"""  # lint-amnesty, pylint: disable=django-not-configured
Check code quality using pycodestyle, pylint, and diff_quality.
"""

import json
import os
import re
from datetime import datetime
from xml.sax.saxutils import quoteattr

from paver.easy import BuildFailure, cmdopts, needs, sh, task

from .utils.envs import Env
from .utils.timer import timed

ALL_SYSTEMS = 'lms,cms,common,openedx,pavelib,scripts'
JUNIT_XML_TEMPLATE = """<?xml version="1.0" encoding="UTF-8"?>
<testsuite name="{name}" tests="1" errors="0" failures="{failure_count}" skip="0">
<testcase classname="pavelib.quality" name="{name}" time="{seconds}">{failure_element}</testcase>
</testsuite>
"""
JUNIT_XML_FAILURE_TEMPLATE = '<failure message={message}/>'
START_TIME = datetime.utcnow()


def write_junit_xml(name, message=None):
    """
    Write a JUnit results XML file describing the outcome of a quality check.
    """
    if message:
        failure_element = JUNIT_XML_FAILURE_TEMPLATE.format(message=quoteattr(message))
    else:
        failure_element = ''
    data = {
        'failure_count': 1 if message else 0,
        'failure_element': failure_element,
        'name': name,
        'seconds': (datetime.utcnow() - START_TIME).total_seconds(),
    }
    Env.QUALITY_DIR.makedirs_p()
    filename = Env.QUALITY_DIR / f'{name}.xml'
    with open(filename, 'w') as f:
        f.write(JUNIT_XML_TEMPLATE.format(**data))


def fail_quality(name, message):
    """
    Fail the specified quality check by generating the JUnit XML results file
    and raising a ``BuildFailure``.
    """
    write_junit_xml(name, message)
    raise BuildFailure(message)


def top_python_dirs(dirname):
    """
    Find the directories to start from in order to find all the Python files in `dirname`.
    """
    top_dirs = []

    dir_init = os.path.join(dirname, "__init__.py")
    if os.path.exists(dir_init):
        top_dirs.append(dirname)

    for directory in ['djangoapps', 'lib']:
        subdir = os.path.join(dirname, directory)
        subdir_init = os.path.join(subdir, "__init__.py")
        if os.path.exists(subdir) and not os.path.exists(subdir_init):
            dirs = os.listdir(subdir)
            top_dirs.extend(d for d in dirs if os.path.isdir(os.path.join(subdir, d)))

    modules_to_remove = ['__pycache__']
    for module in modules_to_remove:
        if module in top_dirs:
            top_dirs.remove(module)

    return top_dirs


def _get_pep8_violations(clean=True):
    """
    Runs pycodestyle. Returns a tuple of (number_of_violations, violations_string)
    where violations_string is a string of all PEP 8 violations found, separated
    by new lines.
    """
    report_dir = (Env.REPORT_DIR / 'pep8')
    if clean:
        report_dir.rmtree(ignore_errors=True)
    report_dir.makedirs_p()
    report = report_dir / 'pep8.report'

    # Make sure the metrics subdirectory exists
    Env.METRICS_DIR.makedirs_p()

    if not report.exists():
        sh(f'pycodestyle . | tee {report} -a')

    violations_list = _pep8_violations(report)

    return len(violations_list), violations_list


def _pep8_violations(report_file):
    """
    Returns the list of all PEP 8 violations in the given report_file.
    """
    with open(report_file) as f:
        return f.readlines()


@task
@cmdopts([
    ("system=", "s", "System to act on"),
])
@timed
def run_pep8(options):  # pylint: disable=unused-argument
    """
    Run pycodestyle on system code.
    Fail the task if any violations are found.
    """
    (count, violations_list) = _get_pep8_violations()
    violations_list = ''.join(violations_list)

    # Print number of violations to log
    violations_count_str = f"Number of PEP 8 violations: {count}"
    print(violations_count_str)
    print(violations_list)

