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

import json
import os
import subprocess
import sys

from lxcmgr.paths import LXC_STORAGE_DIR

from . import crypto
from .paths import APP_DIR, IMAGE_DIR, META_FILE, PRIVATE_KEY, ROOT_DIR, SIGNATURE_FILE

class PackageExistsError(Exception):
    pass

class Packer:
    def __init__(self):
        self.app = None
        self.image = None
        self.tar_path = None
        self.xz_path = None

    def load_packages_meta(self):
        if os.path.exists(PKG_META):
            with open(PKG_META, 'r') as f:
                return json.load(f)
        else:
            return {'apps': {}, 'images': {}}

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


    def pack_image(self, image, force):
        self.image = image
        # Prepare package file names
        self.tar_path = os.path.join(IMAGE_DIR, '{}.tar'.format(self.image.name))
        self.xz_path = '{}.xz'.format(self.tar_path)
        if os.path.exists(self.xz_path):
            if force:
                self.unregister_image()
                os.unlink(self.xz_path)
            else:
                raise PackageExistsError(self.xz_path)
        self.create_image_archive()
        self.register_image()
        self.sign_packages()

    def create_image_archive(self):
        # Create archive
        print('Archiving', self.image.path)
        subprocess.run(['tar', '--xattrs', '-cpf', self.tar_path, self.image.name], cwd=LXC_STORAGE_DIR)
        self.compress_archive()

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

    def register_image(self):
        # Register package in global repository metadata file
        print('Registering package {}'.format(self.image.name))
        packages = self.load_packages_meta()
        packages['images'][self.image.name] = self.image.conf.copy()
        packages['images'][self.image.name]['size'] = os.path.getsize(self.xz_path)
        packages['images'][self.image.name]['sha512'] = crypto.hash_file(self.xz_path)
        self.save_packages_meta(packages)

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

    def unregister_image(self):
        # Removes package from global repository metadata file
        packages = self.load_packages_meta()
        if self.image.name in packages['images']:
            del packages['images'][self.image.name]
            self.save_packages_meta(packages)

    def pack_app(self, app):
        self.app = app
        # Prepare package file names
        self.tar_path = os.path.join(APP_DIR, '{}.tar'.format(self.image.name))
        self.xz_path = '{}.xz'.format(self.tar_path)
        if os.path.exists(self.xz_path):
            os.unlink(self.xz_path)
        self.create_app_archive()
        self.register_app()
        self.sign_packages()

    def create_app_archive(self):
        # Create archive with application setup scripts
        print('Archiving setup scripts for', self.app.name)
        scripts = ('install', 'install.sh', 'upgrade', 'upgrade.sh', 'uninstall', 'uninstall.sh')
        scripts = [s for s in scripts if os.path.exists(os.path.join(self.app.build_dir, s))]
        subprocess.run(['tar', '--xattrs', '-cpf', self.tar_path] + scripts, cwd=self.app.build_dir)
        self.compress_archive()

    def register_app(self):
        # Register package in global repository metadata file
        print('Registering package {}'.format(self.app.name))
        packages = self.load_packages_meta()
        packages['apps'][self.image.name] = self.app.conf.copy()
        packages['apps'][self.image.name]['size'] = os.path.getsize(self.xz_path)
        packages['apps'][self.image.name]['sha512'] = crypto.hash_file(self.xz_path)
        self.save_packages_meta(packages)