"""
Classes wrapping HTTP responses from the Nominatim API.
"""
from collections import OrderedDict
import re
import json
import xml.etree.ElementTree as ET

from check_functions import Almost

def _geojson_result_to_json_result(geojson_result):
    result = geojson_result['properties']
    result['geojson'] = geojson_result['geometry']
    if 'bbox' in geojson_result:
        # bbox is  minlon, minlat, maxlon, maxlat
        # boundingbox is minlat, maxlat, minlon, maxlon
        result['boundingbox'] = [geojson_result['bbox'][1],
                                 geojson_result['bbox'][3],
                                 geojson_result['bbox'][0],
                                 geojson_result['bbox'][2]]
    return result

class BadRowValueAssert:
    """ Lazily formatted message for failures to find a field content.
    """

    def __init__(self, response, idx, field, value):
        self.idx = idx
        self.field = field
        self.value = value
        self.row = response.result[idx]

    def __str__(self):
        return "\nBad value for row {} field '{}'. Expected: {}, got: {}.\nFull row: {}"""\
                   .format(self.idx, self.field, self.value,
                           self.row[self.field], json.dumps(self.row, indent=4))


class GenericResponse:
    """ Common base class for all API responses.
    """
    def __init__(self, page, fmt, errorcode=200):
        self.page = page
        self.format = fmt
        self.errorcode = errorcode
        self.result = []
        self.header = dict()

        if errorcode == 200:
            getattr(self, '_parse_' + fmt)()

    def _parse_json(self):
        m = re.fullmatch(r'([\w$][^(]*)\((.*)\)', self.page)
        if m is None:
            code = self.page
        else:
            code = m.group(2)
            self.header['json_func'] = m.group(1)
        self.result = json.JSONDecoder(object_pairs_hook=OrderedDict).decode(code)
        if isinstance(self.result, OrderedDict):
            self.result = [self.result]

    def _parse_geojson(self):
        self._parse_json()
        if 'error' in self.result[0]:
            self.result = []
        else:
            self.result = list(map(_geojson_result_to_json_result, self.result[0]['features']))

    def _parse_geocodejson(self):
        self._parse_geojson()
        if self.result is not None:
            self.result = [r['geocoding'] for r in self.result]

    def assert_field(self, idx, field, value):
        """ Check that result row `idx` has a field `field` with value `value`.
            Float numbers are matched approximately. When the expected value
            starts with a carat, regular expression matching is used.
        """
        assert field in self.result[idx], \
               "Result row {} has no field '{}'.\nFull row: {}"\
                   .format(idx, field, json.dumps(self.result[idx], indent=4))

        if isinstance(value, float):
            assert Almost(value) == float(self.result[idx][field]), \
                   BadRowValueAssert(self, idx, field, value)
        elif value.startswith("^"):
            assert re.fullmatch(value, self.result[idx][field]), \
                   BadRowValueAssert(self, idx, field, value)
        else:
            assert str(self.result[idx][field]) == str(value), \
                   BadRowValueAssert(self, idx, field, value)

    def match_row(self, row):
        """ Match the result fields against the given behave table row.
        """
        if 'ID' in row.headings:
            todo = [int(row['ID'])]
        else:
            todo = range(len(self.result))

        for i in todo:
            for name, value in zip(row.headings, row.cells):
                if name == 'ID':
                    pass
                elif name == 'osm':
                    self.assert_field(i, 'osm_type', value[0])
                    self.assert_field(i, 'osm_id', value[1:])
                elif name == 'centroid':
                    lon, lat = value.split(' ')
                    self.assert_field(i, 'lat', float(lat))
                    self.assert_field(i, 'lon', float(lon))
                else:
                    self.assert_field(i, name, value)

    def property_list(self, prop):
        return [x[prop] for x in self.result]


class SearchResponse(GenericResponse):
    """ Specialised class for search and lookup responses.
        Transforms the xml response in a format similar to json.
    """

    def _parse_xml(self):
        xml_tree = ET.fromstring(self.page)

        self.header = dict(xml_tree.attrib)

        for child in xml_tree:
            assert child.tag == "place"
            self.result.append(dict(child.attrib))

            address = {}
            for sub in child:
                if sub.tag == 'extratags':
                    self.result[-1]['extratags'] = {}
                    for tag in sub:
                        self.result[-1]['extratags'][tag.attrib['key']] = tag.attrib['value']
                elif sub.tag == 'namedetails':
                    self.result[-1]['namedetails'] = {}
                    for tag in sub:
                        self.result[-1]['namedetails'][tag.attrib['desc']] = tag.text
                elif sub.tag == 'geokml':
                    self.result[-1][sub.tag] = True
                else:
                    address[sub.tag] = sub.text

            if address:
                self.result[-1]['address'] = address


class ReverseResponse(GenericResponse):
    """ Specialised class for reverse responses.
        Transforms the xml response in a format similar to json.
    """

    def _parse_xml(self):
        xml_tree = ET.fromstring(self.page)

        self.header = dict(xml_tree.attrib)
        self.result = []

        for child in xml_tree:
            if child.tag == 'result':
                assert not self.result, "More than one result in reverse result"
                self.result.append(dict(child.attrib))
            elif child.tag == 'addressparts':
                address = {}
                for sub in child:
                    address[sub.tag] = sub.text
                self.result[0]['address'] = address
            elif child.tag == 'extratags':
                self.result[0]['extratags'] = {}
                for tag in child:
                    self.result[0]['extratags'][tag.attrib['key']] = tag.attrib['value']
            elif child.tag == 'namedetails':
                self.result[0]['namedetails'] = {}
                for tag in child:
                    self.result[0]['namedetails'][tag.attrib['desc']] = tag.text
            elif child.tag == 'geokml':
                self.result[0][child.tag] = True
            else:
                assert child.tag == 'error', \
                       "Unknown XML tag {} on page: {}".format(child.tag, self.page)


class StatusResponse(GenericResponse):
    """ Specialised class for status responses.
        Can also parse text responses.
    """

    def _parse_text(self):
        pass