# SPDX-License-Identifier: GPL-3.0-or-later
#
# This file is part of Nominatim. (https://nominatim.org)
#
# Copyright (C) 2024 by the Nominatim developer community.
# For a full list of authors see the git log.
"""
Complex datatypes used by the Nominatim API.
"""
from typing import Optional, Union, Tuple, NamedTuple, TypeVar, Type, Dict, \
                   Any, List, Sequence
from collections import abc
import dataclasses
import enum
import math
from struct import unpack
from binascii import unhexlify

from .errors import UsageError
from .localization import Locales


@dataclasses.dataclass
class PlaceID:
    """ Reference a place by Nominatim's internal ID.

        A PlaceID may reference place from the main table placex, from
        the interpolation tables or the postcode tables. Place IDs are not
        stable between installations. You may use this type theefore only
        with place IDs obtained from the same database.
    """
    place_id: int
    """
    The internal ID of the place to reference.
    """


@dataclasses.dataclass
class OsmID:
    """ Reference a place by its OSM ID and potentially the basic category.

        The OSM ID may refer to places in the main table placex and OSM
        interpolation lines.
    """
    osm_type: str
    """ OSM type of the object. Must be one of `N`(node), `W`(way) or
        `R`(relation).
    """
    osm_id: int
    """ The OSM ID of the object.
    """
    osm_class: Optional[str] = None
    """ The same OSM object may appear multiple times in the database under
        different categories. The optional class parameter allows to distinguish
        the different categories and corresponds to the key part of the category.
        If there are multiple objects in the database and `osm_class` is
        left out, then one of the objects is returned at random.
    """

    def __post_init__(self) -> None:
        if self.osm_type not in ('N', 'W', 'R'):
            raise ValueError(f"Illegal OSM type '{self.osm_type}'. Must be one of N, W, R.")

    def class_as_housenumber(self) -> Optional[int]:
        """ Interpret the class property as a housenumber and return it.

            If the OSM ID points to an interpolation, then the class may be
            a number pointing to the exact number requested. This function
            returns the housenumber as an int, if class is set and is a number.
        """
        if self.osm_class and self.osm_class.isdigit():
            return int(self.osm_class)
        return None


PlaceRef = Union[PlaceID, OsmID]


class Point(NamedTuple):
    """ A geographic point in WGS84 projection.
    """
    x: float
    y: float

    @property
    def lat(self) -> float:
        """ Return the latitude of the point.
        """
        return self.y

    @property
    def lon(self) -> float:
        """ Return the longitude of the point.
        """
        return self.x

    def to_geojson(self) -> str:
        """ Return the point in GeoJSON format.
        """
        return f'{{"type": "Point","coordinates": [{self.x}, {self.y}]}}'

    @staticmethod
    def from_wkb(wkb: Union[str, bytes]) -> 'Point':
        """ Create a point from EWKB as returned from the database.
        """
        if isinstance(wkb, str):
            wkb = unhexlify(wkb)
        if len(wkb) != 25:
            raise ValueError(f"Point wkb has unexpected length {len(wkb)}")
        if wkb[0] == 0:
            gtype, srid, x, y = unpack('>iidd', wkb[1:])
        elif wkb[0] == 1:
            gtype, srid, x, y = unpack('<iidd', wkb[1:])
        else:
            raise ValueError("WKB has unknown endian value.")

        if gtype != 0x20000001:
            raise ValueError("WKB must be a point geometry.")
        if srid != 4326:
            raise ValueError("Only WGS84 WKB supported.")

        return Point(x, y)

    @staticmethod
    def from_param(inp: Any) -> 'Point':
        """ Create a point from an input parameter. The parameter
            may be given as a point, a string or a sequence of
            strings or floats. Raises a UsageError if the format is
            not correct.
        """
        if isinstance(inp, Point):
            return inp

        seq: Sequence[str]
        if isinstance(inp, str):
            seq = inp.split(',')
        elif isinstance(inp, abc.Sequence):
            seq = inp

        if len(seq) != 2:
            raise UsageError('Point parameter needs 2 coordinates.')
        try:
            x, y = filter(math.isfinite, map(float, seq))
        except ValueError as exc:
            raise UsageError('Point parameter needs to be numbers.') from exc

        if not -180 <= x <= 180 or not -90 <= y <= 90.0:
            raise UsageError('Point coordinates invalid.')

        return Point(x, y)

    def to_wkt(self) -> str:
        """ Return the WKT representation of the point.
        """
        return f'POINT({self.x} {self.y})'


AnyPoint = Union[Point, Tuple[float, float]]

WKB_BBOX_HEADER_LE = b'\x01\x03\x00\x00\x20\xE6\x10\x00\x00\x01\x00\x00\x00\x05\x00\x00\x00'
WKB_BBOX_HEADER_BE = b'\x00\x20\x00\x00\x03\x00\x00\x10\xe6\x00\x00\x00\x01\x00\x00\x00\x05'


class Bbox:
    """ A bounding box in WGS84 projection.

