"""Import the given python module(s) and report error(s) encountered."""
from __future__ import annotations


def main():
    """
    Main program function used to isolate globals from imported code.
    Changes to globals in imported modules on Python 2.x will overwrite our own globals.
    """
    import os
    import sys
    import types

    # preload an empty ansible._vendor module to prevent use of any embedded modules during the import test
    vendor_module_name = 'ansible._vendor'

    vendor_module = types.ModuleType(vendor_module_name)
    vendor_module.__file__ = os.path.join(os.path.sep.join(os.path.abspath(__file__).split(os.path.sep)[:-8]), 'lib/ansible/_vendor/__init__.py')
    vendor_module.__path__ = []
    vendor_module.__package__ = vendor_module_name

    sys.modules[vendor_module_name] = vendor_module

    import ansible
    import contextlib
    import datetime
    import json
    import re
    import runpy
    import subprocess
    import traceback
    import warnings

    ansible_path = os.path.dirname(os.path.dirname(ansible.__file__))
    temp_path = os.environ['SANITY_TEMP_PATH'] + os.path.sep
    external_python = os.environ.get('SANITY_EXTERNAL_PYTHON')
    yaml_to_json_path = os.environ.get('SANITY_YAML_TO_JSON')
    collection_full_name = os.environ.get('SANITY_COLLECTION_FULL_NAME')
    collection_root = os.environ.get('ANSIBLE_COLLECTIONS_PATH')
    import_type = os.environ.get('SANITY_IMPORTER_TYPE')

    try:
        # noinspection PyCompatibility
        from importlib import import_module
    except ImportError:
        def import_module(name, package=None):  # type: (str, str | None) -> types.ModuleType
            assert package is None
            __import__(name)
            return sys.modules[name]

    from io import BytesIO, TextIOWrapper

    try:
        from importlib.util import spec_from_loader, module_from_spec
        from importlib.machinery import SourceFileLoader, ModuleSpec  # pylint: disable=unused-import
    except ImportError:
        has_py3_loader = False
    else:
        has_py3_loader = True

    if collection_full_name:
        # allow importing code from collections when testing a collection
        from ansible.module_utils.common.text.converters import to_bytes, to_text, to_native, text_type

        # noinspection PyProtectedMember
        from ansible.utils.collection_loader._collection_finder import _AnsibleCollectionFinder
        from ansible.utils.collection_loader import _collection_finder

        yaml_to_dict_cache = {}

        # unique ISO date marker matching the one present in yaml_to_json.py
        iso_date_marker = 'isodate:f23983df-f3df-453c-9904-bcd08af468cc:'
        iso_date_re = re.compile('^%s([0-9]{4})-([0-9]{2})-([0-9]{2})$' % iso_date_marker)

        def parse_value(value):
            """Custom value parser for JSON deserialization that recognizes our internal ISO date format."""
            if isinstance(value, text_type):
                match = iso_date_re.search(value)

                if match:
                    value = datetime.date(int(match.group(1)), int(match.group(2)), int(match.group(3)))

            return value

        def object_hook(data):
            """Object hook for custom ISO date deserialization from JSON."""
            return dict((key, parse_value(value)) for key, value in data.items())

        def yaml_to_dict(yaml, content_id):
            """
            Return a Python dict version of the provided YAML.
            Conversion is done in a subprocess since the current Python interpreter does not have access to PyYAML.
            """
            if content_id in yaml_to_dict_cache:
                return yaml_to_dict_cache[content_id]

            try:
                cmd = [external_python, yaml_to_json_path]
                proc = subprocess.Popen([to_bytes(c) for c in cmd],  # pylint: disable=consider-using-with
                                        stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                stdout_bytes, stderr_bytes = proc.communicate(to_bytes(yaml))

                if proc.returncode != 0:
                    raise Exception('command %s failed with return code %d: %s' % ([to_native(c) for c in cmd], proc.returncode, to_native(stderr_bytes)))

                data = yaml_to_dict_cache[content_id] = json.loads(to_text(stdout_bytes), object_hook=object_hook)

                return data
            except Exception as ex:
                raise Exception('internal importer error - failed to parse yaml: %s' % to_native(ex))

