#!/usr/bin/env python3
import os
import json

import xarray as xr

import numpy as np
import matplotlib.pyplot as plt
from metpy.plots import MapPanel, PanelContainer, RasterPlot, ContourPlot, BarbPlot

from .. import misc

config = {
    'source': 'dwd_icon-eu/combined.grib2',
    'plots': [
        {
            'name':'r_t-750',
            'area': None,
            'layers': [
                {
                    'layertype': 'raster',
                    'field': 'r',
                    'level': 750,
                },
                {
                    'layertype': 'contour',
                    'field': 't',
                    'level': 750,
                    'contours': 5,
                    'clabels': True
                },
            ]
        },
    ]
}

def run(data, plots, output='.'):
    misc.create_output_dir(output)
    index = []

    for plot in plots:
        index.append(_plot(data, output, **plot))

    return index

def _plot(data, output, name, layers, area = None):
    index = []

    for step in data.coords['step']:
        this_step = data.sel(step=step)

        map_layers = []

        for layer in layers:
            map_layers.append(_layer(this_step, **layer))

        valid = misc.np_time_convert(step.valid_time.values)
        init = misc.np_time_convert(step.time.values)

        valid_str = valid.strftime('%d %b %Y - %HUTC')
        init_str = init.strftime('%d %b %Y - %HUTC')
        hours_since_init_str = str(int(this_step.step.values / np.timedelta64(1,'h'))).zfill(2)
        init_for_filename = init.strftime('%Y-%m-%d-%HUTC')

        panel = MapPanel()
        if area is not None:
            panel.area = area
        panel.projection = 'mer'
        panel.layers = ['coastline', 'borders']
        panel.plots = map_layers
        panel.left_title = f'{name} VALID: {valid_str} (INIT +{hours_since_init_str}) INIT: {init_str}'
        if '_description' in data.attrs:
            panel.right_title = data.attrs['_description']

        pc = PanelContainer()
        pc.size = (12.8, 9.6)
        #pc.figure.layout='constrained'
        pc.panels = [panel]
        pc.draw()
        #pc.show()
        outname = f'{name}_{init_for_filename}+{hours_since_init_str}.png'
        pc.save(os.path.join(output, outname))
        plt.close('all')

        index.append(
            {
                'file': outname,
                'init': init_str,
                'valid': valid_str,
                'valid_offset': hours_since_init_str,
                'display_name': hours_since_init_str,
                'id': name
            }
        )

    with open(os.path.join(output, f'{name}.index.json'), 'w') as f:
        f.write(json.dumps(index, indent=4))

    return { 'name': name, 'indexfile': f'{name}.index.json', 'list_title': 'INIT+' }

def _layer(data, layertype, **kwargs):
    layertypes={
        'raster': {
            'obj': RasterPlot,
            'defaults': {
                'colorbar': 'vertical',
            }
        },
        'contour': {
            'obj': ContourPlot,
            'defaults': {}
        },
        'barbs': {
            'obj': BarbPlot,
            'defaults': {}
        }
    }

    args = layertypes[layertype]['defaults'] | kwargs

    ret = layertypes[layertype]['obj'](**args)
    ret.data = data

    return ret

if __name__ == '__main__':
    run(**config)