#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (C) 2012  Étienne Loks  <etienne.loks_AT_peacefrogsDOTnet>

# 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 3 of the
# License, or (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# See the file COPYING for details.

"""
Utilitaries
"""

import datetime
import os
import re
import StringIO
import tempfile
import urllib2
import unicodedata
import zipfile

from lxml import etree

from django.conf import settings
from django.contrib.gis.gdal import DataSource, Driver, OGRGeometry, \
                                    OGRGeomType, SpatialReference, check_err
from django.contrib.gis.gdal.libgdal import lgdal
from django.core.exceptions import ObjectDoesNotExist
from django.shortcuts import render_to_response
from django.utils.translation import ugettext_lazy as _

from chimere import get_version
from external_utils import OsmApi

def unicode_normalize(string):
    return ''.join(
        (c for c in unicodedata.normalize('NFD', string)
        if unicodedata.category(c) != 'Mn'))

class ImportManager:
    u"""
    Generic class for specific importers
    """
    def __init__(self, importer_instance):
        self.importer_instance = importer_instance

    def get(self):
        pass

    def put(self):
        pass

    @classmethod
    def get_files_inside_zip(cls, zippedfile, suffixes, dest_dir=None):
        try:
            flz = zipfile.ZipFile(zippedfile)
        except zipfile.BadZipfile:
            return [], _(u"Bad zip file")
        namelist = flz.namelist()
        filenames = []
        for suffix in suffixes:
            current_file_name = None
            for name in namelist:
                if name.endswith(suffix) \
                  or name.endswith(suffix.lower()) \
                  or name.endswith(suffix.upper()):
                    current_file_name = name
            filenames.append(current_file_name)
        files = []
        for filename in filenames:
            if filename:
                if dest_dir:
                    files.append(filename)
                    flz.extract(filename, dest_dir)
                else:
                    files.append(flz.open(filename))
            else:
                files.append(None)
        return files

    def get_source_file(self, source, suffixes, dest_dir=None):
        if not source:
            try:
                remotehandle = urllib2.urlopen(self.importer_instance.source)
                source = StringIO.StringIO(remotehandle.read())
                remotehandle.close()
            except ValueError:
                # assume it is a local file
                try:
                    source = open(self.importer_instance.source)
                except IOError, msg:
                    return (None, msg)
            except urllib2.URLError as error:
                return (None, error.message)
        if self.importer_instance.zipped:
            try:
                files = self.get_files_inside_zip(source, suffixes, dest_dir)
            except zipfile.BadZipfile:
                return (None, _(u"Bad zip file"))
            if not files or None in files:
                return (None,
                        _(u"Missing file(s) inside the zip file"))
            source = files[0] if len(suffixes) == 1 else files
        return (source, None)

class KMLManager(ImportManager):
    u"""
    KML importer
    The filtr argument has to be defined as the exact name of the folder to be
    imported
    """
    XPATH = '//kml:Folder/kml:name[text()="%s"]/../kml:Placemark'
    DEFAULT_XPATH = '//kml:Placemark'
    def __init__(self, importer_instance, ns=''):
        self.importer_instance = importer_instance
        self.ns = ns

    def get(self, source=None):
        u"""
        Get data from the source
        Args:
         - source (None): input file if not provided get it from the distant
         source provided in the importer instance.