    # Also write the number of violations to a file
    with open(Env.METRICS_DIR / "pep8", "w") as f:
        f.write(violations_count_str + '\n\n')
        f.write(violations_list)

    # Fail if any violations are found
    if count:
        failure_string = "FAILURE: Too many PEP 8 violations. " + violations_count_str
        failure_string += f"\n\nViolations:\n{violations_list}"
        fail_quality('pep8', failure_string)
    else:
        write_junit_xml('pep8')


@task
@needs(
    'pavelib.prereqs.install_node_prereqs',
    'pavelib.utils.test.utils.ensure_clean_package_lock',
)
@cmdopts([
    ("limit=", "l", "limit for number of acceptable violations"),
])
@timed
def run_eslint(options):
    """
    Runs eslint on static asset directories.
    If limit option is passed, fails build if more violations than the limit are found.
    """

    eslint_report_dir = (Env.REPORT_DIR / "eslint")
    eslint_report = eslint_report_dir / "eslint.report"
    _prepare_report_dir(eslint_report_dir)
    violations_limit = int(getattr(options, 'limit', -1))

    sh(
        "node --max_old_space_size=4096 node_modules/.bin/eslint "
        "--ext .js --ext .jsx --format=compact . | tee {eslint_report}".format(
            eslint_report=eslint_report
        ),
        ignore_error=True
    )

    try:
        num_violations = int(_get_count_from_last_line(eslint_report, "eslint"))
    except TypeError:
        fail_quality(
            'eslint',
            "FAILURE: Number of eslint violations could not be found in {eslint_report}".format(
                eslint_report=eslint_report
            )
        )

    # Record the metric
    _write_metric(num_violations, (Env.METRICS_DIR / "eslint"))

    # Fail if number of violations is greater than the limit
    if num_violations > violations_limit > -1:
        fail_quality(
            'eslint',
            "FAILURE: Too many eslint violations ({count}).\nThe limit is {violations_limit}.".format(
                count=num_violations, violations_limit=violations_limit
            )
        )
    else:
        write_junit_xml('eslint')


def _get_stylelint_violations():
    """
    Returns the number of Stylelint violations.
    """
    stylelint_report_dir = (Env.REPORT_DIR / "stylelint")
    stylelint_report = stylelint_report_dir / "stylelint.report"
    _prepare_report_dir(stylelint_report_dir)
    formatter = 'node_modules/stylelint-formatter-pretty'

    sh(
        "stylelint **/*.scss --custom-formatter={formatter} | tee {stylelint_report}".format(
            formatter=formatter,
            stylelint_report=stylelint_report,
        ),
        ignore_error=True
    )

    try:
        return int(_get_count_from_last_line(stylelint_report, "stylelint"))
    except TypeError:
        fail_quality(
            'stylelint',
            "FAILURE: Number of stylelint violations could not be found in {stylelint_report}".format(
                stylelint_report=stylelint_report
            )
        )


@task
@needs('pavelib.prereqs.install_node_prereqs')
@cmdopts([
    ("limit=", "l", "limit for number of acceptable violations"),
])
@timed
def run_stylelint(options):
    """
    Runs stylelint on Sass files.
    If limit option is passed, fails build if more violations than the limit are found.
    """
    violations_limit = 0
    num_violations = _get_stylelint_violations()

    # Record the metric
    _write_metric(num_violations, (Env.METRICS_DIR / "stylelint"))

    # Fail if number of violations is greater than the limit
    if num_violations > violations_limit:
        fail_quality(
            'stylelint',
            "FAILURE: Stylelint failed with too many violations: ({count}).\nThe limit is {violations_limit}.".format(
                count=num_violations,
                violations_limit=violations_limit,
            )
        )
    else:
        write_junit_xml('stylelint')


