#!/usr/bin/env python
# coding=utf-8

import urlparse
import urllib
from lxml import objectify
from lxml import etree
import os,sys
import tempfile
import logging
import ConfigParser
import md5
import mapscript
from string import Template
from osgeo import osr
from osgeo import ogr
import OWSExceptions
from owslib import crs as CRS
import shutil
from xml.etree import ElementTree

class OWS:

    capabilities = None
    url = None
    requestUrl = None
    mapobj = None
    qstring = None
    owsns11 = "http://www.opengis.net/ows/1.1"
    owsns = "http://www.opengis.net/ows"
    cachedir = None
    mapfileName = "mapfile.map"
    config = None
    parsedUrl = None
    service = None
    mapfilename = None

    def __init__(self,url=None,qstring=None,configFile=None):
        self.requestUrl = url
        configFiles = [ os.path.join(os.path.dirname(__file__),"config.cfg") ]

        if sys.platform == "win32":
            pass # TODO Default conf. file on windows platform
        elif sys.platform == "linux2":
            configFiles.append("/etc/owsviewer.cfg")

        if configFile:
            configFiles.append(configFile)

        self.config = ConfigParser.ConfigParser()
        self.config.read(configFiles)

        logging.debug("Creating cachedir for %s in %s" % (self.url,self.config.get("Proxy4OWS","cachedir")))
        logging.debug("%s initialized"%self.service)

        if url:
            self.url = url
            logging.debug("OWS.py::__init__()::url: '%s'" % url)
            self.__getCapabilities()
        if qstring:
            self.qstring = qstring


    def __getCapabilities(self):
        self.__getCacheDir()
        logging.debug("OWS.py::__getCapabilities::self.url: '%s'" % self.url)
        self.parsedUrl = urlparse.urlparse(self.url)

        if self.service == "WFS":
            from owslib.wfs import WebFeatureService
            try:
                self.capabilities = WebFeatureService(url=self.url,version="1.1.0")
            except:
                self.capabilities = WebFeatureService(url=self.url,version="1.0.0")

            logging.debug("OWS Capabilities: %s",self.capabilities)
        elif self.service == "WCS":
            from owslib.wcs import WebCoverageService
            self.capabilities = WebCoverageService(url=self.url,version="1.0.0")

        # cache capabilities document
        open(os.path.join(self.cachedir,"capabilities.xml"),"w").write(ElementTree.tostring(self.capabilities._capabilities))

    def getParams(self):
        params =  urlparse.parse_qs(self.qstring)

        if not "VERSION" in params.keys():
            params["VERSION"] = params.pop("version")
        if not "LAYERS" in params.keys():
            params["LAYERS"] = params.pop("layers")
        if not "FORMAT" in params.keys():
            params["FORMAT"] = params.pop("format")
        if not "STYLES" in params.keys():
            params["STYLES"] = params.pop("styles")
        if not "TRANSPARENT" in params.keys():
            params["TRANSPARENT"] = params.pop("transparent")
        return params

    def getOnlineResource(self,onlineresource,mapfilename=None):
        o = urlparse.urlparse(onlineresource)
        params = urlparse.parse_qs(o.query,keep_blank_values=True)
        params["owsUrl"] = self.url
        params["owsService"] = self.service
        params["map"] = self.getMapfileLocation(mapfilename)

        location = urlparse.urlunparse((o[0],o[1],o[2],o[3],urllib.urlencode(params,True),o[5]))
        logging.debug("Setting OnlineResource to %s"% location)
        return location

    def getMapfileLocation(self,mapfilename=None):

        # save the map if possible
        if mapfilename:
            mapfilename.replace("..","") # remove potential path change

            # mapfile must end with .map and cachedir must be at the
            # beginning of the mapfile name
            if mapfilename.endswith(".map") and \
               mapfilename.find(self.cachedir) == 0:
                    return mapfilename
                    
            else:
                # do not save anything
                return
        # save to new location otherwice
        else:
            return os.path.join(self.cachedir,self.mapfileName)

    def __getCacheDir(self):
        
        dirname = os.path.join(self.config.get("Proxy4OWS","cachedir"),
                                "%s-%s" % (self.service, md5.new(self.url).hexdigest()))

