"""hug/routing.py

Defines the chainable classes responsible for defining the routing of Python functions for use with Falcon
and CLIs

Copyright (C) 2016  Timothy Edmund Crosley

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
documentation files (the "Software"), to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and
to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

"""
from __future__ import absolute_import

import os
import re
from collections import OrderedDict
from functools import wraps
from urllib.parse import urljoin

import falcon
from falcon import HTTP_METHODS

import hug.api
import hug.interface
import hug.output_format
from hug import introspect
from hug.exceptions import InvalidTypeData


class Router(object):
    """The base chainable router object"""

    __slots__ = ("route",)

    def __init__(
        self,
        transform=None,
        output=None,
        validate=None,
        api=None,
        requires=(),
        map_params=None,
        args=None,
        **kwargs
    ):
        self.route = {}
        if transform is not None:
            self.route["transform"] = transform
        if output:
            self.route["output"] = output
        if validate:
            self.route["validate"] = validate
        if api:
            self.route["api"] = api
        if requires:
            self.route["requires"] = (
                (requires,) if not isinstance(requires, (tuple, list)) else requires
            )
        if map_params:
            self.route["map_params"] = map_params
        if args:
            self.route["args"] = args

    def output(self, formatter, **overrides):
        """Sets the output formatter that should be used to render this route"""
        return self.where(output=formatter, **overrides)

    def transform(self, function, **overrides):
        """Sets the function that should be used to transform the returned Python structure into something
           serializable by specified output format
        """
        return self.where(transform=function, **overrides)

    def validate(self, validation_function, **overrides):
        """Sets the secondary validation fucntion to use for this handler"""
        return self.where(validate=validation_function, **overrides)

    def api(self, api, **overrides):
        """Sets the API that should contain this route"""
        return self.where(api=api, **overrides)

    def requires(self, requirements, **overrides):
        """Adds additional requirements to the specified route"""
        return self.where(
            requires=tuple(self.route.get("requires", ())) + tuple(requirements), **overrides
        )

    def doesnt_require(self, requirements, **overrides):
        """Removes individual requirements while keeping all other defined ones within a route"""
        return self.where(
            requires=tuple(
                set(self.route.get("requires", ())).difference(
                    requirements if type(requirements) in (list, tuple) else (requirements,)
                )
            )
        )

    def map_params(self, **map_params):
        """Map interface specific params to an internal name representation"""
        return self.where(map_params=map_params)

    def where(self, **overrides):
        """Creates a new route, based on the current route, with the specified overrided values"""
        route_data = self.route.copy()
        route_data.update(overrides)
        return self.__class__(**route_data)


class CLIRouter(Router):
    """The CLIRouter provides a chainable router that can be used to route a CLI command to a Python function"""

    __slots__ = ()

    def __init__(self, name=None, version=None, doc=None, **kwargs):
        super().__init__(**kwargs)
        if name is not None:
            self.route["name"] = name
        if version:
            self.route["version"] = version
        if doc:
            self.route["doc"] = doc

    def name(self, name, **overrides):
        """Sets the name for the CLI interface"""
        return self.where(name=name, **overrides)

    def version(self, version, **overrides):
        """Sets the version for the CLI interface"""
        return self.where(version=version, **overrides)

    def doc(self, documentation, **overrides):
        """Sets the documentation for the CLI interface"""
        return self.where(doc=documentation, **overrides)

    def __call__(self, api_function):
        """Enables exposing a Hug compatible function as a Command Line Interface"""
        hug.interface.CLI(self.route, api_function)
        return api_function


class InternalValidation(Router):
    """Defines the base route for interfaces that define their own internal validation"""

    __slots__ = ()

    def __init__(self, raise_on_invalid=False, on_invalid=None, output_invalid=None, **kwargs):
        super().__init__(**kwargs)
        if raise_on_invalid:
            self.route["raise_on_invalid"] = raise_on_invalid
        if on_invalid is not None:
            self.route["on_invalid"] = on_invalid
        if output_invalid is not None:
            self.route["output_invalid"] = output_invalid

    def raise_on_invalid(self, setting=True, **overrides):
        """Sets the route to raise validation errors instead of catching them"""
        return self.where(raise_on_invalid=setting, **overrides)

    def on_invalid(self, function, **overrides):
        """Sets a function to use to transform data on validation errors.

        Defaults to the transform function if one is set to ensure no special
        handling occurs for invalid data set to `False`.
        """
        return self.where(on_invalid=function, **overrides)

    def output_invalid(self, output_handler, **overrides):
        """Sets an output handler to be used when handler validation fails.

