#   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.
"""
This Python module contains tests for the refpixel.py PyRate module.
"""
import os
import copy
import shutil
from subprocess import run
from pathlib import Path
import pytest
import itertools
import numpy as np
from numpy import nan, mean, std, isnan

import pyrate.configuration
import pyrate.core.refpixel
from pyrate.core import config as cf
from pyrate.core.refpixel import ref_pixel, _step, RefPixelError, ref_pixel_calc_wrapper, \
    convert_geographic_coordinate_to_pixel_value, convert_pixel_value_to_geographic_coordinate
from pyrate.core import shared, ifgconstants as ifc
from pyrate import correct, conv2tif, prepifg
from pyrate.configuration import Configuration
from tests.common import TEST_CONF_ROIPAC, TEST_CONF_GAMMA, SML_TEST_DEM_TIF
from tests.common import small_data_setup, MockIfg, copy_small_ifg_file_list, \
    copy_and_setup_small_data, manipulate_test_conf, assert_two_dirs_equal, PYTHON3P6


# TODO: figure out how  editing  resource.setrlimit fixes the error
# to fix the open to many files error
# https://stackoverflow.com/questions/18280612/ioerror-errno-24-too-many-open-files

# default testing values
REFNX = 5
REFNY = 7
MIN_FRAC = 0.7
CHIPSIZE = 3
PARALLEL = False


class TestReferencePixelInputTests:
    '''
    Verifies error checking capabilities of the reference pixel function
    '''

    @classmethod
    def setup_method(cls):
        cls.ifgs = small_data_setup()
        cls.params = cf.get_config_params(TEST_CONF_ROIPAC)
        cls.params[cf.REFNX] = REFNX
        cls.params[cf.REFNY] = REFNY
        cls.params[cf.REF_CHIP_SIZE] = CHIPSIZE
        cls.params[cf.REF_MIN_FRAC] = MIN_FRAC
        cls.params[cf.PARALLEL] = PARALLEL

    def test_missing_chipsize(self):
        self.params[cf.REF_CHIP_SIZE] = None
        with pytest.raises(cf.ConfigException):
            ref_pixel(self.ifgs, self.params)

    def test_chipsize_valid(self):
        for illegal in [0, -1, -15, 1, 2, self.ifgs[0].ncols+1, 4, 6, 10, 20]:
            self.params[cf.REF_CHIP_SIZE] = illegal
            with pytest.raises(RefPixelError):
                ref_pixel(self.ifgs, self.params)

    def test_minimum_fraction_missing(self):
        self.params[cf.REF_MIN_FRAC] = None
        with pytest.raises(cf.ConfigException):
            ref_pixel(self.ifgs, self.params)

    def test_minimum_fraction_threshold(self):
        for illegal in [-0.1, 1.1, 1.000001, -0.0000001]:
            self.params[cf.REF_MIN_FRAC] = illegal
            with pytest.raises(RefPixelError):
                ref_pixel(self.ifgs, self.params)

    def test_search_windows(self):
        # 45 is max # cells a width 3 sliding window can iterate over
        for illegal in [-5, -1, 0, 46, 50, 100]:
            self.params[cf.REFNX] = illegal
            with pytest.raises(RefPixelError):
                ref_pixel(self.ifgs, self.params)

        # 40 is max # cells a width 3 sliding window can iterate over
        for illegal in [-5, -1, 0, 71, 85, 100]:
            self.params[cf.REFNY] = illegal
            with pytest.raises(RefPixelError):
                ref_pixel(self.ifgs, self.params)

    def test_missing_search_windows(self):
        self.params[cf.REFNX] = None
        with pytest.raises(cf.ConfigException):
            ref_pixel(self.ifgs, self.params)

        self.params[cf.REFNX] = REFNX
        self.params[cf.REFNY] = None

        with pytest.raises(cf.ConfigException):
            ref_pixel(self.ifgs, self.params)


class TestReferencePixelTests:
    """
    Tests reference pixel search
    """

