# -*- coding: utf-8 -*-
# SPDX-FileCopyrightText: : 2017-2023 The PyPSA-Eur Authors
#
# SPDX-License-Identifier: MIT
"""
Creates Voronoi shapes for each bus representing both onshore and offshore
regions.

Relevant Settings
-----------------

.. code:: yaml

    countries:

.. seealso::
    Documentation of the configuration file ``config/config.yaml`` at
    :ref:`toplevel_cf`

Inputs
------

- ``resources/country_shapes.geojson``: confer :ref:`shapes`
- ``resources/offshore_shapes.geojson``: confer :ref:`shapes`
- ``networks/base.nc``: confer :ref:`base`

Outputs
-------

- ``resources/regions_onshore.geojson``:

    .. image:: img/regions_onshore.png
        :scale: 33 %

- ``resources/regions_offshore.geojson``:

    .. image:: img/regions_offshore.png
        :scale: 33 %

Description
-----------
"""

import logging

import geopandas as gpd
import numpy as np
import pandas as pd
import pypsa
from _helpers import REGION_COLS, configure_logging, set_scenario_config
from scipy.spatial import Voronoi
from shapely.geometry import Polygon

logger = logging.getLogger(__name__)


def voronoi_partition_pts(points, outline):
    """
    Compute the polygons of a voronoi partition of `points` within the polygon
    `outline`. Taken from
    https://github.com/FRESNA/vresutils/blob/master/vresutils/graph.py.

    Attributes
    ----------
    points : Nx2 - ndarray[dtype=float]
    outline : Polygon
    Returns
    -------
    polygons : N - ndarray[dtype=Polygon|MultiPolygon]
    """
    points = np.asarray(points)

    if len(points) == 1:
        polygons = [outline]
    else:
        xmin, ymin = np.amin(points, axis=0)
        xmax, ymax = np.amax(points, axis=0)
        xspan = xmax - xmin
        yspan = ymax - ymin

        # to avoid any network positions outside all Voronoi cells, append
        # the corners of a rectangle framing these points
        vor = Voronoi(
            np.vstack(
                (
                    points,
                    [
                        [xmin - 3.0 * xspan, ymin - 3.0 * yspan],
                        [xmin - 3.0 * xspan, ymax + 3.0 * yspan],
                        [xmax + 3.0 * xspan, ymin - 3.0 * yspan],
                        [xmax + 3.0 * xspan, ymax + 3.0 * yspan],
                    ],
                )
            )
        )

        polygons = []
        for i in range(len(points)):
            poly = Polygon(vor.vertices[vor.regions[vor.point_region[i]]])

            if not poly.is_valid:
                poly = poly.buffer(0)

            with np.errstate(invalid="ignore"):
                poly = poly.intersection(outline)

            polygons.append(poly)

    return polygons


if __name__ == "__main__":
    if "snakemake" not in globals():
        from _helpers import mock_snakemake

        snakemake = mock_snakemake("build_bus_regions")
    configure_logging(snakemake)
    set_scenario_config(snakemake)

    countries = snakemake.params.countries

    n = pypsa.Network(snakemake.input.base_network)

    country_shapes = gpd.read_file(snakemake.input.country_shapes).set_index("name")[
        "geometry"
    ]
    offshore_shapes = gpd.read_file(snakemake.input.offshore_shapes)
    offshore_shapes = offshore_shapes.reindex(columns=REGION_COLS).set_index("name")[
        "geometry"
    ]

    onshore_regions = []
    offshore_regions = []

    for country in countries:
        c_b = n.buses.country == country

        onshore_shape = country_shapes[country]
        onshore_locs = (
            n.buses.loc[c_b & n.buses.onshore_bus]
            .sort_values(
                by="substation_lv", ascending=False
            )  # preference for substations
            .drop_duplicates(subset=["x", "y"], keep="first")[["x", "y"]]
        )
        onshore_regions.append(
            gpd.GeoDataFrame(
                {
                    "name": onshore_locs.index,
                    "x": onshore_locs["x"],
                    "y": onshore_locs["y"],
                    "geometry": voronoi_partition_pts(
                        onshore_locs.values, onshore_shape
                    ),
                    "country": country,
                }
            )
        )

        if country not in offshore_shapes.index:
            continue
        offshore_shape = offshore_shapes[country]
        offshore_locs = n.buses.loc[c_b & n.buses.substation_off, ["x", "y"]]
        offshore_regions_c = gpd.GeoDataFrame(
            {
                "name": offshore_locs.index,
                "x": offshore_locs["x"],
                "y": offshore_locs["y"],
                "geometry": voronoi_partition_pts(offshore_locs.values, offshore_shape),
                "country": country,
            }
        )
        offshore_regions_c = offshore_regions_c.loc[offshore_regions_c.area > 1e-2]
        offshore_regions.append(offshore_regions_c)

    pd.concat(onshore_regions, ignore_index=True).to_file(
        snakemake.output.regions_onshore
    )
    if offshore_regions:
        pd.concat(offshore_regions, ignore_index=True).to_file(
            snakemake.output.regions_offshore
        )
    else:
        offshore_shapes.to_frame().to_file(snakemake.output.regions_offshore)