.childCount()):
            twiDataset = twItem.child(iDataset)
            twiDataset.setCheckState(0, twItem.checkState(0))
            
        if twItem.childCount() > 0:
            twItem.setExpanded(twItem.checkState(0) == Qt.Checked)
            
        self.datasetSelectionChanged()
        
    def taxaTwClick(self, twItem, iCol):
        
        #If current item is checked, uncheck all others
        #Only one taxon can be checked.
        
        if twItem.checkState(0) == Qt.Checked:
            for iGroup in range(self.twTaxa.topLevelItemCount()):
                twiGroup = self.twTaxa.topLevelItem(iGroup)
                for iTaxa in range(twiGroup.childCount()):
                    twiTaxa = twiGroup.child(iTaxa)
                    if not twiTaxa == twItem:
                        twiTaxa.setCheckState(0, Qt.Unchecked)
                        
        self.checkFilters()
        
    def designationTwClick(self, twItem, iCol):
        
        #If current item is checked, uncheck all others
        #Only one designation can be checked.
        
        if twItem.checkState(0) == Qt.Checked:
            for iDesignation in range(self.twDesignations.topLevelItemCount()):
                twiDesignation = self.twDesignations.topLevelItem(iDesignation)
                if not twiDesignation == twItem:
                    twiDesignation.setCheckState(0, Qt.Unchecked)
            
        self.checkFilters()
        
    def datasetSelectionChanged(self):
        
        iChecked = 0
        for iProvider in range(self.twDatasets.topLevelItemCount()):
            twiProvider = self.twDatasets.topLevelItem(iProvider)
            for iDataset in range(twiProvider.childCount()):
                twiDataset = twiProvider.child(iDataset)
                if twiDataset.checkState(0) == Qt.Checked:
                    iChecked += 1
                    
        if iChecked == 0:
            self.lblDatasetFilter.setText("No datasets selected.")
        else:
            self.lblDatasetFilter.setText(str(iChecked) + " datasets selected.")
            
        self.checkFilters()
         
    def groupTwClick(self, twItem, iCol):
        
        #If current item is checked, uncheck all others
        #Only one group can be checked.
        
        if twItem.checkState(0) == Qt.Checked:
            for iGroup in range(self.twGroups.topLevelItemCount()):
                twiGroup = self.twGroups.topLevelItem(iGroup)
                if not twiGroup == twItem:
                    twiGroup.setCheckState(0, Qt.Unchecked)
        
        self.checkFilters()        
        
    def siteTwClick(self, twItem, iCol):
        
        #If current item is checked, uncheck all others
        #Only one site can be checked.
        
        if twItem.checkState(0) == Qt.Checked:
            for iSite in range(self.twAreas.topLevelItemCount()):
                twiSite = self.twAreas.topLevelItem(iSite)
                if not twiSite == twItem:
                    twiSite.setCheckState(0, Qt.Unchecked)
        
        self.checkFilters()
         
    def refreshGroups(self):
        
        self.twGroups.clear()
        
        try:
            data = urllib2.urlopen('https://data.nbn.org.uk/api/taxonOutputGroups').read()
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return

        # Write the json data to a file
        datafile = self.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "taxongroups.json"))
        with open(datafile, 'w') as jsonfile:
            jsonfile.write(data)
            
        # Rebuild designation tree
        self.readGroupFile()
        
        self.checkFilters()
        
    def refreshAreaCategories(self):
        
        self.twAreaCategories.clear()
        
        try:
            data = urllib2.urlopen('https://data.nbn.org.uk/api/siteBoundaryCategories').read()
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return

        # Write the json data to a file
        datafile = self.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "siteboundarycats.json"))
        with open(datafile, 'w') as jsonfile:
            jsonfile.write(data)
            
        # Rebuild area category tree
        self.readAreaCategoriesFile()
        
    def refreshBothAreas(self):
        self.refreshAreaCategories()
        self.refreshAreas()
        
    def refreshAreas(self):
        
        self.twAreas.clear()
        
        twis = self.twAreaCategories.selectedItems()
        if len(twis) == 0:
            #self.infoMessage("First select a site boundary dataset.")
            return
            
        twi = twis[0]
        nbnKey = twi.toolTip(0)
        
        try:
            data = urllib2.urlopen('https://data.nbn.org.uk/api/siteBoundaryDatasets/%s/siteBoundaries' % nbnKey).read()
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return

        # Write the json data to a file
        datafile = self.pathPlugin % ("NBNCache%s%s%s" % (os.path.sep, nbnKey, ".json"))
        with open(datafile, 'w') as jsonfile:
            jsonfile.write(data)
            
        # Rebuild area tree
        self.readAreaFile()
    
    def readGroupFile(self):
    
        datafile = self.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "taxongroups.json"))
        if not os.path.isfile(datafile):
            self.infoMessage("NBN group file not found.")
            return
        try:
            with open(datafile) as f:
                jsonData = json.load(f)
        except:
            self.warningMessage("NBN group file failed to load. Use the refresh button to generate a new one.")
            return
          
        """
        groups = {}
       
        for jGroup in jsonData:
                 
            try:
                keyParent = jGroup["parentTaxonGroupKey"]
            except:
                keyParent = "NoParentKey"
                
            key = jGroup["key"]
            name = jGroup["name"]
            
            if keyParent in groups:
                parentDict = groups[keyParent]
            else:
                parentDict = groups[keyParent] = {}
                
            parentDict[name] = key
            
        #Iterate in the desired order
        for keyParent in sorted(groups.keys()):
            parentDict = groups[keyParent]
            for nameKey in sorted(parentDict.keys()):
                key = parentDict[nameKey]

                # Create a tree item for the group
                twiGroup = QTreeWidgetItem(self.twGroups)
                twiGroup.setText(0, nameKey)
                twiGroup.setFlags(Qt.ItemIsEnabled | Qt.ItemIsUserCheckable)
                twiGroup.setCheckState(0, Qt.Unchecked) # 0 is the column number 
                twiGroup.setToolTip(0, key)
                self.twGroups.addTopLevelItem(twiGroup)
        """
        for jGroup in jsonData:
                 