    @classmethod
    def setup_method(cls):
        cls.params = cf.get_config_params(TEST_CONF_ROIPAC)
        cls.params[cf.OUT_DIR], cls.ifgs = copy_and_setup_small_data()
        cls.params[cf.REFNX] = REFNX
        cls.params[cf.REFNY] = REFNY
        cls.params[cf.REF_CHIP_SIZE] = CHIPSIZE
        cls.params[cf.REF_MIN_FRAC] = MIN_FRAC
        cls.params[cf.PARALLEL] = PARALLEL

    def test_all_below_threshold_exception(self):
        # test failure when no valid stacks in dataset

        # rig mock data to be below threshold
        mock_ifgs = [MockIfg(i, 6, 7) for i in self.ifgs]
        for m in mock_ifgs:
            m.phase_data[:1] = nan
            m.phase_data[1:5] = 0.1
            m.phase_data[5:] = nan

        self.params[cf.REFNX] = 2
        self.params[cf.REFNY] = 2
        self.params[cf.REF_CHIP_SIZE] = CHIPSIZE
        self.params[cf.REF_MIN_FRAC] = MIN_FRAC
        self.params[cf.PARALLEL] = PARALLEL
        with pytest.raises(ValueError):
            ref_pixel(mock_ifgs, self.params)

    def test_refnxy_step_1(self):
        # test step of 1 for refnx|y gets the reference pixel for axis centre
        mock_ifgs = [MockIfg(i, 47, 72) for i in self.ifgs]
        for m in mock_ifgs:
            m.phase_data[:1] = 0.2
            m.phase_data[1:5] = 0.1
            m.phase_data[5:] = 0.3
        exp_refpx = (1, 1)
        self.params[cf.REFNX] = 1
        self.params[cf.REFNY] = 1
        self.params[cf.REF_CHIP_SIZE] = CHIPSIZE
        self.params[cf.REF_MIN_FRAC] = MIN_FRAC
        self.params[cf.PARALLEL] = PARALLEL
        res = ref_pixel(mock_ifgs, self.params)
        assert exp_refpx == res

    def test_large_window(self):
        # 5x5 view over a 5x5 ifg with 1 window/ref pix search
        chps = 5
        mockifgs = [MockIfg(i, chps, chps) for i in self.ifgs]
        self.params[cf.REFNX] = 1
        self.params[cf.REFNY] = 1
        self.params[cf.REF_CHIP_SIZE] = chps
        self.params[cf.REF_MIN_FRAC] = MIN_FRAC
        self.params[cf.PARALLEL] = PARALLEL
        res = ref_pixel(mockifgs, self.params)
        assert (2, 2) == res

    def test_step(self):
        # test different search windows to verify x/y step calculation

        # convenience testing function
        def assert_equal(actual, expected):
            for a, e in zip(actual, expected):
                assert a == e

        # start with simple corner only test
        width = 47
        radius = 2
        refnx = 2
        exp = [2, 25, 44]
        act = _step(width, refnx, radius)
        assert_equal(act, exp)

        # test with 3 windows
        refnx = 3
        exp = [2, 17, 32]
        act = _step(width, refnx, radius)
        assert_equal(act, exp)

        # test 4 search windows
        refnx = 4
        exp = [2, 13, 24, 35]
        act = _step(width, refnx, radius)
        assert_equal(act, exp)

    def test_ref_pixel(self):
        exp_refpx = (2, 25)
        self.params[cf.REFNX] = 2
        self.params[cf.REFNY] = 2
        self.params[cf.REF_CHIP_SIZE] = 5
        self.params[cf.REF_MIN_FRAC] = MIN_FRAC
        self.params[cf.PARALLEL] = PARALLEL
        res = ref_pixel(self.ifgs, self.params)
        assert res == exp_refpx

        # Invalidate first data stack, get new refpix coods & retest
        for i in self.ifgs:
            i.phase_data[:30, :50] = nan

        exp_refpx = (38, 2)
        res = ref_pixel(self.ifgs, self.params)
        assert res == exp_refpx


def _expected_ref_pixel(ifgs, cs):
    """Helper function for finding reference pixel when refnx/y=2"""