        _collection_finder._meta_yml_to_dict = yaml_to_dict  # pylint: disable=protected-access

        collection_loader = _AnsibleCollectionFinder(paths=[collection_root])
        # noinspection PyProtectedMember
        collection_loader._install()  # pylint: disable=protected-access
    else:
        # do not support collection loading when not testing a collection
        collection_loader = None

    if collection_loader and import_type == 'plugin':
        # do not unload ansible code for collection plugin (not module) tests
        # doing so could result in the collection loader being initialized multiple times
        pass
    else:
        # remove all modules under the ansible package, except the preloaded vendor module
        list(map(sys.modules.pop, [m for m in sys.modules if m.partition('.')[0] == ansible.__name__ and m != vendor_module_name]))

    if import_type == 'module':
        # pre-load an empty ansible package to prevent unwanted code in __init__.py from loading
        # this more accurately reflects the environment that AnsiballZ runs modules under
        # it also avoids issues with imports in the ansible package that are not allowed
        ansible_module = types.ModuleType(ansible.__name__)
        ansible_module.__file__ = ansible.__file__
        ansible_module.__path__ = ansible.__path__
        ansible_module.__package__ = ansible.__package__

        sys.modules[ansible.__name__] = ansible_module

    class ImporterAnsibleModuleException(Exception):
        """Exception thrown during initialization of ImporterAnsibleModule."""

    class ImporterAnsibleModule:
        """Replacement for AnsibleModule to support import testing."""
        def __init__(self, *args, **kwargs):
            raise ImporterAnsibleModuleException()

    class RestrictedModuleLoader:
        """Python module loader that restricts inappropriate imports."""
        def __init__(self, path, name, restrict_to_module_paths):
            self.path = path
            self.name = name
            self.loaded_modules = set()
            self.restrict_to_module_paths = restrict_to_module_paths

        def find_spec(self, fullname, path=None, target=None):  # pylint: disable=unused-argument
            # type: (RestrictedModuleLoader, str, list[str], types.ModuleType | None ) -> ModuleSpec | None | ImportError
            """Return the spec from the loader or None"""
            loader = self._get_loader(fullname, path=path)
            if loader is not None:
                if has_py3_loader:
                    # loader is expected to be Optional[importlib.abc.Loader], but RestrictedModuleLoader does not inherit from importlib.abc.Loader
                    return spec_from_loader(fullname, loader)  # type: ignore[arg-type]
                raise ImportError("Failed to import '%s' due to a bug in ansible-test. Check importlib imports for typos." % fullname)
            return None

        def find_module(self, fullname, path=None):
            # type: (RestrictedModuleLoader, str, list[str]) -> RestrictedModuleLoader | None
            """Return self if the given fullname is restricted, otherwise return None."""
            return self._get_loader(fullname, path=path)

        def _get_loader(self, fullname, path=None):
            # type: (RestrictedModuleLoader, str, list[str]) -> RestrictedModuleLoader | None
            """Return self if the given fullname is restricted, otherwise return None."""
            if fullname in self.loaded_modules:
                return None  # ignore modules that are already being loaded

            if is_name_in_namepace(fullname, ['ansible']):
                if not self.restrict_to_module_paths:
                    return None  # for non-modules, everything in the ansible namespace is allowed

                if fullname in ('ansible.module_utils.basic',):
                    return self  # intercept loading so we can modify the result

                if is_name_in_namepace(fullname, ['ansible.module_utils', self.name]):
                    return None  # module_utils and module under test are always allowed

                if any(os.path.exists(candidate_path) for candidate_path in convert_ansible_name_to_absolute_paths(fullname)):
                    return self  # restrict access to ansible files that exist

                return None  # ansible file does not exist, do not restrict access

            if is_name_in_namepace(fullname, ['ansible_collections']):
                if not collection_loader:
                    return self  # restrict access to collections when we are not testing a collection

                if not self.restrict_to_module_paths:
                    return None  # for non-modules, everything in the ansible namespace is allowed

                if is_name_in_namepace(fullname, ['ansible_collections...plugins.module_utils', self.name]):
                    return None  # module_utils and module under test are always allowed

                if collection_loader.find_module(fullname, path):
                    return self  # restrict access to collection files that exist