        Return a tuple with:
         - number of new item ;
         - number of item updated ;
         - error detail on error
        """
        from models import Marker
        new_item, updated_item, msg = 0, 0, ''
        source, msg = self.get_source_file(source, ['.kml'])
        if msg:
            return (0, 0, msg)
        tree = etree.parse(source)
        # try to get default namespace
        if not self.ns:
            self.ns = tree.getroot().nsmap[None]
        xpath = self.XPATH % self.importer_instance.filtr \
                  if self.importer_instance.filtr else self.DEFAULT_XPATH
        for placemark in tree.xpath(xpath,
                                    namespaces={'kml':self.ns}):
            name, point, linestring = None, None, None
            pl_id = placemark.attrib.get('id')
            pl_key = 'kml-%d' % self.importer_instance.pk
            ns = '{%s}' % self.ns
            for item in placemark:
                if item.tag == ns + 'name':
                    name = item.text
                elif item.tag == ns + 'description':
                    description = item.text
                elif item.tag == ns + 'Point':
                    for coord in item:
                        if coord.tag == ns + 'coordinates':
                            x, y, z = coord.text.split(',')
                            point = 'SRID=4326;POINT(%s %s)' % (x, y)
            if point:
                dct = {'point':point,
                       'description':description,
                       'name':name,}
                m = None
                if pl_id:
                    dct_import = {
                        'import_key__icontains':'%s:%s;' % (pl_key, pl_id),
                        'import_source':self.importer_instance.source}
                    try:
                        m = Marker.objects.get(**dct_import)
                        for k in dct:
                            setattr(m, k, dct[k])
                        m.save()
                        updated_item += 1
                    except ObjectDoesNotExist:
                        m = None
                        dct.update({
                            'import_source':self.importer_instance.source})
                if not m:
                    dct['status'] = 'I'
                    m = Marker.objects.create(**dct)
                    new_item += 1
                if pl_id:
                    m.set_key(pl_key, pl_id)
                m.categories.clear()
                for cat in self.importer_instance.categories.all():
                    m.categories.add(cat)
        return (new_item, updated_item, msg)

    @classmethod
    def export(cls, queryset):
        dct = {'name':settings.PROJECT_NAME,
               'description':unicode(datetime.date.today()),
               'locations':queryset.all()
        }
        filename = unicode_normalize(settings.PROJECT_NAME + dct['description']\
                                     + '.kml')
        result = render_to_response('chimere/export.kml', dct)
        return filename, result

class ShapefileManager(ImportManager):
    u"""
    Shapefile importer
    """
    def get(self, source=None):
        u"""
        Get data from the source
        Args:
         - source (None): input file if not provided get it from the distant
         source provided in the importer instance.

        Return a tuple with:
         - number of new item ;
         - number of item updated ;
         - error detail on error
        """
        from models import Marker
        new_item, updated_item, msg = 0, 0, ''
        tmpdir = tempfile.mkdtemp()
        sources, msg = self.get_source_file(source,
                                            ['.shp', '.dbf', '.prj', '.shx'],
                                            dest_dir=tmpdir)
        if msg:
            return (0, 0, msg)
        if not sources:
            return (0, 0, _(u"Error while reading the data source."))
        # get the srid
        srid = self.importer_instance.srid
        if not srid:
            prjfilename = tmpdir + os.sep + sources[2]
            try:
                from osgeo import osr
                with open(prjfilename, 'r') as prj_file:
                    prj_txt = prj_file.read()
                    srs = osr.SpatialReference()
                    srs.ImportFromESRI([prj_txt])
                    srs.AutoIdentifyEPSG()
                    srid = srs.GetAuthorityCode(None)
            except ImportError:
                pass
            if not srid:
                # try with the default projection
                srid = settings.CHIMERE_EPSG_DISPLAY_PROJECTION
        shapefilename = tmpdir + os.sep + sources[0]
        ds = DataSource(shapefilename)
        lyr = ds[0]
        if lyr.geom_type not in ('Point',):
            return (0, 0, _(u"Type of geographic item of this shapefile "
                            u"is not managed by Chimère."))
        # for this first version it is assumed that the first field is a
        # id name and the second field is the name
        id_name = lyr.fields[0] if len(lyr.fields) > 0 else None
        # test if id_name is well guess
        if id_name:
            ids = lyr.get_fields(id_name)
            if len(ids) != len(set(ids)):
                id_name = None
        lbl_name = None
        if len(lyr.fields) > 1:
            lbl_name = lyr.fields[1]
        elif id_name:
            lbl_name = id_name
        indexes = []
        for idx, feat in enumerate(lyr):
            name = unicode(idx)
            if lbl_name:
                name = feat.get(lbl_name)
                try:
                    name = unicode(name)
                except UnicodeDecodeError:
                    try:
                        name = unicode(
                               name.decode(settings.CHIMERE_SHAPEFILE_ENCODING))
                    except:
                        continue
            geom = feat.geom.wkt
            dct = {'point':'SRID=%s;%s' % (srid, feat.geom.wkt),
                   'name':name
                  }
            m = None
            if id_name:
                c_id = feat.get(id_name)
                dct_import = {
                    'import_key__icontains':'%s:%s;' % (id_name, c_id),
                    'import_source':self.importer_instance.source}
                try:
                    m = Marker.objects.get(**dct_import)
                    for k in dct:
                        setattr(m, k, dct[k])
                    m.save()
                    updated_item += 1
                except ObjectDoesNotExist:
                    m = None
                    dct.update({
                        'import_source':self.importer_instance.source})
            if not m:
                dct['status'] = 'I'
                m = Marker.objects.create(**dct)
                new_item += 1
            if id_name:
                m.set_key(id_name, c_id)
            m.categories.clear()
            for cat in self.importer_instance.categories.all():
                m.categories.add(cat)
        # clean up
        tmpdirs = set()
        for src in sources:
            dirs = os.sep.join(src.split(os.sep)[:-1])
            if dirs:
                tmpdirs.add(tmpdir + os.sep + dirs)
            os.remove(tmpdir + os.sep + src)
        for dr in tmpdirs:
            os.removedirs(dr)
        return (new_item, updated_item, msg)

