"""Sanity test which executes mypy."""

from __future__ import annotations

import dataclasses
import os
import pathlib
import re
import subprocess
import sys
import typing as t

vendored_paths = (
    'lib/ansible/module_utils/six/__init__.py',
    'lib/ansible/module_utils/distro/_distro.py',
)

config_dir = pathlib.Path(__file__).parent / 'mypy'


def main() -> None:
    """Main program entry point."""
    paths = sys.argv[1:] or sys.stdin.read().splitlines()
    paths = [path for path in paths if path not in vendored_paths]  # FUTURE: define the exclusions in config so the paths can be skipped earlier

    if not paths:
        return

    python_version = os.environ['ANSIBLE_TEST_TARGET_PYTHON_VERSION']
    controller_python_versions = os.environ['ANSIBLE_TEST_CONTROLLER_PYTHON_VERSIONS'].split(',')
    remote_only_python_versions = os.environ['ANSIBLE_TEST_REMOTE_ONLY_PYTHON_VERSIONS'].split(',')

    contexts = (
        MyPyContext('ansible-test', ['test/lib/ansible_test/'], controller_python_versions),
        MyPyContext('ansible-test', ['test/lib/ansible_test/_util/target/'], remote_only_python_versions),

        MyPyContext('ansible-core', ['lib/ansible/'], controller_python_versions),
        MyPyContext('ansible-core', ['lib/ansible/modules/', 'lib/ansible/module_utils/'], remote_only_python_versions),

        MyPyContext('ansible-core', ['test/units/'], controller_python_versions),
        MyPyContext('ansible-core', ['test/units/modules/', 'test/units/module_utils/'], remote_only_python_versions),

        MyPyContext('packaging', ['packaging/'], controller_python_versions),
    )

    unfiltered_messages: list[SanityMessage] = []

    for context in contexts:
        if python_version not in context.python_versions:
            continue

        unfiltered_messages.extend(test_context(python_version, context, paths))

    notices = []
    messages = []

    for message in unfiltered_messages:
        if message.level != 'error':
            notices.append(message)
            continue

        match = re.search(r'^(?P<message>.*) {2}\[(?P<code>.*)]$', message.message)

        messages.append(SanityMessage(
            message=match.group('message'),
            path=message.path,
            line=message.line,
            column=message.column,
            level=message.level,
            code=match.group('code'),
        ))

    # FUTURE: provide a way for script based tests to report non-error messages (in this case, notices)

    # The following error codes from mypy indicate that results are incomplete.
    # That prevents the test from completing successfully, just as if mypy were to traceback or generate unexpected output.
    fatal_error_codes = {
        'import',
        'syntax',
    }

    fatal_errors = [message for message in messages if message.code in fatal_error_codes]

    if fatal_errors:
        error_message = '\n'.join(error.format() for error in fatal_errors)
        raise Exception(f'Encountered {len(fatal_errors)} fatal errors reported by mypy:\n{error_message}')

    paths_set = set(paths)

    # Only report messages for paths that were specified as targets.
    # Imports in our code are followed by mypy in order to perform its analysis, which is important for accurate results.
    # However, it will also report issues on those files, which is not the desired behavior.
    messages = [message for message in messages if message.path in paths_set]

    for message in messages:
        print(message.format())


def test_context(
    python_version: str,
    context: MyPyContext,
    paths: list[str],
) -> list[SanityMessage]:
    """Run mypy tests for the specified context."""
    context_paths = [path for path in paths if any(path.startswith(match_path) for match_path in context.paths)]

    if not context_paths:
        return []

    config_path = config_dir / f'{context.name}.ini'

    # FUTURE: provide a way for script based tests to report progress and other diagnostic information
    # display.info(f'Checking context "{context.name}"', verbosity=1)

    env = os.environ.copy()
    env['MYPYPATH'] = env['PYTHONPATH']

    # The --no-site-packages option should not be used, as it will prevent loading of type stubs from the sanity test virtual environment.

