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

# This notebook documents how to solve the famous [zebra puzzle](http://en.wikipedia.org/wiki/Zebra_puzzle) by A. Einstein with the help of semantic web tools for python.
# 
# 
# It is based on theses Links/Projects
# 
# - https://pythonhosted.org/Owlready2/index.html
# - https://github.com/RDFLib/OWL-RL/issues/3 "Solving Einstein's riddle (zebra puzzle"
#     - Linked owl-files:
#     - https://github.com/RDFLib/OWL-RL/files/1533408/einsteins_riddle.owl.txt ← works
#         - created by [D. Ponomaryov](https://persons.iis.nsk.su/en/ponom/ontologies)
# 
# For installation I did:
# 
# ```bash
# pip install owlready
# ``` 
# 
# Note there is also https://github.com/RDFLib/OWL-RL/files/1533409/zebra.n3.txt but the N3-Format is not supported by Owlready.
# 

# In[1]:


import os
import owlready2 as owl2


# # Solution
# 
# Assumption: ontology file has been downloaded to `./ontology_data/<filename>`. 

# In[2]:


data_path = "ontology_data"
path1 = os.path.join(data_path, "einsteins_riddle.owl.txt")


# In[3]:


# get an overview what is inside the Ontology
onto = owl2.get_ontology(path1).load()
print("classes (concepts):\n", list(onto.classes()), "\n"*2)
print("properties (roles):\n", list(onto.properties()), "\n"*2)
print("individuals:\n", list(onto.individuals()))


# ### Relations before calling the reasoner

# In[4]:


list(onto.lives_in.get_relations())


# In[5]:


list(onto.owns.get_relations())


# ### Calling the reasoner and inspect relations again

# In[6]:


get_ipython().run_line_magic('time', 'owl2.sync_reasoner_pellet(infer_property_values=True, infer_data_property_values=True, debug=0)')


# In[7]:


rels = list(onto.lives_in.get_relations())
print(rels)


# In[8]:


rels = list(onto.owns.get_relations())
print(rels)


# In[9]:


for r in rels:
    print(f"n.{r[0].name}.owns: n.{r[1].name}")


# ### Conclusion
# 
# The puzzle could be solved easily by the reasoner
# 
# ---
# 
# Note: This Puzzle is also an example of [yamlpyowl](https://github.com/cknoll/yamlpyowl) – an experimental package to represent OWL-Ontologies in YAML:
# 
# <https://github.com/cknoll/yamlpyowl/blob/main/doc/demo_notebooks/zebra_puzzle.ipynb>
# 
#