import unittest
import os
import subprocess
from shutil import copyfile
import pandas as pd
from pandas.testing import assert_frame_equal
from io import StringIO
import tracemalloc
from typing import Final

# Make references to files and wikiq relative to this file, not to the current working directory.
TEST_DIR: Final[str] = os.path.dirname(os.path.realpath(__file__))
WIKIQ: Final[str] = os.path.join(os.path.dirname(TEST_DIR), "wikiq")
TEST_OUTPUT_DIR: Final[str] = os.path.join(TEST_DIR, "test_output")
BASELINE_DIR: Final[str] = os.path.join(TEST_DIR, "baseline_output")


def setup():
    tracemalloc.start()

    # Perform directory check and reset here as this is a one-time setup step as opposed to per-test setup.
    if not os.path.exists(TEST_OUTPUT_DIR):
        os.mkdir(TEST_OUTPUT_DIR)
    else:
        # Avoid subsequent calls to tests interfering with each other.
        # Otherwise, a test may erroneously pass if the program has no output
        # but a previous run output what was expected.
        for f in os.listdir(TEST_OUTPUT_DIR):
            os.remove(os.path.join(TEST_OUTPUT_DIR, f))


# Always run setup, even if this is executed via "python -m unittest" rather
# than as __main__.
setup()


def call_wikiq(input_file: str, *args: str, out: bool = True):
    if out:
        call = ' '.join([WIKIQ, input_file, "-o", TEST_OUTPUT_DIR, *args])
    else:
        call = ' '.join([WIKIQ, input_file, *args])

    print(call)
    return subprocess.check_output(call, stderr=subprocess.PIPE, shell=True)


def tmp_test_file(name: str) -> (str, str):
    """
    Removes any existing test file with the given name and returns the path to
    the that file.
    :param name: The test case name. Should be unique to each test case.
    :return: The path to the test file.
    """
    baseline_file = os.path.join(BASELINE_DIR, name)
    test_file = os.path.join(TEST_OUTPUT_DIR, name)
    if os.path.exists(test_file):
        os.remove(test_file)

    return baseline_file, test_file


# with / without pwr DONE
# with / without url encode DONE
# with / without collapse user DONE
# with output to stdout DONE
# note that the persistence radius is 7 by default
# reading various file formats including
#        7z, gz, bz2, xml  DONE
# wikia and wikipedia data DONE
# malformed xmls DONE

class Test_Wikipedia(unittest.TestCase):
    def setUp(self):
        wiki = 'ikwiki-20180301-pages-meta-history'
        self.wikiq_out_name = "{0}.tsv".format(wiki)
        self.call_output = os.path.join(TEST_OUTPUT_DIR, self.wikiq_out_name)

        infile = "{0}.xml.bz2".format(wiki)
        input_dir = os.path.join(TEST_DIR, "dumps")
        self.input_file = os.path.join(TEST_DIR, input_dir, infile)

    def test_WP_url_encode(self):
        baseline_file, test_file = tmp_test_file("url-encode_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file, "--url-encode")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        # as a test let's make sure that we get equal data frames
        test = pd.read_table(test_file)
        baseline = pd.read_table(baseline_file)
        assert_frame_equal(test, baseline, check_like=True)

    def test_WP_namespaces(self):
        baseline_file, test_file = tmp_test_file("namespaces_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file, "-n 0", "-n 1")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        # as a test let's make sure that we get equal data frames
        test = pd.read_table(test_file)
        num_wrong_ns = sum(~ test.namespace.isin({0, 1}))
        self.assertEqual(num_wrong_ns, 0)
        baseline = pd.read_table(baseline_file)
        assert_frame_equal(test, baseline, check_like=True)

    def test_WP_revert_radius(self):
        baseline_file, test_file = tmp_test_file("revert_radius_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file, "-n 0", "-n 1", "-rr 1")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        # as a test let's make sure that we get equal data frames
        test = pd.read_table(test_file)
        num_wrong_ns = sum(~ test.namespace.isin({0, 1}))
        self.assertEqual(num_wrong_ns, 0)
        baseline = pd.read_table(baseline_file)
        assert_frame_equal(test, baseline, check_like=True)