            # Create a tree item for the group
            twiGroup = QTreeWidgetItem(self.twGroups)
            twiGroup.setText(0, jGroup["name"])
            twiGroup.setFlags(Qt.ItemIsEnabled | Qt.ItemIsUserCheckable)
            twiGroup.setCheckState(0, Qt.Unchecked) # 0 is the column number 
            twiGroup.setToolTip(0, jGroup["key"])
            self.twGroups.addTopLevelItem(twiGroup)
                
        self.twGroups.sortItems(0, Qt.AscendingOrder)
    
    def readAreaCategoriesFile(self):
    
        datafile = self.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "siteboundarycats.json"))
        if not os.path.isfile(datafile):
            self.infoMessage("NBN site boundary category file not found. Use the refresh button to generate a new one.")
            return
        try:
            with open(datafile) as f:
                jsonData = json.load(f)
        except:
            self.warningMessage("NBN site boundary category file failed to load. Use the refresh button to generate a new one.")
            return

        for jAC in jsonData:
                 
            # Create a top-level tree item for the dataset category
            twiAC = QTreeWidgetItem(self.twAreaCategories)
            twiAC.setText(0, jAC["name"])
            self.twAreaCategories.addTopLevelItem(twiAC)
            
            for jDataset in jAC["siteBoundaryDatasets"]:
                # Create a tree item for the dataset
                twiDataset = QTreeWidgetItem(twiAC)
                twiDataset.setText(0, jDataset["title"])
                twiDataset.setToolTip(0, str(jDataset["datasetKey"]))
                self.twAreaCategories.addTopLevelItem(twiDataset)
        
    def readAreaFile(self):
    
        self.twAreas.clear()
        QCoreApplication.processEvents()
        
        twis = self.twAreaCategories.selectedItems()
        
        if len(twis) == 0:
            return
        
        if twis[0].childCount() > 0:
            return

        twi = twis[0]
        nbnKey = twi.toolTip(0)
        nbnName = twi.text(0)
        
        
        datafile = self.pathPlugin % ("NBNCache%s%s%s" % (os.path.sep, nbnKey, ".json"))
        if not os.path.isfile(datafile):
            self.refreshAreas()
            #self.infoMessage("File not found for '%s'. Use the site refresh button to generate a new one." % nbnName)
            return
        try:
            with open(datafile) as f:
                jsonData = json.load(f)
        except:
            self.warningMessage("File not found for '%s' failed to load. Use the refresh button to generate a new one." % nbnName)
            return
        
        self.lblSiteDataset.setText("%s:" % nbnName)
        
        for jSite in jsonData:
                 
            # Create a tree item for the group
            twiSite = QTreeWidgetItem(self.twAreas)
            twiSite.setText(0, jSite["name"])
            twiSite.setFlags(Qt.ItemIsEnabled | Qt.ItemIsUserCheckable)
            twiSite.setCheckState(0, Qt.Unchecked) # 0 is the column number 
            twiSite.setToolTip(0, str(jSite["identifier"]))
            self.twAreas.addTopLevelItem(twiSite)
                
        self.twAreas.sortItems(0, Qt.AscendingOrder)
        
    def refreshDesignations(self):
        
        self.twDesignations.clear()
        
        try:
            data = urllib2.urlopen('https://data.nbn.org.uk/api/designations').read()
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return

        # Write the json data to a file
        datafile = self.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "designations.json"))
        with open(datafile, 'w') as jsonfile:
            jsonfile.write(data)
            
        # Rebuild designation tree
        self.readDesignationFile()
  
        self.checkFilters()
        
    def readDesignationFile(self):
    
        datafile = self.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "designations.json"))
        if not os.path.isfile(datafile):
            self.infoMessage("NBN designation file not found.")
            return
            
        try:
            with open(datafile) as f:
                jsonData = json.load(f)
        except:
            self.warningMessage("NBN designation file failed to load. Use the refresh button to generate a new one.")
            return
            
        treeNodes = {} #Dictionary
        
        for jDesignation in jsonData:
                 
            # Create a tree item for the designation
            twiDesignation = QTreeWidgetItem(self.twDesignations)
            twiDesignation.setText(0, jDesignation["code"])
            twiDesignation.setFlags(Qt.ItemIsEnabled | Qt.ItemIsUserCheckable)
            twiDesignation.setCheckState(0, Qt.Unchecked) # 0 is the column number 
            twiDesignation.setToolTip(0, jDesignation["name"])
            self.twDesignations.addTopLevelItem(twiDesignation)
                
        self.twDesignations.sortItems(0, Qt.AscendingOrder)
        
    def refreshDatasets(self):
        
        self.twDatasets.clear()
        
        try:
            data = urllib2.urlopen('https://data.nbn.org.uk/api/datasets').read()
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return
        
        #jsonData = json.loads(data)

        # Write the json data to a file
        datafile = self.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "datasets.json"))
        with open(datafile, 'w') as jsonfile:
            jsonfile.write(data)
            
        # Rebuild dataset tree
        self.readDatasetFile()
        self.datasetSelectionChanged()
            
    def readDatasetFile(self):
    
        datafile = self.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "datasets.json"))
        if not os.path.isfile(datafile):
            self.infoMessage("NBN dataset file not found.")
            return
            
        try:
            with open(datafile) as f:
                jsonData = json.load(f)
        except:
            self.warningMessage("NBN dataset file failed to load. Use the refresh button to generate a new one.")
            return
            
        treeNodes = {} #Dictionary
        
        for jDataset in jsonData:
        
            if not jDataset["organisationName"] in(treeNodes.keys()):
                #Create a new top level tree item for the dataset provider organisation
                twiOrganisation = QTreeWidgetItem(self.twDatasets)
                twiOrganisation.setText(0, jDataset["organisationName"])
                twiOrganisation.setExpanded(False)
                twiOrganisation.setFlags(Qt.ItemIsEnabled | Qt.ItemIsUserCheckable)
                twiOrganisation.setCheckState(0, Qt.Unchecked) # 0 is the column number 
                self.twDatasets.addTopLevelItem(twiOrganisation)
                #Add to dictionary
                treeNodes[jDataset["organisationName"]] = twiOrganisation
            else:
                twiOrganisation = treeNodes[jDataset["organisationName"]]
            