        # get existing cache dir
        if not os.path.isdir(dirname):
            os.mkdir(dirname)
            logging.debug("Cachedir %s created" % dirname)
            os.chmod(dirname,  0777)
            open(os.path.join(self.cachedir,"url.txt"),"w").write(self.url)
        else:
            logging.debug("Cachedir %s found" % dirname)

        self.cachedir = dirname

        return self.cachedir

    def dispatch(self):
        """Dispatch given request
        """
        request = mapscript.OWSRequest()
        request.loadParams()
        mapobj = None

        self.request=request.getValueByName("REQUEST")

        # if no 'map' parameter in URL, create new mapfile
        if not request.getValueByName("map"):
            logging.debug("Creating new mapfile")
            mapobj = self.makeMap()
        else:
            # there is 'map' parameter in URL and the file exists, load it
            logging.debug("Using existing mapfile %s" % request.getValueByName("map"))
            if os.path.isfile(request.getValueByName("map")):
                mapobj = mapscript.mapObj(request.getValueByName("map"))
            # there is 'map' parameter in URL BUT the file does not exist:
            # create
            else:
                mapobj = self.makeMap(request.getValueByName("map"))

        # WFS Filter encoding, if available
        if request.getValueByName("fes"):
            self.setFilter(mapobj,request)

        # mapobj.getLayerByName(request.getValueByName("layers")).metadata.get("wfs_filter")
        # here is still fine, but it fails on dispatch:
        res = mapobj.OWSDispatch(request)
        if mapscript.MS_DONE == res:
            raise OWSExceptions.NoValidRequest("No valid OWS Request")
        elif mapscript.MS_FAILURE == res:
            pass
            #raise OWSExceptions.RequestFailed("Request failed")

    def getMapObj(self,mapfilename=None):


        if self.url is not None and self.capabilities is None:
            self.__getCapabilities()

        # nothing has changed in the capabilities document since last
        # request ?
        if os.path.exists(os.path.join(self.cachedir,"capabilities.xml")):
            oldCapsFile = open(os.path.join(self.cachedir,"capabilities.xml"))
            oldCaps = oldCapsFile.read()
            oldCapsFile.close()
            # the capabilities document is up-to-date, load existing
            # mapfile
            newXml = ElementTree.tostring(self.capabilities._capabilities)
            if md5.new(oldCaps).hexdigest() == md5.new(newXml).hexdigest():
                newCapsFile = open(os.path.join(self.cachedir,"capabilities.xml"),"w")
                newCapsFile.write(newXml)
                logging.debug("Capabilities unchanged, using existing mapfile %s" % self.getMapfileLocation())
                return mapscript.mapObj(self.getMapfileLocation())

        # finally

        # clear existing cached files
        logging.debug("Cached capabilities document is outdated, creating new one")
        shutil.rmtree(self.cachedir)
        # reate new one
        self.__getCacheDir()
        return self._createNewMapObj(mapfilename)


    def _createNewMapObj(self,mapfilename=None):

        mapobj = mapscript.mapObj()

        mapobj.setMetaData("wms_onlineresource",self.getOnlineResource(self.config.get("MapServer","onlineresource"),mapfilename))

        logging.debug("Setting SRS to %s"%self.config.get("MapServer","srs"))
        mapobj.setMetaData("wms_srs",self.config.get("MapServer","srs"))

        mapobj.setProjection("init=epsg:4326")
        mapobj.setSize(500,500)
        mapobj.setExtent(-180,-90,90,180)
        mapobj.shapepath = self.cachedir
        mapobj.setMetaData("wms_encoding","utf-8")

        errfile = self.config.get("MapServer","errorfile")
        logging.debug("Setting ERRORFILE to %s"%errfile)
        if not os.path.exists(errfile) and errfile != "stderr":
            tmp = open(errfile,"w")
            tmp.close()

        # file
        if os.access(errfile, os.W_OK):
            mapobj.setConfigOption("MS_ERRORFILE",errfile)
        # stderr
        elif errfile == "stderr":
            mapobj.setConfigOption("MS_ERRORFILE",errfile)
        # no error file set
        else:
            logging.warning("Cannot set ERRORFILE to %s: %s " % (errfile,"Write access denided"))

        logging.debug("Setting IMAGEPATH to %s"%self.config.get("MapServer","imagepath"))
        mapobj.web.imagepath=self.config.get("MapServer","imagepath")

        mapobj.setMetaData("ows_enable_request","*")

        return mapobj

    def saveMapfile(self,mapobj,mapfilename):

        self.mapfilename = self.getMapfileLocation(mapfilename)
        if self.mapfilename:

