import re
import os
import datetime as dt

import numpy as np

from datalayers.datasources.tiff_layer import TiffLayer
from datalayers.datasources.base_layer import LayerTimeResolution, LayerValueType


class ChirtsTmax(TiffLayer):
    def __init__(self):
        super().__init__()
        self.value_type = LayerValueType.FLOAT
        self.time_col = LayerTimeResolution.DAY
        self.manual_nodata = -9999

        self.format_suffix = "°C"

    def download(self):
        start_date = dt.date(2015, 1, 1)
        end_date = dt.date(2016, 12, 31)  # last date available for data source

        base_url = "http://data.chc.ucsb.edu/products/CHIRTSdaily/v1.0/global_tifs_p05/Tmax/{year}/Tmax.{year}.{month:02d}.{day:02d}.tif"

        # download all required files
        for date in self.date_range(start_date, end_date):
            url = base_url.format(year=date.year, month=date.month, day=date.day)
            self._save_url_to_file(url)

    def date_range(self, start_date, end_date):
        for n in range(int((end_date - start_date).days) + 1):
            yield start_date + dt.timedelta(n)

    def consume(self, file, band, shape):
        x = re.search(
            r"([0-9]{4})\.([0-9]{2})\.([0-9]{2})\.tif", os.path.basename(file)
        )
        date = dt.date(int(x[1]), int(x[2]), int(x[3]))

        self.add_value(shape, date, np.nanmean(band))