import requests
import urlparse
import urllib
import isodate

from . import signature


class WcsApiError(Exception):
    pass


class BaseObject(object):
    def __init__(self, wcs_api, **kwargs):
        self.__wcs_api = wcs_api
        self.__dict__.update(**kwargs)


class FormDataWorkflow(BaseObject):
    status = None

    def __init__(self, wcs_api, **kwargs):
        super(FormDataWorkflow, self).__init__(wcs_api, **kwargs)
        if self.status is not None:
            self.status = BaseObject(wcs_api, **self.status)


class Evolution(BaseObject):
    user = None
    status = None
    parts = None

    def __init__(self, wcs_api, **kwargs):
        super(Evolution, self).__init__(wcs_api, **kwargs)
        self.time = isodate.parse_datetime(self.time)
        if self.parts:
            self.parts = [BaseObject(wcs_api, **part) for part in self.parts]


class FormData(BaseObject):
    geolocations = None
    evolution = None

    def __init__(self, wcs_api, **kwargs):
        super(FormData, self).__init__(wcs_api, **kwargs)
        self.receipt_time = isodate.parse_datetime(self.receipt_time)
        self.submission = BaseObject(wcs_api, **self.submission)
        self.workflow = FormDataWorkflow(wcs_api, **self.workflow)
        self.evolution = [Evolution(wcs_api, **evo) for evo in self.evolution or []]
        self.functions = {}
        self.concerned_roles = []
        self.action_roles = []
        for function in self.roles:
            roles = [Role(wcs_api, **r) for r in self.roles[function]]
            if function == 'concerned':
                self.concerned_roles.extend(roles)
            elif function == 'actions':
                self.concerned_roles.extend(roles)
            else:
                try:
                    self.functions[function] = roles[0]
                except IndexError:
                    self.functions[function] = None
        del self.roles

    def __repr__(self):
        return '<{klass} {display_id!r}>'.format(klass=self.__class__.__name__,
                                                 display_id=self.id)

    @property
    def endpoint_delay(self):
        '''Compute delay as the time when the last not endpoint status precedes an endpoint
           status.'''
        statuses_map = self.formdef.schema.workflow.statuses_map
        s = 0
        for evo in self.evolution[::-1]:
            if evo.status:
                try:
                    status = statuses_map[evo.status]
                except KeyError:  # happen when workflow has changed
                    return
                if status.endpoint:
                    s = 1
                    last = evo.time - self.receipt_time
                else:
                    if s == 1:
                        return last
                    else:
                        return


class Workflow(BaseObject):
    status = None

    def __init__(self, wcs_api, **kwargs):
        super(Workflow, self).__init__(wcs_api, **kwargs)
        self.statuses = [BaseObject(wcs_api, **v) for v in self.statuses]
        self.statuses_map = dict((s.id, s) for s in self.statuses)


class Field(BaseObject):
    items = None
    options = None
    varname = None
    in_filters = False


class Schema(BaseObject):
    category_id = None
    category = None
    geolocations = None

    def __init__(self, wcs_api, **kwargs):
        super(Schema, self).__init__(wcs_api, **kwargs)
        self.workflow = Workflow(wcs_api, **self.workflow)
        self.fields = [Field(wcs_api, **f) for f in self.fields]
        self.geolocations = sorted((k, v) for k, v in (self.geolocations or {}).items())


class FormDef(BaseObject):
    geolocations = None

    def __init__(self, wcs_api, **kwargs):
        self.__wcs_api = wcs_api
        self.__dict__.update(**kwargs)

    def __unicode__(self):
        return self.title

    @property
    def datas(self):
        datas = self.__wcs_api.get_formdata(self.slug)
        for data in datas:
            data.formdef = self
            yield data

    @property
    def schema(self):
        return self.__wcs_api.get_schema(self.slug)

    def __repr__(self):
        return '<{klass} {slug!r}>'.format(klass=self.__class__.__name__, slug=self.slug)


class Role(BaseObject):
    pass


class Category(BaseObject):
    pass


class WcsApi(object):
    def __init__(self, url, orig, key, verify=True, slugs=None):
        self.url = url
        self.orig = orig
        self.key = key
        self.verify = verify
        self.cache = {}
        self.slugs = slugs or []

    @property
    def formdefs_url(self):
        return urlparse.urljoin(self.url, 'api/formdefs/')

    @property
    def forms_url(self):
        return urlparse.urljoin(self.url, 'api/forms/')

    @property
    def roles_url(self):
        return urlparse.urljoin(self.url, 'api/roles')

    def get_json(self, *url_parts):
        url = reduce(lambda x, y: urlparse.urljoin(x, y), url_parts)
        params = {'orig': self.orig}
        query_string = urllib.urlencode(params)
        presigned_url = url + ('&' if '?' in url else '?') + query_string
        if presigned_url in self.cache:
            return self.cache[presigned_url]
        signed_url = signature.sign_url(presigned_url, self.key)
        try:
            response = requests.get(signed_url, verify=self.verify)
            response.raise_for_status()
        except requests.RequestException, e:
            raise WcsApiError('GET request failed', signed_url, e)
        else:
            try:
                content = response.json()
                self.cache[presigned_url] = content
                return content
            except ValueError, e:
                raise WcsApiError('Invalid JSON content', signed_url, e)

    @property
    def roles(self):
        return [Role(wcs_api=self, **d) for d in self.get_json(self.roles_url)['data']]

    @property
    def formdefs(self):
        return [FormDef(wcs_api=self, **d) for d in self.get_json(self.formdefs_url)
                if not self.slugs or d['slug'] in self.slugs]

    @property
    def categories(self):
        d = {}
        for f in self.formdefs:
            if hasattr(f.schema, 'category'):
                d[f.schema.category_id] = f.schema.category
        return [Category(wcs_api=self, id=k, name=v) for k, v in d.items()]

    def get_formdata(self, slug):
        for d in self.get_json(self.forms_url, slug + '/list?anonymise&full=on'):
            # w.cs. had a bug where some formdata lost their draft status, skip them
            if not d.get('receipt_time'):
                continue
            yield FormData(wcs_api=self, **d)

    def get_schema(self, slug):
        json_schema = self.get_json(self.formdefs_url, slug + '/', 'schema?anonymise')
        return Schema(wcs_api=self, **json_schema)