class Test_Basic(unittest.TestCase):

    def setUp(self):
        wiki = 'sailormoon'
        self.wikiq_out_name = wiki + ".tsv"
        self.call_output = os.path.join(TEST_OUTPUT_DIR, self.wikiq_out_name)

        infile = "{0}.xml.7z".format(wiki)
        input_dir = os.path.join(TEST_DIR, "dumps")
        self.input_file = os.path.join(TEST_DIR, input_dir, infile)

    def test_noargs(self):
        baseline_file, test_file = tmp_test_file("noargs_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file)
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        test = pd.read_table(test_file)
        baseline = pd.read_table(baseline_file)
        assert_frame_equal(test, baseline, check_like=True)

    def test_collapse_user(self):
        baseline_file, test_file = tmp_test_file("collapse-user_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file, "--collapse-user")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        test = pd.read_table(test_file)
        baseline = pd.read_table(baseline_file)
        assert_frame_equal(test, baseline, check_like=True)

    def test_pwr_segment(self):
        baseline_file, test_file = tmp_test_file("persistence_segment_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file, "--persistence segment")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        test = pd.read_table(test_file)
        baseline = pd.read_table(baseline_file)
        assert_frame_equal(test, baseline, check_like=True)

    def test_pwr_legacy(self):
        baseline_file, test_file = tmp_test_file("persistence_legacy_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file, "--persistence legacy")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        test = pd.read_table(test_file)
        baseline = pd.read_table(baseline_file)
        assert_frame_equal(test, baseline, check_like=True)

    def test_pwr(self):
        baseline_file, test_file = tmp_test_file("persistence_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file, "--persistence")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        test = pd.read_table(test_file)
        baseline = pd.read_table(baseline_file)

        test = test.reindex(columns=sorted(test.columns))
        assert_frame_equal(test, baseline, check_like=True)

    def test_url_encode(self):
        baseline_file, test_file = tmp_test_file("url-encode_" + self.wikiq_out_name)

        try:
            call_wikiq(self.input_file, "--url-encode")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)
        test = pd.read_table(test_file)
        baseline = pd.read_table(baseline_file)

        test = test.reindex(columns=sorted(test.columns))
        assert_frame_equal(test, baseline, check_like=True)


class Test_Malformed(unittest.TestCase):
    def setUp(self):
        wiki = 'twinpeaks'

        infile = "{0}.xml.7z".format(wiki)
        input_dir = os.path.join(TEST_DIR, "dumps")
        self.input_file = os.path.join(TEST_DIR, input_dir, infile)

    def test_malformed_noargs(self):
        want_exception = 'xml.etree.ElementTree.ParseError: no element found: line 1369, column 0'

        try:
            call_wikiq(self.input_file)
        except subprocess.CalledProcessError as exc:
            errlines = exc.stderr.decode("utf8").splitlines()
            self.assertEqual(errlines[-1], want_exception)
        else:
            self.fail("No exception raised, want: {}".format(want_exception))


class Test_Stdout(unittest.TestCase):

    def setUp(self):
        wiki = 'sailormoon'
        self.wikiq_out_name = wiki + ".tsv"
        self.call_output = os.path.join(TEST_OUTPUT_DIR, self.wikiq_out_name)

        infile = "{0}.xml.7z".format(wiki)
        self.base_call = WIKIQ + " {0} --stdout"
        input_dir = os.path.join(TEST_DIR, "dumps")
        self.input_file = os.path.join(TEST_DIR, input_dir, infile)

    def test_noargs(self):
        baseline_file, test_file = tmp_test_file("noargs_" + self.wikiq_out_name)

        outs = ""
        try:
            outs = call_wikiq(self.input_file, "--stdout", out=False).decode("utf8")
        except subprocess.CalledProcessError as exc:
            self.fail(exc.stderr.decode("utf8"))