                return None  # collection file does not exist, do not restrict access

            # not a namespace we care about
            return None

        def create_module(self, spec):  # pylint: disable=unused-argument
            # type: (RestrictedModuleLoader, ModuleSpec) -> None
            """Return None to use default module creation."""
            return None

        def exec_module(self, module):
            # type: (RestrictedModuleLoader, types.ModuleType) -> None | ImportError
            """Execute the module if the name is ansible.module_utils.basic and otherwise raise an ImportError"""
            fullname = module.__spec__.name
            if fullname == 'ansible.module_utils.basic':
                self.loaded_modules.add(fullname)
                for path in convert_ansible_name_to_absolute_paths(fullname):
                    if not os.path.exists(path):
                        continue
                    loader = SourceFileLoader(fullname, path)
                    spec = spec_from_loader(fullname, loader)
                    real_module = module_from_spec(spec)
                    loader.exec_module(real_module)
                    real_module.AnsibleModule = ImporterAnsibleModule  # type: ignore[attr-defined]
                    real_module._load_params = lambda *args, **kwargs: {}  # type: ignore[attr-defined] # pylint: disable=protected-access
                    sys.modules[fullname] = real_module
                    return None
                raise ImportError('could not find "%s"' % fullname)
            raise ImportError('import of "%s" is not allowed in this context' % fullname)

        def load_module(self, fullname):
            # type: (RestrictedModuleLoader, str) -> types.ModuleType | ImportError
            """Return the module if the name is ansible.module_utils.basic and otherwise raise an ImportError."""
            if fullname == 'ansible.module_utils.basic':
                module = self.__load_module(fullname)

                # stop Ansible module execution during AnsibleModule instantiation
                module.AnsibleModule = ImporterAnsibleModule  # type: ignore[attr-defined]
                # no-op for _load_params since it may be called before instantiating AnsibleModule
                module._load_params = lambda *args, **kwargs: {}  # type: ignore[attr-defined] # pylint: disable=protected-access

                return module

            raise ImportError('import of "%s" is not allowed in this context' % fullname)

        def __load_module(self, fullname):
            # type: (RestrictedModuleLoader, str) -> types.ModuleType
            """Load the requested module while avoiding infinite recursion."""
            self.loaded_modules.add(fullname)
            return import_module(fullname)

    def run(restrict_to_module_paths):
        """Main program function."""
        base_dir = os.getcwd()
        messages = set()

        for path in sys.argv[1:] or sys.stdin.read().splitlines():
            name = convert_relative_path_to_name(path)
            test_python_module(path, name, base_dir, messages, restrict_to_module_paths)

        if messages:
            sys.exit(10)

    def test_python_module(path, name, base_dir, messages, restrict_to_module_paths):
        """Test the given python module by importing it.
        :type path: str
        :type name: str
        :type base_dir: str
        :type messages: set[str]
        :type restrict_to_module_paths: bool
        """
        if name in sys.modules:
            return  # cannot be tested because it has already been loaded

        is_ansible_module = (path.startswith('lib/ansible/modules/') or path.startswith('plugins/modules/')) and os.path.basename(path) != '__init__.py'
        run_main = is_ansible_module

        if path == 'lib/ansible/modules/async_wrapper.py':
            # async_wrapper is a non-standard Ansible module (does not use AnsibleModule) so we cannot test the main function
            run_main = False

        capture_normal = Capture()
        capture_main = Capture()

        run_module_ok = False

        try:
            with monitor_sys_modules(path, messages):
                with restrict_imports(path, name, messages, restrict_to_module_paths):
                    with capture_output(capture_normal):
                        import_module(name)

            if run_main:
                run_module_ok = is_ansible_module

                with monitor_sys_modules(path, messages):
                    with restrict_imports(path, name, messages, restrict_to_module_paths):
                        with capture_output(capture_main):
                            runpy.run_module(name, run_name='__main__', alter_sys=True)
        except ImporterAnsibleModuleException:
            # module instantiated AnsibleModule without raising an exception
            if not run_module_ok:
                if is_ansible_module:
                    report_message(path, 0, 0, 'module-guard', "AnsibleModule instantiation not guarded by `if __name__ == '__main__'`", messages)
                else:
                    report_message(path, 0, 0, 'non-module', "AnsibleModule instantiated by import of non-module", messages)
        except BaseException as ex:  # pylint: disable=locally-disabled, broad-except
            # intentionally catch all exceptions, including calls to sys.exit
            exc_type, _exc, exc_tb = sys.exc_info()
            message = str(ex)
            results = list(reversed(traceback.extract_tb(exc_tb)))
            line = 0
            offset = 0
            full_path = os.path.join(base_dir, path)
            base_path = base_dir + os.path.sep
            source = None