        Defaults to the output formatter set globally for the route.
        """
        return self.where(output_invalid=output_handler, **overrides)


class LocalRouter(InternalValidation):
    """The LocalRouter defines how interfaces should be handled when accessed locally from within Python code"""

    __slots__ = ()

    def __init__(self, directives=True, validate=True, version=None, **kwargs):
        super().__init__(**kwargs)
        if version is not None:
            self.route["version"] = version
        if not directives:
            self.route["skip_directives"] = True
        if not validate:
            self.route["skip_validation"] = True

    def directives(self, use=True, **kwargs):
        return self.where(directives=use)

    def validate(self, enforce=True, **kwargs):
        return self.where(validate=enforce)

    def version(self, supported, **kwargs):
        return self.where(version=supported)

    def __call__(self, api_function):
        """Enables exposing a hug compatible function locally"""
        return hug.interface.Local(self.route, api_function)


class HTTPRouter(InternalValidation):
    """The HTTPRouter provides the base concept of a router from an HTTPRequest to a Python function"""

    __slots__ = ()

    def __init__(
        self,
        versions=any,
        parse_body=False,
        parameters=None,
        defaults=None,
        status=None,
        response_headers=None,
        private=False,
        inputs=None,
        **kwargs
    ):
        if defaults is None:
            defaults = {}
        super().__init__(**kwargs)
        if versions is not any:
            self.route["versions"] = (
                (versions,) if isinstance(versions, (int, float, None.__class__)) else versions
            )
            self.route["versions"] = tuple(
                int(version) if version else version for version in self.route["versions"]
            )
        if parse_body:
            self.route["parse_body"] = parse_body
        if parameters:
            self.route["parameters"] = parameters
        if defaults:
            self.route["defaults"] = defaults
        if status:
            self.route["status"] = status
        if response_headers:
            self.route["response_headers"] = response_headers
        if private:
            self.route["private"] = private
        if inputs:
            self.route["inputs"] = inputs

    def versions(self, supported, **overrides):
        """Sets the versions that this route should be compatiable with"""
        return self.where(versions=supported, **overrides)

    def parse_body(self, automatic=True, **overrides):
        """Tells hug to automatically parse the input body if it matches a registered input format"""
        return self.where(parse_body=automatic, **overrides)

    def set_status(self, status, **overrides):
        """Sets the status that will be returned by default"""
        return self.where(status=status, **overrides)

    def parameters(self, parameters, **overrides):
        """Sets the custom parameters that will be used instead of those found introspecting the decorated function"""
        return self.where(parameters=parameters, **overrides)

    def defaults(self, defaults, **overrides):
        """Sets the custom defaults that will be used for custom parameters"""
        return self.where(defaults=defaults, **overrides)

    def _create_interface(self, api, api_function, catch_exceptions=True):
        interface = hug.interface.HTTP(self.route, api_function, catch_exceptions)
        return (interface, api_function)

    def response_headers(self, headers, **overrides):
        """Sets the response headers automatically injected by the router"""
        return self.where(response_headers=headers, **overrides)

    def add_response_headers(self, headers, **overrides):
        """Adds the specified response headers while keeping existing ones in-tact"""
        response_headers = self.route.get("response_headers", {}).copy()
        response_headers.update(headers)
        return self.where(response_headers=response_headers, **overrides)

    def cache(
        self,
        private=False,
        max_age=31536000,
        s_maxage=None,
        no_cache=False,
        no_store=False,
        must_revalidate=False,
        **overrides
    ):
        """Convenience method for quickly adding cache header to route"""
        parts = (
            "private" if private else "public",
            "max-age={0}".format(max_age),
            "s-maxage={0}".format(s_maxage) if s_maxage is not None else None,
            no_cache and "no-cache",
            no_store and "no-store",
            must_revalidate and "must-revalidate",
        )
        return self.add_response_headers(
            {"cache-control": ", ".join(filter(bool, parts))}, **overrides
        )

    def allow_origins(
        self, *origins, methods=None, max_age=None, credentials=None, headers=None, **overrides
    ):
        """Convenience method for quickly allowing other resources to access this one"""
        response_headers = {}
        if origins:

            @hug.response_middleware(api=self.route.get("api", None))
            def process_data(request, response, resource):
                if "ORIGIN" in request.headers:
                    origin = request.headers["ORIGIN"]
                    if origin in origins:
                        response.set_header("Access-Control-Allow-Origin", origin)

        else:
            response_headers["Access-Control-Allow-Origin"] = "*"

        if methods:
            response_headers["Access-Control-Allow-Methods"] = ", ".join(methods)
        if max_age:
            response_headers["Access-Control-Max-Age"] = max_age
        if credentials:
            response_headers["Access-Control-Allow-Credentials"] = str(credentials).lower()
        if headers:
            response_headers["Access-Control-Allow-Headers"] = headers
        return self.add_response_headers(response_headers, **overrides)


class NotFoundRouter(HTTPRouter):
    """Provides a chainable router that can be used to route 404'd request to a Python function"""

    __slots__ = ()

    def __init__(self, output=None, versions=any, status=falcon.HTTP_NOT_FOUND, **kwargs):
        super().__init__(output=output, versions=versions, status=status, **kwargs)

    def __call__(self, api_function):
        api = self.route.get("api", hug.api.from_object(api_function))
        (interface, callable_method) = self._create_interface(api, api_function)
        for version in self.route.get("versions", (None,)):
            api.http.set_not_found_handler(interface, version)

        return callable_method


class SinkRouter(HTTPRouter):
    """Provides a chainable router that can be used to route all routes pass a certain base URL (essentially route/*)"""

    __slots__ = ()

    def __init__(self, urls=None, output=None, **kwargs):
        super().__init__(output=output, **kwargs)
        if urls:
            self.route["urls"] = (urls,) if isinstance(urls, str) else urls

    def __call__(self, api_function):
        api = self.route.get("api", hug.api.from_object(api_function))
        (interface, callable_method) = self._create_interface(api, api_function)
        for base_url in self.route.get("urls", ("/{0}".format(api_function.__name__),)):
            api.http.add_sink(interface, base_url)
        return callable_method


class StaticRouter(SinkRouter):
    """Provides a chainable router that can be used to return static files automatically from a set of directories"""

    __slots__ = ("route",)

    def __init__(self, urls=None, output=hug.output_format.file, cache=False, **kwargs):
        super().__init__(urls=urls, output=output, **kwargs)
        if cache is True:
            self.cache()
        elif cache is not False:
            self.cache(**cache)

    def __call__(self, api_function):
        directories = []
        for directory in api_function():
            path = os.path.abspath(directory)
            directories.append(path)

        api = self.route.get("api", hug.api.from_object(api_function))
        for base_url in self.route.get("urls", ("/{0}".format(api_function.__name__),)):

            def read_file(request=None, path=""):
                filename = path.lstrip("/")
                for directory in directories:
                    path = os.path.abspath(os.path.join(directory, filename))
                    if not path.startswith(directory):
                        hug.redirect.not_found()
                    if os.path.isdir(path):
                        new_path = os.path.join(path, "index.html")
                        if os.path.exists(new_path) and os.path.isfile(new_path):
                            path = new_path
                    if os.path.exists(path) and os.path.isfile(path):
                        return path

                hug.redirect.not_found()

            api.http.add_sink(self._create_interface(api, read_file)[0], base_url)
        return api_function


class ExceptionRouter(HTTPRouter):
    """Provides a chainable router that can be used to route exceptions thrown during request handling"""

    __slots__ = ()

    def __init__(self, exceptions=(Exception,), exclude=(), output=None, **kwargs):
        super().__init__(output=output, **kwargs)
        self.route["exceptions"] = (
            (exceptions,) if not isinstance(exceptions, (list, tuple)) else exceptions
        )
        self.route["exclude"] = (exclude,) if not isinstance(exclude, (list, tuple)) else exclude

    def __call__(self, api_function):
        api = self.route.get("api", hug.api.from_object(api_function))
        (interface, callable_method) = self._create_interface(
            api, api_function, catch_exceptions=False
        )
        for version in self.route.get("versions", (None,)):
            for exception in self.route["exceptions"]:
                api.http.add_exception_handler(exception, interface, version)

        return callable_method

    def _create_interface(self, api, api_function, catch_exceptions=False):
        interface = hug.interface.ExceptionRaised(self.route, api_function, catch_exceptions)
        return (interface, api_function)


class URLRouter(HTTPRouter):
    """Provides a chainable router that can be used to route a URL to a Python function"""