@task
@needs('pavelib.prereqs.install_python_prereqs')
@cmdopts([
    ("thresholds=", "t", "json containing limit for number of acceptable violations per rule"),
])
@timed
def run_xsslint(options):
    """
    Runs xsslint/xss_linter.py on the codebase
    """

    thresholds_option = getattr(options, 'thresholds', '{}')
    try:
        violation_thresholds = json.loads(thresholds_option)
    except ValueError:
        violation_thresholds = None
    if isinstance(violation_thresholds, dict) is False or \
            any(key not in ("total", "rules") for key in violation_thresholds.keys()):

        fail_quality(
            'xsslint',
            """FAILURE: Thresholds option "{thresholds_option}" was not supplied using proper format.\n"""
            """Here is a properly formatted example, '{{"total":100,"rules":{{"javascript-escape":0}}}}' """
            """with property names in double-quotes.""".format(
                thresholds_option=thresholds_option
            )
        )

    xsslint_script = "xss_linter.py"
    xsslint_report_dir = (Env.REPORT_DIR / "xsslint")
    xsslint_report = xsslint_report_dir / "xsslint.report"
    _prepare_report_dir(xsslint_report_dir)

    sh(
        "{repo_root}/scripts/xsslint/{xsslint_script} --rule-totals --config={cfg_module} >> {xsslint_report}".format(
            repo_root=Env.REPO_ROOT,
            xsslint_script=xsslint_script,
            xsslint_report=xsslint_report,
            cfg_module='scripts.xsslint_config'
        ),
        ignore_error=True
    )

    xsslint_counts = _get_xsslint_counts(xsslint_report)

    try:
        metrics_str = "Number of {xsslint_script} violations: {num_violations}\n".format(
            xsslint_script=xsslint_script, num_violations=int(xsslint_counts['total'])
        )
        if 'rules' in xsslint_counts and any(xsslint_counts['rules']):
            metrics_str += "\n"
            rule_keys = sorted(xsslint_counts['rules'].keys())
            for rule in rule_keys:
                metrics_str += "{rule} violations: {count}\n".format(
                    rule=rule,
                    count=int(xsslint_counts['rules'][rule])
                )
    except TypeError:
        fail_quality(
            'xsslint',
            "FAILURE: Number of {xsslint_script} violations could not be found in {xsslint_report}".format(
                xsslint_script=xsslint_script, xsslint_report=xsslint_report
            )
        )

    metrics_report = (Env.METRICS_DIR / "xsslint")
    # Record the metric
    _write_metric(metrics_str, metrics_report)
    # Print number of violations to log.
    sh(f"cat {metrics_report}", ignore_error=True)

    error_message = ""

    # Test total violations against threshold.
    if 'total' in list(violation_thresholds.keys()):
        if violation_thresholds['total'] < xsslint_counts['total']:
            error_message = "Too many violations total ({count}).\nThe limit is {violations_limit}.".format(
                count=xsslint_counts['total'], violations_limit=violation_thresholds['total']
            )

    # Test rule violations against thresholds.
    if 'rules' in violation_thresholds:
        threshold_keys = sorted(violation_thresholds['rules'].keys())
        for threshold_key in threshold_keys:
            if threshold_key not in xsslint_counts['rules']:
                error_message += (
                    "\nNumber of {xsslint_script} violations for {rule} could not be found in "
                    "{xsslint_report}."
                ).format(
                    xsslint_script=xsslint_script, rule=threshold_key, xsslint_report=xsslint_report
                )
            elif violation_thresholds['rules'][threshold_key] < xsslint_counts['rules'][threshold_key]:
                error_message += \
                    "\nToo many {rule} violations ({count}).\nThe {rule} limit is {violations_limit}.".format(
                        rule=threshold_key, count=xsslint_counts['rules'][threshold_key],
                        violations_limit=violation_thresholds['rules'][threshold_key],
                    )

    if error_message:
        fail_quality(
            'xsslint',
            "FAILURE: XSSLinter Failed.\n{error_message}\n"
            "See {xsslint_report} or run the following command to hone in on the problem:\n"
            "  ./scripts/xss-commit-linter.sh -h".format(
                error_message=error_message, xsslint_report=xsslint_report
            )
        )
    else:
        write_junit_xml('xsslint')