            # avoid line wraps in messages
            message = re.sub(r'\n *', ': ', message)

            for result in results:
                if result[0] == full_path:
                    # save the line number for the file under test
                    line = result[1] or 0

                if not source and result[0].startswith(base_path) and not result[0].startswith(temp_path):
                    # save the first path and line number in the traceback which is in our source tree
                    source = (os.path.relpath(result[0], base_path), result[1] or 0, 0)

            if isinstance(ex, SyntaxError):
                # SyntaxError has better information than the traceback
                if ex.filename == full_path:  # pylint: disable=locally-disabled, no-member
                    # syntax error was reported in the file under test
                    line = ex.lineno or 0  # pylint: disable=locally-disabled, no-member
                    offset = ex.offset or 0  # pylint: disable=locally-disabled, no-member
                elif ex.filename.startswith(base_path) and not ex.filename.startswith(temp_path):  # pylint: disable=locally-disabled, no-member
                    # syntax error was reported in our source tree
                    source = (os.path.relpath(ex.filename, base_path), ex.lineno or 0, ex.offset or 0)  # pylint: disable=locally-disabled, no-member

                # remove the filename and line number from the message
                # either it was extracted above, or it's not really useful information
                message = re.sub(r' \(.*?, line [0-9]+\)$', '', message)

            if source and source[0] != path:
                message += ' (at %s:%d:%d)' % (source[0], source[1], source[2])

            report_message(path, line, offset, 'traceback', '%s: %s' % (exc_type.__name__, message), messages)
        finally:
            capture_report(path, capture_normal, messages)
            capture_report(path, capture_main, messages)

    def is_name_in_namepace(name, namespaces):
        """Returns True if the given name is one of the given namespaces, otherwise returns False."""
        name_parts = name.split('.')

        for namespace in namespaces:
            namespace_parts = namespace.split('.')
            length = min(len(name_parts), len(namespace_parts))

            truncated_name = name_parts[0:length]
            truncated_namespace = namespace_parts[0:length]

            # empty parts in the namespace are treated as wildcards
            # to simplify the comparison, use those empty parts to indicate the positions in the name to be empty as well
            for idx, part in enumerate(truncated_namespace):
                if not part:
                    truncated_name[idx] = part

            # example: name=ansible, allowed_name=ansible.module_utils
            # example: name=ansible.module_utils.system.ping, allowed_name=ansible.module_utils
            if truncated_name == truncated_namespace:
                return True

        return False

    def check_sys_modules(path, before, messages):
        """Check for unwanted changes to sys.modules.
        :type path: str
        :type before: dict[str, module]
        :type messages: set[str]
        """
        after = sys.modules
        removed = set(before.keys()) - set(after.keys())
        changed = set(key for key, value in before.items() if key in after and value != after[key])

        # additions are checked by our custom PEP 302 loader, so we don't need to check them again here

        for module in sorted(removed):
            report_message(path, 0, 0, 'unload', 'unloading of "%s" in sys.modules is not supported' % module, messages)

        for module in sorted(changed):
            report_message(path, 0, 0, 'reload', 'reloading of "%s" in sys.modules is not supported' % module, messages)

    def convert_ansible_name_to_absolute_paths(name):
        """Calculate the module path from the given name.
        :type name: str
        :rtype: list[str]
        """
        return [
            os.path.join(ansible_path, name.replace('.', os.path.sep)),
            os.path.join(ansible_path, name.replace('.', os.path.sep)) + '.py',
        ]

    def convert_relative_path_to_name(path):
        """Calculate the module name from the given path.
        :type path: str
        :rtype: str
        """
        if path.endswith('/__init__.py'):
            clean_path = os.path.dirname(path)
        else:
            clean_path = path

        clean_path = os.path.splitext(clean_path)[0]

        name = clean_path.replace(os.path.sep, '.')

