import glob

import io

import os

import sys

import importlib.metadata

import argparse

import traceback

import contextlib

from io import StringIO

import json

import subprocess

import re

import tempfile

import email.parser

import pathlib

import zipfile

from pyproject_requirements_txt import convert_requirements_txt

# Some valid Python version specifiers are not supported.

# Allow only the forms we know we can handle.

VERSION_RE = re.compile(r'[a-zA-Z0-9.-]+(\.\*)?')

class EndPass(Exception):

    """End current pass of generating requirements"""

# nb: we don't use functools.partial to be able to use pytest's capsys

# see https://github.com/pytest-dev/pytest/issues/8900

def print_err(*args, **kwargs):

    kwargs.setdefault('file', sys.stderr)

    print(*args, **kwargs)

try:

    from packaging.requirements import Requirement, InvalidRequirement

    from packaging.utils import canonicalize_name

except ImportError as e:

    print_err('Import error:', e)

    # already echoed by the %pyproject_buildrequires macro

    sys.exit(0)

# uses packaging, needs to be imported after packaging is verified to be present

from pyproject_convert import convert

@contextlib.contextmanager

def hook_call():

    captured_out = StringIO()

    with contextlib.redirect_stdout(captured_out):

        yield

    for line in captured_out.getvalue().splitlines():

        print_err('HOOK STDOUT:', line)

def guess_reason_for_invalid_requirement(requirement_str):

    if ':' in requirement_str:

        message = (

            'It might be an URL. '

            '%pyproject_buildrequires cannot handle all URL-based requirements. '

            'Add PackageName@ (see PEP 508) to the URL to at least require any version of PackageName.'

        )

        if '@' in requirement_str:

            message += ' (but note that URLs might not work well with other features)'

        return message

    if '/' in requirement_str:

        return (

            'It might be a local path. '

            '%pyproject_buildrequires cannot handle local paths as requirements. '

            'Use an URL with PackageName@ (see PEP 508) to at least require any version of PackageName.'

        )

    # No more ideas

    return None

class Requirements:

    """Requirement printer"""

    def __init__(self, get_installed_version, extras=None,

                 generate_extras=False, python3_pkgversion='3'):

        self.get_installed_version = get_installed_version

        self.extras = set()

        if extras:

            for extra in extras:

                self.add_extras(*extra.split(','))

        self.missing_requirements = False

        self.generate_extras = generate_extras

        self.python3_pkgversion = python3_pkgversion

    def add_extras(self, *extras):

        self.extras |= set(e.strip() for e in extras)

    @property

    def marker_envs(self):

        if self.extras:

            return [{'extra': e} for e in sorted(self.extras)]

        return [{'extra': ''}]

    def evaluate_all_environamnets(self, requirement):

        for marker_env in self.marker_envs:

            if requirement.marker.evaluate(environment=marker_env):

                return True

        return False

    def add(self, requirement_str, *, source=None):

        """Output a Python-style requirement string as RPM dep"""

        print_err(f'Handling {requirement_str} from {source}')

        try:

            requirement = Requirement(requirement_str)

        except InvalidRequirement:

            hint = guess_reason_for_invalid_requirement(requirement_str)

            message = f'Requirement {requirement_str!r} from {source} is invalid.'

            if hint:

                message += f' Hint: {hint}'

            raise ValueError(message)

        if requirement.url:

            print_err(

                f'WARNING: Simplifying {requirement_str!r} to {requirement.name!r}.'

            )

        name = canonicalize_name(requirement.name)

        if (requirement.marker is not None and

                not self.evaluate_all_environamnets(requirement)):

            print_err(f'Ignoring alien requirement:', requirement_str)

            return

        # We need to always accept pre-releases as satisfying the requirement

        # Otherwise e.g. installed cffi version 1.15.0rc2 won't even satisfy the requirement for "cffi"

        # https://bugzilla.redhat.com/show_bug.cgi?id=2014639#c3

        requirement.specifier.prereleases = True

        try:

