"""
Helpers for plugin app
"""
import os
import subprocess
import pathlib
import sysconfig
import traceback
import inspect
import pkgutil

from django.conf import settings
from django.core.exceptions import AppRegistryNotReady


# region logging / errors
class IntegrationPluginError(Exception):
    """
    Error that encapsulates another error and adds the path / reference of the raising plugin
    """
    def __init__(self, path, message):
        self.path = path
        self.message = message

    def __str__(self):
        return self.message


class MixinImplementationError(ValueError):
    """
    Error if mixin was implemented wrong in plugin
    Mostly raised if constant is missing
    """
    pass


class MixinNotImplementedError(NotImplementedError):
    """
    Error if necessary mixin function was not overwritten
    """
    pass


def log_error(error, reference: str = 'general'):
    """
    Log an plugin error
    """
    from plugin import registry

    # make sure the registry is set up
    if reference not in registry.errors:
        registry.errors[reference] = []

    # add error to stack
    registry.errors[reference].append(error)


def handle_error(error, do_raise: bool = True, do_log: bool = True, do_return: bool = False, log_name: str = ''):
    """
    Handles an error and casts it as an IntegrationPluginError
    """
    package_path = traceback.extract_tb(error.__traceback__)[-1].filename
    install_path = sysconfig.get_paths()["purelib"]
    try:
        package_name = pathlib.Path(package_path).relative_to(install_path).parts[0]
    except ValueError:
        # is file - loaded -> form a name for that
        path_obj = pathlib.Path(package_path).relative_to(settings.BASE_DIR)
        path_parts = [*path_obj.parts]
        path_parts[-1] = path_parts[-1].replace(path_obj.suffix, '')  # remove suffix

        # remove path preixes
        if path_parts[0] == 'plugin':
            path_parts.remove('plugin')
            path_parts.pop(0)
        else:
            path_parts.remove('plugins')

        package_name = '.'.join(path_parts)

    if do_log:
        log_kwargs = {}
        if log_name:
            log_kwargs['reference'] = log_name
        log_error({package_name: str(error)}, **log_kwargs)

    new_error = IntegrationPluginError(package_name, str(error))

    if do_raise:
        raise IntegrationPluginError(package_name, str(error))

    if do_return:
        return new_error
# endregion


# region git-helpers
def get_git_log(path):
    """
    Get dict with info of the last commit to file named in path
    """
    path = path.replace(os.path.dirname(settings.BASE_DIR), '')[1:]
    command = ['git', 'log', '-n', '1', "--pretty=format:'%H%n%aN%n%aE%n%aI%n%f%n%G?%n%GK'", '--follow', '--', path]
    try:
        output = str(subprocess.check_output(command, cwd=os.path.dirname(settings.BASE_DIR)), 'utf-8')[1:-1]
        if output:
            output = output.split('\n')
        else:
            output = 7 * ['']
    except subprocess.CalledProcessError:
        output = 7 * ['']
    return {'hash': output[0], 'author': output[1], 'mail': output[2], 'date': output[3], 'message': output[4], 'verified': output[5], 'key': output[6]}


class GitStatus:
    """
    Class for resolving git gpg singing state
    """
    class Definition:
        """
        Definition of a git gpg sing state
        """
        key: str = 'N'
        status: int = 2
        msg: str = ''

        def __init__(self, key: str = 'N', status: int = 2, msg: str = '') -> None:
            self.key = key
            self.status = status
            self.msg = msg

    N = Definition(key='N', status=2, msg='no signature',)
    G = Definition(key='G', status=0, msg='valid signature',)
    B = Definition(key='B', status=2, msg='bad signature',)
    U = Definition(key='U', status=1, msg='good signature, unknown validity',)
    X = Definition(key='X', status=1, msg='good signature, expired',)
    Y = Definition(key='Y', status=1, msg='good signature, expired key',)
    R = Definition(key='R', status=2, msg='good signature, revoked key',)
    E = Definition(key='E', status=1, msg='cannot be checked',)
# endregion


# region plugin finders
def get_modules(pkg):
    """get all modules in a package"""

    context = {}
    for loader, name, ispkg in pkgutil.walk_packages(pkg.__path__):
        try:
            module = loader.find_module(name).load_module(name)
            pkg_names = getattr(module, '__all__', None)
            for k, v in vars(module).items():
                if not k.startswith('_') and (pkg_names is None or k in pkg_names):
                    context[k] = v
            context[name] = module
        except AppRegistryNotReady:
            pass
        except Exception as error:
            # this 'protects' against malformed plugin modules by more or less silently failing

            # log to stack
            log_error({name: str(error)}, 'discovery')

    return [v for k, v in context.items()]


def get_classes(module):
    """get all classes in a given module"""
    return inspect.getmembers(module, inspect.isclass)


def get_plugins(pkg, baseclass):
    """
    Return a list of all modules under a given package.

    - Modules must be a subclass of the provided 'baseclass'
    - Modules must have a non-empty PLUGIN_NAME parameter
    """

    plugins = []

    modules = get_modules(pkg)

    # Iterate through each module in the package
    for mod in modules:
        # Iterate through each class in the module
        for item in get_classes(mod):
            plugin = item[1]
            if issubclass(plugin, baseclass) and plugin.PLUGIN_NAME:
                plugins.append(plugin)

    return plugins
# endregion