    # Enabling the --warn-unused-configs option would help keep the config files clean.
    # However, the option can only be used when all files in tested contexts are evaluated.
    # Unfortunately sanity tests have no way of making that determination currently.
    # The option is also incompatible with incremental mode and caching.

    cmd = [
        # Below are arguments common to all contexts.
        # They are kept here to avoid repetition in each config file.
        sys.executable,
        '-m', 'mypy',
        '--show-column-numbers',
        '--show-error-codes',
        '--no-error-summary',
        # This is a fairly common pattern in our code, so we'll allow it.
        '--allow-redefinition',
        # Since we specify the path(s) to test, it's important that mypy is configured to use the default behavior of following imports.
        '--follow-imports', 'normal',
        # Incremental results and caching do not provide significant performance benefits.
        # It also prevents the use of the --warn-unused-configs option.
        '--no-incremental',
        '--cache-dir', '/dev/null',
        # The platform is specified here so that results are consistent regardless of what platform the tests are run from.
        # In the future, if testing of other platforms is desired, the platform should become part of the test specification, just like the Python version.
        '--platform', 'linux',
        # Despite what the documentation [1] states, the --python-version option does not cause mypy to search for a corresponding Python executable.
        # It will instead use the Python executable that is used to run mypy itself.
        # The --python-executable option can be used to specify the Python executable, with the default being the executable used to run mypy.
        # As a precaution, that option is used in case the behavior of mypy is updated in the future to match the documentation.
        # That should help guarantee that the Python executable providing type hints is the one used to run mypy.
        # [1] https://mypy.readthedocs.io/en/stable/command_line.html#cmdoption-mypy-python-version
        '--python-executable', sys.executable,
        '--python-version', python_version,
        # Below are context specific arguments.
        # They are primarily useful for listing individual 'ignore_missing_imports' entries instead of using a global ignore.
        '--config-file', config_path,
    ]  # fmt: skip

    cmd.extend(context_paths)

    try:
        completed_process = subprocess.run(cmd, env=env, capture_output=True, check=True, text=True)
        stdout, stderr = completed_process.stdout, completed_process.stderr

        if stdout or stderr:
            raise Exception(f'{stdout=} {stderr=}')
    except subprocess.CalledProcessError as ex:
        if ex.returncode != 1 or ex.stderr or not ex.stdout:
            raise

        stdout = ex.stdout

    pattern = re.compile(r'^(?P<path>[^:]*):(?P<line>[0-9]+):((?P<column>[0-9]+):)? (?P<level>[^:]+): (?P<message>.*)$')

    parsed = parse_to_list_of_dict(pattern, stdout or '')

    messages = [SanityMessage(
        level=r['level'],
        message=r['message'],
        path=r['path'],
        line=int(r['line']),
        column=int(r.get('column') or '0'),
        code='',  # extracted from error level messages later
    ) for r in parsed]

    return messages


@dataclasses.dataclass(frozen=True)
class MyPyContext:
    """Context details for a single run of mypy."""

    name: str
    paths: list[str]
    python_versions: list[str]


@dataclasses.dataclass(frozen=True)
class SanityMessage:
    message: str
    path: str
    line: int
    column: int
    level: str
    code: str

    def format(self) -> str:
        if self.code:
            msg = f'{self.code}: {self.message}'
        else:
            msg = self.message

        return f'{self.path}:{self.line}:{self.column}: {msg}'


def parse_to_list_of_dict(pattern: re.Pattern, value: str) -> list[dict[str, t.Any]]:
    matched = []
    unmatched = []

    for line in value.splitlines():
        match = re.search(pattern, line)

        if match:
            matched.append(match.groupdict())
        else:
            unmatched.append(line)

    if unmatched:
        raise Exception(f'Pattern {pattern!r} did not match values:\n' + '\n'.join(unmatched))

    return matched


if __name__ == '__main__':
    main()