import six

from django.shortcuts import render, resolve_url
from django.utils.functional import Promise
from rest_framework.renderers import BaseRenderer, JSONRenderer, TemplateHTMLRenderer
from rest_framework.utils import json

from .app_settings import redoc_settings, swagger_settings
from .codecs import VALIDATORS, OpenAPICodecJson, OpenAPICodecYaml
from .openapi import Swagger
from .utils import filter_none


class _SpecRenderer(BaseRenderer):
    """Base class for text renderers. Handles encoding and validation."""
    charset = 'utf-8'
    validators = []
    codec_class = None

    @classmethod
    def with_validators(cls, validators):
        assert all(vld in VALIDATORS for vld in validators), "allowed validators are " + ", ".join(VALIDATORS)
        return type(cls.__name__, (cls,), {'validators': validators})

    def render(self, data, media_type=None, renderer_context=None):
        assert self.codec_class, "must override codec_class"
        codec = self.codec_class(self.validators)

        if not isinstance(data, Swagger):  # pragma: no cover
            # if `swagger` is not a ``Swagger`` object, it means we somehow got a non-success ``Response``
            # in that case, it's probably better to let the default ``TemplateHTMLRenderer`` render it
            # see https://github.com/axnsan12/drf-yasg/issues/58
            return JSONRenderer().render(data, media_type, renderer_context)
        return codec.encode(data)


class OpenAPIRenderer(_SpecRenderer):
    """Renders the schema as a JSON document with the ``application/openapi+json`` specific mime type."""
    media_type = 'application/openapi+json'
    format = 'openapi'
    codec_class = OpenAPICodecJson


class SwaggerJSONRenderer(_SpecRenderer):
    """Renders the schema as a JSON document with the generic ``application/json`` mime type."""
    media_type = 'application/json'
    format = '.json'
    codec_class = OpenAPICodecJson


class SwaggerYAMLRenderer(_SpecRenderer):
    """Renders the schema as a YAML document."""
    media_type = 'application/yaml'
    format = '.yaml'
    codec_class = OpenAPICodecYaml


class _UIRenderer(BaseRenderer):
    """Base class for web UI renderers. Handles loading and passing settings to the appropriate template."""
    media_type = 'text/html'
    charset = 'utf-8'
    template = ''

    def render(self, swagger, accepted_media_type=None, renderer_context=None):
        if not isinstance(swagger, Swagger):  # pragma: no cover
            # if `swagger` is not a ``Swagger`` object, it means we somehow got a non-success ``Response``
            # in that case, it's probably better to let the default ``TemplateHTMLRenderer`` render it
            # see https://github.com/axnsan12/drf-yasg/issues/58
            return TemplateHTMLRenderer().render(swagger, accepted_media_type, renderer_context)
        self.set_context(renderer_context, swagger)
        return render(
            renderer_context['request'],
            self.template,
            renderer_context
        )

    def set_context(self, renderer_context, swagger):
        renderer_context['title'] = swagger.info.title
        renderer_context['version'] = swagger.info.version
        renderer_context['oauth2_config'] = json.dumps(self.get_oauth2_config())
        renderer_context['USE_SESSION_AUTH'] = swagger_settings.USE_SESSION_AUTH
        renderer_context.update(self.get_auth_urls())

    def resolve_url(self, to):
        if isinstance(to, Promise):
            to = str(to)

        if to is None:
            return None

        args, kwargs = None, None
        if not isinstance(to, six.string_types):
            if len(to) > 2:
                to, args, kwargs = to
            elif len(to) == 2:
                to, kwargs = to

        args = args or ()
        kwargs = kwargs or {}

        return resolve_url(to, *args, **kwargs)

    def get_auth_urls(self):
        urls = {
            'LOGIN_URL': self.resolve_url(swagger_settings.LOGIN_URL),
            'LOGOUT_URL': self.resolve_url(swagger_settings.LOGOUT_URL),
        }

        return filter_none(urls)

    def get_oauth2_config(self):
        data = swagger_settings.OAUTH2_CONFIG
        assert isinstance(data, dict), "OAUTH2_CONFIG must be a dict"
        return data


class SwaggerUIRenderer(_UIRenderer):
    """Renders a swagger-ui web interface for schema browisng."""
    template = 'drf-yasg/swagger-ui.html'
    format = 'swagger'

    def set_context(self, renderer_context, swagger):
        super(SwaggerUIRenderer, self).set_context(renderer_context, swagger)
        renderer_context['swagger_settings'] = json.dumps(self.get_swagger_ui_settings())

    def get_swagger_ui_settings(self):
        data = {
            'url': self.resolve_url(swagger_settings.SPEC_URL),
            'operationsSorter': swagger_settings.OPERATIONS_SORTER,
            'tagsSorter': swagger_settings.TAGS_SORTER,
            'docExpansion': swagger_settings.DOC_EXPANSION,
            'deepLinking': swagger_settings.DEEP_LINKING,
            'showExtensions': swagger_settings.SHOW_EXTENSIONS,
            'defaultModelRendering': swagger_settings.DEFAULT_MODEL_RENDERING,
            'defaultModelExpandDepth': swagger_settings.DEFAULT_MODEL_DEPTH,
            'defaultModelsExpandDepth': swagger_settings.DEFAULT_MODEL_DEPTH,
            'showCommonExtensions': swagger_settings.SHOW_COMMON_EXTENSIONS,
            'oauth2RedirectUrl': swagger_settings.OAUTH2_REDIRECT_URL,
            'supportedSubmitMethods': swagger_settings.SUPPORTED_SUBMIT_METHODS,
            'displayOperationId': swagger_settings.DISPLAY_OPERATION_ID,
        }

        data = filter_none(data)
        if swagger_settings.VALIDATOR_URL != '':
            data['validatorUrl'] = self.resolve_url(swagger_settings.VALIDATOR_URL)

        return data


class ReDocRenderer(_UIRenderer):
    """Renders a ReDoc web interface for schema browisng."""
    template = 'drf-yasg/redoc.html'
    format = 'redoc'

    def set_context(self, renderer_context, swagger):
        super(ReDocRenderer, self).set_context(renderer_context, swagger)
        renderer_context['redoc_settings'] = json.dumps(self.get_redoc_settings())

    def get_redoc_settings(self):
        data = {
            'url': self.resolve_url(redoc_settings.SPEC_URL),
            'lazyRendering': redoc_settings.LAZY_RENDERING,
            'hideHostname': redoc_settings.HIDE_HOSTNAME,
            'expandResponses': redoc_settings.EXPAND_RESPONSES,
            'pathInMiddlePanel': redoc_settings.PATH_IN_MIDDLE,
            'nativeScrollbars': redoc_settings.NATIVE_SCROLLBARS,
            'requiredPropsFirst': redoc_settings.REQUIRED_PROPS_FIRST,
        }

        return filter_none(data)


class ReDocOldRenderer(ReDocRenderer):
    """Renders a ReDoc 1.x.x web interface for schema browisng."""
    template = 'drf-yasg/redoc-old.html'
