# updated SQLA schema display to work with pydot 1.0.2

# download from: http://www.sqlalchemy.org/trac/wiki/UsageRecipes/SchemaDisplay

from sqlalchemy.orm.properties import PropertyLoader

import pydot

import types

__all__ = ['create_uml_graph', 'create_schema_graph', 'show_uml_graph', 'show_schema_graph']

def _mk_label(mapper, show_operations, show_attributes, show_datatypes, bordersize):

    html = '<<TABLE CELLSPACING="0" CELLPADDING="1" BORDER="0" CELLBORDER="%d" BALIGN="LEFT"><TR><TD><FONT POINT-SIZE="10">%s</FONT></TD></TR>' % (bordersize, mapper.class_.__name__)

    def format_col(col):

        colstr = '+%s' % (col.name)

        if show_datatypes:

            colstr += ' : %s' % (col.type.__class__.__name__)

        return colstr

    if show_attributes:

        html += '<TR><TD ALIGN="LEFT">%s</TD></TR>' % '<BR ALIGN="LEFT"/>'.join(format_col(col) for col in sorted(mapper.columns, key=lambda col:not col.primary_key))

    else:

        [format_col(col) for col in sorted(mapper.columns, key=lambda col:not col.primary_key)]

    if show_operations:

        html += '<TR><TD ALIGN="LEFT">%s</TD></TR>' % '<BR ALIGN="LEFT"/>'.join(

            '%s(%s)' % (name,", ".join(default is _mk_label and ("%s") % arg or ("%s=%s" % (arg,repr(default))) for default,arg in 

                zip((func.func_defaults and len(func.func_code.co_varnames)-1-(len(func.func_defaults) or 0) or func.func_code.co_argcount-1)*[_mk_label]+list(func.func_defaults or []), func.func_code.co_varnames[1:])

            ))

            for name,func in mapper.class_.__dict__.items() if isinstance(func, types.FunctionType) and func.__module__ == mapper.class_.__module__

        )

    html+= '</TABLE>>'

    return html

def create_uml_graph(mappers, show_operations=True, show_attributes=True, show_multiplicity_one=False, show_datatypes=True, linewidth=1.0, font="Bitstream-Vera Sans"):

    graph = pydot.Dot(prog='neato',mode="major",overlap="0", sep="0.01",dim="3", pack="True", ratio=".75")

    relations = set()

    for mapper in mappers:

        graph.add_node(pydot.Node(mapper.class_.__name__,

            shape="plaintext", label=_mk_label(mapper, show_operations, show_attributes, show_datatypes, linewidth),

            fontname=font, fontsize="8.0",

        ))

        if mapper.inherits:

            graph.add_edge(pydot.Edge(mapper.inherits.class_.__name__,mapper.class_.__name__,

                arrowhead='none',arrowtail='empty', style="setlinewidth(%s)" % linewidth, arrowsize=str(linewidth)))

        for loader in mapper.iterate_properties:

            if isinstance(loader, PropertyLoader) and loader.mapper in mappers:

                if hasattr(loader, 'reverse_property'):

                    relations.add(frozenset([loader, loader.reverse_property]))

                else:

                    relations.add(frozenset([loader]))

    for relation in relations:

        #if len(loaders) > 2:

        #    raise Exception("Warning: too many loaders for join %s" % join)

        args = {}

        def multiplicity_indicator(prop):

            if prop.uselist:

                return ' *'

            if any(col.nullable for col in prop.local_side):

                return ' 0..1'

            if show_multiplicity_one:

                return ' 1'

            return ''

        if len(relation) == 2:

            src, dest = relation

            from_name = src.parent.class_.__name__

            to_name = dest.parent.class_.__name__

            def calc_label(src,dest):

                return '+' + src.key + multiplicity_indicator(src)

            args['headlabel'] = calc_label(src,dest)

            args['taillabel'] = calc_label(dest,src)

            args['arrowtail'] = 'none'

            args['arrowhead'] = 'none'

            args['constraint'] = False

        else:

            prop, = relation

            from_name = prop.parent.class_.__name__

            to_name = prop.mapper.class_.__name__

            args['headlabel'] = '+%s%s' % (prop.key, multiplicity_indicator(prop))

            args['arrowtail'] = 'none'

            args['arrowhead'] = 'vee'

        graph.add_edge(pydot.Edge(from_name,to_name,

            fontname=font, fontsize="7.0", style="setlinewidth(%s)"%linewidth, arrowsize=str(linewidth),

