import io
import os
import re
import tempfile
import mgzip as gzip
import tarfile
import sqlite3
import pathlib

import crypt


class Backup:
    key = None
    tarball_size = "50M"
    save_location = None

    def __init__(self, key, bdd):
        self.key = key
        self.bdd = DataBase(bdd)

    def recurse(self, path):
        tarball_size = parse_size(self.tarball_size)
        files = []
        print("Start", path, ":", files)
        for f in os.listdir(path):
            uri = os.path.join(path, f)
            if os.path.isfile(uri):
                size = os.path.getsize(uri)
                print(f + " : ", human_size(size))
                if size > tarball_size:
                    crypt_name = self.bdd.add([{'name': f, 'path': path, 'size': size}], compress_mode="gz")
                    enc = crypt(compress(uri), self.key)
                    save(enc, os.path.join(self.save_location, crypt_name))
                else:
                    files.append({'name': f, 'path': path, 'size': size})
            elif os.path.isdir(uri):
                self.recurse(uri)
        if len(files) > 0:
            print("End", path, ":", files)
            crypt_name = self.bdd.add(files, compress_mode="tar.gz")
            tarball = tar(files)
            enc = crypt(compress(tarball), self.key)
            save(enc, os.path.join(self.save_location, crypt_name))


def tar(files):
    tarball = tempfile.SpooledTemporaryFile()
    with tarfile.open(fileobj=tarball, mode='w') as zipfile:
        for file in files:
            zipfile.add(file['path'])
    return tarball


def untar(tar_file, files, save_path):
    if type(tar_file) is io.BufferedRandom or tempfile.SpooledTemporaryFile:
        tar_file.seek(0)
        zipfile = tarfile.open(fileobj=tar_file, mode='r')
    else:
        zipfile = tarfile.open(tar_file, 'r')
    for file in files:
        zipfile.extract(file['path'], path=save_path)
    zipfile.close()


def compress(file):
    if type(file) is str:
        infile = open(file, 'rb')
    elif type(file) is io.BufferedRandom or tempfile.SpooledTemporaryFile:
        file.seek(0)
        infile = file

    compressed_file = tempfile.SpooledTemporaryFile()
    with gzip.open(compressed_file, 'wb') as zipfile:
        while chunk := infile.read(64 * 1024):
            zipfile.write(chunk)
    return compressed_file


def uncompress(file):
    if type(file) is io.BufferedRandom or tempfile.SpooledTemporaryFile:
        file.seek(0)

    decompressed_file = tempfile.SpooledTemporaryFile()
    with gzip.open(file, 'rb') as zipfile:
        while chunk := zipfile.read(64 * 1024):
            decompressed_file.write(chunk)
    return decompressed_file


def crypt(file, key):
    encrypted_file = tempfile.SpooledTemporaryFile()
    crypt.encrypt_file(key, file, encrypted_file)
    return encrypted_file


def uncrypt(file, key):
    decrypted_file = tempfile.SpooledTemporaryFile()
    crypt.decrypt_file(key, file, decrypted_file)
    return decrypted_file


def save(file, save_path):
    if not os.path.isdir(os.path.dirname(save_path)):
        os.mkdir(os.path.dirname(save_path))

    if type(file) is io.BufferedRandom or tempfile.SpooledTemporaryFile:
        file.seek(0)
        with open(save_path, 'wb') as save:
            while chunk := file.read(64 * 1024):
                save.write(chunk)
    else:
        print("Unable to save " + str(file) + " of type " + str(type(file)))
        return


class DataBase:

    def __init__(self, base_file):
        self.conn = sqlite3.connect(base_file)
        self.__create_table()

    def __del__(self):
        self.conn.commit()
        self.conn.close()

    def __create_table(self):
        cursor = self.conn.cursor()

        cursor.execute("""
        CREATE TABLE IF NOT EXISTS files(
            id INTEGER PRIMARY KEY UNIQUE NOT NULL,
            name TEXT,
            path TEXT,
            size TEXT,
            crypt_id INTEGER,
            CONSTRAINT files_crypt_FK FOREIGN KEY (crypt_id) REFERENCES crypt(id)
        )
        """)

        cursor.execute("""
        CREATE TABLE IF NOT EXISTS crypt(
            id INTEGER PRIMARY KEY UNIQUE NOT NULL,
            compress_mode TEXT
        )
        """)

        self.conn.commit()

    def get_crypt_id(self, list_file):
        cursor = self.conn.cursor()
        crypt_id_list = []
        for file in list_file:
            cursor.execute("""SELECT crypt_id FROM files WHERE name=? AND path=?""",
                           (file['name'], file['path']))
            try:
                crypt_id_list.append(cursor.fetchone()[0])
            except TypeError:
                pass
            if len(crypt_id_list) > 0:
                return most_frequent(crypt_id_list)
            else:
                return None

    def exist(self, file):
        cursor = self.conn.cursor()
        cursor.execute("""SELECT EXISTS (SELECT 1 FROM files WHERE name=? AND path=?)""",
                       (file['name'], file['path']))
        return cursor.fetchone()[0]

    def add(self, list_file, compress_mode=None):
        cursor = self.conn.cursor()
        crypt_id = self.get_crypt_id(list_file)
        if crypt_id is None:
            cursor.execute("""SELECT IFNULL(max(id) + 1, 0) FROM crypt""")
            crypt_id = cursor.fetchone()[0]
        cursor.execute("""SELECT IFNULL(max(id) + 1, 0) FROM files""")
        files_id = cursor.fetchone()[0]
        for file in list_file:
            if self.exist(file):
                cursor.execute("""UPDATE files SET size=?, crypt_id=? WHERE name=? AND path=?""",
                               (file['size'], crypt_id, file['name'], file['path']))
            else:
                cursor.execute("""INSERT INTO files VALUES(?, ?, ?, ?, ?)""",
                               (files_id, file['name'], file['path'], file['size'], crypt_id))
                files_id += 1

        cursor.execute("""INSERT OR IGNORE INTO crypt VALUES(?, ?)""", (crypt_id, compress_mode))
        self.conn.commit()
        return str(crypt_id)


def human_size(size, decimal_places=0):
    for unit in ['B', 'K', 'M', 'G', 'T']:
        if size < 1024.0:
            break
        size /= 1024.0
    return f"{size:.{decimal_places}f}{unit}"


def parse_size(size):
    units = {"B": 1, "K": 2**10, "M": 2**20, "G": 2**30, "T": 2**40}
    if size[-1].isdigit():
        size = size + 'K'
    number, unit = re.match(r"([0-9]+)([BKMGT])", size, re.I).groups()
    return int(float(number)*units[unit])


def most_frequent(list):
    return max(set(list), key = list.count)