# Copyright 2016 by Rackspace Hosting, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Copyright 2016 by Rackspace Hosting, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""WSGI test client utilities.

This package includes utilities for simulating HTTP requests against a
WSGI callable, without having to stand up a WSGI server.
"""

import json
import wsgiref.validate

from falcon.testing import helpers
from falcon.testing.srmock import StartResponseMock
from falcon.util import CaseInsensitiveDict, to_query_str


class Result(object):
    """Encapsulates the result of a simulated WSGI request.

    Args:
        iterable (iterable): An iterable that yields zero or more
            bytestrings, per PEP-3333
        status (str): An HTTP status string, including status code and
            reason string
        headers (list): A list of (header_name, header_value) tuples,
            per PEP-3333

    Attributes:
        status (str): HTTP status string given in the response
        status_code (int): The code portion of the HTTP status string
        headers (CaseInsensitiveDict): A case-insensitive dictionary
            containing all the headers in the response
        encoding (str): Text encoding of the response body, or ``None``
            if the encoding can not be determined.
        content (bytes): Raw response body, or ``bytes`` if the
            response body was empty.
        text (str): Decoded response body of type ``unicode``
            under Python 2.6 and 2.7, and of type ``str`` otherwise.
            If the content type does not specify an encoding, UTF-8 is
            assumed.
        json (dict): Deserialized JSON body. Raises an error if the
            response is not JSON.
    """

    def __init__(self, iterable, status, headers):
        self._text = None

        self._content = b''.join(iterable)
        if hasattr(iterable, 'close'):
            iterable.close()

        self._status = status
        self._status_code = int(status[:3])
        self._headers = CaseInsensitiveDict(headers)

        self._encoding = helpers.get_encoding_from_headers(self._headers)

    @property
    def status(self):
        return self._status

    @property
    def status_code(self):
        return self._status_code

    @property
    def headers(self):
        return self._headers

    @property
    def encoding(self):
        return self._encoding

    @property
    def content(self):
        return self._content

    @property
    def text(self):
        if self._text is None:
            if not self.content:
                self._text = u''
            else:
                if self.encoding is None:
                    encoding = 'UTF-8'
                else:
                    encoding = self.encoding

                self._text = self.content.decode(encoding)

        return self._text

    @property
    def json(self):
        return json.loads(self.text)


def simulate_request(app, method='GET', path='/', query_string=None,
                     headers=None, body=None, file_wrapper=None,
                     params=None, params_csv=True):
        """Simulates a request to a WSGI application.

        Performs a request against a WSGI application. Uses
        :any:`wsgiref.validate` to ensure the response is valid
        WSGI.

        Keyword Args:
            app (callable): The WSGI application to call
            method (str): An HTTP method to use in the request
                (default: 'GET')
            path (str): The URL path to request (default: '/')
            params (dict): A dictionary of query string parameters,
                where each key is a parameter name, and each value is
                either a ``str`` or something that can be converted
                into a ``str``, or a list of such values. If a ``list``,
                the value will be converted to a comma-delimited string
                of values (e.g., 'thing=1,2,3').
            params_csv (bool): Set to ``False`` to encode list values
                in query string params by specifying multiple instances
                of the parameter (e.g., 'thing=1&thing=2&thing=3').
                Otherwise, parameters will be encoded as comma-separated
                values (e.g., 'thing=1,2,3'). Defaults to ``True``.
            query_string (str): A raw query string to include in the
                request (default: ``None``). If specified, overrides
                `params`.
            headers (dict): Additional headers to include in the request
                (default: ``None``)
            body (str): A string to send as the body of the request.
                Accepts both byte strings and Unicode strings
                (default: ``None``). If a Unicode string is provided,
                it will be encoded as UTF-8 in the request.
            file_wrapper (callable): Callable that returns an iterable,
                to be used as the value for *wsgi.file_wrapper* in the
                environ (default: ``None``). This can be used to test
                high-performance file transmission when `resp.stream` is
                set to a file-like object.