            # TODO: check if requirements with extras are satisfied

            installed = self.get_installed_version(requirement.name)

        except importlib.metadata.PackageNotFoundError:

            print_err(f'Requirement not satisfied: {requirement_str}')

            installed = None

        if installed and installed in requirement.specifier:

            print_err(f'Requirement satisfied: {requirement_str}')

            print_err(f'   (installed: {requirement.name} {installed})')

            if requirement.extras:

                print_err(f'   (extras are currently not checked)')

        else:

            self.missing_requirements = True

        if self.generate_extras:

            extra_names = [f'{name}[{extra.lower()}]' for extra in sorted(requirement.extras)]

        else:

            extra_names = []

        for name in [name] + extra_names:

            together = []

            for specifier in sorted(

                requirement.specifier,

                key=lambda s: (s.operator, s.version),

            ):

                if not VERSION_RE.fullmatch(str(specifier.version)):

                    raise ValueError(

                        f'Unknown character in version: {specifier.version}. '

                        + '(This might be a bug in pyproject-rpm-macros.)',

                    )

                together.append(convert(python3dist(name, python3_pkgversion=self.python3_pkgversion),

                                        specifier.operator, specifier.version))

            if len(together) == 0:

                print(python3dist(name,

                                  python3_pkgversion=self.python3_pkgversion))

            elif len(together) == 1:

                print(together[0])

            else:

                print(f"({' with '.join(together)})")

    def check(self, *, source=None):

        """End current pass if any unsatisfied dependencies were output"""

        if self.missing_requirements:

            print_err(f'Exiting dependency generation pass: {source}')

            raise EndPass(source)

    def extend(self, requirement_strs, **kwargs):

        """add() several requirements"""

        for req_str in requirement_strs:

            self.add(req_str, **kwargs)

def toml_load(opened_binary_file):

    try:

        # tomllib is in the standard library since 3.11.0b1

        import tomllib as toml_module

        load_from = opened_binary_file

    except ImportError:

        try:

            # note: we could use tomli here,

            # but for backwards compatibility with RHEL 9, we use toml instead

            import toml as toml_module

            load_from = io.TextIOWrapper(opened_binary_file, encoding='utf-8')

        except ImportError as e:

            print_err('Import error:', e)

            # already echoed by the %pyproject_buildrequires macro

            sys.exit(0)

    return toml_module.load(load_from)

def get_backend(requirements):

    try:

        f = open('pyproject.toml', 'rb')

    except FileNotFoundError:

        pyproject_data = {}

    else:

        with f:

            pyproject_data = toml_load(f)

    buildsystem_data = pyproject_data.get('build-system', {})

    requirements.extend(

        buildsystem_data.get('requires', ()),

        source='build-system.requires',

    )

    backend_name = buildsystem_data.get('build-backend')

    if not backend_name:

        # https://www.python.org/dev/peps/pep-0517/:

        # If the pyproject.toml file is absent, or the build-backend key is

        # missing, the source tree is not using this specification, and tools

        # should revert to the legacy behaviour of running setup.py

        # (either directly, or by implicitly invoking the [following] backend).

        # If setup.py is also not present program will mimick pip's behavior

        # and end with an error.

        if not os.path.exists('setup.py'):

            raise FileNotFoundError('File "setup.py" not found for legacy project.')

        backend_name = 'setuptools.build_meta:__legacy__'

        # Note: For projects without pyproject.toml, this was already echoed

        # by the %pyproject_buildrequires macro, but this also handles cases

        # with pyproject.toml without a specified build backend.

        # If the default requirements change, also change them in the macro!

        requirements.add('setuptools >= 40.8', source='default build backend')

        requirements.add('wheel', source='default build backend')

    requirements.check(source='build backend')

    backend_path = buildsystem_data.get('backend-path')

    if backend_path:

        # PEP 517 example shows the path as a list, but some projects don't follow that

        if isinstance(backend_path, str):

            backend_path = [backend_path]

        sys.path = backend_path + sys.path

    module_name, _, object_name = backend_name.partition(":")

    backend_module = importlib.import_module(module_name)

    if object_name:

        return getattr(backend_module, object_name)

    return backend_module

def generate_build_requirements(backend, requirements):

    get_requires = getattr(backend, 'get_requires_for_build_wheel', None)

    if get_requires:

        with hook_call():

            new_reqs = get_requires()

        requirements.extend(new_reqs, source='get_requires_for_build_wheel')

        requirements.check(source='get_requires_for_build_wheel')

def requires_from_metadata_file(metadata_file):

    message = email.parser.Parser().parse(metadata_file, headersonly=True)

    return {k: message.get_all(k, ()) for k in ('Requires', 'Requires-Dist')}

def generate_run_requirements_hook(backend, requirements):

    hook_name = 'prepare_metadata_for_build_wheel'

    prepare_metadata = getattr(backend, hook_name, None)

    if not prepare_metadata:

        raise ValueError(

            'The build backend cannot provide build metadata '

            '(incl. runtime requirements) before build. '

            'Use the provisional -w flag to build the wheel and parse the metadata from it, '

            'or use the -R flag not to generate runtime dependencies.'

