import json
import sqlite3
import tempfile
import zipfile
from json import loads as json_loads


class Loader:
	def load(self, file: str):
		raise NotImplementedError()

	def get_entry(self) -> object:
		raise NotImplementedError()


class JSONLoader(Loader):
	data = None

	def load(self, file: str):
		self.data = json.load(open(file))

	def get_entry(self) -> dict:
		for entry in self.data:
			yield entry


class SQLiteLoader(Loader):
	conn = None

	def load(self, file: str):
		self.conn = sqlite3.connect(file)

	def get_entry(self) -> dict:
		cursor = self.conn.cursor()
		cursor.execute("SELECT * FROM log_entry")
		for seq, timestamp, json in cursor.fetchall():
			yield json_loads(json)


class ZipSQLiteLoader(SQLiteLoader):
	def load(self, file: str):
		with zipfile.ZipFile(file, "r") as zipped_log, tempfile.TemporaryDirectory() as tmp:
			zipped_log.extract("instance_log.sqlite", path=tmp)
			super(ZipSQLiteLoader, self).load("{dir}/instance_log.sqlite".format(dir=tmp))


LOADERS = {
	"json": JSONLoader,
	"sqlite": SQLiteLoader,
	"zip": ZipSQLiteLoader
}