    @classmethod
    def export(cls, queryset):
        date = unicode(datetime.date.today())

        tmp = tempfile.NamedTemporaryFile(suffix='.shp', mode='w+b')
        tmp.close()

        tmp_name = tmp.name
        field_names = [field.name for field in queryset.model._meta.fields]
        geo_field = getattr(queryset.model,
                          'point' if 'point' in field_names else 'route')._field

        dr = Driver('ESRI Shapefile')
        ds = lgdal.OGR_Dr_CreateDataSource(dr._ptr, tmp_name, None)
        if ds is None:
            raise Exception(_(u'Could not create file!'))
        ogr_type = OGRGeomType(geo_field.geom_type).num
        srs = SpatialReference(geo_field.srid)

        layer = lgdal.OGR_DS_CreateLayer(ds, 'lyr', srs._ptr, ogr_type, None)

        for field_name in ('name', 'category'):
            fld = lgdal.OGR_Fld_Create(field_name, 4)
            added = lgdal.OGR_L_CreateField(layer, fld, 0)
            check_err(added)

        feature_def = lgdal.OGR_L_GetLayerDefn(layer)

        for item in queryset:
            # duplicate items when in several categories
            for category in item.categories.all():
                feat = lgdal.OGR_F_Create(feature_def)
                lgdal.OGR_F_SetFieldString(feat, 0,
                                       str(unicode_normalize(item.name)[:80]))
                lgdal.OGR_F_SetFieldString(feat, 1,
                                       str(unicode_normalize(category.name)[:80]))

                geom = getattr(item, geo_field.name)
                if not geom:
                    continue
                ogr_geom = OGRGeometry(geom.wkt, srs)
                check_err(lgdal.OGR_F_SetGeometry(feat, ogr_geom._ptr))
                check_err(lgdal.OGR_L_SetFeature(layer, feat))
        # Cleaning up
        check_err(lgdal.OGR_L_SyncToDisk(layer))
        lgdal.OGR_DS_Destroy(ds)
        lgdal.OGRCleanupAll()

        # writing to a zip file
        filename = unicode_normalize(settings.PROJECT_NAME) + '-' + date
        buff = StringIO.StringIO()
        zip_file = zipfile.ZipFile(buff, 'w', zipfile.ZIP_DEFLATED)
        suffixes = ['shp', 'shx', 'prj', 'dbf']
        for suffix in suffixes:
            name = tmp_name.replace('.shp', '.' + suffix)
            arcname = '.'.join((filename, suffix))
            zip_file.write(name, arcname=arcname)
        zip_file.close()
        buff.flush()
        zip_stream = buff.getvalue()
        buff.close()
        return filename, zip_stream