    # calculate expected data
    data = [i.phase_data for i in ifgs]  # len 17 list of arrays
    ul = [i[:cs, :cs] for i in data]  # upper left corner stack
    ur = [i[:cs, -cs:] for i in data]
    ll = [i[-cs:, :cs] for i in data]
    lr = [i[-cs:, -cs:] for i in data]

    ulm = mean([std(i[~isnan(i)]) for i in ul])  # mean std of all the layers
    urm = mean([std(i[~isnan(i)]) for i in ur])
    llm = mean([std(i[~isnan(i)]) for i in ll])
    lrm = mean([std(i[~isnan(i)]) for i in lr])
    assert isnan([ulm, urm, llm, lrm]).any() is False

    # coords of the smallest mean is the result
    mn = [ulm, urm, llm, lrm]


class TestLegacyEqualityTest:

    @classmethod
    def setup_method(cls):
        cls.params = cf.get_config_params(TEST_CONF_ROIPAC)
        cls.params[cf.PARALLEL] = 0
        cls.params[cf.OUT_DIR], cls.ifg_paths = copy_small_ifg_file_list()
        conf_file = Path(cls.params[cf.OUT_DIR], 'conf_file.conf')
        pyrate.configuration.write_config_file(params=cls.params, output_conf_file=conf_file)
        cls.params = Configuration(conf_file).__dict__
        cls.params_alt_ref_frac = copy.copy(cls.params)
        cls.params_alt_ref_frac[cf.REF_MIN_FRAC] = 0.5
        cls.params_all_2s = copy.copy(cls.params)
        cls.params_all_2s[cf.REFNX] = 2
        cls.params_all_2s[cf.REFNY] = 2
        cls.params_chipsize_15 = copy.copy(cls.params_all_2s)
        cls.params_chipsize_15[cf.REF_CHIP_SIZE] = 15
        cls.params_all_1s = copy.copy(cls.params)
        cls.params_all_1s[cf.REFNX] = 1
        cls.params_all_1s[cf.REFNY] = 1
        cls.params_all_1s[cf.REF_MIN_FRAC] = 0.7

        for p, q in zip(cls.params[cf.INTERFEROGRAM_FILES], cls.ifg_paths):  # hack
            p.sampled_path = q
            p.tmp_sampled_path = q

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

    def test_small_test_data_ref_pixel_lat_lon_provided(self):
        self.params[cf.REFX], self.params[cf.REFY] = 150.941666654, -34.218333314
        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params)
        assert refx == 38
        assert refy == 58
        assert 0.8 == pytest.approx(self.params[cf.REF_MIN_FRAC])

    def test_small_test_data_ref_pixel(self):
        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params)
        assert refx == 38
        assert refy == 58
        assert 0.8 == pytest.approx(self.params[cf.REF_MIN_FRAC])

    def test_small_test_data_ref_chipsize_15(self):

        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params_chipsize_15)
        assert refx == 7
        assert refy == 7
        assert 0.5 == pytest.approx(self.params_alt_ref_frac[cf.REF_MIN_FRAC])

    def test_metadata(self):
        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params_chipsize_15)
        for i in self.ifg_paths:
            ifg = shared.Ifg(i)
            ifg.open(readonly=True)
            md = ifg.meta_data
            for k, v in zip([ifc.PYRATE_REFPIX_X, ifc.PYRATE_REFPIX_Y, ifc.PYRATE_REFPIX_LAT,
                            ifc.PYRATE_REFPIX_LON, ifc.PYRATE_MEAN_REF_AREA, ifc.PYRATE_STDDEV_REF_AREA],
                            [str(refx), str(refy), 0, 0, 0, 0]):
                assert k in md  # metadata present
                # assert values
            ifg.close()

    def test_small_test_data_ref_all_1(self):
        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params_all_1s)
        assert 0.7 == pytest.approx(self.params_all_1s[cf.REF_MIN_FRAC])
        assert 1 == self.params_all_1s[cf.REFNX]
        assert 1 == self.params_all_1s[cf.REFNY]
        assert refx == 2
        assert refy == 2


class TestLegacyEqualityTestMultiprocessParallel:

    @classmethod
    def setup_method(cls):
        cls.params = cf.get_config_params(TEST_CONF_ROIPAC)
        cls.params[cf.PARALLEL] = 1
        cls.params[cf.OUT_DIR], cls.ifg_paths = copy_small_ifg_file_list()
        conf_file = Path(cls.params[cf.OUT_DIR], 'conf_file.conf')
        pyrate.configuration.write_config_file(params=cls.params, output_conf_file=conf_file)
        cls.params = Configuration(conf_file).__dict__
        cls.params_alt_ref_frac = copy.copy(cls.params)
        cls.params_alt_ref_frac[cf.REF_MIN_FRAC] = 0.5
        cls.params_all_2s = copy.copy(cls.params)
        cls.params_all_2s[cf.REFNX] = 2
        cls.params_all_2s[cf.REFNY] = 2
        cls.params_chipsize_15 = copy.copy(cls.params_all_2s)
        cls.params_chipsize_15[cf.REF_CHIP_SIZE] = 15
        cls.params_all_1s = copy.copy(cls.params)
        cls.params_all_1s[cf.REFNX] = 1
        cls.params_all_1s[cf.REFNY] = 1
        cls.params_all_1s[cf.REF_MIN_FRAC] = 0.7

        for p, q in zip(cls.params[cf.INTERFEROGRAM_FILES], cls.ifg_paths):  # hack
            p.sampled_path = q
            p.tmp_sampled_path = q

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

    def test_small_test_data_ref_pixel(self):
        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params)
        assert refx == 38
        assert refy == 58
        assert 0.8 == pytest.approx(self.params[cf.REF_MIN_FRAC])

    def test_more_small_test_data_ref_pixel(self):

        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params_alt_ref_frac)
        assert refx == 38
        assert refy == 58
        assert 0.5 == pytest.approx(self.params_alt_ref_frac[cf.REF_MIN_FRAC])

    def test_small_test_data_ref_pixel_all_2(self):

        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params_all_2s)
        assert refx == 25
        assert refy == 2
        assert 0.5 == pytest.approx(self.params_alt_ref_frac[cf.REF_MIN_FRAC])

    def test_small_test_data_ref_chipsize_15(self):

        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params_chipsize_15)
        assert refx == 7
        assert refy == 7
        assert 0.5 == pytest.approx(self.params_alt_ref_frac[cf.REF_MIN_FRAC])

    def test_small_test_data_ref_all_1(self):

        refx, refy = pyrate.core.refpixel.ref_pixel_calc_wrapper(self.params_all_1s)

        assert 0.7 == pytest.approx(self.params_all_1s[cf.REF_MIN_FRAC])
        assert 1 == self.params_all_1s[cf.REFNX]
        assert 1 == self.params_all_1s[cf.REFNY]
        assert refx == 2
        assert refy == 2


@pytest.mark.slow
@pytest.mark.skipif(PYTHON3P6, reason='Skipped in python3p6')
def test_error_msg_refpixel_out_of_bounds(tempdir, gamma_conf):
    "check correct latitude/longitude refpixel error is raised when specified refpixel is out of bounds"
    for x, (refx, refy) in zip(['longitude', 'latitude', 'longitude and latitude'],
                               [(150., -34.218333314), (150.941666654, -34.), (150, -34)]):
        _, out = _get_mlooked_files(gamma_conf, Path(tempdir()), refx=refx, refy=refy)
        msg = "Supplied {} value is outside the bounds of the interferogram data"
        assert msg.format(x) in out.stderr


@pytest.mark.slow
@pytest.mark.skipif(PYTHON3P6, reason='Skipped in python3p6')
def test_gamma_ref_pixel_search_vs_lat_lon(tempdir, gamma_conf):
    params_1, _ = _get_mlooked_files(gamma_conf, Path(tempdir()), refx=-1, refy=-1)
    params_2, _ = _get_mlooked_files(gamma_conf, Path(tempdir()), refx=150.941666654, refy=-34.218333314)
    assert_two_dirs_equal(params_1[cf.OUT_DIR], params_2[cf.OUT_DIR], ["*_ifg.tif", '*_coh.tif', 'dem.tif'], 35)