        if collection_loader:
            # when testing collections the relative paths (and names) being tested are within the collection under test
            name = 'ansible_collections.%s.%s' % (collection_full_name, name)
        else:
            # when testing ansible all files being imported reside under the lib directory
            name = name[len('lib/'):]

        return name

    class Capture:
        """Captured output and/or exception."""
        def __init__(self):
            # use buffered IO to simulate StringIO; allows Ansible's stream patching to behave without warnings
            self.stdout = TextIOWrapper(BytesIO())
            self.stderr = TextIOWrapper(BytesIO())

    def capture_report(path, capture, messages):
        """Report on captured output.
        :type path: str
        :type capture: Capture
        :type messages: set[str]
        """
        # since we're using buffered IO, flush before checking for data
        capture.stdout.flush()
        capture.stderr.flush()
        stdout_value = capture.stdout.buffer.getvalue()
        if stdout_value:
            first = stdout_value.decode().strip().splitlines()[0].strip()
            report_message(path, 0, 0, 'stdout', first, messages)

        stderr_value = capture.stderr.buffer.getvalue()
        if stderr_value:
            first = stderr_value.decode().strip().splitlines()[0].strip()
            report_message(path, 0, 0, 'stderr', first, messages)

    def report_message(path, line, column, code, message, messages):
        """Report message if not already reported.
        :type path: str
        :type line: int
        :type column: int
        :type code: str
        :type message: str
        :type messages: set[str]
        """
        message = '%s:%d:%d: %s: %s' % (path, line, column, code, message)

        if message not in messages:
            messages.add(message)
            print(message)

    @contextlib.contextmanager
    def restrict_imports(path, name, messages, restrict_to_module_paths):
        """Restrict available imports.
        :type path: str
        :type name: str
        :type messages: set[str]
        :type restrict_to_module_paths: bool
        """
        restricted_loader = RestrictedModuleLoader(path, name, restrict_to_module_paths)

        # noinspection PyTypeChecker
        sys.meta_path.insert(0, restricted_loader)
        sys.path_importer_cache.clear()

        try:
            yield
        finally:
            if import_type == 'plugin' and not collection_loader:
                from ansible.utils.collection_loader._collection_finder import _AnsibleCollectionFinder
                _AnsibleCollectionFinder._remove()  # pylint: disable=protected-access

            if sys.meta_path[0] != restricted_loader:
                report_message(path, 0, 0, 'metapath', 'changes to sys.meta_path[0] are not permitted', messages)

            while restricted_loader in sys.meta_path:
                # noinspection PyTypeChecker
                sys.meta_path.remove(restricted_loader)

            sys.path_importer_cache.clear()

    @contextlib.contextmanager
    def monitor_sys_modules(path, messages):
        """Monitor sys.modules for unwanted changes, reverting any additions made to our own namespaces."""
        snapshot = sys.modules.copy()

        try:
            yield
        finally:
            check_sys_modules(path, snapshot, messages)

            for key in set(sys.modules.keys()) - set(snapshot.keys()):
                if is_name_in_namepace(key, ('ansible', 'ansible_collections')):
                    del sys.modules[key]  # only unload our own code since we know it's native Python

    @contextlib.contextmanager
    def capture_output(capture):
        """Capture sys.stdout and sys.stderr.
        :type capture: Capture
        """
        old_stdout = sys.stdout
        old_stderr = sys.stderr

        sys.stdout = capture.stdout
        sys.stderr = capture.stderr

        # clear all warnings registries to make all warnings available
        for module in sys.modules.values():
            try:
                # noinspection PyUnresolvedReferences
                module.__warningregistry__.clear()
            except AttributeError:
                pass

        with warnings.catch_warnings():
            warnings.simplefilter('error')

            if collection_loader and import_type == 'plugin':
                warnings.filterwarnings(
                    "ignore",
                    "AnsibleCollectionFinder has already been configured")

            try:
                yield
            finally:
                sys.stdout = old_stdout
                sys.stderr = old_stderr

    run(import_type == 'module')


if __name__ == '__main__':
    main()
