# -*- coding: utf-8 -*-
# (c) 2009-2022 Martin Wendt and contributors; see WsgiDAV https://github.com/mar10/wsgidav
# Original PyFileServer (c) 2005 Ho Chun Wei.
# Licensed under the MIT license:
# http://www.opensource.org/licenses/mit-license.php
r"""
::

     _      __         _ ___  ___ _   __
    | | /| / /__ ___  (_) _ \/ _ | | / /
    | |/ |/ (_-</ _ `/ / // / __ | |/ /
    |__/|__/___/\_, /_/____/_/ |_|___/
               /___/

WSGI container, that handles the HTTP requests. This object is passed to the
WSGI server and represents our WsgiDAV application to the outside.

On init:

    Use the configuration dictionary to initialize lock manager, property manager,
    domain controller.

    Create a dictionary of share-to-provider mappings.

    Initialize middleware objects and setup the WSGI application stack.

For every request:

    Find the registered DAV provider for the current request.

    Add or modify info in the WSGI ``environ``:

        environ["SCRIPT_NAME"]
            Mount-point of the current share.
        environ["PATH_INFO"]
            Resource path, relative to the mount path.
        environ["wsgidav.provider"]
            DAVProvider object that is registered for handling the current
            request.
        environ["wsgidav.config"]
            Configuration dictionary.
        environ["wsgidav.verbose"]
            Debug level [0-3].

    Log the HTTP request, then pass the request to the first middleware.

    Note: The OPTIONS method for the '*' path is handled directly.

"""
import copy
import inspect
import platform
import sys
import time
from urllib.parse import unquote

from wsgidav import __version__, util
from wsgidav.dav_provider import DAVProvider
from wsgidav.default_conf import DEFAULT_CONFIG
from wsgidav.fs_dav_provider import FilesystemProvider
from wsgidav.http_authenticator import HTTPAuthenticator
from wsgidav.lock_man.lock_manager import LockManager
from wsgidav.lock_man.lock_storage import LockStorageDict
from wsgidav.mw.base_mw import BaseMiddleware
from wsgidav.prop_man.property_manager import PropertyManager
from wsgidav.util import (
    dynamic_import_class,
    dynamic_instantiate_class_from_opts,
    safe_re_encode,
)

__docformat__ = "reStructuredText"

_logger = util.get_module_logger(__name__)


def _check_config(config):
    errors = []

    mandatory_fields = ("provider_mapping",)
    for field in mandatory_fields:
        if field not in config:
            errors.append(f"Missing required option '{field}'.")

    deprecated_fields = {
        "acceptbasic": "http_authenticator.accept_basic",
        "acceptdigest": "http_authenticator.accept_digest",
        "catchall": "error_printer.catch_all",
        "debug_litmus": "logging.debug_litmus",
        "debug_methods": "logging.debug_methods",
        "defaultdigest": "http_authenticator.default_to_digest",
        "dir_browser.app_class": "middleware_stack",
        "dir_browser.ms_mount": "(removed)",
        "dir_browser.ms_sharepoint_plugin": "dir_browser.ms_sharepoint_support",
        "dir_browser.ms_sharepoint_url": "dir_browser.ms_sharepoint_support",
        "domain_controller": "http_authenticator.domain_controller",
        "domaincontroller": "http_authenticator.domain_controller",
        "emulate_win32_lastmod": "hotfixes.emulate_win32_lastmod",
        "enable_loggers": "logging.enable_loggers",
        "error_printer.catch_all": "(removed)",
        "http_authenticator.preset_domain": "nt_dc.preset_domain",
        "http_authenticator.preset_server": "nt_dc.preset_server",
        "locksmanager": "lock_manager",
        "lock_manager": "lock_storage",
        "logger_date_format": "logging.logger_date_format",
        "logger_format": "logging.logger_format",
        "logging.verbose": "verbose",  # prevent a likely mistake
        "mutableLiveProps": "mutable_live_props",
        "propsmanager": "property_manager",
        "re_encode_path_info": "hotfixes.re_encode_path_info",
        "response_headers": "(see Cors middleware)",
        "trusted_auth_header": "http_authenticator.trusted_auth_header",
        "unquote_path_info": "hotfixes.unquote_path_info",
        "user_mapping": "simple_dc.user_mapping",
        # "dir_browser.enable": "middleware_stack",
    }
    for old, new in deprecated_fields.items():
        if "." in old:
            k, v = old.split(".", 1)
            d = config.get(k, {})
        else:
            d, v = config, old

        if d and v in d:
            errors.append(f"Deprecated option '{old}': use '{new}' instead.")

