"""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)