            # Create a tree item for the dataset
            twiDataset = QTreeWidgetItem(twiOrganisation)
            twiDataset.setText(0, jDataset["title"])
            twiDataset.setExpanded(False)
            twiDataset.setFlags(Qt.ItemIsEnabled | Qt.ItemIsUserCheckable)
            twiDataset.setCheckState(0, Qt.Unchecked) # 0 is the column number 
            twiDataset.setToolTip(0, jDataset["key"])
            self.twDatasets.addTopLevelItem(twiOrganisation)
                
        self.twDatasets.sortItems(0, Qt.AscendingOrder)
        
    def helpFile(self):
        
        #self.nbnTaxonObservations()
        #return
        
        if self.guiFile is None:
            self.guiFile = FileDialog(self.iface, self.infoFile)
        
        self.guiFile.setVisible(True)
        
    def nbnTaxonObservations(self):
        
        if self.nbnAthenticationCookie is None:
             return
             
        cj = cookielib.CookieJar()
        cj.set_cookie(self.nbnAthenticationCookie)
        opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
        params = urllib.urlencode({'datasetKey': 'GA000483', 'ptvk': 'NBNSYS0000008679'})
        try:
            #data = opener.open('https://data.nbn.org.uk/api/taxonObservations', params).read()
            data = opener.open('https://data.nbn.org.uk/api/datasets').read()
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return
        
        self.iface.messageBar().pushMessage("Info", "Success", level=QgsMessageBar.INFO)
        
        self.guiFile = FileDialog(self.iface, data)
        self.guiFile.setVisible(True)
        
    def TaxonSearch(self):
    
        if self.leTaxonSearch.text() == "":
            self.iface.messageBar().pushMessage("No search term specified.", level=QgsMessageBar.INFO)
            return
        try:
            #url = 'https://data.nbn.org.uk/api/search/taxa?q=' + self.leTaxonSearch.text()
            url = 'https://data.nbn.org.uk/api/taxa?q=' + self.leTaxonSearch.text()
            url = url.replace(' ','%20')
            data = urllib2.urlopen(url).read()
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return
    
        jsonData = json.loads(data)
        jResponseList = jsonData["results"]
        
        #Tree view
        self.twTaxa.clear()
        treeNodes = {} #Dictionary
        
        for jTaxon in jResponseList:
        
            if not jTaxon["taxonOutputGroupName"] in(treeNodes.keys()):
                #Create a new top level tree item for the taxon group
                twiGroup = QTreeWidgetItem(self.twTaxa)
                twiGroup.setText(0, jTaxon["taxonOutputGroupName"])
                twiGroup.setExpanded(False)
                twiGroup.setFlags(Qt.ItemIsEnabled) #By resetting the flags, we take off default isSelectable
                twiGroup.setIcon(0, QIcon( self.pathPlugin % "images/Group20x16.png" ))
                self.twTaxa.addTopLevelItem(twiGroup)
                #Add to dictionary
                treeNodes[jTaxon["taxonOutputGroupName"]] = twiGroup
            else:
                twiGroup = treeNodes[jTaxon["taxonOutputGroupName"]]
                
            if not jTaxon["ptaxonVersionKey"] in(treeNodes.keys()):
                #Create a child tree item for the preferred TVK group
                twiPTVK = QTreeWidgetItem(twiGroup)
                twiPTVK.setText(0, jTaxon["ptaxonVersionKey"])
                #twiPTVK.setText(0, self.nameFromTVK(jTaxon["ptaxonVersionKey"]))
                #twiPTVK.setIcon(0, QIcon( self.pathPlugin % "images/Taxon20x16.png" ))
                twiPTVK.setFlags(Qt.ItemIsEnabled | Qt.ItemIsUserCheckable)
                twiPTVK.setCheckState(0, Qt.Unchecked) # 0 is the column number 
                twiPTVK.setExpanded(True)
                self.twTaxa.addTopLevelItem(twiPTVK)
                #Add to dictionary
                treeNodes[jTaxon["ptaxonVersionKey"]] = twiPTVK
            else:
                twiPTVK = treeNodes[jTaxon["ptaxonVersionKey"]]
                
            #Create a new child item for the taxon name
            twiName = QTreeWidgetItem(twiPTVK)
            twiName.setText(0, jTaxon["name"])
            twiName.setIcon(0, QIcon( self.pathPlugin % "images/Synonym20x16.png" ))
            twiName.setFlags(Qt.ItemIsEnabled) #By resetting the flags, we take off default isSelectable
            self.twTaxa.addTopLevelItem(twiName)           
 
    def getSelectedTaxonOutputGroup(self):
        
        #Selected taxon output group
        for iGroup in range(self.twGroups.topLevelItemCount()):
            twiGroup = self.twGroups.topLevelItem(iGroup)
            if twiGroup.checkState(0) == Qt.Checked:
                return twiGroup.toolTip(0)
                
        return None
        
    def getSelectedSite(self):
        
        #Selected site
        for iSite in range(self.twAreas.topLevelItemCount()):
            twiSite = self.twAreas.topLevelItem(iSite)
            if twiSite.checkState(0) == Qt.Checked:
                return twiSite.toolTip(0)
                
        return None
        
    def getSelectedDesignation(self):
        
        #Selected designation
        iDesignationCount = 0
        for iDesignation in range(self.twDesignations.topLevelItemCount()):
            twiDesignation = self.twDesignations.topLevelItem(iDesignation)
            if twiDesignation.checkState(0) == Qt.Checked:
                iDesignationCount += 1
                selectedDesignationKey = twiDesignation.text(0)
                strName = twiDesignation.text(0)
                            
                return (strName, selectedDesignationKey)
        return ()
        
    def WMSFetchDesignation(self):
                            
        ret = self.getSelectedDesignation()
     
