"""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 itertools import cycle

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

from yams import schema2dot as s2d

from cubicweb.selectors import implements

from cubicweb.common.view import EntityView, StartupView

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 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'

    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):

    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'

    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)