"""Generates reST source files for autosummary.

Usable as a library or script to generate automatic RST source files for
items referred to in autosummary:: directives.

Each generated RST file contains a single auto*:: directive which
extracts the docstring of the referred item.

Example Makefile rule::

   generate:
           sphinx-autogen -o source/generated source/*.rst
"""

from __future__ import annotations

import argparse
import importlib
import inspect
import locale
import os
import pkgutil
import pydoc
import re
import sys
from os import path
from pathlib import Path
from typing import TYPE_CHECKING, Any, NamedTuple

from jinja2 import TemplateNotFound
from jinja2.sandbox import SandboxedEnvironment

import sphinx.locale
from sphinx import __display_version__, package_dir
from sphinx.builders import Builder
from sphinx.config import Config
from sphinx.errors import PycodeError
from sphinx.ext.autodoc.importer import import_module
from sphinx.ext.autosummary import (
    ImportExceptionGroup,
    get_documenter,
    import_by_name,
    import_ivar_by_name,
)
from sphinx.locale import __
from sphinx.pycode import ModuleAnalyzer
from sphinx.registry import SphinxComponentRegistry
from sphinx.util import logging, rst
from sphinx.util.inspect import getall, safe_getattr
from sphinx.util.osutil import ensuredir
from sphinx.util.template import SphinxTemplateLoader

if TYPE_CHECKING:
    from collections.abc import Sequence, Set
    from gettext import NullTranslations

    from sphinx.application import Sphinx
    from sphinx.ext.autodoc import Documenter

logger = logging.getLogger(__name__)


class DummyApplication:
    """Dummy Application class for sphinx-autogen command."""

    def __init__(self, translator: NullTranslations) -> None:
        self.config = Config()
        self.registry = SphinxComponentRegistry()
        self.messagelog: list[str] = []
        self.srcdir = '/'
        self.translator = translator
        self.verbosity = 0
        self._warncount = 0
        self._exception_on_warning = False

        self.config.add('autosummary_context', {}, 'env', ())
        self.config.add('autosummary_filename_map', {}, 'env', ())
        self.config.add('autosummary_ignore_module_all', True, 'env', bool)

    def emit_firstresult(self, *args: Any) -> None:
        pass


class AutosummaryEntry(NamedTuple):
    name: str
    path: str | None
    template: str
    recursive: bool


def setup_documenters(app: Any) -> None:
    from sphinx.ext.autodoc import (
        AttributeDocumenter,
        ClassDocumenter,
        DataDocumenter,
        DecoratorDocumenter,
        ExceptionDocumenter,
        FunctionDocumenter,
        MethodDocumenter,
        ModuleDocumenter,
        PropertyDocumenter,
    )

    documenters: list[type[Documenter]] = [
        ModuleDocumenter,
        ClassDocumenter,
        ExceptionDocumenter,
        DataDocumenter,
        FunctionDocumenter,
        MethodDocumenter,
        AttributeDocumenter,
        DecoratorDocumenter,
        PropertyDocumenter,
    ]
    for documenter in documenters:
        app.registry.add_documenter(documenter.objtype, documenter)


def _underline(title: str, line: str = '=') -> str:
    if '\n' in title:
        msg = 'Can only underline single lines'
        raise ValueError(msg)
    return title + '\n' + line * len(title)


class AutosummaryRenderer:
    """A helper class for rendering."""

    def __init__(self, app: Sphinx) -> None:
        if isinstance(app, Builder):
            msg = 'Expected a Sphinx application object!'
            raise ValueError(msg)

        system_templates_path = [
            os.path.join(package_dir, 'ext', 'autosummary', 'templates')
        ]
        loader = SphinxTemplateLoader(
            app.srcdir, app.config.templates_path, system_templates_path
        )

        self.env = SandboxedEnvironment(loader=loader)
        self.env.filters['escape'] = rst.escape
        self.env.filters['e'] = rst.escape
        self.env.filters['underline'] = _underline

        if app.translator:
            self.env.add_extension('jinja2.ext.i18n')
            # ``install_gettext_translations`` is injected by the ``jinja2.ext.i18n`` extension
            self.env.install_gettext_translations(app.translator)  # type: ignore[attr-defined]

    def render(self, template_name: str, context: dict[str, Any]) -> str:
        """Render a template file."""
        try:
            template = self.env.get_template(template_name)
        except TemplateNotFound:
            try:
                # objtype is given as template_name
                template = self.env.get_template('autosummary/%s.rst' % template_name)
            except TemplateNotFound:
                # fallback to base.rst
                template = self.env.get_template('autosummary/base.rst')

        return template.render(context)


def _split_full_qualified_name(name: str) -> tuple[str | None, str]:
    """Split full qualified name to a pair of modname and qualname.