        #Check item in treeview is selected
        if len(ret) == 0:
            self.iface.messageBar().pushMessage("Info", "First select a designation.", level=QgsMessageBar.INFO)
            return
        else:
            strName = ret[0]
            selectedDesignationKey = ret[1]
            
        #selectedDesignationKey = "NOTABLE" # For testing
        
        #Get the map from NBN
        url = 'https://gis.nbn.org.uk/DesignationSpeciesDensity/'
        
        #Designation
        url = url + selectedDesignationKey
        #self.infoMessage(url)
        
        self.WMSFetch(url, strName, self.WMSType.designation)
        
    def getSelectedDatasets(self):
        
        ret = {}
        # Selected datasets
        iDatasetCount = 0
        for iProvider in range(self.twDatasets.topLevelItemCount()):
            twiProvider = self.twDatasets.topLevelItem(iProvider)
            for iDataset in range(twiProvider.childCount()):
                twiDataset = twiProvider.child(iDataset)
                if twiDataset.checkState(0) == Qt.Checked:
                    iDatasetCount += 1
                    selectedDatasetKey = twiDataset.toolTip(0)
                    strName = twiDataset.text(0)
                    
                    ret[selectedDatasetKey] = strName
        return ret
                    
    def WMSFetchDataset(self):
       
        datasets = self.getSelectedDatasets()
         
        #Check item in treeview is selected
        if len(datasets) == 0:
            self.iface.messageBar().pushMessage("Info", "First select a dataset.", level=QgsMessageBar.INFO)
            return
        elif len(datasets) > 1:
            self.iface.messageBar().pushMessage("Info", "More than one dataset selected. You can only use one for the dataset species density map.", level=QgsMessageBar.INFO)
            return
            
        selectedDatasetKey = datasets.keys()[0]
        strName = datasets[selectedDatasetKey]
            
        #selectedDatasetKey = "GA001349" # For testing
        
        #Get the map from NBN
        url = 'https://gis.nbn.org.uk/DatasetSpeciesDensity/'
        
        #Dataset
        url = url + selectedDatasetKey
        
        self.WMSFetch(url, strName, self.WMSType.dataset)
        
    def getSelectedTVK(self):
       
        iCount = 0
        for iGroup in range(self.twTaxa.topLevelItemCount()):
            twiGroup = self.twTaxa.topLevelItem(iGroup)
            for iTaxa in range(twiGroup.childCount()):
                twiTaxa = twiGroup.child(iTaxa)
                if twiTaxa.checkState(0) == Qt.Checked:
                    iCount += 1
                    selectedTVK = twiTaxa.text(0)
                    
        #Check item in treeview is selected
        if iCount == 0:
            return None
        else:
            return selectedTVK
        
    def WMSFetchSpecies(self):
        
        selectedTVK = self.getSelectedTVK()
        if selectedTVK is None:
            self.iface.messageBar().pushMessage("Info", "First check a taxon code (TVK).", level=QgsMessageBar.INFO)
            return
           
        #Get the map from NBN
        url = 'https://gis.nbn.org.uk/SingleSpecies/'
        
        #Taxon
        url = url + selectedTVK
        
        #Name
        strName = self.nameFromTVK(selectedTVK)
        
        #Get the OS map if requested and not already displayed
        if self.cbOS.isChecked():
            if len(QgsMapLayerRegistry.instance().mapLayersByName(self.nbnOSLayerName)) == 0:
                self.osBackdrop(selectedTVK)
        
        #Get the species map
        self.WMSFetch(url, strName, self.WMSType.species)

    def WMSFetch(self, url, strName, wmsType):
        
        bURLextended = False
        
        #Set user login stuff
        if not self.leUsername.text() == "" and not self.lePassword.text() == "":
            url = url + "?username=" + self.leUsername.text()
            hashed_password = hashlib.md5(self.lePassword.text()).hexdigest()
            url = url + "&userkey=" + hashed_password
            bURLextended = True
            
        #Start year filter
        if self.cbStartYear.isChecked():
            if not bURLextended:
                url = url + "?"
            else:
                url = url + "&"
            url = url + "startyear=" + str(self.sbStartYear.value())
            bURLextended = True
            
        #End year filter
        if self.cbEndYear.isChecked():
            if not bURLextended:
                url = url + "?"
            else:
                url = url + "&"
            url = url + "endyear=" + str(self.sbEndYear.value())
            bURLextended = True
            
        #Presence/absence
        if self.rbAbsence.isChecked():
            if not bURLextended:
                url = url + "?"
            else:
                url = url + "&"
            url = url + "abundance=absence"
            bURLextended = True
        
        #Datasets
        if wmsType == self.WMSType.species or wmsType == self.WMSType.designation:
            strDatasets = ""
            for iProvider in range(self.twDatasets.topLevelItemCount()):
                twiProvider = self.twDatasets.topLevelItem(iProvider)
                for iDataset in range(twiProvider.childCount()):
                    twiDataset = twiProvider.child(iDataset)
                    if twiDataset.checkState(0) == Qt.Checked:
                        if strDatasets == "":
                            strDatasets = "datasets=" + twiDataset.toolTip(0)
                        else:
                            strDatasets = strDatasets + "," + twiDataset.toolTip(0)
            
            if strDatasets <> "":
                if not bURLextended:
                    url = url + "?"
                else:
                    url = url + "&"
                url = url + strDatasets
                bURLextended = True
            
