"""Specific views for schema related entities

:organization: Logilab

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

"""

__docformat__ = "restructuredtext en"

from itertools import cycle

from logilab.mtconverter import html_escape

from yams import schema2dot as s2d

from cubicweb.selectors import implements, yes

from cubicweb.schemaviewer import SchemaViewer

from cubicweb.view import EntityView, StartupView

from cubicweb.common import tags, uilib

from cubicweb.web import action

from cubicweb.web.views import TmpFileViewMixin, primary, baseviews

class ViewSchemaAction(action.Action):

    id = 'schema'

    __select__ = yes()

    title = _("site schema")

    category = 'siteactions'

    order = 30

    def url(self):

        return self.build_url(self.id)

# schema entity types views ###################################################

class CWRDEFPrimaryView(primary.PrimaryView):

    __select__ = implements('CWAttribute', 'CWRelation')

    cache_max_age = 60*60*2 # stay in http cache for 2 hours by default

    def render_entity_title(self, entity):

        self.w(u'<h1><span class="etype">%s</span> %s</h1>'

               % (entity.dc_type().capitalize(),

                  html_escape(entity.dc_long_title())))

class CWETypeOneLineView(baseviews.OneLineView):

    __select__ = implements('CWEType')

    def cell_call(self, row, col, **kwargs):

        entity = self.entity(row, col)

        final = entity.final

        if final:

            self.w(u'<em class="finalentity">')

        super(CWETypeOneLineView, self).cell_call(row, col, **kwargs)

        if final:

            self.w(u'</em>')

# in memory schema views (yams class instances) ###############################

SKIPPED_RELS = ('is', 'is_instance_of', 'identity', 'created_by', 'owned_by',

                'has_text',)

class CWETypeSchemaView(primary.PrimaryView):

    id = 'eschema'

    __select__ = implements('CWEType')

    title = _('in memory entity schema')

    main_related_section = False

    skip_rels = SKIPPED_RELS

    def render_entity_attributes(self, entity):

        super(CWETypeSchemaView, self).render_entity_attributes(entity)

        eschema = self.vreg.schema.eschema(entity.name)

        viewer = SchemaViewer(self.req)

        layout = viewer.visit_entityschema(eschema, skiprels=self.skip_rels)

        self.w(uilib.ureport_as_html(layout))

        if not eschema.is_final():

            msg = self.req._('graphical schema for %s') % entity.name

            self.w(tags.img(src=entity.absolute_url(vid='eschemagraph'),

                            alt=msg))

class CWRTypeSchemaView(primary.PrimaryView):

    id = 'eschema'

    __select__ = implements('CWRType')

    title = _('in memory relation schema')

    main_related_section = False

    def render_entity_attributes(self, entity):

        super(CWRTypeSchemaView, self).render_entity_attributes(entity)

        rschema = self.vreg.schema.rschema(entity.name)

        viewer = SchemaViewer(self.req)

        layout = viewer.visit_relationschema(rschema)

        self.w(uilib.ureport_as_html(layout))

        if not rschema.is_final():

            msg = self.req._('graphical schema for %s') % entity.name

            self.w(tags.img(src=entity.absolute_url(vid='eschemagraph'),

                            alt=msg))

# schema images ###############################################################

class ImageView(EntityView):

    __select__ = implements('CWEType')

    id = 'image'

    title = _('image')

    def cell_call(self, row, col):

        entity = self.entity(row, col)

        url = entity.absolute_url(vid='eschemagraph')

        self.w(u'<img src="%s" alt="%s"/>' % (

            html_escape(url),

            html_escape(self.req._('graphical schema for %s') % entity.name)))

class RestrictedSchemaDotPropsHandler(s2d.SchemaDotPropsHandler):

    def __init__(self, req):

        # FIXME: colors are arbitrary

        self.nextcolor = cycle( ('#aa0000', '#00aa00', '#0000aa',

                                 '#000000', '#888888') ).next

        self.req = req

    def display_attr(self, rschema):

        return not rschema.meta and (rschema.has_local_role('read')

