#! /usr/bin/env python
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

"""implementation of the Socorro data service"""

# This app can be invoked like this:
#     .../socorro/middleware/middleware_app.py --help
# replace the ".../" with something that makes sense for your environment
# set both socorro and configman in your PYTHONPATH

import cgi
import json
import re
import web
from socorro.app.generic_app import App, main
from socorro.external import (
    MissingArgumentError,
    BadArgumentError,
    ResourceNotFound,
    ResourceUnavailable
)
from socorro.webapi.webapiService import (
    JsonWebServiceBase,
    Timeout,
    NotFound,
    BadRequest
)

import raven
from configman import Namespace
from configman.converters import class_converter

#------------------------------------------------------------------------------
# Here's the list of URIs mapping to classes and the files they belong to.
# The final lookup depends on the `implementation_list` option inside the app.
SERVICES_LIST = (
    (r'/bugs/(.*)', 'bugs.Bugs'),
    (r'/crash_data/(.*)', 'crash_data.CrashData'),
    (r'/crash/(.*)', 'crash.Crash'),
    (r'/crashes/'
     r'(comments|count_by_day|daily|frequency|paireduuid|signatures|'
     r'signature_history|exploitability|adu_by_signature)/(.*)',
     'crashes.Crashes'),
    (r'/extensions/(.*)', 'extensions.Extensions'),
    (r'/field/(.*)', 'field.Field'),
    (r'/crashtrends/(.*)', 'crash_trends.CrashTrends'),
    (r'/job/(.*)', 'job.Job'),
    (r'/platforms/(.*)', 'platforms.Platforms'),
    (r'/priorityjobs/(.*)', 'priorityjobs.Priorityjobs'),
    (r'/products/builds/(.*)', 'products_builds.ProductsBuilds'),
    (r'/products/(.*)', 'products.Products'),
    (r'/query/', 'query.Query'),
    (r'/releases/(featured)/(.*)', 'releases.Releases'),
    (r'/signatureurls/(.*)', 'signature_urls.SignatureURLs'),
    (r'/signaturesummary/(.*)', 'signature_summary.SignatureSummary'),
    (r'/search/(signatures|crashes)/(.*)', 'search.Search'),
    (r'/supersearch/(.*)', 'supersearch.SuperSearch'),
    (r'/server_status/(.*)', 'server_status.ServerStatus'),
    (r'/report/(list)/(.*)', 'report.Report'),
    (r'/util/(versions_info)/(.*)', 'util.Util'),
    (r'/crontabber_state/(.*)', 'crontabber_state.CrontabberState'),
    (r'/correlations/signatures/(.*)', 'correlations.CorrelationsSignatures'),
    (r'/correlations/(.*)', 'correlations.Correlations'),
    (r'/skiplist/(.*)', 'skiplist.SkipList'),
    (r'/backfill/(.*)', 'backfill.Backfill'),
    (r'/suspicious/(.*)', 'suspicious.SuspiciousCrashSignatures'),
    (r'/laglog/(.*)', 'laglog.LagLog'),
    (r'/gccrashes/(.*)', 'gccrashes.GCCrashes'),
    (r'/graphics_devices/(.*)', 'graphics_devices.GraphicsDevices'),
)

# certain items in a URL path should NOT be split by `+`
DONT_TERM_SPLIT = re.compile("""
  \d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\+\d{2}:\d{2}
""", re.VERBOSE)

# an app running under modwsgi needs to have a name at the module level called
# application.  The value is set in the App's 'main' function below.  Only the
# modwsgi Apache version actually makes use of this variable.
application = None


class ImplementationConfigurationError(Exception):
    pass


#------------------------------------------------------------------------------
def items_list_decode(values):
    """Return a list of 2-pair tuples like this:
        [('key', 'value'), ...]
    from a string like this:
        'key: value, ...'
    """
    assert isinstance(values, basestring)
    return [[e.strip() for e in x.split(':')]
            for x in values.split(',') if x.strip()]


def items_list_encode(values):
    """From a nest iterator like [['one', 'One'], ...]
    return a string like 'one: One, ...'
    """
    assert isinstance(values, (list, tuple))
    return ', '.join(
        '%s: %s' % (one, two)
        for (one, two) in values
    )


def string_to_list(input_str):
    return [x.strip() for x in input_str.split(',') if x.strip()]