        Returns:
            :py:class:`~.Result`: The result of the request
        """

        if not path.startswith('/'):
            raise ValueError("path must start with '/'")

        if query_string and query_string.startswith('?'):
            raise ValueError("query_string should not start with '?'")

        if '?' in path:
            # NOTE(kgriffs): We could allow this, but then we'd need
            #   to define semantics regarding whether the path takes
            #   precedence over the query_string. Also, it would make
            #   tests less consistent, since there would be "more than
            #   one...way to do it."
            raise ValueError(
                'path may not contain a query string. Please use the '
                'query_string parameter instead.'
            )

        if query_string is None:
            query_string = to_query_str(
                params,
                comma_delimited_lists=params_csv,
                prefix=False,
            )

        env = helpers.create_environ(
            method=method,
            path=path,
            query_string=(query_string or ''),
            headers=headers,
            body=body,
            file_wrapper=file_wrapper,
        )

        srmock = StartResponseMock()
        validator = wsgiref.validate.validator(app)
        iterable = validator(env, srmock)

        result = Result(iterable, srmock.status, srmock.headers)

        return result


def simulate_get(app, path, **kwargs):
    """Simulates a GET request to a WSGI application.

    Equivalent to::

         simulate_request(app, 'GET', path, **kwargs)

    Args:
        app (callable): The WSGI application to call
        path (str): The URL path to request

    Keyword Args:
        params (dict): A dictionary of query string parameters,
            where each key is a parameter name, and each value is
            either a ``str`` or something that can be converted
            into a ``str``, or a list of such values. If a ``list``,
            the value will be converted to a comma-delimited string
            of values (e.g., 'thing=1,2,3').
        params_csv (bool): Set to ``False`` to encode list values
            in query string params by specifying multiple instances
            of the parameter (e.g., 'thing=1&thing=2&thing=3').
            Otherwise, parameters will be encoded as comma-separated
            values (e.g., 'thing=1,2,3'). Defaults to ``True``.
        query_string (str): A raw query string to include in the
            request (default: ``None``). If specified, overrides
            `params`.
        headers (dict): Additional headers to include in the request
            (default: ``None``)
        file_wrapper (callable): Callable that returns an iterable,
            to be used as the value for *wsgi.file_wrapper* in the
            environ (default: ``None``). This can be used to test
            high-performance file transmission when `resp.stream` is
            set to a file-like object.
    """
    return simulate_request(app, 'GET', path, **kwargs)


def simulate_head(app, path, **kwargs):
    """Simulates a HEAD request to a WSGI application.

    Equivalent to::

         simulate_request(app, 'HEAD', path, **kwargs)

    Args:
        app (callable): The WSGI application to call
        path (str): The URL path to request

    Keyword Args:
        params (dict): A dictionary of query string parameters,
            where each key is a parameter name, and each value is
            either a ``str`` or something that can be converted
            into a ``str``, or a list of such values. If a ``list``,
            the value will be converted to a comma-delimited string
            of values (e.g., 'thing=1,2,3').
        params_csv (bool): Set to ``False`` to encode list values
            in query string params by specifying multiple instances
            of the parameter (e.g., 'thing=1&thing=2&thing=3').
            Otherwise, parameters will be encoded as comma-separated
            values (e.g., 'thing=1,2,3'). Defaults to ``True``.
        query_string (str): A raw query string to include in the
            request (default: ``None``). If specified, overrides
            `params`.
        headers (dict): Additional headers to include in the request
            (default: ``None``)
    """
    return simulate_request(app, 'HEAD', path, **kwargs)


def simulate_post(app, path, **kwargs):
    """Simulates a POST request to a WSGI application.