        )

    with hook_call():

        dir_basename = prepare_metadata('.')

    with open(dir_basename + '/METADATA') as metadata_file:

        for key, requires in requires_from_metadata_file(metadata_file).items():

            requirements.extend(requires, source=f'hook generated metadata: {key}')

def find_built_wheel(wheeldir):

    wheels = glob.glob(os.path.join(wheeldir, '*.whl'))

    if not wheels:

        return None

    if len(wheels) > 1:

        raise RuntimeError('Found multiple wheels in %{_pyproject_wheeldir}, '

                           'this is not supported with %pyproject_buildrequires -w.')

    return wheels[0]

def generate_run_requirements_wheel(backend, requirements, wheeldir):

    # Reuse the wheel from the previous round of %pyproject_buildrequires (if it exists)

    wheel = find_built_wheel(wheeldir)

    if not wheel:

        import pyproject_wheel

        returncode = pyproject_wheel.build_wheel(wheeldir=wheeldir, stdout=sys.stderr)

        if returncode != 0:

            raise RuntimeError('Failed to build the wheel for %pyproject_buildrequires -w.')

        wheel = find_built_wheel(wheeldir)

    if not wheel:

        raise RuntimeError('Cannot locate the built wheel for %pyproject_buildrequires -w.')

    print_err(f'Reading metadata from {wheel}')

    with zipfile.ZipFile(wheel) as wheelfile:

        for name in wheelfile.namelist():

            if name.count('/') == 1 and name.endswith('.dist-info/METADATA'):

                with io.TextIOWrapper(wheelfile.open(name), encoding='utf-8') as metadata_file:

                    for key, requires in requires_from_metadata_file(metadata_file).items():

                        requirements.extend(requires, source=f'built wheel metadata: {key}')

                break

        else:

            raise RuntimeError('Could not find *.dist-info/METADATA in built wheel.')

def generate_run_requirements(backend, requirements, *, build_wheel, wheeldir):

    if build_wheel:

        generate_run_requirements_wheel(backend, requirements, wheeldir)

    else:

        generate_run_requirements_hook(backend, requirements)

def generate_tox_requirements(toxenv, requirements):

    toxenv = ','.join(toxenv)

    requirements.add('tox-current-env >= 0.0.6', source='tox itself')

    requirements.check(source='tox itself')

    with tempfile.NamedTemporaryFile('r') as deps, \

        tempfile.NamedTemporaryFile('r') as extras, \

            tempfile.NamedTemporaryFile('r') as provision:

        r = subprocess.run(

            [sys.executable, '-m', 'tox',

             '--print-deps-to', deps.name,

             '--print-extras-to', extras.name,

             '--no-provision', provision.name,

             '-q', '-r', '-e', toxenv],

            check=False,

            encoding='utf-8',

            stdout=subprocess.PIPE,

            stderr=subprocess.STDOUT,

        )

        if r.stdout:

            print_err(r.stdout, end='')

        provision_content = provision.read()

        if provision_content and r.returncode != 0:

            provision_requires = json.loads(provision_content)

            if 'minversion' in provision_requires:

                requirements.add(f'tox >= {provision_requires["minversion"]}',

                                 source='tox provision (minversion)')

            if 'requires' in provision_requires:

                requirements.extend(provision_requires["requires"],

                                    source='tox provision (requires)')

            requirements.check(source='tox provision')  # this terminates the script

            raise RuntimeError(

                'Dependencies requested by tox provisioning appear installed, '

                'but tox disagreed.')

        else:

            r.check_returncode()

        deplines = deps.read().splitlines()

        packages = convert_requirements_txt(deplines)

        requirements.add_extras(*extras.read().splitlines())

        requirements.extend(packages,

                            source=f'tox --print-deps-only: {toxenv}')

def python3dist(name, op=None, version=None, python3_pkgversion="3"):

    prefix = f"python{python3_pkgversion}dist"

    if op is None:

        if version is not None:

            raise AssertionError('op and version go together')

        return f'{prefix}({name})'

    else:

        return f'{prefix}({name}) {op} {version}'

def generate_requires(

    *, include_runtime=False, build_wheel=False, wheeldir=None, toxenv=None, extras=None,

    get_installed_version=importlib.metadata.version,  # for dep injection

    generate_extras=False, python3_pkgversion="3", requirement_files=None, use_build_system=True

):

    """Generate the BuildRequires for the project in the current directory

    This is the main Python entry point.

