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

import json
import os
import subprocess

from . import crypto
from .paths import PRIVATE_KEY, REPO_META_FILE, REPO_SIG_FILE

class PackageExistsError(Exception):
    pass

class Packer:
    def __init__(self):
        self.tar_path = None
        self.tar_size = 0
        self.xz_path = None
        self.xz_size = 0
        if os.path.exists(REPO_META_FILE):
            with open(REPO_META_FILE, 'r') as f:
                self.packages = json.load(f)
        else:
            self.packages = {'apps': {}, 'images': {}}

    def save_repo_meta(self):
        with open(REPO_META_FILE, 'w') as f:
            json.dump(self.packages, f, sort_keys=True, indent=4)

    def compress_archive(self):
        # Compress the tarball with xz (LZMA2)
        self.tar_size = os.path.getsize(self.tar_path)
        print('Compressing', self.tar_path, '({:.2f} MB)'.format(self.tar_size/1048576))
        subprocess.run(['xz', '-9', self.tar_path])
        self.xz_size = os.path.getsize(self.xz_path)
        print('Compressed ', self.xz_path, '({:.2f} MB)'.format(self.xz_size/1048576))

    def sign_packages(self):
        signature = crypto.sign_file(PRIVATE_KEY, REPO_META_FILE)
        with open(REPO_SIG_FILE, 'wb') as f:
            f.write(signature)