    Equivalent to::

         simulate_request(app, 'POST', path, **kwargs)

    Args:
        app (callable): The WSGI application to call
        path (str): The URL path to request

    Keyword Args:
        params (dict): A dictionary of query string parameters,
            where each key is a parameter name, and each value is
            either a ``str`` or something that can be converted
            into a ``str``, or a list of such values. If a ``list``,
            the value will be converted to a comma-delimited string
            of values (e.g., 'thing=1,2,3').
        params_csv (bool): Set to ``False`` to encode list values
            in query string params by specifying multiple instances
            of the parameter (e.g., 'thing=1&thing=2&thing=3').
            Otherwise, parameters will be encoded as comma-separated
            values (e.g., 'thing=1,2,3'). Defaults to ``True``.
        headers (dict): Additional headers to include in the request
            (default: ``None``)
        body (str): A string to send as the body of the request.
            Accepts both byte strings and Unicode strings
            (default: ``None``). If a Unicode string is provided,
            it will be encoded as UTF-8 in the request.
    """
    return simulate_request(app, 'POST', path, **kwargs)


def simulate_put(app, path, **kwargs):
    """Simulates a PUT request to a WSGI application.

    Equivalent to::

         simulate_request(app, 'PUT', path, **kwargs)

    Args:
        app (callable): The WSGI application to call
        path (str): The URL path to request

    Keyword Args:
        params (dict): A dictionary of query string parameters,
            where each key is a parameter name, and each value is
            either a ``str`` or something that can be converted
            into a ``str``, or a list of such values. If a ``list``,
            the value will be converted to a comma-delimited string
            of values (e.g., 'thing=1,2,3').
        params_csv (bool): Set to ``False`` to encode list values
            in query string params by specifying multiple instances
            of the parameter (e.g., 'thing=1&thing=2&thing=3').
            Otherwise, parameters will be encoded as comma-separated
            values (e.g., 'thing=1,2,3'). Defaults to ``True``.
        headers (dict): Additional headers to include in the request
            (default: ``None``)
        body (str): A string to send as the body of the request.
            Accepts both byte strings and Unicode strings
            (default: ``None``). If a Unicode string is provided,
            it will be encoded as UTF-8 in the request.
    """
    return simulate_request(app, 'PUT', path, **kwargs)


def simulate_options(app, path, **kwargs):
    """Simulates an OPTIONS request to a WSGI application.

    Equivalent to::

         simulate_request(app, 'OPTIONS', path, **kwargs)

    Args:
        app (callable): The WSGI application to call
        path (str): The URL path to request

    Keyword Args:
        params (dict): A dictionary of query string parameters,
            where each key is a parameter name, and each value is
            either a ``str`` or something that can be converted
            into a ``str``, or a list of such values. If a ``list``,
            the value will be converted to a comma-delimited string
            of values (e.g., 'thing=1,2,3').
        params_csv (bool): Set to ``False`` to encode list values
            in query string params by specifying multiple instances
            of the parameter (e.g., 'thing=1&thing=2&thing=3').
            Otherwise, parameters will be encoded as comma-separated
            values (e.g., 'thing=1,2,3'). Defaults to ``True``.
        headers (dict): Additional headers to include in the request
            (default: ``None``)
    """
    return simulate_request(app, 'OPTIONS', path, **kwargs)


def simulate_patch(app, path, **kwargs):
    """Simulates a PATCH request to a WSGI application.

    Equivalent to::

         simulate_request(app, 'PATCH', path, **kwargs)

    Args:
        app (callable): The WSGI application to call
        path (str): The URL path to request

    Keyword Args:
        params (dict): A dictionary of query string parameters,
            where each key is a parameter name, and each value is
            either a ``str`` or something that can be converted
            into a ``str``, or a list of such values. If a ``list``,
            the value will be converted to a comma-delimited string
            of values (e.g., 'thing=1,2,3').
        params_csv (bool): Set to ``False`` to encode list values
            in query string params by specifying multiple instances
            of the parameter (e.g., 'thing=1&thing=2&thing=3').
            Otherwise, parameters will be encoded as comma-separated
            values (e.g., 'thing=1,2,3'). Defaults to ``True``.
        headers (dict): Additional headers to include in the request
            (default: ``None``)
        body (str): A string to send as the body of the request.
            Accepts both byte strings and Unicode strings
            (default: ``None``). If a Unicode string is provided,
            it will be encoded as UTF-8 in the request.
    """
    return simulate_request(app, 'PATCH', path, **kwargs)


def simulate_delete(app, path, **kwargs):
    """Simulates a DELETE request to a WSGI application.