    if errors:
        raise ValueError("Invalid configuration:\n  - " + "\n  - ".join(errors))

    return True


# ========================================================================
# WsgiDAVApp
# ========================================================================
class WsgiDAVApp:
    def __init__(self, config):

        self.config = copy.deepcopy(DEFAULT_CONFIG)
        util.deep_update(self.config, config)
        config = self.config

        expand = {"${application}": self}

        # Evaluate configuration and set defaults
        _check_config(config)

        self.verbose = config.get("verbose", 3)

        hotfixes = util.get_dict_value(config, "hotfixes", as_dict=True)

        self.re_encode_path_info = hotfixes.get("re_encode_path_info", True)
        if type(self.re_encode_path_info) is not bool:
            raise ValueError("re_encode_path_info must be bool (or omitted)")
        self.unquote_path_info = hotfixes.get("unquote_path_info", False)

        lock_storage = config.get("lock_storage")
        if lock_storage is True:
            lock_storage = LockStorageDict()
        elif isinstance(lock_storage, (str, dict)):
            lock_storage = dynamic_instantiate_class_from_opts(
                lock_storage, expand=expand
            )

        if not lock_storage:
            # Normalize False, 0 to None
            self.lock_manager = None
        else:
            if not hasattr(lock_storage, "refresh"):
                raise ValueError(f"Invalid lock_storage: {lock_storage!r}")
            self.lock_manager = LockManager(lock_storage)

        prop_manager = config.get("property_manager")
        if prop_manager is True:
            prop_manager = PropertyManager()
        elif isinstance(prop_manager, (str, dict)):
            prop_manager = dynamic_instantiate_class_from_opts(
                prop_manager, expand=expand
            )

        if not prop_manager:
            # Normalize False, 0 to None
            self.prop_manager = None
        else:
            self.prop_manager = prop_manager

        # If mount path is configured, it must start with "/" (but no trailing slash)
        mount_path = config.get("mount_path")
        if mount_path:
            if not mount_path.startswith("/") or mount_path.endswith("/"):
                raise ValueError(
                    f"If a mount_path is set, it must start (but not end) with '/': '{mount_path}'."
                )
        else:
            mount_path = ""
        self.mount_path = mount_path

        auth_conf = util.get_dict_value(config, "http_authenticator", as_dict=True)

        # Instantiate DAV resource provider objects for every share.
        # provider_mapping may contain the args that are passed to a
        # `FilesystemProvider` instance:
        #     <share_path>: <folder_path>
        # or
        #     <share_path>: { "root": <folder_path>, "readonly": True }
        # or contain a complete new instance:
        #     <share_path>: <DAVProvider Instance>

        provider_mapping = self.config["provider_mapping"]

        self.provider_map = {}
        self.sorted_share_list = None
        for share, provider in provider_mapping.items():
            self.add_provider(share, provider)

        self.http_authenticator = None
        domain_controller = None

        # Define WSGI application stack
        middleware_stack = config.get("middleware_stack", [])
        mw_list = []

        # This is the 'outer' application, i.e. the WSGI application object that
        # is eventually called by the server.
        self.application = self

        # The `middleware_stack` is configured such that the first app in the
        # list should be called first. Since every app wraps its predecessor, we
        # iterate in reverse order:
        for mw in reversed(middleware_stack):
            # The middleware stack configuration may contain plain strings, dicts,
            # classes, or objects
            app = None
            if util.is_basestring(mw):
                # If a plain string is passed, try to import it, assuming
                # `BaseMiddleware` signature
                app_class = dynamic_import_class(mw)
                app = app_class(self, self.application, config)
            elif type(mw) is dict:
                # If a dict with one entry is passed, expect {class: ..., kwargs: ...}
                expand = {"${application}": self.application}
                app = dynamic_instantiate_class_from_opts(mw, expand=expand)
            elif inspect.isclass(mw):
                # If a class is passed, assume BaseMiddleware (or compatible)
                # TODO: remove this assert with 3.0
                assert issubclass(mw, BaseMiddleware)
                app = mw(self, self.application, config)
            else:
                # Otherwise assume an initialized middleware instance
                app = mw

            # Remember
            if isinstance(app, HTTPAuthenticator):
                self.http_authenticator = app
                domain_controller = app.get_domain_controller()