        #URL encode      
        url = urllib.quote_plus(url) # encode the url
        
        #Set layer stuff
        strStyles="&styles="
        if self.cbGridSize.currentIndex() == 4:
            strLayers = "&layers=Grid-100m"
            strName = strName + " NBN 100 m"
            self.addWMSRaster(url, strLayers, strStyles, strName, wmsType)
        elif self.cbGridSize.currentIndex() == 3:
            strLayers = "&layers=Grid-1km"
            strName = strName + " NBN monad"
            self.addWMSRaster(url, strLayers, strStyles, strName, wmsType)
        elif self.cbGridSize.currentIndex() == 2:
            strLayers = "&layers=Grid-2km"
            strName = strName + " NBN tetrad"
            self.addWMSRaster(url, strLayers, strStyles, strName, wmsType)
        elif self.cbGridSize.currentIndex() == 1:
            strLayers = "&layers=Grid-10km"
            strName = strName + " NBN hectad"
            self.addWMSRaster(url, strLayers, strStyles, strName, wmsType)
        #elif self.cbGridSize.currentIndex() == 1:
        #    strLayers = "&layers=Grid-10km&layers=Grid-2km&layers=Grid-1km&layers=Grid-100m"
        #    strStyles="&styles=&styles=&styles=&styles="
        #    strName = strName + " NBN auto"
        #    self.addWMSRaster(url, strLayers, strStyles, strName, wmsType)
        else:
            strNamePrefix = strName
            strLayers = "&layers=Grid-100m"
            strName = strNamePrefix + " NBN 100 m (auto)"
            self.addWMSRaster(url, strLayers, strStyles, strName, wmsType, 0, 15000)
            strLayers = "&layers=Grid-1km"
            strName = strNamePrefix + " NBN monad (auto)"
            self.addWMSRaster(url, strLayers, strStyles, strName, wmsType, 15001, 100000)
            strLayers = "&layers=Grid-2km"
            strName = strNamePrefix + " NBN tetrad (auto)"
            self.addWMSRaster(url, strLayers, strStyles, strName, wmsType, 100001, 250000)
            strLayers = "&layers=Grid-10km"
            strName = strNamePrefix + " NBN hectad (auto)"
            self.addWMSRaster(url, strLayers, strStyles, strName, wmsType, 250000, 100000000)
                 
        if strName.endswith("auto") or strName.endswith("(auto)"):
            #self.canvas.extentsChanged.emit() #Doesn't seem to invoke the web service, perhaps because the extents haven't actually changed
            rectExtent = self.canvas.extent()
            self.canvas.setExtent(QgsRectangle())
            self.canvas.refresh()
            self.canvas.setExtent(rectExtent)
            self.canvas.refresh()
            
    def osBackdrop(self, tvk="NBNSYS0000530739"):
    
        url = urllib.quote_plus('https://gis.nbn.org.uk/SingleSpecies/%s' % tvk) 
        strStyles="&styles="
        strLayers = "&layers=OS-Scale-Dependent"
        self.addWMSRaster(url, strLayers, strStyles, self.nbnOSLayerName, self.WMSType.species)
            
    def addWMSRaster(self, url, strLayers, strStyles, strName, wmsType, minExtent=0, maxExtent=0):
    
        url = 'url=' + url + strLayers + strStyles + "&format=image/png&crs=EPSG:27700" #falls over without the styles argument
        url = url.replace(' ','%20')      
        rlayer = QgsRasterLayer(url, 'layer', 'wms')
        
        if not rlayer.isValid():
            self.iface.messageBar().pushMessage("Error", "Layer failed to load. URL: " + url, level=QgsMessageBar.CRITICAL)
            return None

        rlayer.setLayerName(strName)
        opacity = (100-self.hsTransparency.value()) * 0.01
        rlayer.renderer().setOpacity(opacity)
        
        """
        #Doesn't work at the anticipated zoom levels
        #So we set visibility manually using mapExtentsChanged event
        if not (minExtent == 0 and  maxExtent == 0):
            rlayer.setMinimumScale(minExtent)
            rlayer.setMaximumScale(maxExtent)
            rlayer.toggleScaleBasedVisibility(True)
        """
        
        if strName != self.nbnOSLayerName:
            self.layers.append(rlayer.id())
        QgsMapLayerRegistry.instance().addMapLayer(rlayer)
        if not wmsType == self.WMSType.species:
            self.iface.legendInterface().setLayerExpanded(rlayer, False)
        self.canvas.refresh()
        return rlayer
            
    def checkTransform(self):
        
        try:
            # Not sure why, but this sometimes crashes after another failure in module
            if self.canvasCrs != self.canvas.mapRenderer().destinationCrs():
                self.canvasCrs = self.canvas.mapRenderer().destinationCrs()
                self.transformCrs = QgsCoordinateTransform(self.canvasCrs, self.osgbCrs)
        except:
            pass
        
    def mapExtentsChanged(self):
   
        rectExtent = self.canvas.extent()
        self.checkTransform()
        if self.canvasCrs != self.osgbCrs:
            mapWidth = self.transformCrs.transformBoundingBox(rectExtent).width()
        else:
            mapWidth = rectExtent.width()
        
        #self.iface.messageBar().pushMessage("Info", "Map width: " + str(int(mapWidth)), level=QgsMessageBar.INFO)
        
        for layerID in self.layers:
            rlayer = None
            try:
                rlayer = QgsMapLayerRegistry.instance().mapLayer(layerID)
            except:
                pass
                
            if not rlayer is None:
           
                if rlayer.name().endswith("auto") or rlayer.name().endswith("(auto)"):
                