    __slots__ = ()

    def __init__(
        self,
        urls=None,
        accept=HTTP_METHODS,
        output=None,
        examples=(),
        versions=any,
        suffixes=(),
        prefixes=(),
        response_headers=None,
        parse_body=True,
        **kwargs
    ):
        super().__init__(
            output=output,
            versions=versions,
            parse_body=parse_body,
            response_headers=response_headers,
            **kwargs
        )
        if urls is not None:
            self.route["urls"] = (urls,) if isinstance(urls, str) else urls
        if accept:
            self.route["accept"] = (accept,) if isinstance(accept, str) else accept
        if examples:
            self.route["examples"] = (examples,) if isinstance(examples, str) else examples
        if suffixes:
            self.route["suffixes"] = (suffixes,) if isinstance(suffixes, str) else suffixes
        if prefixes:
            self.route["prefixes"] = (prefixes,) if isinstance(prefixes, str) else prefixes

    def __call__(self, api_function):
        api = self.route.get("api", hug.api.from_object(api_function))
        api.http.routes.setdefault(api.http.base_url, OrderedDict())
        (interface, callable_method) = self._create_interface(api, api_function)

        use_examples = self.route.get("examples", ())
        if not interface.required and not use_examples:
            use_examples = (True,)

        for base_url in self.route.get("urls", ("/{0}".format(api_function.__name__),)):
            expose = [base_url]
            for suffix in self.route.get("suffixes", ()):
                if suffix.startswith("/"):
                    expose.append(os.path.join(base_url, suffix.lstrip("/")))
                else:
                    expose.append(base_url + suffix)
            for prefix in self.route.get("prefixes", ()):
                expose.append(prefix + base_url)
            for url in expose:
                handlers = api.http.routes[api.http.base_url].setdefault(url, {})
                for method in self.route.get("accept", ()):
                    version_mapping = handlers.setdefault(method.upper(), {})
                    for version in self.route.get("versions", (None,)):
                        version_mapping[version] = interface
                        api.http.versioned.setdefault(version, {})[
                            callable_method.__name__
                        ] = callable_method

        interface.examples = use_examples
        return callable_method

    def urls(self, *urls, **overrides):
        """Sets the URLs that will map to this API call"""
        return self.where(urls=urls, **overrides)

    def accept(self, *accept, **overrides):
        """Sets a list of HTTP methods this router should accept"""
        return self.where(accept=accept, **overrides)

    def get(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to a GET"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="GET", **overrides)

    def delete(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to DELETE"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="DELETE", **overrides)

    def post(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to POST"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="POST", **overrides)

    def put(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to PUT"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="PUT", **overrides)

    def trace(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to TRACE"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="TRACE", **overrides)

    def patch(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to PATCH"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="PATCH", **overrides)

    def options(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to OPTIONS"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="OPTIONS", **overrides)

    def head(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to HEAD"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="HEAD", **overrides)

    def connect(self, urls=None, **overrides):
        """Sets the acceptable HTTP method to CONNECT"""
        if urls is not None:
            overrides["urls"] = urls
        return self.where(accept="CONNECT", **overrides)

    def call(self, **overrides):
        """Sets the acceptable HTTP method to all known"""
        return self.where(accept=HTTP_METHODS, **overrides)

    def http(self, **overrides):
        """Sets the acceptable HTTP method to all known"""
        return self.where(accept=HTTP_METHODS, **overrides)

    def get_post(self, **overrides):
        """Exposes a Python method externally under both the HTTP POST and GET methods"""
        return self.where(accept=("GET", "POST"), **overrides)

    def put_post(self, **overrides):
        """Exposes a Python method externally under both the HTTP POST and PUT methods"""
        return self.where(accept=("PUT", "POST"), **overrides)

    def examples(self, *examples, **overrides):
        """Sets the examples that the route should use"""
        return self.where(examples=examples, **overrides)

    def suffixes(self, *suffixes, **overrides):
        """Sets the suffixes supported by the route"""
        return self.where(suffixes=suffixes, **overrides)

    def prefixes(self, *prefixes, **overrides):
        """Sets the prefixes supported by the route"""
        return self.where(prefixes=prefixes, **overrides)

    def where(self, **overrides):
        if "urls" in overrides:
            existing_urls = self.route.get("urls", ())
            use_urls = []
            for url in (
                (overrides["urls"],) if isinstance(overrides["urls"], str) else overrides["urls"]
            ):
                if url.startswith("/") or not existing_urls:
                    use_urls.append(url)
                else:
                    for existing in existing_urls:
                        use_urls.append(urljoin(existing.rstrip("/") + "/", url))
            overrides["urls"] = tuple(use_urls)

        return super().where(**overrides)