            # Add middleware to the stack
            if app:
                if callable(getattr(app, "is_disabled", None)) and app.is_disabled():
                    _logger.warning(
                        "App {}.is_disabled() returned True: skipping.".format(app)
                    )
                else:
                    mw_list.append(app)
                    self.application = app
            else:
                _logger.error("Could not add middleware {}.".format(mw))

        _logger.info(
            "WsgiDAV/{} Python/{} {}".format(
                __version__, util.PYTHON_VERSION, platform.platform(aliased=True)
            )
        )
        if self.verbose >= 4:
            _logger.info(
                "Default encoding: {!r} (file system: {!r})".format(
                    sys.getdefaultencoding(), sys.getfilesystemencoding()
                )
            )

        if self.verbose >= 3:
            _logger.info(f"Lock manager:      {self.lock_manager}")
            _logger.info(f"Property manager:  {self.prop_manager}")
            _logger.info(f"Domain controller: {domain_controller}")

        if self.verbose >= 4:
            # We traversed the stack in reverse order. Now revert again, so
            # we see the order that was configured:
            _logger.info("Middleware stack:")
            for mw in reversed(mw_list):
                _logger.info(f"  - {mw}")

        if self.verbose >= 3:
            _logger.info("Registered DAV providers by route:")
            for share in self.sorted_share_list:
                provider = self.provider_map[share]
                if domain_controller:
                    if domain_controller.is_share_anonymous(share):
                        hint = " (anonymous)"
                    else:
                        hint = ""
                else:
                    hint = " (custom auth)"
                _logger.info(f"  - '{share}': {provider}{hint}")

        if auth_conf.get("accept_basic") and not config.get("ssl_certificate"):
            _logger.warning(
                "Basic authentication is enabled: It is highly recommended to enable SSL."
            )

        if domain_controller:
            for share, provider in self.provider_map.items():
                if domain_controller.is_share_anonymous(share):
                    _logger.warning(
                        "Share '{}' will allow anonymous {} access.".format(
                            share, "read" if provider.is_readonly() else "write"
                        )
                    )

        if self.mount_path:
            _logger.info(f"Configured mount path: '{self.mount_path}'.")

        return

    def add_provider(self, share, provider, *, readonly=False):
        """Add a provider to the provider_map routing table."""
        # Make sure share starts with, or is '/'
        share = "/" + share.strip("/")
        assert share not in self.provider_map

        if type(provider) is str:
            # Syntax:
            #   <>: <folder_path>
            # We allow a simple string as 'provider'. In this case we interpret
            # it as a file system root folder that is published.
            provider = util.fix_path(provider, self.config)
            provider = FilesystemProvider(provider, readonly=readonly)

        elif type(provider) in (dict,):
            if "class" in provider:
                # Syntax:
                #   <>: {"class": <class_path>, "args": <pos_args>, "kwargs": <named_args>}
                expand = {"${application}": self}
                provider = dynamic_instantiate_class_from_opts(provider, expand=expand)
            elif "root" in provider:
                # Syntax:
                #   <share_path>: {"root": <path>, "redaonly": <bool>}
                provider = FilesystemProvider(
                    util.fix_path(provider["root"], self.config),
                    readonly=bool(provider.get("readonly", False)),
                )
            else:
                raise ValueError(
                    f"Provider expected {{'class': ...}}` or {{'root': ...}}: {provider}"
                )
        elif type(provider) in (list, tuple):
            raise ValueError(
                f"Provider {provider}: tuple/list syntax is no longer supported"
            )
            # provider = FilesystemProvider(provider[0], provider[1])

        if not isinstance(provider, DAVProvider):
            raise ValueError(f"Invalid provider {provider}")

        provider.set_share_path(share)
        if self.mount_path:
            provider.set_mount_path(self.mount_path)

        # TODO: someday we may want to configure different lock/prop
        # managers per provider
        provider.set_lock_manager(self.lock_manager)
        provider.set_prop_manager(self.prop_manager)

        self.provider_map[share] = provider
        # self.provider_map[share] = {"provider": provider, "allow_anonymous": False}

        # Store the list of share paths, ordered by length, so route lookups
        # will return the most specific match
        self.sorted_share_list = [s.lower() for s in self.provider_map.keys()]
        self.sorted_share_list = sorted(self.sorted_share_list, key=len, reverse=True)

        return provider

    def resolve_provider(self, path):
        """Get the registered DAVProvider for a given path.

