"""
This module provides a way to construct (persistent) databases
used by ``autoimport``. In normal mode this module is replaced
by ``tmpdb``, however it might be useful to keep the data produced
by ``autoimport``.
"""

import sqlite3
import abc
import os

class AbstractDatabase(abc.ABC):
    """
    Abstract base class for all ``TemporaryDatabase``
    implementations. 

    **Note**: ``__init__`` must set ``self._db`` to an
          open sqlite3 connection.
    """
    def __init__(self):
        abc.ABC.__init__(self)
        self._db = None

    @abc.abstractmethod
    def close(self):
        pass

    def cursor(self):
        return self._db.cursor()

    def dump_db(self, file):
        for line in self._db.iterdump():
            file.write("{}\n".format(line))
    def commit(self):
        return self._db.commit()

class PersistentDatabase(AbstractDatabase):
    def __init__(self, database_path):
        AbstractDatabase.__init__(self)
        self._database_path = database_path
        self._db = sqlite3.connect(database_path)

    def close(self):
        self._db.close()

def initialize_database(db):
    cursor = db.cursor()

    cursor.execute(
        '''CREATE TABLE FILES(
            name TEXT,
            DateTime TEXT,
            DateTimeDigitized TEXT,
            DateTimeOriginal TEXT,
            Model TEXT,
            Make TEXT,
            Software TEXT)'''
        )

    cursor.execute(
        '''CREATE TABLE DIRECTORIES(
            name TEXT)'''
        )

    cursor.execute(
        '''CREATE TABLE ASSOCIATIONS(file_id INTEGER,
            directory_id INTEGER)'''
        )

    cursor.execute(
        '''CREATE TABLE KV(key TEXT,
            value TEXT)'''
        )
    cursor.execute(
        '''CREATE TABLE EXTENSIONS_SEARCHED(extension TEXT)'''
        )
    db.commit()


def get_persistent_db(path):
    if(not os.path.exists(path)):
        if(not os.path.dirname(path)):
            db = PersistentDatabase(path)
            initialize_database(db)
            return db
        if(not os.path.exists(os.path.dirname(path))):
            raise IOError("path '{}' does not exist".format(os.path.dirname(path)))
        db = PersistentDatabase(path)
        initialize_database(db)
        return db
    return PersistentDatabase(path)