                                     or rschema.has_perm(self.req, 'read'))

    # XXX remove this method once yams > 0.20 is out

    def node_properties(self, eschema):

        """return default DOT drawing options for an entity schema"""

        label = ['{', eschema.type, '|']

        label.append(r'\l'.join(rel.type for rel in eschema.subject_relations()

                                if rel.final and self.display_attr(rel)))

        label.append(r'\l}') # trailing \l ensure alignement of the last one

        return {'label' : ''.join(label), 'shape' : "record",

                'fontname' : "Courier", 'style' : "filled"}

    def edge_properties(self, rschema, subjnode, objnode):

        kwargs = super(RestrictedSchemaDotPropsHandler, self).edge_properties(rschema, subjnode, objnode)

        # symetric rels are handled differently, let yams decide what's best

        if not rschema.symetric:

            kwargs['color'] = self.nextcolor()

        kwargs['fontcolor'] = kwargs['color']

        # dot label decoration is just awful (1 line underlining the label

        # + 1 line going to the closest edge spline point)

        kwargs['decorate'] = 'false'

        return kwargs

class RestrictedSchemaVisitorMiIn:

    def __init__(self, req, *args, **kwargs):

        # hack hack hack

        assert len(self.__class__.__bases__) == 2

        self.__parent = self.__class__.__bases__[1]

        self.__parent.__init__(self, *args, **kwargs)

        self.req = req

    def nodes(self):

        for etype, eschema in self.__parent.nodes(self):

            if eschema.has_local_role('read') or eschema.has_perm(self.req, 'read'):

                yield eschema.type, eschema

    def edges(self):

        for setype, oetype, rschema in self.__parent.edges(self):

            if rschema.has_local_role('read') or rschema.has_perm(self.req, 'read'):

                yield setype, oetype, rschema

class FullSchemaVisitor(RestrictedSchemaVisitorMiIn, s2d.FullSchemaVisitor):

    pass

class OneHopESchemaVisitor(RestrictedSchemaVisitorMiIn, s2d.OneHopESchemaVisitor):

    pass

class OneHopRSchemaVisitor(RestrictedSchemaVisitorMiIn, s2d.OneHopRSchemaVisitor):

    pass

class SchemaImageView(TmpFileViewMixin, StartupView):

    id = 'schemagraph'

    content_type = 'image/png'

    skip_rels = SKIPPED_RELS

    def _generate(self, tmpfile):

        """display global schema information"""

        skipmeta = not int(self.req.form.get('withmeta', 0))

        visitor = FullSchemaVisitor(self.req, self.schema, skiprels=self.skip_rels, skipmeta=skipmeta)

        s2d.schema2dot(outputfile=tmpfile, visitor=visitor,

                       prophdlr=RestrictedSchemaDotPropsHandler(self.req))

class CWETypeSchemaImageView(TmpFileViewMixin, EntityView):

    id = 'eschemagraph'

    __select__ = implements('CWEType')

    content_type = 'image/png'

    skip_rels = SKIPPED_RELS

    def _generate(self, tmpfile):

        """display schema information for an entity"""

        entity = self.entity(self.row, self.col)

        eschema = self.vreg.schema.eschema(entity.name)

        visitor = OneHopESchemaVisitor(self.req, eschema, skiprels=self.skip_rels)

        s2d.schema2dot(outputfile=tmpfile, visitor=visitor,

                       prophdlr=RestrictedSchemaDotPropsHandler(self.req))

class CWRTypeSchemaImageView(CWETypeSchemaImageView):

    __select__ = implements('CWRType')

    def _generate(self, tmpfile):

        """display schema information for an entity"""

        entity = self.entity(self.row, self.col)

        rschema = self.vreg.schema.rschema(entity.name)

        visitor = OneHopRSchemaVisitor(self.req, rschema)

        s2d.schema2dot(outputfile=tmpfile, visitor=visitor,

                       prophdlr=RestrictedSchemaDotPropsHandler(self.req))