        Returns:
            tuple: (share, provider)
        """
        # Find DAV provider that matches the share
        share = None
        lower_path = path.lower()
        for r in self.sorted_share_list:
            # @@: Case sensitivity should be an option of some sort here;
            # os.path.normpath might give the preferred case for a filename.
            if r == "/":
                share = r
                break
            elif lower_path == r or lower_path.startswith(r + "/"):
                share = r
                break

        if share is None:
            return None, None
        return share, self.provider_map.get(share)

    def __call__(self, environ, start_response):

        # util.log("SCRIPT_NAME='{}', PATH_INFO='{}'".format(
        #    environ.get("SCRIPT_NAME"), environ.get("PATH_INFO")))

        path = environ["PATH_INFO"]

        # WSGI always assumes iso-8859-1. Modern clients send UTF-8, so we may
        # have to re-encode.
        # See also:
        # - Issue #73
        # - https://www.python.org/dev/peps/pep-3333/#unicode-issues
        # - https://bugs.python.org/issue16679#msg177450
        # (The hotfixes.re_encode_path_info option is true by default.)
        if self.re_encode_path_info:
            path = environ["PATH_INFO"] = util.re_encode_wsgi(path)

        # We optionally unquote PATH_INFO here, although this should already be
        # done by the server (#8, #228).
        if self.unquote_path_info:
            path = unquote(environ["PATH_INFO"])

        # GC issue 22: Pylons sends root as u'/'
        if not util.is_str(path):
            _logger.warning(f"Got non-native PATH_INFO: {path!r}")
            # path = path.encode("utf8")
            path = util.to_str(path)

        # Always adding these values to environ:
        environ["wsgidav.config"] = self.config
        environ["wsgidav.provider"] = None
        environ["wsgidav.verbose"] = self.verbose

        # Find DAV provider that matches the share
        share, provider = self.resolve_provider(path)
        # share = None
        # lower_path = path.lower()
        # for r in self.sorted_share_list:
        #     # @@: Case sensitivity should be an option of some sort here;
        #     # os.path.normpath might give the preferred case for a filename.
        #     if r == "/":
        #         share = r
        #         break
        #     elif lower_path == r or lower_path.startswith(r + "/"):
        #         share = r
        #         break

        # Note: we call the next app, even if provider is None, because OPTIONS
        #       must still be handled.
        #       All other requests will result in '404 Not Found'
        # if share is not None:
        #     share_data = self.provider_map.get(share)
        #     environ["wsgidav.provider"] = share_data["provider"]

        environ["wsgidav.provider"] = provider
        # TODO: test with multi-level realms: 'aa/bb'
        # TODO: test security: url contains '..'

        # Transform SCRIPT_NAME and PATH_INFO
        # (Since path and share are unquoted, this also fixes quoted values.)
        if share == "/" or not share:
            environ["PATH_INFO"] = path
        else:
            environ["SCRIPT_NAME"] += share
            environ["PATH_INFO"] = path[len(share) :]

        # assert isinstance(path, str)
        assert util.is_str(path)
        # See http://mail.python.org/pipermail/web-sig/2007-January/002475.html
        # for some clarification about SCRIPT_NAME/PATH_INFO format
        # SCRIPT_NAME starts with '/' or is empty
        assert environ["SCRIPT_NAME"] == "" or environ["SCRIPT_NAME"].startswith("/")
        # SCRIPT_NAME must not have a trailing '/'
        assert environ["SCRIPT_NAME"] in ("", "/") or not environ[
            "SCRIPT_NAME"
        ].endswith("/")
        # PATH_INFO starts with '/'
        assert environ["PATH_INFO"] == "" or environ["PATH_INFO"].startswith("/")

        start_time = time.time()

        def _start_response_wrapper(status, response_headers, exc_info=None):
            # Postprocess response headers
            headerDict = {}
            for header, value in response_headers:
                if header.lower() in headerDict:
                    _logger.error(f"Duplicate header in response: {header}")
                headerDict[header.lower()] = value

            # Check if we should close the connection after this request.
            # http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.4
            forceCloseConnection = False
            currentContentLength = headerDict.get("content-length")
            statusCode = int(status.split(" ", 1)[0])
            contentLengthRequired = (
                environ["REQUEST_METHOD"] != "HEAD"
                and statusCode >= 200
                and statusCode not in (204, 304)
            )
            # _logger.info(environ["REQUEST_METHOD"], statusCode, contentLengthRequired)
            if contentLengthRequired and currentContentLength in (None, ""):
                # A typical case: a GET request on a virtual resource, for which
                # the provider doesn't know the length
                _logger.error(
                    "Missing required Content-Length header in {}-response: closing connection".format(
                        statusCode
                    )
                )
                forceCloseConnection = True
            elif not type(currentContentLength) is str:
                _logger.error(
                    "Invalid Content-Length header in response ({!r}): closing connection".format(
                        headerDict.get("content-length")
                    )
                )
                forceCloseConnection = True

