# -*- coding: utf-8 -*-

from sqlalchemy import create_engine,  MetaData
from sqlalchemy.ext.automap import automap_base
from sqlalchemy.orm import Session


class Project():
    """ A helper class representing a Citavi project. """
    def __init__(self, sqlite_file):
        """ Constructor to get absolute path to sqlite. """
        self.sqlite_file = sqlite_file
        self._is_open = False
        self._is_error = False
        self._sa = {} # Object namespace for sqlalchemy related objects
        
    def __del__(self):
        """ Destructor to close the citavi file. """
        self.close()

    def is_valid(self):
        """ This method returns False in case the given sqlite file is not a valid Citavi project. """
        self.open()
        return self._is_open and not self._is_error

    def get_persons(self):
        """ Returns all persons from the Citavi project. """
        try:
            person_class = self._sa_sqlite_autobase.classes.Person
            citavi_persons = self._sa_sqlite_session.query(person_class).all()
            return citavi_persons
        except:
            self._is_error = True
            # TODO: better error handling!
            print "An error occured within a get_person call!"
            return False

    def open(self):
        """ Public method to open a citavi project file. """
        if not self._is_open:
            self._open()

    def close(self):
        """ Public method to close a citavi project file. """
        if self._is_open:
            self._close()

    def _open(self):
        """ Internal method to open a citavi project file. """
        try:
            self._sa_sqlite_engine = create_engine('sqlite+pysqlite:///' + self.sqlite_file)
            self._sa_sqlite_session = Session(self._sa_sqlite_engine)
            self._sa_sqlite_meta = MetaData(bind=self._sa_sqlite_engine)
            self._sa_sqlite_meta.reflect()
            self._sa_sqlite_autobase = automap_base()
            self._sa_sqlite_autobase.prepare(self._sa_sqlite_engine, reflect=True)
            self._is_open = True
        except:
            self._is_error = True
            self._is_open = False

    def _close(self):
        """ Internal method to actually close a citavi project file. """
        try:
            del self._sa.sqlite_engine
            del self._sa.sqlite_session
            del self._sa.sqlite_meta
            del self._sa.sqlite_autobase
            del self._sa.sqlite_engine
            self._is_open = False
        except:
            self._is_error = True
            self._is_open = True



    pass


class Mapper():
    """ A class encapsulating the django models for mapping against Citavi projects. """
    def __init__(self):
        pass
    
    def __del__(self):
        pass
    
    



"""

def import_sqlite(project_id, sqlite_file):
    print "This is import_sqlite speaking!"
    print project_id
    print sqlite_file
    print "Importing data..."
        
    # Initialize sqlite part
    sqlite_engine = create_engine('sqlite+pysqlite:///project_import_9.ctt4', echo=True)
    sqlite_session = Session(sqlite_engine)
    sqlite_meta = MetaData(bind=sqlite_engine)
    sqlite_meta.reflect()
    
    # Initialize postresql part
    psql_engine = create_engine("postgresql://citavi_mapper:foobar2000@localhost:5432/citavi_mapper")
    psql_session = Session(psql_engine)
    psql_engine.execute(CreateSchema('alchemytest')) # TODO: Catch Exception/Warning/Whatever here
    psql_meta = MetaData(bind=psql_engine, schema='alchemytest')
    
    # Reflect the origin - maybe psql_meta.reflect() is enough?
    sqlite_autobase = automap_base()
    sqlite_autobase.prepare(sqlite_engine, reflect=True)
    
    
    # This small snippet prints python class code for sqlalchemy reflected classes
    for table in sqlite_meta.sorted_tables:
        table_name = str(table)
        columns = table.columns.items()
        print "class " + table_name + "(Base):"
        print "    __tablename__ = '" + table_name + "'"
        print
        for column_tuple in columns:
            column_name = column_tuple[0]
            actual_sqlalchemy_column = column_tuple[1]
            column_type = str(vars(actual_sqlalchemy_column)['type'])
            column_type = str(vars(actual_sqlalchemy_column)['type'])
            #print table_name + "." + column_name + ': ' + column_type
            print "    " + column_name + " = Column(" + column_type + ")"
        print
        print
        
    # Shove it up into postgresql's ... you know.
    psql_meta.create_all(psql_engine)
    
    #sqlite_meta.reflect()
    
    #meta.tables['Reference']
    #meta.tables['ReferenceAuthor'].select().execute().fetchall()
    
    # Now we need to "convert" unsupported types :-/
    for table in meta.sorted_tables:
        table_name = str(table)
        columns = table.columns.items()
        for column_tuple in columns:
            column_name = column_tuple[0]
            actual_sqlalchemy_column = column_tuple[1]
            column_type = str(vars(actual_sqlalchemy_column)['type'])
            print table_name + "." + column_name + ': ' + column_type
        print
    print
"""