        copyfile(self.call_output, test_file)

        test = pd.read_table(StringIO(outs))
        baseline = pd.read_table(baseline_file)
        assert_frame_equal(test, baseline, check_like=True)


class Test_Regex(unittest.TestCase):
    def setUp(self):
        wiki = 'regextest'
        self.wikiq_out_name = wiki + '.tsv'
        infile = "{0}.xml.bz2".format(wiki)

        input_dir = os.path.join(TEST_DIR, "dumps")
        self.input_file = os.path.join(TEST_DIR, input_dir, infile)

        self.call_output = os.path.join(TEST_OUTPUT_DIR, self.wikiq_out_name)

        # sample arguments for checking that bad arguments get terminated / test_regex_arguments
        self.bad_arguments_list = [
            # label is missing
            "-RP '\\b\\d+\\b'",
            # number of reg and number of labels do not match
            "-RP 'NPO V' -RP THE -RPl testlabel",
            # cp but rp label
            "-CP '(Tamil|Li)' -RPl testlabel",
            # regex is missing
            "-CPl testlabel",
            "-RP '\\b\\w{3}\\b' -RPl threeletters -CP '\\b\\w{3}\\b'"
        ]

        # sample arguments for checking the outcomes of good arguments / test_basic_regex
        self.good_arguments_list = [
            "-RP '\\b\\d{3}\\b' -RPl threedigits",
            "-RP 'TestCase' -RP 'page' -RPl testcases -RPl page_word",
            "-CP 'Chevalier' -CPl chev_com -RP 'welcome to Wikipedia' -RPl wiki_welcome -CP 'Warning' -CPl warning",
            "-CP 'WP:EVADE' -CPl wp_evade"
        ]

        self.cap_arguments_list = [
            "-RP 'Li Chevalier' -RPl li_cheval -CP '(?P<letter>\\b[a-zA-Z]{3}\\b)|(?P<number>\\b\\d+\\b)|(?P<cat>\\bcat\\b)' -CPl three",
            "-CP '(?P<a>\\bTestCaseA\\b)|(?P<b>\\bTestCaseB\\b)|(?P<c>\\bTestCaseC\\b)|(?P<d>\\bTestCaseD\\b)' -CPl testcase -RP '(?P<npov>npov|NPOV)|(?P<neutral>neutral point of view)' -RPl npov"
        ]

    def test_regex_arguments(self):
        for arguments in self.bad_arguments_list:
            try:
                call_wikiq(self.input_file, "--stdout", arguments, out=False)
            except subprocess.CalledProcessError as exc:
                # we want to check that the bad arguments were caught and sys.exit is stopping the code
                print(exc.stderr.decode("utf-8"))
            else:
                self.fail("No exception raised, want Exception")

    def test_basic_regex(self):
        for i, arguments in enumerate(self.good_arguments_list):
            test_filename = "basic_{0}_{1}.tsv".format(self.wikiq_out_name[:-4], str(i))
            baseline_file, test_file = tmp_test_file(test_filename)

            try:
                call_wikiq(self.input_file, arguments)
            except subprocess.CalledProcessError as exc:
                self.fail(exc.stderr.decode("utf8"))

            copyfile(self.call_output, test_file)

            test = pd.read_table(test_file)

            baseline = pd.read_table(baseline_file)
            assert_frame_equal(test, baseline, check_like=True)
            print(i)

    def test_capturegroup_regex(self):
        for i, arguments in enumerate(self.cap_arguments_list):
            test_filename = "capturegroup_{0}_{1}.tsv".format(self.wikiq_out_name[:-4], str(i))
            baseline_file, test_file = tmp_test_file(test_filename)

            try:
                call_wikiq(self.input_file, arguments)
            except subprocess.CalledProcessError as exc:
                self.fail(exc.stderr.decode("utf8"))

            copyfile(self.call_output, test_file)

            test = pd.read_table(test_file)

            baseline = pd.read_table(baseline_file)
            assert_frame_equal(test, baseline, check_like=True)


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