"""
core.pkg.backend - Remote backend constructor

This package will exposes the major important object for the package core
remote part of the vxsdk.

    =========================== ============================================
    Object name                 Description
    =========================== ============================================
      PKG_CORE_BACKEND_REMOTE   Remote ackend object
      PKG_CORE_BACKEND_LOCAL    Local backend object
      VxRemoteBackend           Abstract class for backend implementation
    =========================== ======================================

This part of the vxsdk can be manually configured using a TOML configuration
which need to be located at <~/.config/vxsdk/configure.toml>. A special
section named 'package.remote' can be added to specify backend information:

    [pkg]
    backend.name = 'gitea'
    backend.url  = 'https://personal.gitea.instance.gaming'

This is the only configuration that you can set here.
"""
import os
import sys

from core.pkg.backend.local import VxBackendLocal
from core.logger import log
from core.config import config

__all__ = [
    'PKG_CORE_BACKEND_REMOTE',
    'PKG_CORE_BACKEND_LOCAL',
]

#---
# Internals
#---

class _VxPKGBackendException(Exception):
    """ custom backend exception wrapper """

#---
# Public
#---

backend_remote_name = config.get('pkg.backend.name')
backend_remote_url  = config.get('pkg.backend.url')
backend_local_url   = os.path.expanduser(config.get('pkg.local_storage'))

PKG_CORE_BACKEND_REMOTE = None
PKG_CORE_BACKEND_LOCAL = None
try:
    mod = __import__(
        f'core.pkg.backend.{backend_remote_name}',
        fromlist=['VxBackendRemote']
    )
    if not hasattr(mod, 'VxBackendRemote'):
        raise _VxPKGBackendException(
            f"backend '{backend_remote_name}' doesn't expose "
            "VxBackendRemote class"
        )
    PKG_CORE_BACKEND_REMOTE = mod.VxBackendRemote(backend_remote_url)
    PKG_CORE_BACKEND_LOCAL = VxBackendLocal(backend_local_url)
except ImportError as err:
    log.emergency("[backend] unable to load remote backend, abord")
    log.emergency(err)
    sys.exit(84)