def _get_mlooked_files(gamma_conf, tdir, refx, refy):
    params = manipulate_test_conf(gamma_conf, tdir)
    params[cf.REFX] = refx
    params[cf.REFY] = refy
    output_conf_file = 'config.conf'
    output_conf = tdir.joinpath(output_conf_file)
    pyrate.configuration.write_config_file(params=params, output_conf_file=output_conf)
    params = Configuration(output_conf).__dict__
    conv2tif.main(params)
    params = Configuration(output_conf).__dict__
    prepifg.main(params)
    stdout = run(f"pyrate correct -f {output_conf}", shell=True, capture_output=True, text=True)
    return params, stdout


class TestRefPixelReuseLoadsSameFileAndPixels:

    @classmethod
    def setup_method(cls):
        cls.conf = TEST_CONF_GAMMA
        params = Configuration(cls.conf).__dict__
        conv2tif.main(params)
        params = Configuration(cls.conf).__dict__
        prepifg.main(params)
        params = Configuration(cls.conf).__dict__
        correct._copy_mlooked(params)
        cls.params = params

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

    @pytest.mark.slow()
    def test_ref_pixel_multiple_runs_reuse_from_disc(self, ref_pixel):
        params = self.params
        params[cf.REFX], params[cf.REFY] = ref_pixel
        params[cf.REF_PIXEL_FILE] = Configuration.ref_pixel_path(params)
        ref_pixel_calc_wrapper(params)

        ref_pixel_file = self.params[cf.REF_PIXEL_FILE]
        time_written = os.stat(ref_pixel_file).st_mtime
        assert self.params[cf.REFX_FOUND] == 38
        assert self.params[cf.REFY_FOUND] == 58
        # run again
        ref_pixel_calc_wrapper(self.params)
        ref_pixel_file = self.params[cf.REF_PIXEL_FILE]
        time_written_1 = os.stat(ref_pixel_file).st_mtime
        assert self.params[cf.REFX_FOUND] == 38
        assert self.params[cf.REFY_FOUND] == 58

        # run a third time
        ref_pixel_calc_wrapper(self.params)
        ref_pixel_file = self.params[cf.REF_PIXEL_FILE]
        time_written_2 = os.stat(ref_pixel_file).st_mtime
        assert time_written == time_written_2 == time_written_1
        assert self.params[cf.REFX], self.params[cf.REFY] == ref_pixel
        assert self.params[cf.REFX_FOUND] == 38
        assert self.params[cf.REFY_FOUND] == 58


@pytest.fixture(scope='module')
def x_y_pixel():
    dem = shared.DEM(SML_TEST_DEM_TIF)
    dem.open()
    Y = dem.nrows
    X = dem.ncols
    x = np.random.choice(range(X), 5)
    y = np.random.choice(range(Y), 5)
    return itertools.product(x, y)  # returns a matrix of 5x5 random x, y pairs


@pytest.mark.skipif(PYTHON3P6, reason='Skipped in python3p6')
def test_convert_pixel_value_to_geographic_coordinate(x_y_pixel):
    transform = dem_transform()
    for x, y in x_y_pixel:
        lon, lat = convert_pixel_value_to_geographic_coordinate(x, y, transform)
        out = run(f"gdallocationinfo -geoloc {SML_TEST_DEM_TIF} {lon} {lat}", shell=True, capture_output=True,
                  text=True).stdout
        xs = (x, x+1, x-1)
        ys = (y, y+1, y-1)
        assert any(f"({xx}P,{yy}L)" in out for xx, yy in itertools.product(xs, ys))


def dem_transform():
    dem = shared.DEM(SML_TEST_DEM_TIF)
    dem.open()
    transform = dem.dataset.GetGeoTransform()
    return transform


@pytest.mark.skipif(PYTHON3P6, reason='Skipped in python3p6')
def test_convert_geographic_coordinate_to_pixel_value(x_y_pixel):
    transform = dem_transform()
    for x, y in x_y_pixel:
        lon, lat = convert_pixel_value_to_geographic_coordinate(x, y, transform)
        xp, yp = convert_geographic_coordinate_to_pixel_value(lon, lat, transform)
        assert (xp == x) & (yp == y)