RE_NODE = re.compile('node\[([^\]]*)\]')

# manage deleted item from OSM

class OSMManager(ImportManager):
    u"""
    OSM importer/exporter
    The source url is a path to an OSM file or a XAPI url
    The filtr argument is XAPI args or empty if it is an OSM file.
    """

    def get(self, source=None):
        u"""
        Get data from the source
        Args:
         - source (None): input file if not provided get it from the distant
         source provided in the importer instance.

        Return a tuple with:
        - new items;
        - updated items;
        - error detail on error.
        """
        from models import Marker
        new_item, updated_item = 0 , 0
        items = []
        source, msg = self.get_source_file(source, ['.osm'])
        if msg:
            return (0, 0, msg)
        tree = etree.parse(source)
        for node in tree.xpath('//node'):
            name, point, linestring = None, None, None
            node_id = node.attrib.get('id')
            version = node.attrib.get('version')
            for item in node:
                k = item.attrib.get('k')
                if k == 'name':
                    name = item.attrib.get('v')
            point = 'SRID=4326;POINT(%s %s)' % (node.get('lon'),
                                                node.get('lat'))
            if point:
                dct = {'point':point,
                       'name':name,
                       'import_version':version}
                m = None
                if node_id:
                    dct_import = {
                        'import_key__icontains':'OSM:%s;' % (node_id),
                        'import_source':self.importer_instance.source}
                    try:
                        m = Marker.objects.get(**dct_import)
                        items.append(m)
                        if version and m.import_version == int(version):
                            # no update since the last import
                            continue
                        for k in dct:
                            setattr(m, k, dct[k])
                        m.save()
                        updated_item += 1
                    except ObjectDoesNotExist:
                        m = None
                        dct.update({
                            'import_source':self.importer_instance.source})
                if not m:
                    dct['status'] = 'I'
                    m = Marker.objects.create(**dct)
                    new_item += 1
                    items.append(m)
                if node_id:
                    m.set_key('OSM', node_id)
                m.categories.clear()
                for cat in self.importer_instance.categories.all():
                    m.categories.add(cat)
        return (new_item, updated_item, msg)

    def put(self):
        # first of all: reimport in order to verify that no changes has been
        # made since the last import
        from models import Marker
        new_item, updated_item, msg = self.get()
        # check if import is possible
        if msg:
            return 0, msg
        if new_item:
            return 0, _(u"New items imported - validate them before exporting")
        if Marker.objects.filter(status='I').count():
            return 0, _(u"There are items from a former import not yet "
                        u"validated - validate them before exporting")
        # start import
        api = OsmApi.OsmApi(api=settings.CHIMERE_OSM_API_URL,
                     username=settings.CHIMERE_OSM_USER,
                     password=settings.CHIMERE_OSM_PASSWORD)
        api.ChangesetCreate({u"comment": u"Import from Chimère %s" % \
                                                            get_version()})
        tag = RE_NODE.finddall(self.importer_instance.filtr)
        if not tag:
            return 0, _(u"Bad param")
        tag = tag[0].split('=')
        default_dct = {'tag':{tag[0]:tag[1]},
                       'import_source':self.importer_instance.source}
        for idx, item in Marker.objects.filter(status='A',
                categories=self.importer_instance.categories.all()):
            dct = default_dct.update({
                        'name':item.name,
                        'lon':item.point.lon,
                        'lat':item.point.lat})
            node = None
            import_key = marker.get_key('OSM')
            if not import_key:
                node = OsmApi.NodeCreate(dct)
                item.set_key('OSM', node['id'])
            else:
                dct['id'] = import_key
                node = OsmApi.NodeUpdate(dct)
            item.import_version = node['version']
            item.save()
        api.ChangesetClose()
        return idx+1, None