                    #for strSub in rlayer.subLayers():
                    #    self.iface.messageBar().pushMessage("Info", strSub, level=QgsMessageBar.INFO)
                        
                    if mapWidth < 15000:
                        #self.iface.messageBar().pushMessage("Info", "Grid-100m", level=QgsMessageBar.INFO)
                        if rlayer.name().endswith("auto"):
                            rlayer.setSubLayerVisibility("Grid-10km", False)
                            rlayer.setSubLayerVisibility("Grid-2km", False)
                            rlayer.setSubLayerVisibility("Grid-1km", False)
                            rlayer.setSubLayerVisibility("Grid-100m", True)
                        elif " 100 m " in rlayer.name():
                            self.iface.legendInterface().setLayerVisible(rlayer, True)
                        else:
                            self.iface.legendInterface().setLayerVisible(rlayer, False)
                            
                    elif mapWidth < 100000:
                        #self.iface.messageBar().pushMessage("Info", "Grid-1km", level=QgsMessageBar.INFO)
                        if rlayer.name().endswith("auto"):
                            rlayer.setSubLayerVisibility("Grid-10km", False)
                            rlayer.setSubLayerVisibility("Grid-2km", False)
                            rlayer.setSubLayerVisibility("Grid-1km", True)
                            rlayer.setSubLayerVisibility("Grid-100m", False)
                        elif " monad " in rlayer.name():
                            self.iface.legendInterface().setLayerVisible(rlayer, True)
                        else:
                            self.iface.legendInterface().setLayerVisible(rlayer, False)
                            
                    elif mapWidth < 250000:
                        #self.iface.messageBar().pushMessage("Info", "Grid-2km", level=QgsMessageBar.INFO)
                        if rlayer.name().endswith("auto"):
                            rlayer.setSubLayerVisibility("Grid-10km", False)
                            rlayer.setSubLayerVisibility("Grid-2km", True)
                            rlayer.setSubLayerVisibility("Grid-1km", False)
                            rlayer.setSubLayerVisibility("Grid-100m", False)
                        elif " tetrad " in rlayer.name():
                            self.iface.legendInterface().setLayerVisible(rlayer, True)
                        else:
                            self.iface.legendInterface().setLayerVisible(rlayer, False)
                            
                    else:
                        #self.iface.messageBar().pushMessage("Info", "Grid-10km", level=QgsMessageBar.INFO)
                        if rlayer.name().endswith("auto"):
                            rlayer.setSubLayerVisibility("Grid-10km", True)
                            rlayer.setSubLayerVisibility("Grid-2km", False)
                            rlayer.setSubLayerVisibility("Grid-1km", False)
                            rlayer.setSubLayerVisibility("Grid-100m", False)
                        elif " hectad " in rlayer.name():
                            self.iface.legendInterface().setLayerVisible(rlayer, True)
                        else:
                            self.iface.legendInterface().setLayerVisible(rlayer, False)
            
            
    def nameFromTVK(self, tvk):
       
        #Get the preferred taxon name for the TVK
        try:
            url = 'https://data.nbn.org.uk/api/taxa/' + tvk
            data = urllib2.urlopen(url).read()
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return ('')
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return ('')
    
        jsonData = json.loads(data)
        return (jsonData["name"])
        
    def removeMap(self):
        if len(self.layers) > 0:
            layerID = self.layers[-1]
            try:
                QgsMapLayerRegistry.instance().removeMapLayer(layerID)
            except:
                pass
            self.layers = self.layers[:-1]
            
    def removeBuffer(self):
        if len(self.buffers) > 0:
            layerID = self.buffers[-1]
            try:
                QgsMapLayerRegistry.instance().removeMapLayer(layerID)
            except:
                pass
            self.buffers = self.buffers[:-1]
            
    def removeMaps(self):
        for layerID in self.layers:
            try:
                QgsMapLayerRegistry.instance().removeMapLayer(layerID)
            except:
                pass
        self.layers = [] 
        
    def loginNBN(self):
        
        if not self.nbnAthenticationCookie is None:
            self.infoMessage("You are already logged in to the NBN as '" + self.currentNBNUser + "'")
            return
  
        username = self.leUsername.text()
        password = self.lePassword.text()
        cj = cookielib.CookieJar()
        opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
        login_data = urllib.urlencode({'username' : username, 'password' : password})
        try:
            opener.open('https://data.nbn.org.uk/api/user/login', login_data)
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "NBN Login failed. HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            strErr = ""
            try:
                strErr = e.reason.args[1]
            except:
                strErr = "Unspecified network error."
                
            self.iface.messageBar().pushMessage("Error", "NBN Login failed. Network error: %s" % strErr, level=QgsMessageBar.CRITICAL)
            return
    
        for cookie in cj:
            if cookie.name == 'nbn.token_key':
                self.nbnAthenticationCookie = cookie
                self.currentNBNUser = self.leUsername.text()
                self.lblLoginStatus.setText ("You are logged in as '" + self.currentNBNUser + "'")
        return
        
        
    def logoutNBN(self):
        
        if self.nbnAthenticationCookie is None:
            self.infoMessage("Can't logout because you are not logged in to the NBN")
            return
            
        cj = cookielib.CookieJar()
        cj.set_cookie(self.nbnAthenticationCookie)
        opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
        try:
            opener.open('https://data.nbn.org.uk/api/user/logout')
        except urllib2.HTTPError, e:
            self.iface.messageBar().pushMessage("Error", "HTTP error: %d" % e.code, level=QgsMessageBar.CRITICAL)
            return
        except urllib2.URLError, e:
            self.iface.messageBar().pushMessage("Error", "Network error: %s" % e.reason.args[1], level=QgsMessageBar.CRITICAL)
            return
            
        self.lblLoginStatus.setText (self.noLoginText)
        self.currentNBNUser = ""
        self.nbnAthenticationCookie = None
        
    def downloadNBNObservations(self):
        """
        The filters applicable to this resource are as follows;

          *  Year Filters
               *  startYear (...&startYear=2000&...)
               *  endYear (...&endYear=2012&...)
          *  Taxonomic Filters
               *  ptvk (....&ptvk=[NHMSYS0020706144, NBNSYS0000176784,....]&....)
               *  designation (...&designation=BERN-A1&...)
               *  taxonOutputGroup (...&taxonOutputGroup=NHMSYS0000079976&...)
          *  Dataset Filters
               *  datasetKey (...&datasetKey=[GA000466,....]&...)
          *  Spatial Filters
               *  featureID AND spatialRelationship (within / overlaps) (...&featureID=GA0008850&spatialRelationship=within&...)
               *  gridRef (OSGB, OSI, 10km down to 100m sqaures) (...&gridRef=TA2172&...)
               *  polygon (WKT WGS-84 polygon string) (...&polygon=...&...)
          *  Other Filters
               * absence (...&absence=true&...)
               * sensitive (...&sensitive=true&...)
        """
        
