from IPython.html import widgets # Loads the Widget framework.
from IPython.core.magics.namespace import NamespaceMagics # Used to query namespace.

# For this example, hide these names, just to avoid polluting the namespace further
get_ipython().user_ns_hidden['widgets'] = widgets
get_ipython().user_ns_hidden['NamespaceMagics'] = NamespaceMagics

class VariableInspectorWindow(object):
    instance = None
    
    def __init__(self, ipython):
        """Public constructor."""
        if VariableInspectorWindow.instance is not None:
            raise Exception("""Only one instance of the Variable Inspector can exist at a 
                time.  Call close() on the active instance before creating a new instance.
                If you have lost the handle to the active instance, you can re-obtain it
                via `VariableInspectorWindow.instance`.""")
        
        VariableInspectorWindow.instance = self
        self.closed = False
        self.namespace = NamespaceMagics()
        self.namespace.shell = ipython.kernel.shell
        
        self._box = widgets.Box()
        self._box._dom_classes = ['inspector']
        self._box.background_color = '#fff'
        self._box.border_color = '#ccc'
        self._box.border_width = 1
        self._box.border_radius = 5

        self._modal_body = widgets.VBox()
        self._modal_body.overflow_y = 'scroll'

        self._modal_body_label = widgets.HTML(value = 'Not hooked')
        self._modal_body.children = [self._modal_body_label]

        self._box.children = [
            self._modal_body, 
        ]
        
        self._ipython = ipython
        self._ipython.events.register('post_run_cell', self._fill)
        
    def close(self):
        """Close and remove hooks."""
        if not self.closed:
            self._ipython.events.unregister('post_run_cell', self._fill)
            self._box.close()
            self.closed = True
            VariableInspectorWindow.instance = None

    def _fill(self):
        """Fill self with variable information."""
        values = self.namespace.who_ls()
        self._modal_body_label.value = '<table class="table table-bordered table-striped"><tr><th>Name</th><th>Type</th><th>Value</th></tr><tr><td>' + \
            '</td></tr><tr><td>'.join(['{0}</td><td>{1}</td><td>{2}'.format(v, type(eval(v)).__name__, str(eval(v))) for v in values]) + \
            '</td></tr></table>'

    def _ipython_display_(self):
        """Called when display() or pyout is used to display the Variable 
        Inspector."""
        self._box._ipython_display_()


inspector = VariableInspectorWindow(get_ipython())
inspector

"""
Explanation: Variable Inspector Widget
A short example implementation
This notebook demonstrates how one can use the widgets already built-in to IPython to create a working variable inspector much like the ones seen in popular commercial scientific computing environments.
End of explanation
"""


%%javascript
$('div.inspector')
    .detach()
    .prependTo($('body'))
    .css({
        'z-index': 999, 
        position: 'fixed',
        'box-shadow': '5px 5px 12px -3px black',
        opacity: 0.9
    })
    .draggable();

"""
Explanation: Pop the inspector out of the widget area using Javascript.  To close the inspector, click the close button on the widget area that it was spawned from.
End of explanation
"""


a = 5

b = 3.0

c = a * b

d = "String"

del b

inspector.close()

"""
Explanation: Test
End of explanation
"""