    """

    requirements = Requirements(

        get_installed_version, extras=extras or [],

        generate_extras=generate_extras,

        python3_pkgversion=python3_pkgversion

    )

    try:

        if (include_runtime or toxenv) and not use_build_system:

            raise ValueError('-N option cannot be used in combination with -r, -e, -t, -x options')

        if requirement_files:

            for req_file in requirement_files:

                requirements.extend(

                    convert_requirements_txt(req_file, pathlib.Path(req_file.name)),

                    source=f'requirements file {req_file.name}'

                )

            requirements.check(source='all requirements files')

        if use_build_system:

            backend = get_backend(requirements)

            generate_build_requirements(backend, requirements)

        if toxenv:

            include_runtime = True

            generate_tox_requirements(toxenv, requirements)

        if include_runtime:

            generate_run_requirements(backend, requirements, build_wheel=build_wheel, wheeldir=wheeldir)

    except EndPass:

        return

def main(argv):

    parser = argparse.ArgumentParser(

        description='Generate BuildRequires for a Python project.'

    )

    parser.add_argument(

        '-r', '--runtime', action='store_true', default=True,

        help='Generate run-time requirements (default, disable with -R)',

    )

    parser.add_argument(

        '-w', '--wheel', action='store_true', default=False,

        help=('Generate run-time requirements by building the wheel '

              '(useful for build backends without the prepare_metadata_for_build_wheel hook)'),

    )

    parser.add_argument(

        '--wheeldir', metavar='PATH', default=None,

        help='The directory with wheel, used when -w.',

    )

    parser.add_argument(

        '-R', '--no-runtime', action='store_false', dest='runtime',

        help="Don't generate run-time requirements (implied by -N)",

    )

    parser.add_argument(

        '-e', '--toxenv', metavar='TOXENVS', action='append',

        help=('specify tox environments (comma separated and/or repeated)'

              '(implies --tox)'),

    )

    parser.add_argument(

        '-t', '--tox', action='store_true',

        help=('generate test tequirements from tox environment '

              '(implies --runtime)'),

    )

    parser.add_argument(

        '-x', '--extras', metavar='EXTRAS', action='append',

        help='comma separated list of "extras" for runtime requirements '

             '(e.g. -x testing,feature-x) (implies --runtime, can be repeated)',

    )

    parser.add_argument(

        '--generate-extras', action='store_true',

        help='Generate build requirements on Python Extras',

    )

    parser.add_argument(

        '-p', '--python3_pkgversion', metavar='PYTHON3_PKGVERSION',

        default="3", help=('Python version for pythonXdist()'

                           'or pythonX.Ydist() requirements'),

    )

    parser.add_argument(

        '-N', '--no-use-build-system', dest='use_build_system',

        action='store_false', help='Use -N to indicate that project does not use any build system',

    )

    parser.add_argument(

       'requirement_files', nargs='*', type=argparse.FileType('r'),

        help=('Add buildrequires from file'),

    )

    args = parser.parse_args(argv)

    if not args.use_build_system:

        args.runtime = False

    if args.wheel:

        if not args.wheeldir:

            raise ValueError('--wheeldir must be set when -w.')

    if args.toxenv:

        args.tox = True

    if args.tox:

        args.runtime = True

        if not args.toxenv:

            _default = f'py{sys.version_info.major}{sys.version_info.minor}'

            args.toxenv = [os.getenv('RPM_TOXENV', _default)]

    if args.extras:

        args.runtime = True

    try:

        generate_requires(

            include_runtime=args.runtime,

            build_wheel=args.wheel,

            wheeldir=args.wheeldir,

            toxenv=args.toxenv,

            extras=args.extras,

            generate_extras=args.generate_extras,

            python3_pkgversion=args.python3_pkgversion,

            requirement_files=args.requirement_files,

            use_build_system=args.use_build_system,

        )

    except Exception:

        # Log the traceback explicitly (it's useful debug info)

        traceback.print_exc()

        exit(1)

if __name__ == '__main__':

    main(sys.argv[1:])