#==============================================================================
class MiddlewareApp(App):
    app_name = 'middleware'
    app_version = '3.1'
    app_description = __doc__

    #--------------------------------------------------------------------------
    # in this section, define any configuration requirements
    required_config = Namespace()

    #--------------------------------------------------------------------------
    # implementations namespace
    #     the namespace is for external implementations of the services
    #-------------------------------------------------------------------------
    required_config.namespace('implementations')
    required_config.implementations.add_option(
        'implementation_list',
        doc='list of packages for service implementations',
        default='psql:socorro.external.postgresql, '
                'hbase:socorro.external.hb, '
                'es:socorro.external.elasticsearch, '
                'fs:socorro.external.fs, '
                'http:socorro.external.http, '
                'rabbitmq:socorro.external.rabbitmq',
        from_string_converter=items_list_decode,
        to_string_converter=items_list_encode
    )

    required_config.implementations.add_option(
        'service_overrides',
        doc='comma separated list of class overrides, e.g `Crashes: hbase`',
        default='CrashData: fs, '
                'Correlations: http, '
                'CorrelationsSignatures: http, '
                'SuperSearch: es, '
                'Priorityjobs: rabbitmq, '
                'Query: es',
        from_string_converter=items_list_decode,
        to_string_converter=items_list_encode
    )

    #--------------------------------------------------------------------------
    # database namespace
    #     the namespace is for external implementations of the services
    #-------------------------------------------------------------------------
    required_config.namespace('database')
    required_config.database.add_option(
        'database_class',
        default='socorro.external.postgresql.connection_context.'
                'ConnectionContext',
        from_string_converter=class_converter
    )

    #--------------------------------------------------------------------------
    # hbase namespace
    #     the namespace is for external implementations of the services
    #-------------------------------------------------------------------------
    required_config.namespace('hbase')
    required_config.hbase.add_option(
        'hbase_class',
        default='socorro.external.hb.crashstorage.HBaseCrashStorage',
        from_string_converter=class_converter
    )

    #--------------------------------------------------------------------------
    # filesystem namespace
    #     the namespace is for external implementations of the services
    #-------------------------------------------------------------------------
    required_config.namespace('filesystem')
    required_config.filesystem.add_option(
        'filesystem_class',
        default='socorro.external.fs.crashstorage.FSLegacyRadixTreeStorage',
        from_string_converter=class_converter
    )

    #--------------------------------------------------------------------------
    # rabbitmq namespace
    #     the namespace is for external implementations of the services
    #-------------------------------------------------------------------------
    required_config.namespace('rabbitmq')
    required_config.rabbitmq.add_option(
        'rabbitmq_class',
        default='socorro.external.rabbitmq.connection_context.'
                'ConnectionContext',
        from_string_converter=class_converter
    )