    A qualname is an abbreviation for "Qualified name" introduced at PEP-3155
    (https://peps.python.org/pep-3155/).  It is a dotted path name
    from the module top-level.

    A "full" qualified name means a string containing both module name and
    qualified name.

    .. note:: This function actually imports the module to check its existence.
              Therefore you need to mock 3rd party modules if needed before
              calling this function.
    """
    parts = name.split('.')
    for i, _part in enumerate(parts, 1):
        try:
            modname = '.'.join(parts[:i])
            importlib.import_module(modname)
        except ImportError:
            if parts[: i - 1]:
                return '.'.join(parts[: i - 1]), '.'.join(parts[i - 1 :])
            else:
                return None, '.'.join(parts)
        except IndexError:
            pass

    return name, ''


# -- Generating output ---------------------------------------------------------


class ModuleScanner:
    def __init__(self, app: Any, obj: Any) -> None:
        self.app = app
        self.object = obj

    def get_object_type(self, name: str, value: Any) -> str:
        return get_documenter(self.app, value, self.object).objtype

    def is_skipped(self, name: str, value: Any, objtype: str) -> bool:
        try:
            return self.app.emit_firstresult(
                'autodoc-skip-member', objtype, name, value, False, {}
            )
        except Exception as exc:
            logger.warning(
                __(
                    'autosummary: failed to determine %r to be documented, '
                    'the following exception was raised:\n%s'
                ),
                name,
                exc,
                type='autosummary',
            )
            return False

    def scan(self, imported_members: bool) -> list[str]:
        members = []
        try:
            analyzer = ModuleAnalyzer.for_module(self.object.__name__)
            attr_docs = analyzer.find_attr_docs()
        except PycodeError:
            attr_docs = {}

        for name in members_of(self.object, self.app.config):
            try:
                value = safe_getattr(self.object, name)
            except AttributeError:
                value = None

            objtype = self.get_object_type(name, value)
            if self.is_skipped(name, value, objtype):
                continue

            try:
                if ('', name) in attr_docs:
                    imported = False
                elif inspect.ismodule(value):  # NoQA: SIM114
                    imported = True
                elif safe_getattr(value, '__module__') != self.object.__name__:
                    imported = True
                else:
                    imported = False
            except AttributeError:
                imported = False

            respect_module_all = not self.app.config.autosummary_ignore_module_all
            if (
                # list all members up
                imported_members
                # list not-imported members
                or imported is False
                # list members that have __all__ set
                or (respect_module_all and '__all__' in dir(self.object))
            ):
                members.append(name)

        return members


def members_of(obj: Any, conf: Config) -> Sequence[str]:
    """Get the members of ``obj``, possibly ignoring the ``__all__`` module attribute

    Follows the ``conf.autosummary_ignore_module_all`` setting.
    """
    if conf.autosummary_ignore_module_all:
        return dir(obj)
    else:
        return getall(obj) or dir(obj)


def generate_autosummary_content(
    name: str,
    obj: Any,
    parent: Any,
    template: AutosummaryRenderer,
    template_name: str,
    imported_members: bool,
    app: Any,
    recursive: bool,
    context: dict[str, Any],
    modname: str | None = None,
    qualname: str | None = None,
) -> str:
    doc = get_documenter(app, obj, parent)

    ns: dict[str, Any] = {}
    ns.update(context)

    if doc.objtype == 'module':
        scanner = ModuleScanner(app, obj)
        ns['members'] = scanner.scan(imported_members)

        respect_module_all = not app.config.autosummary_ignore_module_all
        imported_members = imported_members or (
            '__all__' in dir(obj) and respect_module_all
        )

        ns['functions'], ns['all_functions'] = _get_members(
            doc, app, obj, {'function'}, imported=imported_members
        )
        ns['classes'], ns['all_classes'] = _get_members(
            doc, app, obj, {'class'}, imported=imported_members
        )
        ns['exceptions'], ns['all_exceptions'] = _get_members(
            doc, app, obj, {'exception'}, imported=imported_members
        )
        ns['attributes'], ns['all_attributes'] = _get_module_attrs(name, ns['members'])
        ispackage = hasattr(obj, '__path__')
        if ispackage and recursive:
            # Use members that are not modules as skip list, because it would then mean
            # that module was overwritten in the package namespace
            skip = (
                ns['all_functions']
                + ns['all_classes']
                + ns['all_exceptions']
                + ns['all_attributes']
            )