def _write_metric(metric, filename):
    """
    Write a given metric to a given file
    Used for things like reports/metrics/eslint, which will simply tell you the number of
    eslint violations found
    """
    Env.METRICS_DIR.makedirs_p()

    with open(filename, "w") as metric_file:
        metric_file.write(str(metric))


def _prepare_report_dir(dir_name):
    """
    Sets a given directory to a created, but empty state
    """
    dir_name.rmtree_p()
    dir_name.mkdir_p()


def _get_report_contents(filename, report_name, last_line_only=False):
    """
    Returns the contents of the given file. Use last_line_only to only return
    the last line, which can be used for getting output from quality output
    files.

    Arguments:
        last_line_only: True to return the last line only, False to return a
            string with full contents.

    Returns:
        String containing full contents of the report, or the last line.

    """
    if os.path.isfile(filename):
        with open(filename) as report_file:
            if last_line_only:
                lines = report_file.readlines()
                for line in reversed(lines):
                    if line != '\n':
                        return line
                return None
            else:
                return report_file.read()
    else:
        file_not_found_message = f"FAILURE: The following log file could not be found: {filename}"
        fail_quality(report_name, file_not_found_message)


def _get_count_from_last_line(filename, file_type):
    """
    This will return the number in the last line of a file.
    It is returning only the value (as a floating number).
    """
    report_contents = _get_report_contents(filename, file_type, last_line_only=True)

    if report_contents is None:
        return 0

    last_line = report_contents.strip()
    # Example of the last line of a compact-formatted eslint report (for example): "62829 problems"
    regex = r'^\d+'

    try:
        return float(re.search(regex, last_line).group(0))
    # An AttributeError will occur if the regex finds no matches.
    # A ValueError will occur if the returned regex cannot be cast as a float.
    except (AttributeError, ValueError):
        return None


def _get_xsslint_counts(filename):
    """
    This returns a dict of violations from the xsslint report.

    Arguments:
        filename: The name of the xsslint report.

    Returns:
        A dict containing the following:
            rules: A dict containing the count for each rule as follows:
                violation-rule-id: N, where N is the number of violations
            total: M, where M is the number of total violations

    """
    report_contents = _get_report_contents(filename, 'xsslint')
    rule_count_regex = re.compile(r"^(?P<rule_id>[a-z-]+):\s+(?P<count>\d+) violations", re.MULTILINE)
    total_count_regex = re.compile(r"^(?P<count>\d+) violations total", re.MULTILINE)
    violations = {'rules': {}}
    for violation_match in rule_count_regex.finditer(report_contents):
        try:
            violations['rules'][violation_match.group('rule_id')] = int(violation_match.group('count'))
        except ValueError:
            violations['rules'][violation_match.group('rule_id')] = None
    try:
        violations['total'] = int(total_count_regex.search(report_contents).group('count'))
    # An AttributeError will occur if the regex finds no matches.
    # A ValueError will occur if the returned regex cannot be cast as a float.
    except (AttributeError, ValueError):
        violations['total'] = None
    return violations


def _extract_missing_pii_annotations(filename):
    """
    Returns the number of uncovered models from the stdout report of django_find_annotations.

    Arguments:
        filename: Filename where stdout of django_find_annotations was captured.

