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

# # NbConvert

# ## Command line usage

# `NbConvert` is both a library and command line tool that allows you to convert notebooks to other formats.  It ships with many common formats: `html`, `latex`, `markdown`, `python`, `rst`, and  `slides`
# NbConvert relys on the Jinja templating engine, so implementing a new format or tweeking an existing one is easy.

# You can invoke nbconvert by running
# 
# ```bash
# $ ipython nbconvert <options and arguments>
# ```
# 
# Call `ipython nbconvert` with the `--help` flag or without any aruments to display the basic help.  For detailed configuration help, use the `--help-all` flag.

# ### Basic export

# As a test, the `Index.ipynb` notebook in the directory will be convert. 
# 
# If you're converting a notebook with code in it, make sure to run the code cells that you're interested in before attempting to convert the notebook.  Unless explicitly requested, nbconvert **does not execute the code cells** of the notebooks that it converts.

# In[ ]:


get_ipython().run_cell_magic('bash', '', "ipython nbconvert  'Index.ipynb'\n")


# Html is the (configurable) default value.  The verbose form of the same command as above is 

# In[ ]:


get_ipython().run_cell_magic('bash', '', "ipython nbconvert  --to=html 'Index.ipynb'\n")


# You can also convert to latex, which will extract the embeded images.  If the embeded images are SVGs, inkscape is used to convert them to pdf:

# In[ ]:


get_ipython().run_cell_magic('bash', '', "ipython nbconvert  --to=latex 'Index.ipynb'\n")


# Note that the latex conversion creates latex, not a PDF.  To create a PDF you need the required third party packages to compile the latex.
# 
# A `--post` flag is provided for convinience which allows you to have nbconvert automatically compile a PDF for you from your output.

# In[ ]:


get_ipython().run_cell_magic('bash', '', "ipython nbconvert  --to=latex 'Index.ipynb' --post=pdf\n")


# ## Custom templates

# Look at the first 20 lines of the `python` exporter

# In[ ]:


pyfile = get_ipython().getoutput("ipython nbconvert --to python 'Index.ipynb' --stdout")
for l in pyfile[20:40]:
    print l


# From the code, you can see that non-code cells are also exported.  If you want to change this behavior, you can use a custom template.  The custom template inherits from the Python template and overwrites the markdown blocks so that they are empty.

# In[ ]:


get_ipython().run_cell_magic('writefile', 'simplepython.tpl', "{% extends 'python.tpl'%}\n\n{% block markdowncell -%}\n{% endblock markdowncell %}\n\n## we also want to get rig of header cell\n{% block headingcell -%}\n{% endblock headingcell %}\n\n## and let's change the appearance of input prompt\n{% block in_prompt %}\n# This was input cell with prompt number : {{ cell.prompt_number if cell.prompt_number else ' ' }}\n{%- endblock in_prompt %}\n")


# In[ ]:


pyfile = get_ipython().getoutput("ipython nbconvert --to python 'Index.ipynb' --stdout --template=simplepython.tpl")

for l in pyfile[4:40]:
    print l
print '...'


# For details about the template syntax, refer to [Jinja's manual](http://jinja2.readthedocs.org/en/latest/intro.html).

# ## Template that use cells metadata

# The notebook file format supports attaching arbitrary JSON metadata to each cell.  Here, as an exercise, you will use the metadata to tags cells.

# First you need to choose another notebook you want to convert to html, and tag some of the cells with metadata.  You can refere to the file `soln/celldiff.js` as an example or follow the Javascript tutorial to figure out how do change cell metadata.  Assuming you have a notebook with some of the cells tagged as `Easy`|`Medium`|`Hard`|`<None>`, the notebook can be converted specially using a custom template.  Design your template in the cells provided below.
# 
# The following, unorganized lines of code, may be of help:

# ```
# {% extends 'html_full.tpl'%}
# {% block any_cell %}
# {{ super() }}
# <div style="background-color:red">
# <div style='background-color:orange'>
# ```
# 
# If your key name under `cell.metadata.example.difficulty`, the following code would get the value of it:
# 
# `cell['metadata'].get('example',{}).get('difficulty','')`
# 
# Tip: Use `%%writefile` to edit the template in the notebook.

# In[ ]:


get_ipython().run_cell_magic('bash', '', '# ipython nbconvert --to html <your chosen notebook.ipynb> --template=<your template file>\n')


# In[ ]:


get_ipython().run_line_magic('loadpy', 'soln/coloreddiff.tpl')


# In[ ]:


# ipython nbconvert --to html '04 - Custom Display Logic.ipynb' --template=soln/coloreddiff.tpl


# ### Get rid of all command line flags.

# IPython nbconvert can be configured using the default profile or a profile specified via the `--profile` flag.  Additionally, if a `config.py` file exist in current working directory, nbconvert will use that as config.