        The coordinates are available as an array in the 'coord'
        property in the order (minx, miny, maxx, maxy).
    """
    def __init__(self, minx: float, miny: float, maxx: float, maxy: float) -> None:
        """ Create a new bounding box with the given coordinates in WGS84
            projection.
        """
        self.coords = (minx, miny, maxx, maxy)

    @property
    def minlat(self) -> float:
        """ Southern-most latitude, corresponding to the minimum y coordinate.
        """
        return self.coords[1]

    @property
    def maxlat(self) -> float:
        """ Northern-most latitude, corresponding to the maximum y coordinate.
        """
        return self.coords[3]

    @property
    def minlon(self) -> float:
        """ Western-most longitude, corresponding to the minimum x coordinate.
        """
        return self.coords[0]

    @property
    def maxlon(self) -> float:
        """ Eastern-most longitude, corresponding to the maximum x coordinate.
        """
        return self.coords[2]

    @property
    def area(self) -> float:
        """ Return the area of the box in WGS84.
        """
        return (self.coords[2] - self.coords[0]) * (self.coords[3] - self.coords[1])

    def contains(self, pt: Point) -> bool:
        """ Check if the point is inside or on the boundary of the box.
        """
        return self.coords[0] <= pt[0] and self.coords[1] <= pt[1]\
            and self.coords[2] >= pt[0] and self.coords[3] >= pt[1]

    def to_wkt(self) -> str:
        """ Return the WKT representation of the Bbox. This
            is a simple polygon with four points.
        """
        return 'POLYGON(({0} {1},{0} {3},{2} {3},{2} {1},{0} {1}))'\
            .format(*self.coords)

    @staticmethod
    def from_wkb(wkb: Union[None, str, bytes]) -> 'Optional[Bbox]':
        """ Create a Bbox from a bounding box polygon as returned by
            the database. Returns `None` if the input value is None.
        """
        if wkb is None:
            return None

        if isinstance(wkb, str):
            wkb = unhexlify(wkb)

        if len(wkb) != 97:
            raise ValueError("WKB must be a bounding box polygon")
        if wkb.startswith(WKB_BBOX_HEADER_LE):
            x1, y1, _, _, x2, y2 = unpack('<dddddd', wkb[17:65])
        elif wkb.startswith(WKB_BBOX_HEADER_BE):
            x1, y1, _, _, x2, y2 = unpack('>dddddd', wkb[17:65])
        else:
            raise ValueError("WKB has wrong header")

        return Bbox(min(x1, x2), min(y1, y2), max(x1, x2), max(y1, y2))

    @staticmethod
    def from_point(pt: Point, buffer: float) -> 'Bbox':
        """ Return a Bbox around the point with the buffer added to all sides.
        """
        return Bbox(pt[0] - buffer, pt[1] - buffer,
                    pt[0] + buffer, pt[1] + buffer)

    @staticmethod
    def from_param(inp: Any) -> 'Bbox':
        """ Return a Bbox from an input parameter. The box may be
            given as a Bbox, a string or a list or strings or integer.
            Raises a UsageError if the format is incorrect.
        """
        if isinstance(inp, Bbox):
            return inp

        seq: Sequence[str]
        if isinstance(inp, str):
            seq = inp.split(',')
        elif isinstance(inp, abc.Sequence):
            seq = inp

        if len(seq) != 4:
            raise UsageError('Bounding box parameter needs 4 coordinates.')
        try:
            x1, y1, x2, y2 = filter(math.isfinite, map(float, seq))
        except ValueError as exc:
            raise UsageError('Bounding box parameter needs to be numbers.') from exc

        x1 = min(180, max(-180, x1))
        x2 = min(180, max(-180, x2))
        y1 = min(90, max(-90, y1))
        y2 = min(90, max(-90, y2))

        if x1 == x2 or y1 == y2:
            raise UsageError('Bounding box with invalid parameters.')

