"""dynamically generated image views

:organization: Logilab

:copyright: 2001-2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

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

"""

__docformat__ = "restructuredtext en"

import os

from tempfile import mktemp

from logilab.common.graph import escape, GraphGenerator, DotBackend

from yams import schema2dot as s2d

from cubicweb.common.view import EntityView, StartupView

class RestrictedSchemaDotPropsHandler(s2d.SchemaDotPropsHandler):

    def __init__(self, req):

        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"}

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 TmpFileViewMixin(object):

    binary = True

    content_type = 'application/octet-stream'

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

    def call(self):

        self.cell_call()

    def cell_call(self, row=0, col=0):

        self.row, self.col = row, col # in case one need it

        tmpfile = mktemp('.png')

        try:

            self._generate(tmpfile)

            self.w(open(tmpfile).read())

        finally:

            os.unlink(tmpfile)

class SchemaImageView(TmpFileViewMixin, StartupView):

    id = 'schemagraph'

    content_type = 'image/png'

    skip_rels = ('owned_by', 'created_by', 'identity', 'is', 'is_instance_of')

    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 EETypeSchemaImageView(TmpFileViewMixin, EntityView):

    id = 'eschemagraph'

    content_type = 'image/png'

    accepts = ('EEType',)

    skip_rels = ('owned_by', 'created_by', 'identity', 'is', 'is_instance_of')

    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 ERTypeSchemaImageView(EETypeSchemaImageView):

    accepts = ('ERType',)

    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))

class WorkflowDotPropsHandler(object):

    def __init__(self, req):

        self._ = req._

    def node_properties(self, stateortransition):

        """return default DOT drawing options for a state or transition"""

        props = {'label': stateortransition.name, 

                 'fontname': 'Courier'}

        if hasattr(stateortransition, 'state_of'):

            props['shape'] = 'box'

            props['style'] = 'filled'

            if stateortransition.reverse_initial_state:

                props['color'] = '#88CC88'

        else:

            props['shape'] = 'ellipse'

            descr = []

            tr = stateortransition

            if tr.require_group:

                descr.append('%s %s'% (

                    self._('groups:'),

                    ','.join(g.name for g in tr.require_group)))

            if tr.condition:

                descr.append('%s %s'% (self._('condition:'), tr.condition))

            if descr:

                props['label'] += escape('\n'.join(descr))

        return props

    def edge_properties(self, transition, fromstate, tostate):

        return {'label': '', 'dir': 'forward',

                'color': 'black', 'style': 'filled'}

class WorkflowVisitor:

    def __init__(self, entity):

        self.entity = entity

    def nodes(self):

        for state in self.entity.reverse_state_of:

            state.complete()

            yield state.eid, state

        for transition in self.entity.reverse_transition_of:

            transition.complete()

            yield transition.eid, transition

    def edges(self):

        for transition in self.entity.reverse_transition_of:

            for incomingstate in transition.reverse_allowed_transition:

                yield incomingstate.eid, transition.eid, transition

            yield transition.eid, transition.destination().eid, transition

class EETypeWorkflowImageView(TmpFileViewMixin, EntityView):

    id = 'ewfgraph'

    content_type = 'image/png'

    accepts = ('EEType',)

    def _generate(self, tmpfile):

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

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

        visitor = WorkflowVisitor(entity)

        prophdlr = WorkflowDotPropsHandler(self.req)

        generator = GraphGenerator(DotBackend('workflow', 'LR',

                                              ratio='compress', size='30,12'))

        return generator.generate(visitor, prophdlr, tmpfile)