            **args)

        )

    return graph

#from sqlalchemy import Table, text

def _render_table_html(table, metadata, show_indexes, show_datatypes):

    def format_col_type(col):

        try:

            return col.type.get_col_spec()

        except NotImplementedError:

            return str(col.type)

        except AttributeError:

            return str(col.type)

    def format_col_str(col):

         if show_datatypes:

             return "- %s : %s" % (col.name, format_col_type(col))

         else:

             return "- %s" % col.name

    html = '<<TABLE BORDER="1" CELLBORDER="0" CELLSPACING="0"><TR><TD ALIGN="CENTER">%s</TD></TR><TR><TD BORDER="1" CELLPADDING="0"></TD></TR>' % table.name 

    html += ''.join('<TR><TD ALIGN="LEFT" PORT="%s">%s</TD></TR>' % (col.name, format_col_str(col)) for col in table.columns)

    html += '</TABLE>>'

    return html

def create_schema_graph(tables=None, metadata=None, show_indexes=True, show_datatypes=True, font="Bitstream-Vera Sans",

    concentrate=True, relation_options={}, rankdir='TB'):

    relation_kwargs = {

        'fontsize':"7.0"

    }

    relation_kwargs.update(relation_options)

    if not metadata and len(tables):

        metadata = tables[0].metadata

    elif not tables and metadata:

        if not len(metadata.tables):

            metadata.reflect()

        tables = metadata.tables.values()

    else:

        raise Exception("You need to specify at least tables or metadata")

    graph = pydot.Dot(prog="dot",mode="ipsep",overlap="ipsep",sep="0.01",concentrate=str(concentrate), rankdir=rankdir)

    for table in tables:

        graph.add_node(pydot.Node(str(table.name),

            shape="plaintext",

            label=_render_table_html(table, metadata, show_indexes, show_datatypes),

            fontname=font, fontsize="7.0"

        ))

    for table in tables:

        for fk in table.foreign_keys:

            edge = [table.name, fk.column.table.name]

            is_inheritance = fk.parent.primary_key and fk.column.primary_key

            if is_inheritance:

                edge = edge[::-1]

            graph_edge = pydot.Edge(

                headlabel="+ %s"%fk.column.name, taillabel='+ %s'%fk.parent.name,

                arrowhead=is_inheritance and 'none' or 'odot' ,

                arrowtail=(fk.parent.primary_key or fk.parent.unique) and 'empty' or 'crow' ,

                fontname=font, 

                #samehead=fk.column.name, sametail=fk.parent.name,

                *edge, **relation_kwargs

            )

            graph.add_edge(graph_edge)

# not sure what this part is for, doesn't work with pydot 1.0.2

#            graph_edge.parent_graph = graph.parent_graph

#            if table.name not in [e.get_source() for e in graph.get_edge_list()]:

#                graph.edge_src_list.append(table.name)

#            if fk.column.table.name not in graph.edge_dst_list:

#                graph.edge_dst_list.append(fk.column.table.name)

#            graph.sorted_graph_elements.append(graph_edge)

    return graph

def show_uml_graph(*args, **kwargs):

    from cStringIO import StringIO

    from PIL import Image

    iostream = StringIO(create_uml_graph(*args, **kwargs).create_png())

    Image.open(iostream).show(command=kwargs.get('command','gwenview'))

def show_schema_graph(*args, **kwargs):

    from cStringIO import StringIO

    from PIL import Image

    iostream = StringIO(create_schema_graph(*args, **kwargs).create_png())

    Image.open(iostream).show(command=kwargs.get('command','gwenview'))