        return Bbox(min(x1, x2), min(y1, y2), max(x1, x2), max(y1, y2))


class GeometryFormat(enum.Flag):
    """ All search functions support returning the full geometry of a place in
        various formats. The internal geometry is converted by PostGIS to
        the desired format and then returned as a string. It is possible to
        request multiple formats at the same time.
    """
    NONE = 0
    """ No geometry requested. Alias for a empty flag.
    """
    GEOJSON = enum.auto()
    """
    [GeoJSON](https://geojson.org/) format
    """
    KML = enum.auto()
    """
    [KML](https://en.wikipedia.org/wiki/Keyhole_Markup_Language) format
    """
    SVG = enum.auto()
    """
    [SVG](http://www.w3.org/TR/SVG/paths.html) format
    """
    TEXT = enum.auto()
    """
    [WKT](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry) format
    """


class DataLayer(enum.Flag):
    """ The `DataLayer` flag type defines the layers that can be selected
        for reverse and forward search.
    """
    ADDRESS = enum.auto()
    """ The address layer contains all places relevant for addresses:
        fully qualified addresses with a house number (or a house name equivalent,
        for some addresses) and places that can be part of an address like
        roads, cities, states.
    """
    POI = enum.auto()
    """ Layer for points of interest like shops, restaurants but also
        recycling bins or postboxes.
    """
    RAILWAY = enum.auto()
    """ Layer with railway features including tracks and other infrastructure.
        Note that in Nominatim's standard configuration, only very few railway
        features are imported into the database. Thus a custom configuration
        is required to make full use of this layer.
    """
    NATURAL = enum.auto()
    """ Layer with natural features like rivers, lakes and mountains.
    """
    MANMADE = enum.auto()
    """ Layer with other human-made features and boundaries. This layer is
        the catch-all and includes all features not covered by the other
        layers. A typical example for this layer are national park boundaries.
    """


def format_country(cc: Any) -> List[str]:
    """ Extract a list of country codes from the input which may be either
        a string or list of strings. Filters out all values that are not
        a two-letter string.
    """
    clist: Sequence[str]
    if isinstance(cc, str):
        clist = cc.split(',')
    elif isinstance(cc, abc.Sequence):
        clist = cc
    else:
        raise UsageError("Parameter 'country' needs to be a comma-separated list "
                         "or a Python list of strings.")

    return [cc.lower() for cc in clist if isinstance(cc, str) and len(cc) == 2]


def format_excluded(ids: Any) -> List[int]:
    """ Extract a list of place ids from the input which may be either
        a string or a list of strings or ints. Ignores empty value but
        throws a UserError on anything that cannot be converted to int.
    """
    plist: Sequence[str]
    if isinstance(ids, str):
        plist = [s.strip() for s in ids.split(',')]
    elif isinstance(ids, abc.Sequence):
        plist = ids
    else:
        raise UsageError("Parameter 'excluded' needs to be a comma-separated list "
                         "or a Python list of numbers.")
    if not all(isinstance(i, int) or
               (isinstance(i, str) and (not i or i.isdigit())) for i in plist):
        raise UsageError("Parameter 'excluded' only takes place IDs.")

    return [int(id) for id in plist if id] or [0]


def format_categories(categories: List[Tuple[str, str]]) -> List[Tuple[str, str]]:
    """ Extract a list of categories. Currently a noop.
    """
    return categories


TParam = TypeVar('TParam', bound='LookupDetails')


@dataclasses.dataclass
class LookupDetails:
    """ Collection of parameters that define which kind of details are
        returned with a lookup or details result.
    """
    geometry_output: GeometryFormat = GeometryFormat.NONE
    """ Add the full geometry of the place to the result. Multiple
        formats may be selected. Note that geometries can become quite large.
    """
    address_details: bool = False
    """ Get detailed information on the places that make up the address
        for the result.
    """
    linked_places: bool = False
    """ Get detailed information on the places that link to the result.
    """
    parented_places: bool = False
    """ Get detailed information on all places that this place is a parent
        for, i.e. all places for which it provides the address details.
        Only POI places can have parents.
    """
    keywords: bool = False
    """ Add information about the search terms used for this place.
    """
    geometry_simplification: float = 0.0
    """ Simplification factor for a geometry in degrees WGS. A factor of
        0.0 means the original geometry is kept. The higher the value, the
        more the geometry gets simplified.
    """
    locales: Locales = Locales()
    """ Preferred languages for localization of results.
    """

    @classmethod
    def from_kwargs(cls: Type[TParam], kwargs: Dict[str, Any]) -> TParam:
        """ Load the data fields of the class from a dictionary.
            Unknown entries in the dictionary are ignored, missing ones
            get the default setting.