        #Initialise filter parameters
        startYear = None
        endYear = None
        ptvk = None
        designation = None
        taxonOutputGroup = None
        datasetKey = None
        gridRef = None
        polygon = None
        absence = None

        # Update filter display
        self.checkFilters()
        
        # Check that user is logged in
        if self.nbnAthenticationCookie is None:
            self.infoMessage("You must be logged in to the NBN to use this service.")
            return   
    
        # Build params dictionary
        params = {}
        
        # startYear
        if self.cbStartYear.checkState() == Qt.Checked:
            startYear = self.sbStartYear.value()
            params["startYear"] = startYear
            
        # endYear
        if self.cbEndYear.checkState() == Qt.Checked:
            endYear = self.sbEndYear.value()
            params["endYear"] = endYear
            
        # Year validity check
        if not startYear is None and not endYear is None:
            if startYear > endYear:
                self.infoMessage("End year, if specified, must come after start year (or be equal to it), if specified.")
                return
        
        # ptvk
        ptvk = self.getSelectedTVK() # Returns None if none selected
        if not ptvk is None:
            params["ptvk"] = ptvk
            
        # designation
        ret = self.getSelectedDesignation()
        if len(ret) > 0:
            designation = ret[1]
            params["designation"] = designation
            
        # taxonOutputGroup
        taxonOutputGroup = self.getSelectedTaxonOutputGroup()
        if not taxonOutputGroup is None:
            params["taxonOutputGroup"] = taxonOutputGroup
            
        # datasetKey
        selectedDatasets = self.getSelectedDatasets()
        
        # It should be possible to select more than one dataset (if another
        # filter is specified, but this does not appear to currently work
        # 17th Dec 2014
        if len(selectedDatasets) > 1:
            self.infoMessage("Currently, only one dataset can  be specified for each download query.")
            return
            
        if len(selectedDatasets) > 0:
            datasetKey = ""
            for key in selectedDatasets.keys():
                if datasetKey <> "":
                    datasetKey = datasetKey + ","
                datasetKey = datasetKey + key
            params["datasetKey"] = datasetKey
            
            #self.infoMessage("datasetKey=" + params["datasetKey"])
            
        # featureID
        featureID = self.getSelectedSite()
        if not featureID is None:
            params["featureID"] = featureID
            params["spatialRelationship"] = "overlaps"
            
        # gridRef
        
        #params["spatialRelationship"] = "within"
        
        if self.leGridRef.text().strip() <> "":
            gridRef = self.leGridRef.text().strip()
            
            ret = self.osgr.checkGR(gridRef)
            
            if ret[0] == 0:
                self.warningMessage(ret[1])
                return
                
            if ret[0] < 100 or ret[0] > 10000 or ret[0] == 5000:
                self.warningMessage("Grid reference, if specified, must be 6 fig, monad, tetrad or hectad.")
                return
                
            params["gridRef"] = gridRef
            
        # polygon
        polygon = self.getSelectedFeatureWKT()
        if not polygon is None:
            #self.infoMessage("WKT: " + polygon)
            params["polygon"] = polygon
            
        # absence
        if self.rbAbsence.isChecked():
            absence = "true"
            params["absence"] = absence
                     
        # Check that the a valid combination of filters has been specified
        """
        You must supply at least one of the following filters;
          *  A Taxonomic Filter
          *  Spatial Filter
          *  Dataset filter
        """
        bValidFilters = False
        for param in params.keys():
            if param == "ptvk":
                bValidFilters = True
                break
            if param == "datasetKey":
                bValidFilters = True
                break
            if param == "polygon":
                bValidFilters = True
                break
            if param == "featureID":
                bValidFilters = True
                break
            if param == "gridRef":
                bValidFilters = True
                break
                
        if not bValidFilters:
            self.infoMessage("You must specify at least one of the following filters: taxon, dataset, polygon, Site or grid reference.")
            return
            
        #Get a location for the output file.
        self.env.loadEnvironment()
        
        if os.path.exists(self.env.getEnvValue("nbn.downloadfolder")):
            strInitPath = self.env.getEnvValue("nbn.downloadfolder")
        else:
            strInitPath = ""
            
        dlg = QFileDialog
        fileName = dlg.getSaveFileName(self, "Specify output CSV for downloaded records", strInitPath, "CSV Files (*.csv)")
        if not fileName:
            return
            
        # Set current tab to last (download) tab
        self.tabWidget.setCurrentIndex(self.tabWidget.count()-1)
        
        # Start asynchronous thread
        download = AsyncNBNDownload(self, fileName, params)
        download.error.connect(self.downloadError)
        download.start()
        
    def checkFilters(self):

        # Start year
        self.cbIndStartYear.setChecked(self.cbStartYear.isChecked())
        # End year
        self.cbIndEndYear.setChecked(self.cbEndYear.isChecked())
        # Taxon
        self.cbIndTaxon.setChecked(self.getSelectedTVK() is not None)
        # Designation
        self.cbIndDesignation.setChecked(len(self.getSelectedDesignation()) > 0)
        # Taxon group
        self.cbIndGroup.setChecked(self.getSelectedTaxonOutputGroup() is not None)
        # Dataset
        self.cbIndDataset.setChecked(len(self.getSelectedDatasets()) > 0)
            
        # Site
        self.cbIndSite.setChecked(self.getSelectedSite() is not None)
       
        # gridRef
        self.cbIndGridRef.setChecked(self.leGridRef.text().strip() <> "")
          
        # polygon
        self.cbIndPolygon.setChecked(self.getSelectedFeatureWKT() is not None)
        
        # Absence
        self.cbIndAbsence.setChecked(self.rbAbsence.isChecked())

    def downloadError(self, strError):

        self.errorMessage(strError)
        
    def displayCSV(self):
    
