import logging

try: from cStringIO import StringIO
except ImportError: from StringIO import StringIO

from geoalchemy import WKTSpatialElement, functions
from pylons import response
from pkg_resources import resource_stream
from lxml import etree

from ckan.lib.base import request, config, abort
from ckan.controllers.api import ApiController as BaseApiController
from ckan.model import Session

from ckanext.harvest.model import HarvestObject, HarvestObjectExtra
from ckanext.spatial.lib import get_srid, validate_bbox, bbox_query

log = logging.getLogger(__name__)

class ApiController(BaseApiController):

    def spatial_query(self):

        error_400_msg = 'Please provide a suitable bbox parameter [minx,miny,maxx,maxy]'

        if not 'bbox' in request.params:
            abort(400,error_400_msg)

        bbox = validate_bbox(request.params['bbox'])

        if not bbox:
            abort(400,error_400_msg)

        srid = get_srid(request.params.get('crs')) if 'crs' in request.params else None

        extents = bbox_query(bbox,srid)

        format = request.params.get('format','')

        return self._output_results(extents,format)

    def _output_results(self,extents,format=None):

        ids = [extent.package_id for extent in extents]

        output = dict(count=len(ids),results=ids)

        return self._finish_ok(output)

class HarvestMetadataApiController(BaseApiController):

    def _get_content(self, id):

        obj = Session.query(HarvestObject) \
                        .filter(HarvestObject.id==id).first()
        if obj:
            return obj.content
        else:
            return None

    def _get_original_content(self, id):
        extra = Session.query(HarvestObjectExtra).join(HarvestObject) \
                        .filter(HarvestObject.id==id) \
                        .filter(HarvestObjectExtra.key=='original_document').first()
        if extra:
            return extra.value
        else:
            return None

    def _transform_to_html(self, content, xslt_package=None, xslt_path=None):

        xslt_package = xslt_package or 'ckanext.spatial'
        xslt_path = xslt_path or 'templates/ckanext/spatial/gemini2-html-stylesheet.xsl'

        ## optimise -- read transform only once and compile rather
        ## than at each request
        with resource_stream(xslt_package, xslt_path) as style:
            style_xml = etree.parse(style)
            transformer = etree.XSLT(style_xml)

        xml = etree.parse(StringIO(content.encode('utf-8')))
        html = transformer(xml)

        response.headers['Content-Type'] = 'text/html; charset=utf-8'
        response.headers['Content-Length'] = len(content)

        result = etree.tostring(html, pretty_print=True)

        return result

    def _get_xslt(self, original=False):

        if original:
            config_option = 'ckanext.spatial.harvest.xslt_html_content_original'
        else:
            config_option = 'ckanext.spatial.harvest.xslt_html_content'

        xslt_package = None
        xslt_path = None
        xslt = config.get(config_option, None)
        if xslt:
            if ':' in xslt:
                xslt = xslt.split(':')
                xslt_package = xslt[0]
                xslt_path = xslt[1]
            else:
                log.error('XSLT should be defined in the form <package>:<path>' +
                        ', eg ckanext.myext:templates/my.xslt')

        return xslt_package, xslt_path

    def display_xml_original(self, id):
        content = self._get_original_content(id)

        if not content:
            abort(404)

        response.headers['Content-Type'] = 'application/xml; charset=utf-8'
        response.headers['Content-Length'] = len(content)

        if not '<?xml' in content.split('\n')[0]:
            content = u'<?xml version="1.0" encoding="UTF-8"?>\n' + content
        return content.encode('utf-8')

    def display_html(self,id):
        content = self._get_content(id)

        if not content:
            abort(404)

        xslt_package, xslt_path = self._get_xslt()
        return self._transform_to_html(content, xslt_package, xslt_path)

    def display_html_original(self, id):
        content = self._get_original_content(id)

        if content is None:
            abort(404)

        xslt_package, xslt_path = self._get_xslt(original=True)
        return self._transform_to_html(content, xslt_package, xslt_path)