    Returns:
        three-tuple containing:
            1. The number of uncovered models,
            2. A bool indicating whether the coverage is still below the threshold, and
            3. The full report as a string.
    """
    uncovered_models = 0
    pii_check_passed = True
    if os.path.isfile(filename):
        with open(filename) as report_file:
            lines = report_file.readlines()

            # Find the count of uncovered models.
            uncovered_regex = re.compile(r'^Coverage found ([\d]+) uncovered')
            for line in lines:
                uncovered_match = uncovered_regex.match(line)
                if uncovered_match:
                    uncovered_models = int(uncovered_match.groups()[0])
                    break

            # Find a message which suggests the check failed.
            failure_regex = re.compile(r'^Coverage threshold not met!')
            for line in lines:
                failure_match = failure_regex.match(line)
                if failure_match:
                    pii_check_passed = False
                    break

            # Each line in lines already contains a newline.
            full_log = ''.join(lines)
    else:
        fail_quality('pii', f'FAILURE: Log file could not be found: {filename}')

    return (uncovered_models, pii_check_passed, full_log)


@task
@needs('pavelib.prereqs.install_python_prereqs')
@cmdopts([
    ("report-dir=", "r", "Directory in which to put PII reports"),
])
@timed
def run_pii_check(options):
    """
    Guarantee that all Django models are PII-annotated.
    """
    pii_report_name = 'pii'
    default_report_dir = (Env.REPORT_DIR / pii_report_name)
    report_dir = getattr(options, 'report_dir', default_report_dir)
    output_file = os.path.join(report_dir, 'pii_check_{}.report')
    env_report = []
    pii_check_passed = True
    for env_name, env_settings_file in (("CMS", "cms.envs.test"), ("LMS", "lms.envs.test")):
        try:
            print()
            print(f"Running {env_name} PII Annotation check and report")
            print("-" * 45)
            run_output_file = str(output_file).format(env_name.lower())
            sh(
                "mkdir -p {} && "  # lint-amnesty, pylint: disable=duplicate-string-formatting-argument
                "export DJANGO_SETTINGS_MODULE={}; "
                "code_annotations django_find_annotations "
                "--config_file .pii_annotations.yml --report_path {} --app_name {} "
                "--lint --report --coverage | tee {}".format(
                    report_dir, env_settings_file, report_dir, env_name.lower(), run_output_file
                )
            )
            uncovered_model_count, pii_check_passed_env, full_log = _extract_missing_pii_annotations(run_output_file)
            env_report.append((
                uncovered_model_count,
                full_log,
            ))

        except BuildFailure as error_message:
            fail_quality(pii_report_name, f'FAILURE: {error_message}')

        if not pii_check_passed_env:
            pii_check_passed = False

    # Determine which suite is the worst offender by obtaining the max() keying off uncovered_count.
    uncovered_count, full_log = max(env_report, key=lambda r: r[0])

    # Write metric file.
    if uncovered_count is None:
        uncovered_count = 0
    metrics_str = f"Number of PII Annotation violations: {uncovered_count}\n"
    _write_metric(metrics_str, (Env.METRICS_DIR / pii_report_name))

    # Finally, fail the paver task if code_annotations suggests that the check failed.
    if not pii_check_passed:
        fail_quality('pii', full_log)


@task
@needs('pavelib.prereqs.install_python_prereqs')
@timed
def check_keywords():
    """
    Check Django model fields for names that conflict with a list of reserved keywords
    """
    report_path = os.path.join(Env.REPORT_DIR, 'reserved_keywords')
    sh(f"mkdir -p {report_path}")

    overall_status = True
    for env, env_settings_file in [('lms', 'lms.envs.test'), ('cms', 'cms.envs.test')]:
        report_file = f"{env}_reserved_keyword_report.csv"
        override_file = os.path.join(Env.REPO_ROOT, "db_keyword_overrides.yml")
        try:
            sh(
                "export DJANGO_SETTINGS_MODULE={settings_file}; "
                "python manage.py {app} check_reserved_keywords "
                "--override_file {override_file} "
                "--report_path {report_path} "
                "--report_file {report_file}".format(
                    settings_file=env_settings_file, app=env, override_file=override_file,
                    report_path=report_path, report_file=report_file
                )
            )
        except BuildFailure:
            overall_status = False

    if not overall_status:
        fail_quality(
            'keywords',
            'Failure: reserved keyword checker failed. Reports can be found here: {}'.format(
                report_path
            )
        )