    #--------------------------------------------------------------------------
    # webapi namespace
    #     this is all config options that used to belong to webapiconfig.py
    #-------------------------------------------------------------------------
    required_config.namespace('webapi')
    required_config.webapi.add_option(
        'elasticSearchHostname',
        default='localhost',
        doc='String containing the URI of the Elastic Search instance.',
        reference_value_from='resource.elasticsearch',
    )
    required_config.webapi.add_option(
        'elasticSearchPort',
        default='9200',
        doc='String containing the port on which calling the Elastic '
            'Search instance.',
        reference_value_from='resource.elasticsearch',
    )
    required_config.webapi.add_option(
        'elasticsearch_urls',
        default=['http://localhost:9200'],
        doc='the urls to the elasticsearch instances',
        from_string_converter=string_to_list,
        reference_value_from='resource.elasticsearch',
    )
    required_config.webapi.add_option(
        'elasticsearch_index',
        default='socorro%Y%W',
        doc='an index format to pull crashes from elasticsearch '
            "(use datetime's strftime format to have "
            'daily, weekly or monthly indexes)',
        reference_value_from='resource.elasticsearch',
    )
    required_config.webapi.add_option(
        'elasticsearch_doctype',
        default='crash_reports',
        doc='the default doctype to use in elasticsearch',
        reference_value_from='resource.elasticsearch',
    )
    required_config.webapi.add_option(
        'elasticsearch_timeout',
        default=30,
        doc='the time in seconds before a query to elasticsearch fails',
        reference_value_from='resource.elasticsearch',
    )
    required_config.webapi.add_option(
        'elasticsearch_timeout_extended',
        default=120,
        doc='the time in seconds before a query to elasticsearch fails in '
            'restricted sections',
        reference_value_from='resource.elasticsearch',
    )
    required_config.webapi.add_option(
        'facets_max_number',
        default=50,
        doc='the maximum number of results a facet will return in search'
    )
    required_config.webapi.add_option(
        'searchMaxNumberOfDistinctSignatures',
        default=1000,
        doc='Integer containing the maximum allowed number of distinct '
            'signatures the system should retrieve. Used mainly for '
            'performances in ElasticSearch'
    )
    required_config.webapi.add_option(
        'search_default_date_range',
        default=7,  # in days
        doc='the default date range for searches, in days'
    )
    required_config.webapi.add_option(
        'search_maximum_date_range',
        default=365,  # in days
        doc='the maximum date range for searches, in days'
    )
    required_config.webapi.add_option(
        'platforms',
        default=[
            {
                "id": "windows",
                "name": "Windows NT"
            },
            {
                "id": "mac",
                "name": "Mac OS X"
            },
            {
                "id": "linux",
                "name": "Linux"
            },
        ],
        doc='Array associating OS ids to full names.',
        from_string_converter=lambda x: json.loads(x)
    )
    required_config.webapi.add_option(
        'non_release_channels',
        default=['beta', 'aurora', 'nightly'],
        doc='List of channels, excluding the `release` one.',
        from_string_converter=string_to_list
    )
    required_config.webapi.add_option(
        'restricted_channels',
        default=['beta'],
        doc='List of channels to restrict based on build ids.',
        from_string_converter=string_to_list
    )

    #--------------------------------------------------------------------------
    # web_server namespace
    #     the namespace is for config parameters the web server
    #--------------------------------------------------------------------------
    required_config.namespace('web_server')
    required_config.web_server.add_option(
        'wsgi_server_class',
        doc='a class implementing a wsgi web server',
        default='socorro.webapi.servers.CherryPy',
        from_string_converter=class_converter
    )

    #--------------------------------------------------------------------------
    # http namespace
    #     the namespace is for config parameters the http modules
    #--------------------------------------------------------------------------
    required_config.namespace('http')
    required_config.http.namespace('correlations')
    required_config.http.correlations.add_option(
        'base_url',
        doc='Base URL where correlations text files are',
        default='https://crash-analysis.mozilla.com/crash_analysis/',
    )
    required_config.http.correlations.add_option(
        'save_download',
        doc='Whether files downloaded for correlations should be '
            'temporary stored on disk',
        default=True,
    )
    required_config.http.correlations.add_option(
        'save_seconds',
        doc='Number of seconds that the downloaded .txt file is stored '
            'in a temporary place',
        default=60 * 10,
    )
    required_config.http.correlations.add_option(
        'save_root',
        doc='Directory where the temporary downloads are stored '
            '(if left empty will become the systems tmp directory)',
        default='',
    )

    #--------------------------------------------------------------------------
    # sentry namespace
    #     the namespace is for Sentry error capturing with Raven
    #--------------------------------------------------------------------------
    required_config.namespace('sentry')
    required_config.sentry.add_option(
        'dsn',
        doc='DSN for Sentry via raven',
        default='',
        reference_value_from='secrets.sentry',
    )
    #--------------------------------------------------------------------------
    # laglog namespace
    #     the namespace for the replica lag log
    #--------------------------------------------------------------------------
    required_config.namespace('laglog')
    required_config.laglog.add_option(
        'max_bytes_warning',
        default=16 * 1024 * 1024,
        doc="Number of bytes that warrents a warning"
    )
    required_config.laglog.add_option(
        'max_bytes_critical',
        default=32 * 1024 * 1024,
        doc="Number of bytes that warrents a critial"
    )

