import unittest

import sys
import os
import math
from itertools import islice
import numpy as np
import galsim
import yaml

from observation_sim.instruments import Chip, Filter, FilterParam, FocalPlane

### test FUNCTION --- START ###


def get_base_img(img, chip, read_noise, readout_time, dark_noise, exptime=150., InputDark=None):
    if InputDark == None:
        # base_level = read_noise**2 + dark_noise*(exptime+0.5*readout_time)
        # base_level = dark_noise*(exptime+0.5*readout_time)
        base_level = dark_noise*(exptime)
        base_img1 = base_level * np.ones_like(img.array)
    else:
        base_img1 = np.zeros_like(img.array)

    ny = int(chip.npix_y/2)
    nx = chip.npix_x
    arr = np.arange(ny).reshape(ny, 1)
    arr = np.broadcast_to(arr, (ny, nx))
    base_img2 = np.zeros_like(img.array)
    base_img2[:ny, :] = arr
    base_img2[ny:, :] = arr[::-1, :]
    base_img2[:, :] = base_img2[:, :]*(readout_time/ny)*dark_noise
    return base_img1+base_img2
### test FUNCTION --- END ###


def defineCCD(iccd, config_file):
    with open(config_file, "r") as stream:
        try:
            config = yaml.safe_load(stream)
            # for key, value in config.items():
            #    print (key + " : " + str(value))
        except yaml.YAMLError as exc:
            print(exc)
    chip = Chip(chipID=iccd, config=config)
    chip.img = galsim.ImageF(chip.npix_x, chip.npix_y)
    focal_plane = FocalPlane(chip_list=[iccd])
    chip.img.wcs = focal_plane.getTanWCS(
        192.8595, 27.1283, -113.4333*galsim.degrees, chip.pix_scale)
    return chip


def defineFilt(chip):
    filter_param = FilterParam()
    filter_id, filter_type = chip.getChipFilter()
    filt = Filter(
        filter_id=filter_id,
        filter_type=filter_type,
        filter_param=filter_param,
        ccd_bandpass=chip.effCurve)
    bandpass_list = filt.bandpass_sub_list
    return bandpass_list


class detModule_coverage(unittest.TestCase):
    def __init__(self, methodName='runTest'):
        super(detModule_coverage, self).__init__(methodName)
        self.dataPath = os.path.join(
            os.getenv('UNIT_TEST_DATA_ROOT'), 'csst_msc_sim/csst_fz_msc')
        self.iccd = 1

    def test_add_dark(self):
        config_file = os.path.join(self.dataPath, 'config_test.yaml')
        chip = defineCCD(self.iccd, config_file)
        bandpass = defineFilt(chip)
        print(chip.chipID)
        print(chip.cen_pix_x, chip.cen_pix_y)

        exptime = 150.
        base_img = get_base_img(img=chip.img, chip=chip, read_noise=chip.read_noise,
                                readout_time=chip.readout_time, dark_noise=chip.dark_noise, exptime=exptime, InputDark=None)

        ny = int(chip.npix_y/2)
        self.assertTrue(np.abs(np.max(base_img) - (exptime*chip.dark_noise +
                        (ny-1)*(chip.readout_time/ny)*chip.dark_noise)) < 1e-6)
        self.assertTrue(np.min(base_img) == 3)

        base_img = get_base_img(img=chip.img, chip=chip, read_noise=chip.read_noise,
                                readout_time=chip.readout_time, dark_noise=chip.dark_noise, exptime=150., InputDark="testTag")
        self.assertTrue(np.abs(np.max(base_img) - ((ny-1) *
                        (chip.readout_time/ny)*chip.dark_noise)) < 1e-6)


if __name__ == '__main__':
    unittest.main()