__docformat__ = "restructuredtext en"

from lxml import etree

from lxml.builder import E

from cubicweb.view import StartupView, AnyRsetView

## sparql resultset views #####################################################

YAMS_XMLSCHEMA_MAPPING = {

    'String': 'string',

    'Int': 'integer',

    'Float': 'float',

    'Boolean': 'boolean',

    'Datetime': 'dateTime',

    'Date': 'date',

    'Time': 'time',

    # XXX the following types don't have direct mapping

    'Decimal': 'string',

    'Interval': 'duration',

    'Password': 'string',

    'Bytes': 'base64Binary',

    }

def xmlschema(yamstype):

    return 'http://www.w3.org/2001/XMLSchema#%s' % YAMS_XMLSCHEMA_MAPPING[yamstype]

class SparqlResultXmlView(AnyRsetView):

    """The spec can be found here: http://www.w3.org/TR/rdf-sparql-XMLres/

    """

    id = 'sparql'

    content_type = 'application/sparql-results+xml'

    templatable = False

    # XXX use accept-headers-selectors to choose among the sparql result views

    def call(self):

        # XXX handle UNION

        rqlst = self.rset.syntax_tree().children[0]

        varnames = [var.name for var in rqlst.selection]

        results = E.results()

        for rowidx in xrange(len(self.rset)):

            result = E.result()

            for colidx, varname in enumerate(varnames):

                result.append(self.cell_binding(rowidx, colidx, varname))

            results.append(result)

        sparql = E.sparql(E.head(*(E.variable(name=name) for name in varnames)),

                          results)

        self.w(u'<?xml version="1.0"?>\n')

        self.w(etree.tostring(sparql, encoding=unicode))

    def cell_binding(self, row, col, varname):

        celltype = self.rset.description[row][col]

        if self.schema.eschema(celltype).is_final():

            cellcontent = self.view('cell', self.rset, row=row, col=col)

            return E.binding(E.literal(cellcontent,

                                       datatype=xmlschema(celltype)),

                             name=varname)

        else:

            entity = self.entity(row, col)

            return E.binding(E.uri(entity.absolute_url()), name=varname)