    # because the socorro.webapi.servers classes bring up their own default
    # configurations like port number, the only way to override the default
    # is like this:
    from socorro.webapi.servers import StandAloneServer
    StandAloneServer.required_config.port.set_default(8883, force=True)

    #--------------------------------------------------------------------------
    def main(self):
        # Apache modwsgi requireds a module level name 'application'
        global application

        # 1 turn these names of classes into real references to classes
        def lookup(file_and_class):
            file_name, class_name = file_and_class.rsplit('.', 1)
            overrides = dict(self.config.implementations.service_overrides)
            _list = self.config.implementations.implementation_list
            for prefix, base_module_path in _list:
                if class_name in overrides:
                    if prefix != overrides[class_name]:
                        continue
                try:
                    module = __import__(
                        '%s.%s' % (base_module_path, file_name),
                        globals(),
                        locals(),
                        [class_name]
                    )
                except ImportError:
                    raise ImportError(
                        "Unable to import %s.%s.%s" %
                        (base_module_path, file_name, class_name)
                    )
                return getattr(module, class_name)
            raise ImplementationConfigurationError(file_and_class)

        # This list will hold the collection of url/service-implementations.
        # It is populated in the for loop a few lines lower in this file.
        # This list is used in the 'wrap' function so that all services have
        # place to lookup dependent services.

        all_services_mapping = {}

        # 2 wrap each service class with the ImplementationWrapper class
        def wrap(cls, file_and_class):
            return type(
                cls.__name__,
                (ImplementationWrapper,),
                {
                    'cls': cls,
                    'file_and_class': file_and_class,
                    # give lookup access of dependent services to all services
                    'all_services': all_services_mapping,
                }
            )

        services_list = []
        # populate the 'services_list' with the tuples that will define the
        # urls and services offered by the middleware.
        for url, impl_class in SERVICES_LIST:
            impl_instance = lookup(impl_class)
            wrapped_impl = wrap(impl_instance, impl_class)
            services_list.append((url, wrapped_impl))
            all_services_mapping[impl_instance.__name__] = wrapped_impl

        self.web_server = self.config.web_server.wsgi_server_class(
            self.config,  # needs the whole config not the local namespace
            services_list
        )

        # for modwsgi the 'run' method returns the wsgi function that Apache
        # will use.  For other webservers, the 'run' method actually starts
        # the standalone web server.
        application = self.web_server.run()


class ImplementationWrapper(JsonWebServiceBase):

    def GET(self, *args, **kwargs):
        # prepare parameters
        params = self._get_query_string_params()
        params.update(kwargs)

        # override implementation class if needed
        if params.get('_force_api_impl'):
            impl_code = params['_force_api_impl']

            file_name, class_name = self.file_and_class.rsplit('.', 1)
            implementations = dict(
                self.context.implementations.implementation_list
            )

            try:
                base_module_path = implementations[impl_code]
            except KeyError:
                raise BadRequest(
                    'Implementation code "%s" does not exist' % impl_code
                )

            try:
                module = __import__(
                    '%s.%s' % (base_module_path, file_name),
                    globals(),
                    locals(),
                    [class_name]
                )
            except ImportError:
                raise BadRequest(
                    "Unable to import %s.%s.%s (implementation code is %s)" %
                    (base_module_path, file_name, class_name, impl_code)
                )
            instance = getattr(module, class_name)(
                config=self.context,
                all_services=self.all_services
            )
        else:
            instance = self.cls(
                config=self.context,
                all_services=self.all_services
            )