        #Check that single file is selected in list
        if len(self.lwDownloaded.selectedItems()) != 1:
            self.infoMessage("First select a single CSV file from the list")
            return
            
        lwiSelected = self.lwDownloaded.selectedItems()[0]
        csvFile = lwiSelected.toolTip()
        
        #Emit signal that will cause biorec tool to display file
        self.displayNBNCSVFile.emit(csvFile)
                        
    def getSelectedFeatureWKT(self):
        
        ret = None
        filterGeom = None
        
        layer = self.iface.activeLayer()

        try:
            if layer is not None:
                if layer.type() == QgsMapLayer.VectorLayer:
                    selectedFeatures = layer.selectedFeatures()
                    if len(selectedFeatures) == 1:
                        feature = selectedFeatures[0]
                        if feature.geometry().wkbType() == QGis.WKBPolygon:
                            filterGeom = feature.geometry()
        except:
            filterGeom = None
        
        if filterGeom is not None:
            # If the CRS of the layer is not WGS84, then
            # convert geometry, otherwise use as is.
            if layer.crs() != QgsCoordinateReferenceSystem("EPSG:4326"):
                tcrs = QgsCoordinateTransform(layer.crs(), QgsCoordinateReferenceSystem("EPSG:4326"))
                filterGeom.transform(tcrs)

            ret = filterGeom.exportToWkt()
            
        return ret  
        
    def checkMapSelectionFilter(self):
        # Whenever the map selection changes, update the  
        # polygon filter indicator accordingly.
        
        if self.getSelectedFeatureWKT() is None:
            self.cbIndPolygon.setChecked(False)
        else:
            self.cbIndPolygon.setChecked(True)
        
class AsyncNBNDownload(QObject, threading.Thread):
    
    error = pyqtSignal(basestring)

    def __init__(self, nbnDialog, csv, params):
        threading.Thread.__init__(self)
        QObject.__init__(self)
        self.csv = csv
        self.nbnDialog = nbnDialog
        self.params = params
        
    def run(self):
 
        # Add file to listbox
        splitName = os.path.split(self.csv)
        self.nbnDialog.lwDownloaded.addItem(splitName[1])
        lwi = self.nbnDialog.lwDownloaded.item(self.nbnDialog.lwDownloaded.count()-1)
        lwi.setToolTip(self.csv)
        
        # NBN Authentication
        cj = cookielib.CookieJar()
        cj.set_cookie(self.nbnDialog.nbnAthenticationCookie)
        opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
        
        lwi.setIcon(QIcon( self.nbnDialog.pathPlugin % "images/download.png" ))
        
        # Download the data from NBN
        try:
            if len(self.params) == 1 and (self.params.keys()[0] == "ptvk" or self.params.keys()[0] == "datasetKey"):      
                # If only a tvk or dataset key passed, we use specific endpoints for them
                endpoint = 'https://data.nbn.org.uk/api/taxonObservations/' + self.params.values()[0]
                data = opener.open(endpoint).read()
            else:
                # Otherwise we use the general combined filter endpoint
                params = urllib.urlencode(self.params)
                data = opener.open('https://data.nbn.org.uk/api/taxonObservations', params).read()
        except urllib2.HTTPError, e:
            self.error.emit("HTTP error: %s" % str(e))
            lwi.setIcon(QIcon( self.nbnDialog.pathPlugin % "images/cross.png" ))
            return
        except urllib2.URLError, e:
            self.error.emit("Network error: %s" % str(e))
            lwi.setIcon(QIcon( self.nbnDialog.pathPlugin % "images/cross.png" ))
            return
        except Exception, e:
            self.error.emit("Error: %s" % str(e))
            lwi.setIcon(QIcon( self.nbnDialog.pathPlugin % "images/cross.png" ))
            return
            
        lwi.setIcon(QIcon( self.nbnDialog.pathPlugin % "images/eggtimer.jpg" ))
        
        
        
        # Write the json data to csv
        try:
            # If csv is to be enriched with dataset names, create datasets dictionary from file
            datasets={}
            if self.nbnDialog.cbDatasetNames.isChecked():
                datafile = self.nbnDialog.pathPlugin % ("NBNCache%s%s" % (os.path.sep, "datasets.json"))
                if os.path.isfile(datafile):
                    with open(datafile) as f:
                        jsonDatasets = json.load(f)       
                    for dataset in jsonDatasets:
                        datasets[dataset["key"]] = dataset["title"]

            jsonData = json.loads(data)

            with open(self.csv, 'wb') as csvfile:
                #csvw = csv.writer(csvfile, delimiter=' ', quotechar='|', quoting=csv.QUOTE_MINIMAL)
                csvw = csv.writer(csvfile, dialect='excel')
                headerRow = []
                for jRecord in jsonData:
                    # Have to go through entire file because different records
                    # have different attributes. So to get all names, parse
                    # all records.
                    headerRow = list(set(headerRow + jRecord.keys()))
                    
                if len(datasets) > 0:
                    headerRow.append("datasetName")
                    
                csvw.writerow(headerRow)
                
                for jRecord in jsonData:
                    attrRow = []
                    for header in headerRow:
                        if header in jRecord.keys():
                            attrRow.append(jRecord[header])
                        elif header == "datasetName":
                            try:
                                #If the dataset is missing, the line below will fail
                                attrRow.append(datasets[jRecord["datasetKey"]])
                            except Exception, e:
                                attrRow.append("Dataset not found. Try refreshing Tom.bio NBN dataset filter.")
                        else:
                            attrRow.append("")
                        
                    csvw.writerow([unicode(s).encode("utf-8") for s in attrRow])
                        
            lwi.setIcon(QIcon( self.nbnDialog.pathPlugin % "images/tick.jpg" ))
        except Exception, e:
            self.error.emit("Failed to write output file '" + self.csv + "'. Error: %s" % str(e))
            lwi.setIcon(QIcon( self.nbnDialog.pathPlugin % "images/cross.png" ))
            return
            
        
        
        
        
         
