#!/usr/bin/env python
# coding: utf-8

# # Automatic creation of new code cells via widgets
# 
# This code was originally written by Jonathan Frederic. For full context, see [GH issue 4983 in IPython](https://github.com/ipython/ipython/issues/4983), as well as [5006](https://github.com/ipython/ipython/issues/5006) and [#44 in ipywidgets](https://github.com/ipython/ipywidgets/issues/44).
# 
# The code below demonstrates quickly how to make a widget that injects a new code cell into the notebook.

# In[1]:


import base64
from IPython.display import Javascript, display
from IPython.utils.py3compat import str_to_bytes, bytes_to_str

def create_code_cell(code='', where='below'):
    """Create a code cell in the IPython Notebook.

    Parameters
    code: unicode
        Code to fill the new code cell with.
    where: unicode
        Where to add the new code cell.
        Possible values include:
            at_bottom
            above
            below"""
    encoded_code = bytes_to_str(base64.b64encode(str_to_bytes(code)))
    display(Javascript("""
        var code = IPython.notebook.insert_cell_{0}('code');
        code.set_text(atob("{1}"));
    """.format(where, encoded_code)))


# In[2]:


from ipywidgets import Button
def on_click(button):
    create_code_cell('print("Hello world!")')
    
button = Button(description="Create code")
button.on_click(on_click)

button


# In[ ]:


print("Hello world!")