        # find the method to call
        default_method = kwargs.pop('default_method', 'get')
        if default_method not in ('get', 'post', 'put', 'delete'):
            raise ValueError('%s not a recognized method' % default_method)
        method_name = default_method
        if len(args) > 1:
            method_name = args[0]
        try:
            method = getattr(instance, method_name)
        except AttributeError:
            try:
                if (method_name == 'post' and
                    getattr(instance, 'create', None)):
                    # use the `create` alias
                    method = instance.create
                elif (method_name == 'put' and
                      getattr(instance, 'update', None)):
                    # use the `update` alias
                    method = instance.update
                elif (default_method == 'post' and
                      getattr(instance, 'create_%s' % method_name, None)):
                    # use `create_<method>`
                    method = getattr(instance, 'create_%s' % method_name)
                elif (default_method == 'put' and
                      getattr(instance, 'update_%s' % method_name, None)):
                    # use `update_<method>`
                    method = getattr(instance, 'update_%s' % method_name)
                else:
                    if method_name.startswith(default_method):
                        raise AttributeError
                    method = getattr(
                        instance,
                        '%s_%s' % (default_method, method_name)
                    )
            except AttributeError:
                self.context.logger.warning(
                    'The method %r does not exist on %r' %
                    (method_name, instance)
                )
                raise web.webapi.NoMethod(instance)
        try:
            result = method(**params)
            if isinstance(result, tuple):
                web.header('Content-Type', result[1])
                return result[0]
            web.header('Content-Type', 'application/json')
            dumped = json.dumps(result)
            web.header('Content-Length', len(dumped))
            return dumped

        except (MissingArgumentError, BadArgumentError), msg:
            raise BadRequest({
                'error': {
                    'message': str(msg)
                }
            })
        except ResourceNotFound, msg:
            raise NotFound({
                'error': {
                    'message': str(msg)
                }
            })
        except ResourceUnavailable, msg:
            raise Timeout({
                'error': {
                    'message': str(msg)
                }
            })
        except Exception, msg:
            if self.context.sentry and self.context.sentry.dsn:
                client = raven.Client(dsn=self.context.sentry.dsn)
                identifier = client.get_ident(client.captureException())
                self.context.logger.info(
                    'Error captured in Sentry. Reference: %s' % identifier
                )
            raise

    def POST(self, *args, **kwargs):
        # this is necessary in case some other method (e.g PUT) overrides
        # this method.
        default_method = kwargs.pop('default_method', 'post')
        params = self._get_web_input_params()
        data = web.data()
        if data:
            # If you post a payload as the body it gets picked up by
            # webapi in `web.data()` as a string.
            # It will also, rather annoyingly, make this data a key
            # in the output of `web.input()` which we also rely on.
            # So, in that case try to remove it as a key.
            try:
                params.pop(data)
            except KeyError:
                pass
            params['data'] = data
        return self.GET(default_method=default_method, *args, **params)

    def PUT(self, *args, **kwargs):
        return self.POST(default_method='put', *args, **kwargs)

    def DELETE(self, *args, **kwargs):
        params = self._get_web_input_params()
        return self.GET(default_method='delete', *args, **params)

    def _get_query_string_params(self):
        params = {}
        query_string = web.ctx.query[1:]

        for key, values in cgi.parse_qs(query_string).items():
            if len(values) == 1:
                values = values[0]
            params[key] = values

        return params

    def _get_web_input_params(self, **extra):
        """Because of the stupidify of web.py we can't say that all just tell
        it to collect all POST or GET variables as arrays unless we explicitely
        list the defaults.

        So, try to look ahead at the class that will need the input and see
        if there are certain filters it expects to be lists.
        """
        defaults = {}
        for name, __, conversions in getattr(self.cls, 'filters', []):
            if conversions[0] == 'list':
                defaults[name] = []
        if extra is not None:
            defaults.update(extra)
        return web.input(**defaults)

    def parse_url_path(self, path):
        """
        Take a string of parameters and return a dictionary of key, value.

        Example 1:
            "param/value/"
            =>
            {
                "param": "value"
            }

        Example 2:
            "param1/value1/param2/value21+value22+value23/"
            =>
            {
                "param1": "value1",
                "param2": [
                    "value21",
                    "value22",
                    "value23"
                ]
            }

        Example 3:
            "param1/value1/param2/"
            =>
            {
                "param1": "value1"
            }

        """
        terms_sep = "+"
        params_sep = "/"

        args = path.split(params_sep)

        params = {}
        for i in range(0, len(args), 2):
            try:
                if args[i]:
                    params[args[i]] = args[i + 1]
            except IndexError:
                pass

        for key, value in params.iteritems():
            if value.count(terms_sep) and not DONT_TERM_SPLIT.match(value):
                params[key] = value.split(terms_sep)

        return params


if __name__ == '__main__':
    main(MiddlewareApp)