    Equivalent to::

         simulate_request(app, 'DELETE', path, **kwargs)

    Args:
        app (callable): The WSGI application to call
        path (str): The URL path to request

    Keyword Args:
        params (dict): A dictionary of query string parameters,
            where each key is a parameter name, and each value is
            either a ``str`` or something that can be converted
            into a ``str``, or a list of such values. If a ``list``,
            the value will be converted to a comma-delimited string
            of values (e.g., 'thing=1,2,3').
        params_csv (bool): Set to ``False`` to encode list values
            in query string params by specifying multiple instances
            of the parameter (e.g., 'thing=1&thing=2&thing=3').
            Otherwise, parameters will be encoded as comma-separated
            values (e.g., 'thing=1,2,3'). Defaults to ``True``.
        headers (dict): Additional headers to include in the request
            (default: ``None``)
    """
    return simulate_request(app, 'DELETE', path, **kwargs)


class TestClient(object):
    """"Simulates requests to a WSGI application.

    This class provides a contextual wrapper for Falcon's simulate_*
    test functions. It lets you replace this::

        simulate_get(app, '/messages')
        simulate_head(app, '/messages')

    with this::

        client = TestClient(app)
        client.simulate_get('/messages')
        client.simulate_head('/messages')

    Args:
        app (callable): A WSGI application to target when simulating
            requests
    """

    def __init__(self, app):
        self.app = app

    def simulate_get(self, path='/', **kwargs):
        """Simulates a GET request to a WSGI application.

        See also: :py:meth:`falcon.testing.simulate_get`.
        """
        return simulate_get(self.app, path, **kwargs)

    def simulate_head(self, path='/', **kwargs):
        """Simulates a HEAD request to a WSGI application.

        See also: :py:meth:`falcon.testing.simulate_head`.
        """
        return simulate_head(self.app, path, **kwargs)

    def simulate_post(self, path='/', **kwargs):
        """Simulates a POST request to a WSGI application.

        See also: :py:meth:`falcon.testing.simulate_post`.
        """
        return simulate_post(self.app, path, **kwargs)

    def simulate_put(self, path='/', **kwargs):
        """Simulates a PUT request to a WSGI application.

        See also: :py:meth:`falcon.testing.simulate_put`.
        """
        return simulate_put(self.app, path, **kwargs)

    def simulate_options(self, path='/', **kwargs):
        """Simulates an OPTIONS request to a WSGI application.

        See also: :py:meth:`falcon.testing.simulate_options`.
        """
        return simulate_options(self.app, path, **kwargs)

    def simulate_patch(self, path='/', **kwargs):
        """Simulates a PATCH request to a WSGI application.

        See also: :py:meth:`falcon.testing.simulate_patch`.
        """
        return simulate_patch(self.app, path, **kwargs)

    def simulate_delete(self, path='/', **kwargs):
        """Simulates a DELETE request to a WSGI application.

        See also: :py:meth:`falcon.testing.simulate_delete`.
        """
        return simulate_delete(self.app, path, **kwargs)

    def simulate_request(self, *args, **kwargs):
        """Simulates a request to a WSGI application.

        Wraps :py:meth:`falcon.testing.simulate_request` to perform a
        WSGI request directly against ``self.app``. Equivalent to::

            falcon.testing.simulate_request(self.app, *args, **kwargs)
        """

        return simulate_request(self.app, *args, **kwargs)