#!/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 osgeo import ogr, osr
from lxml import etree

from django.conf import settings
from django.contrib.gis.gdal import DataSource, OGRGeomType, check_err
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
    """
    default_source = None
    def __init__(self, importer_instance):
        self.importer_instance = importer_instance
        self.default_name = " - ".join([cat.name
           for cat in self.importer_instance.categories.order_by('name').all()])

    def get(self):
        pass

    def put(self):
        pass

    def create_or_update_item(self, cls, values, import_key, version=None):
        updated, created, item = False, False, None
        if import_key:
            dct_import = {
                'import_key__icontains':'%s:%s;' % (
                        self.importer_instance.importer_type,
                        import_key),
                'import_source':self.importer_instance.source}
            try:
                item = cls.objects.get(**dct_import)
                if version and item.import_version == int(version):
                    # no update since the last import
                    return item, None, None
                for k in values:
                    setattr(item, k, values[k])
                item.save()
                updated = True
            except ObjectDoesNotExist:
                pass
        if not item:
            values.update({
                'import_source':self.importer_instance.source})
            values['status'] = 'I'
            item = cls.objects.create(**values)
            created = True
        if import_key:
            item.set_key(self.importer_instance.importer_type,
                         import_key)
        item.categories.clear()
        for cat in self.importer_instance.categories.all():
            item.categories.add(cat)
        return item, updated, created

    @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,
                        extra_url=None):
        if not hasattr(source, 'read'):
            if not source:
                source = self.importer_instance.source \
                       if self.importer_instance.source else self.default_source
            try:
                url = source
                if extra_url:
                    url += extra_url
                remotehandle = urllib2.urlopen(url)
                source = StringIO.StringIO(remotehandle.read())
                remotehandle.close()
            except ValueError:
                # assume it is a local file
                try:
                    source = open(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)
        doc = source
        # remove empty lines before declaration (bad XML file)
        if hasattr(source, 'getvalue'):
            splitted = source.getvalue().split('\n')
            for idx, line in enumerate(splitted):
                if line.strip():
                    break
            doc = StringIO.StringIO("\n".join(splitted[idx:]))
        tree = etree.parse(doc)
        # 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 = 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, Route
        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]
        # 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
        if lyr.geom_type not in ('Point', 'LineString'):
            return (0, 0, _(u"Type of geographic item of this shapefile "
                            u"is not managed by Chimère."))
        geom_key = 'point' if lyr.geom_type == 'Point' else 'route'
        geom_cls = Marker if lyr.geom_type == 'Point' else Route
        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 = {geom_key:'SRID=%s;%s' % (srid, feat.geom.wkt),
                   'name':name
                  }
            import_key = feat.get(id_name) if id_name else ''
            item, updated, created = self.create_or_update_item(
                                    geom_cls, dct, import_key)
            if updated:
                updated_item += 1
            if created:
                new_item += 1

            """
            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 = ogr.GetDriverByName('ESRI Shapefile')
        ds = dr.CreateDataSource(tmp_name)
        if ds is None:
            raise Exception(_(u'Could not create file!'))
        ogr_type = OGRGeomType(geo_field.geom_type).num
        srs = osr.SpatialReference()
        srs.ImportFromEPSG(geo_field.srid)

        layer = ds.CreateLayer('lyr', srs=srs, geom_type=ogr_type)

        for field_name in ('name', 'category'):
            field_defn = ogr.FieldDefn(str(field_name), ogr.OFTString)
            field_defn.SetWidth(255)
            if layer.CreateField(field_defn) != 0:
                raise Exception(_(u'Failed to create field'))

        feature_def = layer.GetLayerDefn()

        for item in queryset:
            # duplicate items when in several categories
            for category in item.categories.all():
                feat = ogr.Feature(feature_def)
                feat.SetField('name', str(unicode_normalize(item.name)[:80]))
                feat.SetField('category',
                                   str(unicode_normalize(category.name)[:80]))

                geom = getattr(item, geo_field.name)
                if not geom:
                    continue
                ogr_geom = ogr.CreateGeometryFromWkt(geom.wkt)
                check_err(feat.SetGeometry(ogr_geom))
            check_err(layer.CreateFeature(feat))
        # Cleaning up
        ds.Destroy()

        # 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.
    """
    default_source = settings.CHIMERE_XAPI_URL

    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.
        """
        source, msg = self.get_source_file(source, ['.osm'],
                                         extra_url=self.importer_instance.filtr)
        if not source:
            return (0, 0, msg)

        tree = etree.parse(source)
        # only import node or ways
        if tree.xpath('count(//way)') and tree.xpath('count(//node)'):
            return self.import_ways(tree)
        elif tree.xpath('count(//node)'):
            return self.import_nodes(tree)
        return 0, 0, _(u"Nothing to import")

    def import_ways(self, tree):
        from chimere.models import Marker, Route
        msg, items, new_item, updated_item = "", [], 0 , 0
        nodes = {}
        for node in tree.xpath('//node'):
            node_id = node.attrib.get('id')
            for item in node:
                k = item.attrib.get('k')
            if node_id:
                nodes[node_id] = '%s %s' % (node.get('lon'),
                                            node.get('lat'))
        for way in tree.xpath('//way'):
            name = None
            points = []
            node_id = way.attrib.get('id')
            version = way.attrib.get('version')
            for item in way:
                k = item.attrib.get('k')
                if k == 'name':
                    name = item.attrib.get('v')
                if item.tag == 'nd':
                    points.append(item.get('ref'))
            if not name:
                name = self.default_name
            if not points:
                continue
            wkt = 'SRID=4326;LINESTRING(%s)' % ",".join([nodes[point_id]
                            for point_id in points if point_id in nodes])
            dct = {'route':wkt,
                   'name':name,
                   'import_version':version}
            item, updated, created = self.create_or_update_item(
                                    Route, dct, node_id, version)
            if updated:
                updated_item += 1
            if created:
                new_item += 1
            items.append(item)
        return new_item, updated_item, msg

    def import_nodes(self, tree):
        from chimere.models import Marker
        msg, items, new_item, updated_item = "", [], 0 , 0
        for node in tree.xpath('//node'):
            name = None
            node_id = node.attrib.get('id')
            if not node_id:
                continue
            version = node.attrib.get('version')
            for item in node:
                k = item.attrib.get('k')
                if k == 'name':
                    name = item.attrib.get('v')
            if not name:
                name = self.default_name
            point = 'SRID=4326;POINT(%s %s)' % (node.get('lon'),
                                                node.get('lat'))
            dct = {'point':point,
                   'name':name,
                   'import_version':version}
            item, updated, created = self.create_or_update_item(
                                    Marker, dct, node_id, version)
            if updated:
                updated_item += 1
            if created:
                new_item += 1
            items.append(item)
        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