            # save mapfile ONLY if GetCapabilities requested - it makes no
            # sense for other cases
            logging.info("Saving mapfile to %s" %  self.mapfilename)
            mapobj.save(self.mapfilename)
        else:
            logging.info("Mapfile NOT saved")

        return self.mapfilename

    def getLayerUrl(self):

        layerurl = self.url

        if self.url.find("?") > -1:
            if not self.url.endswith("?") and\
                not self.url.endswith("&"):
                layerurl += "&"
        else:
            layerurl += "?"

        return layerurl

    def createLayerDefinitionFile(self, name,
            templatefile,time="",target=None):

            layerurl = self.getLayerUrl()
            defFileName = None
            if target:
                defFileName = target
            else:
                defFileName = os.path.join(self.cachedir,'%s.%s'%(name,self.service.lower()))
            if time:
                time = "<DefaultTime>"+time+"</DefaultTime>"

            if not os.path.isfile(defFileName):
                open(defFileName,'w').write(
                        Template(open(templatefile).read()).substitute( 
                                dict(url= layerurl,
                                    name=name,time=time,extras="&BAND=1,2,3")))
                                # FIXME always takes band 1,2,3 ^^

                logging.debug("Created %s layer definition file" % defFileName)
            else:
                logging.debug("Using existing layer definition file %s" % defFileName)

            return defFileName

    def getLayerExtent(self,layer,crs=None):
        """Get extent of layer in form of minx, miny, maxx,maxy
        
        :returns: [minx, miny, maxx, maxy]
        """

        bbox = None
        if layer.boundingBoxWGS84:

            dest = osr.SpatialReference()
            dest.ImportFromEPSG(crs.code)

            source = osr.SpatialReference()
            source.ImportFromEPSG(4326)

            bbox = []

            # TODO rewrite this using ogr CoordinateTransformation
            # http://www.gdal.org/ogr/osr_tutorial.html
            # WELL: it does NOT seem to be THAT better
            geom = ogr.CreateGeometryFromWkt("""POINT(%s %s)""" % (layer.boundingBoxWGS84[0],layer.boundingBoxWGS84[1]),source)
            geom.TransformTo(dest)
            bbox.append(geom.GetX())
            bbox.append(geom.GetY())

            geom = ogr.CreateGeometryFromWkt("""POINT(%s %s)""" % (layer.boundingBoxWGS84[2],layer.boundingBoxWGS84[3]),source)
            geom.TransformTo(dest)
            bbox.append(geom.GetX())
            bbox.append(geom.GetY())

            logging.debug("Setting extent for layer <%s> to %s" %\
                    (layer.id,bbox))
        return bbox

    def setFilter(self,mapobj,request):
        """ Set WFS filter encoding 
        """
        # get the layer
        layerobj = mapobj.getLayerByName(request.getValueByName("layers"))

        # get the filter
        fes = request.getValueByName("fes")
        logging.debug("FES received from HSLayers: %s" % fes)

        # cut off the opening and closing <Filter> tag
        # - this is needed for mapserver
        root = etree.XML(fes)
        msFilter = ""
        for child in root:
            msFilter += etree.tostring(child)
        logging.debug("Setting the filter %s" % msFilter)

        # set the filter
        layerobj.setMetaData("wfs_filter",msFilter)

def getService(configFile=None):

    qstring = os.environ["QUERY_STRING"]
    params = urlparse.parse_qs(qstring)

    for p in params:
        if p.lower() == "owsurl":
            v = params[p]
            del params[p]
            params["owsUrl"] = v

        if p.lower() == "owsservice":
            v = params[p]
            del params[p]
            params["owsService"] = v

    
    if "owsUrl" in params.keys() and\
        "owsService" in params.keys():
        owsUrl = urllib.unquote(params["owsUrl"][0])

        if params["owsService"][0].lower() == "wfs":
            from wfs import WFS
            logging.debug("OWS.py::getService()::owsUrl: '%s'" % owsUrl)
            return WFS(owsUrl,qstring,configFile = configFile )
        elif params["owsService"][0].lower() == "wcs":
            from wcs import WCS
            return WCS(owsUrl,qstring, configFile = configFile)
        elif params["owsService"][0].lower() == "wms":
            from wms import WMS
            return WMS(owsUrl,qstring, configFile = configFile)
    else:
        raise OWSExceptions.MissingParameterValue("""owsUrl or owsService""")