#   This Python module is part of the PyRate software package.
#
#   Copyright 2020 Geoscience Australia
#
#   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.
# coding: utf-8
"""
This Python module contains tests for the stack.py PyRate module.
"""
import os
import shutil
import pytest

from numpy import eye, array, ones, nan
import numpy as np
from numpy.testing import assert_array_almost_equal, assert_array_equal

import pyrate.core.orbital
import pyrate.core.ref_phs_est
import pyrate.core.refpixel
import tests.common
from pyrate.core import shared, config as cf, covariance as vcm_module
from pyrate.core.stack import stack_rate_pixel, mask_rate
from pyrate import correct, prepifg, conv2tif
from pyrate.configuration import Configuration
from tests import common
from tests.common import SML_TEST_DIR, prepare_ifgs_without_phase, pre_prepare_ifgs


def default_params():
    return {'pthr': 3, 'nsig': 3, 'maxsig': 2, 'parallel': 1, 'processes': 8}


class SinglePixelIfg(object):

    def __init__(self, timespan, phase):
        self.time_span = timespan
        self.phase_data = array([[phase]])


class TestStackRatePixel:
    """
    Tests the weighted least squares algorithm for determining
    the best fitting velocity
    """

    def setup_method(self):
        self.phase = array([0.5, 3.5, 4, 2.5, 3.5, 1])
        self.timespan = array([[0.1, 0.7, 0.8, 0.5, 0.7, 0.2]])
        self.vcmt = eye(6, 6)
        self.mst = ones((6, 1, 1))
        self.mst[4] = 0
        self.params = default_params()

    def test_stack_rate_pixel(self):
        # Simple test with one pixel and equal weighting
        exprate = array([[5.0]])
        experr = array([[0.836242010007091]])
        expsamp = array([[5]])
        rate, error, samples = stack_rate_pixel(self.phase, self.mst, self.vcmt,
                self.timespan, self.params['nsig'], self.params['pthr'])
        assert_array_almost_equal(rate, exprate)
        assert_array_almost_equal(error, experr)
        assert_array_almost_equal(samples, expsamp)


class TestMaskRate:
    """
    Test the maxsig threshold masking algorithm
    """

    def setup_method(self):
        self.r = array([5.0, 4.5]) # rates for 2 pixels
        self.e = array([1.1, 2.1]) # errors for 2 pixels

    def test_mask_rate_maxsig1(self):
        # both rate and error values masked
        rate, error = mask_rate(self.r, self.e, 1)
        assert_array_equal(rate, array([nan, nan]))
        assert_array_equal(error, array([nan, nan]))

    def test_mask_rate_maxsig2(self):
        # one rate and one error masked
        rate, error = mask_rate(self.r, self.e, 2)
        assert_array_equal(rate, array([5.0, nan]))
        assert_array_equal(error, array([1.1, nan]))

    def test_mask_rate_maxsig3(self):
        # No values masked in rate or error
        rate, error = mask_rate(self.r, self.e, 3)
        assert_array_equal(rate, self.r)
        assert_array_equal(error, self.e)


class TestLegacyEquality:
    """
    Tests equality with legacy data
    """

    @classmethod
    def setup_class(cls):
        params = Configuration(common.TEST_CONF_ROIPAC).__dict__
        params[cf.TEMP_MLOOKED_DIR] = os.path.join(params[cf.OUT_DIR], cf.TEMP_MLOOKED_DIR)
        conv2tif.main(params)
        prepifg.main(params)

        params[cf.REF_EST_METHOD] = 2

        xlks, _, crop = cf.transform_params(params)

        dest_paths, headers = common.repair_params_for_correct_tests(params[cf.OUT_DIR], params)
        correct._copy_mlooked(params)
        copied_dest_paths = [os.path.join(params[cf.TEMP_MLOOKED_DIR], os.path.basename(d)) for d in dest_paths]
        del dest_paths
        # start run_pyrate copy
        ifgs = pre_prepare_ifgs(copied_dest_paths, params)
        mst_grid = tests.common.mst_calculation(copied_dest_paths, params)

        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(params)

        params[cf.REFX] = refx
        params[cf.REFY] = refy
        params[cf.ORBFIT_OFFSET] = True

        # Estimate and remove orbit errors
        pyrate.core.orbital.remove_orbital_error(ifgs, params)
        ifgs = prepare_ifgs_without_phase(copied_dest_paths, params)
        for ifg in ifgs:
            ifg.close()
        correct._update_params_with_tiles(params)
        _, ifgs = pyrate.core.ref_phs_est.ref_phase_est_wrapper(params)
        ifgs[0].open()
        r_dist = vcm_module.RDist(ifgs[0])()
        ifgs[0].close()
        maxvar = [vcm_module.cvd(i, params, r_dist)[0] for i in copied_dest_paths]
        for ifg in ifgs:
            ifg.open()
        vcmt = vcm_module.get_vcmt(ifgs, maxvar)    
        for ifg in ifgs:
            ifg.close()     
            ifg.open()
        
        # Calculate stacked rate map
        params[cf.PARALLEL] = 1
        cls.rate, cls.error, cls.samples = tests.common.calculate_stack_rate(ifgs, params, vcmt, mst_mat=mst_grid)

        # Calculate stacked rate map
        params[cf.PARALLEL] = 0
        cls.rate_s, cls.error_s, cls.samples_s = tests.common.calculate_stack_rate(ifgs, params, vcmt, mst_mat=mst_grid)

        stackrate_dir = os.path.join(SML_TEST_DIR, 'stackrate')

        cls.rate_container = np.genfromtxt(os.path.join(stackrate_dir, 'stackmap.csv'), delimiter=',')
        cls.error_container = np.genfromtxt(os.path.join(stackrate_dir, 'errormap.csv'), delimiter=',')
        cls.samples_container = np.genfromtxt(os.path.join(stackrate_dir, 'coh_sta.csv'), delimiter=',')
    
        for ifg in ifgs:
            ifg.close()

        cls.params = params

    @classmethod
    def teardown_class(cls):
        shutil.rmtree(cls.params[cf.OUT_DIR])

    def test_stack_rate_full_parallel(self):
        """
        python multiprocessing by rows vs serial
        """
        assert_array_almost_equal(self.rate, self.rate_s, decimal=3)

    def test_stackrate_error_parallel(self):
        """
        python multiprocessing by rows vs serial
        """
        assert_array_almost_equal(self.error, self.error_s, decimal=3)

    def test_stackrate_samples_parallel(self):
        """
        python multiprocessing by rows vs serial
        """
        assert_array_almost_equal(self.samples, self.samples_s, decimal=3)

    def test_stack_rate(self):
        """
        Compare with legacy data
        """
        assert_array_almost_equal(self.rate_s, self.rate_container, decimal=3)

    def test_stackrate_error(self):
        """
        Compare with legacy data
        """
        assert_array_almost_equal(self.error_s, self.error_container, decimal=3)

    def test_stackrate_samples(self):
        """
        Compare with legacy data
        """
        assert_array_almost_equal(self.samples_s, self.samples_container, decimal=3)