            The function supports type checking and throws a UsageError
            when the value does not fit.
        """
        def _check_field(v: Any, field: 'dataclasses.Field[Any]') -> Any:
            if v is None:
                return field.default_factory() \
                       if field.default_factory != dataclasses.MISSING \
                       else field.default
            if field.metadata and 'transform' in field.metadata:
                return field.metadata['transform'](v)
            if not isinstance(v, field.type):  # type: ignore[arg-type]
                raise UsageError(f"Parameter '{field.name}' needs to be of {field.type!s}.")
            return v

        return cls(**{f.name: _check_field(kwargs[f.name], f)
                      for f in dataclasses.fields(cls) if f.name in kwargs})


@dataclasses.dataclass
class ReverseDetails(LookupDetails):
    """ Collection of parameters for the reverse call.
    """

    max_rank: int = dataclasses.field(default=30,
                                      metadata={'transform': lambda v: max(0, min(v, 30))})
    """ Highest address rank to return.
    """

    layers: DataLayer = DataLayer.ADDRESS | DataLayer.POI
    """ Filter which kind of data to include.
    """


@dataclasses.dataclass
class SearchDetails(LookupDetails):
    """ Collection of parameters for the search call.
    """
    max_results: int = 10
    """ Maximum number of results to be returned. The actual number of results
        may be less.
    """

    min_rank: int = dataclasses.field(default=0,
                                      metadata={'transform': lambda v: max(0, min(v, 30))})
    """ Lowest address rank to return.
    """

    max_rank: int = dataclasses.field(default=30,
                                      metadata={'transform': lambda v: max(0, min(v, 30))})
    """ Highest address rank to return.
    """

    layers: Optional[DataLayer] = dataclasses.field(default=None,
                                                    metadata={'transform': lambda r: r})
    """ Filter which kind of data to include. When 'None' (the default) then
        filtering by layers is disabled.
    """

    countries: List[str] = dataclasses.field(default_factory=list,
                                             metadata={'transform': format_country})
    """ Restrict search results to the given countries. An empty list (the
        default) will disable this filter.
    """

    excluded: List[int] = dataclasses.field(default_factory=list,
                                            metadata={'transform': format_excluded})
    """ List of OSM objects to exclude from the results. Currently only
        works when the internal place ID is given.
        An empty list (the default) will disable this filter.
    """

    viewbox: Optional[Bbox] = dataclasses.field(default=None,
                                                metadata={'transform': Bbox.from_param})
    """ Focus the search on a given map area.
    """

    bounded_viewbox: bool = False
    """ Use 'viewbox' as a filter and restrict results to places within the
        given area.
    """

    near: Optional[Point] = dataclasses.field(default=None,
                                              metadata={'transform': Point.from_param})
    """ Order results by distance to the given point.
    """

    near_radius: Optional[float] = dataclasses.field(default=None,
                                                     metadata={'transform': lambda r: r})
    """ Use near point as a filter and drop results outside the given
        radius. Radius is given in degrees WSG84.
    """

    categories: List[Tuple[str, str]] = dataclasses.field(default_factory=list,
                                                          metadata={'transform': format_categories})
    """ Restrict search to places with one of the given class/type categories.
        An empty list (the default) will disable this filter.
    """

    viewbox_x2: Optional[Bbox] = None

    def __post_init__(self) -> None:
        if self.viewbox is not None:
            xext = (self.viewbox.maxlon - self.viewbox.minlon)/2
            yext = (self.viewbox.maxlat - self.viewbox.minlat)/2
            self.viewbox_x2 = Bbox(self.viewbox.minlon - xext, self.viewbox.minlat - yext,
                                   self.viewbox.maxlon + xext, self.viewbox.maxlat + yext)

    def restrict_min_max_rank(self, new_min: int, new_max: int) -> None:
        """ Change the min_rank and max_rank fields to respect the
            given boundaries.
        """
        assert new_min <= new_max
        self.min_rank = max(self.min_rank, new_min)
        self.max_rank = min(self.max_rank, new_max)

    def is_impossible(self) -> bool:
        """ Check if the parameter configuration is contradictionary and
            cannot yield any results.
        """
        return (self.min_rank > self.max_rank
                or (self.bounded_viewbox
                    and self.viewbox is not None and self.near is not None
                    and self.viewbox.contains(self.near))
                or (self.layers is not None and not self.layers)
                or (self.max_rank <= 4 and
                    self.layers is not None and not self.layers & DataLayer.ADDRESS))

    def layer_enabled(self, layer: DataLayer) -> bool:
        """ Check if the given layer has been chosen. Also returns
            true when layer restriction has been disabled completely.
        """
        return self.layers is None or bool(self.layers & layer)
