from pypy.translator.tool.make_dot import DotGen
from dotviewer.graphclient import display_page


class Graph(DotGen):

    def highlight(self, word, text, linked_to=None):
        if not hasattr(self, '_links'):
            self._links = {}
            self._links_to = {}
        self._links[word] = text
        if linked_to:
            self._links_to[word] = linked_to

    def display(self):
        "Display a graph page locally."
        display_page(_Page(self))


class NoGraph(Exception):
    pass

class _Page:
    def __init__(self, graph_builder):
        if callable(graph_builder):
            graph = graph_builder()
        else:
            graph = graph_builder
        if graph is None:
            raise NoGraph
        self.graph_builder = graph_builder

    def content(self):
        return _PageContent(self.graph_builder)

class _PageContent:
    def __init__(self, graph_builder):
        if callable(graph_builder):
            graph = graph_builder()
        else:
            graph = graph_builder
        assert graph is not None
        self.graph_builder = graph_builder
        self.graph = graph
        self.links = getattr(graph, '_links', {})
        if not hasattr(graph, '_source'):
            graph._source = graph.generate(target=None)
        self.source = graph._source

    def followlink(self, link):
        try:
            return _Page(self.graph._links_to[link])
        except NoGraph:
            return _Page(self.graph_builder)

# ____________________________________________________________

def test_graph():
    g1 = Graph('test')
    g2 = Graph('test2')
    g1.emit_node('a', shape="box", label="a")
    g1.emit_node('b', shape="box", label="b")
    g1.emit_node('c', shape="box", label="c")
    g1.emit_edge('a', 'b', 'ablink')
    g1.emit_edge('a', 'c', 'aclink')
    g1.highlight('b', 'This is b.', g2)
    g2.emit_node('mini', shape="box", label="mini")
    g1.display()

if __name__ == '__main__':
    test_graph()