            # HOTFIX for Vista and Windows 7 (GC issue 13, issue 23)
            # It seems that we must read *all* of the request body, otherwise
            # clients may miss the response.
            # For example Vista MiniRedir didn't understand a 401 response,
            # when trying an anonymous PUT of big files. As a consequence, it
            # doesn't retry with credentials and the file copy fails.
            # (XP is fine however).
            util.read_and_discard_input(environ)

            # Make sure the socket is not reused, unless we are 100% sure all
            # current input was consumed
            if util.get_content_length(environ) != 0 and not environ.get(
                "wsgidav.all_input_read"
            ):
                _logger.warning(
                    "Input stream not completely consumed: closing connection."
                )
                forceCloseConnection = True

            if forceCloseConnection and headerDict.get("connection") != "close":
                _logger.warning("Adding 'Connection: close' header.")
                response_headers.append(("Connection", "close"))

            # Log request
            if self.verbose >= 3:
                userInfo = environ.get("wsgidav.auth.user_name")
                if not userInfo:
                    userInfo = "(anonymous)"
                extra = []
                if "HTTP_DESTINATION" in environ:
                    extra.append('dest="{}"'.format(environ.get("HTTP_DESTINATION")))
                if environ.get("CONTENT_LENGTH", "") != "":
                    extra.append("length={}".format(environ.get("CONTENT_LENGTH")))
                if "HTTP_DEPTH" in environ:
                    extra.append("depth={}".format(environ.get("HTTP_DEPTH")))
                if "HTTP_RANGE" in environ:
                    extra.append("range={}".format(environ.get("HTTP_RANGE")))
                if "HTTP_OVERWRITE" in environ:
                    extra.append("overwrite={}".format(environ.get("HTTP_OVERWRITE")))
                if self.verbose >= 3 and "HTTP_EXPECT" in environ:
                    extra.append('expect="{}"'.format(environ.get("HTTP_EXPECT")))
                if self.verbose >= 4 and "HTTP_CONNECTION" in environ:
                    extra.append(
                        'connection="{}"'.format(environ.get("HTTP_CONNECTION"))
                    )
                if self.verbose >= 4 and "HTTP_USER_AGENT" in environ:
                    extra.append('agent="{}"'.format(environ.get("HTTP_USER_AGENT")))
                if self.verbose >= 4 and "HTTP_TRANSFER_ENCODING" in environ:
                    extra.append(
                        "transfer-enc={}".format(environ.get("HTTP_TRANSFER_ENCODING"))
                    )
                if self.verbose >= 3:
                    extra.append("elap={:.3f}sec".format(time.time() - start_time))
                extra = ", ".join(extra)

                # This is the CherryPy format:
                #   127.0.0.1 - - [08/Jul/2009:17:25:23] "GET /loginPrompt?redirect=/renderActionList%3Frelation%3Dpersonal%26key%3D%26filter%3DprivateSchedule&reason=0 HTTP/1.1" 200 1944 "http://127.0.0.1:8002/command?id=CMD_Schedule" "Mozilla/5.0 (Windows; U; Windows NT 6.0; de; rv:1.9.1) Gecko/20090624 Firefox/3.5"  # noqa
                _logger.info(
                    '{addr} - {user} - [{time}] "{method} {path}" {extra} -> {status}'.format(
                        addr=environ.get("REMOTE_ADDR", ""),
                        user=userInfo,
                        time=util.get_log_time(),
                        method=environ.get("REQUEST_METHOD"),
                        path=safe_re_encode(
                            environ.get("PATH_INFO", ""),
                            sys.stdout.encoding if sys.stdout.encoding else "utf-8",
                        ),
                        extra=extra,
                        status=status,
                        # response_headers.get(""), # response Content-Length
                        # referer
                    )
                )
            return start_response(status, response_headers, exc_info)

        # Call first middleware
        app_iter = self.application(environ, _start_response_wrapper)
        try:
            for v in app_iter:
                yield v
        finally:
            if hasattr(app_iter, "close"):
                app_iter.close()

        return
