"""
    This file is part of mss.

    :copyright: Copyright 2021 by the mss team, see AUTHORS.
    :license: APACHE-2.0, see LICENSE for details.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
"""

import logging
import numpy as np
import matplotlib.pyplot as plt
import mpl_toolkits.axes_grid1.inset_locator
import matplotlib.colors
import mpl_toolkits.basemap
from matplotlib import patheffects
from mslib.mswms.mpl_hsec import MPLBasemapHorizontalSectionStyle
from mslib.mswms.utils import Targets, get_style_parameters, get_cbar_label_format, make_cbar_labels_readable
from mslib.utils import thermolib
from mslib.utils.units import convert_to

class HS_RelativeHumidityStyle_PL_01(MPLBasemapHorizontalSectionStyle):
    """
    Upper Air Field: Relative Humidity
    Relative humidity and geopotential on pressure levels.
    """
    name = "PLRelHum01"
    title = "Relative Humditiy (%) and Geopotential Height (m)"

    # Variables with the highest number of dimensions first (otherwise
    # MFDatasetCommonDims will throw an exception)!
    required_datafields = [
        ("pl", "air_temperature", "K"),
        ("pl", "geopotential_height", "m"),
        ("pl", "specific_humidity", "kg/kg")]

    def _prepare_datafields(self):
        """
        Computes relative humidity from p, t, q.
        """
        pressure = convert_to(self.level, self.get_elevation_units(), "Pa")
        self.data["relative_humidity"] = thermolib.rel_hum(
            pressure, self.data["air_temperature"], self.data["specific_humidity"])

    def _plot_style(self):
        """
        """
        bm = self.bm
        ax = self.bm.ax
        data = self.data

        filled_contours = np.arange(70, 140, 15)
        thin_contours = np.arange(10, 140, 15)

        rh = data["relative_humidity"]

        rhc = bm.contourf(self.lonmesh, self.latmesh, rh,
                          filled_contours, cmap=plt.cm.winter_r)
        self.add_colorbar(rhc, "Relative Humidity (%)")

        # Colors in python2.6/site-packages/matplotlib/colors.py
        cs = bm.contour(self.lonmesh, self.latmesh, rh,
                        thin_contours, colors="grey",
                        linewidths=0.5, linestyles="solid")
        ax.clabel(cs, colors="grey", fontsize=10, fmt='%i')
        cs = bm.contour(self.lonmesh, self.latmesh, rh,
                        np.arange(100, 170, 15), colors="yellow", linewidths=1)

        # Plot geopotential height contours.
        gpm = self.data["geopotential_height"]
        gpm_interval = 40 if self.level <= 500 else 20
        geop_contours = np.arange(400, 28000, gpm_interval)
        cs = bm.contour(self.lonmesh, self.latmesh, gpm,
                        geop_contours, colors="darkred", linewidths=2)
        if cs.levels[0] in geop_contours[::2]:
            lablevels = cs.levels[::2]
        else:
            lablevels = cs.levels[1::2]
        ax.clabel(cs, lablevels, fontsize=10, fmt='%i')

        titlestring = "Relative Humditiy (%%) and Geopotential Height (m) at " \
            f"{self.level:.0f} hPa"
        titlestring += f'\nValid: {self.valid_time.strftime("%a %Y-%m-%d %H:%M UTC")}'
        if self.uses_inittime_dimension():
            time_step = self.valid_time - self.init_time
            time_step_hrs = (time_step.days * 86400 + time_step.seconds) // 3600
            titlestring += f' (step {time_step_hrs:d} hrs from {self.init_time.strftime("%a %Y-%m-%d %H:%M UTC")})'

        if not self.noframe:
            ax.set_title(titlestring,
                         horizontalalignment='left', x=0, fontsize=14)
        else:
            ax.text(bm.llcrnrx, bm.llcrnry, titlestring,
                    fontsize=10, bbox=dict(facecolor='white', alpha=0.6))