            # If respect_module_all and module has a __all__ attribute, first get
            # modules that were explicitly imported. Next, find the rest with the
            # get_modules method, but only put in "public" modules that are in the
            # __all__ list
            #
            # Otherwise, use get_modules method normally
            if respect_module_all and '__all__' in dir(obj):
                imported_modules, all_imported_modules = _get_members(
                    doc, app, obj, {'module'}, imported=True
                )
                skip += all_imported_modules
                public_members = getall(obj)
            else:
                imported_modules, all_imported_modules = [], []
                public_members = None

            modules, all_modules = _get_modules(
                obj, skip=skip, name=name, public_members=public_members
            )
            ns['modules'] = imported_modules + modules
            ns['all_modules'] = all_imported_modules + all_modules
    elif doc.objtype == 'class':
        ns['members'] = dir(obj)
        ns['inherited_members'] = set(dir(obj)) - set(obj.__dict__.keys())
        ns['methods'], ns['all_methods'] = _get_members(
            doc, app, obj, {'method'}, include_public={'__init__'}
        )
        ns['attributes'], ns['all_attributes'] = _get_members(
            doc, app, obj, {'attribute', 'property'}
        )

    if modname is None or qualname is None:
        modname, qualname = _split_full_qualified_name(name)

    if doc.objtype in ('method', 'attribute', 'property'):
        ns['class'] = qualname.rsplit('.', 1)[0]

    if doc.objtype == 'class':
        shortname = qualname
    else:
        shortname = qualname.rsplit('.', 1)[-1]

    ns['fullname'] = name
    ns['module'] = modname
    ns['objname'] = qualname
    ns['name'] = shortname

    ns['objtype'] = doc.objtype
    ns['underline'] = len(name) * '='

    if template_name:
        return template.render(template_name, ns)
    else:
        return template.render(doc.objtype, ns)


def _skip_member(app: Sphinx, obj: Any, name: str, objtype: str) -> bool:
    try:
        return app.emit_firstresult(
            'autodoc-skip-member', objtype, name, obj, False, {}
        )
    except Exception as exc:
        logger.warning(
            __(
                'autosummary: failed to determine %r to be documented, '
                'the following exception was raised:\n%s'
            ),
            name,
            exc,
            type='autosummary',
        )
        return False


def _get_class_members(obj: Any) -> dict[str, Any]:
    members = sphinx.ext.autodoc.importer.get_class_members(obj, None, safe_getattr)
    return {name: member.object for name, member in members.items()}


def _get_module_members(app: Sphinx, obj: Any) -> dict[str, Any]:
    members = {}
    for name in members_of(obj, app.config):
        try:
            members[name] = safe_getattr(obj, name)
        except AttributeError:
            continue
    return members


def _get_all_members(doc: type[Documenter], app: Sphinx, obj: Any) -> dict[str, Any]:
    if doc.objtype == 'module':
        return _get_module_members(app, obj)
    elif doc.objtype == 'class':
        return _get_class_members(obj)
    return {}


def _get_members(
    doc: type[Documenter],
    app: Sphinx,
    obj: Any,
    types: set[str],
    *,
    include_public: Set[str] = frozenset(),
    imported: bool = True,
) -> tuple[list[str], list[str]]:
    items: list[str] = []
    public: list[str] = []

    all_members = _get_all_members(doc, app, obj)
    for name, value in all_members.items():
        documenter = get_documenter(app, value, obj)
        if documenter.objtype in types:
            # skip imported members if expected
            if imported or getattr(value, '__module__', None) == obj.__name__:
                skipped = _skip_member(app, value, name, documenter.objtype)
                if skipped is True:
                    pass
                elif skipped is False:
                    # show the member forcedly
                    items.append(name)
                    public.append(name)
                else:
                    items.append(name)
                    if name in include_public or not name.startswith('_'):
                        # considers member as public
                        public.append(name)
    return public, items


def _get_module_attrs(name: str, members: Any) -> tuple[list[str], list[str]]:
    """Find module attributes with docstrings."""
    attrs, public = [], []
    try:
        analyzer = ModuleAnalyzer.for_module(name)
        attr_docs = analyzer.find_attr_docs()
        for namespace, attr_name in attr_docs:
            if namespace == '' and attr_name in members:
                attrs.append(attr_name)
                if not attr_name.startswith('_'):
                    public.append(attr_name)
    except PycodeError:
        pass  # give up if ModuleAnalyzer fails to parse code
    return public, attrs


def _get_modules(
    obj: Any,
    *,
    skip: Sequence[str],
    name: str,
    public_members: Sequence[str] | None = None,
) -> tuple[list[str], list[str]]:
    items: list[str] = []
    public: list[str] = []
    for _, modname, _ispkg in pkgutil.iter_modules(obj.__path__):
        if modname in skip:
            # module was overwritten in __init__.py, so not accessible
            continue
        fullname = f'{name}.{modname}'
        try:
            module = import_module(fullname)
        except ImportError:
            pass
        else:
            if module and hasattr(module, '__sphinx_mock__'):
                continue

        items.append(modname)
        if public_members is not None:
            if modname in public_members:
                public.append(modname)
        else:
            if not modname.startswith('_'):
                public.append(modname)
    return public, items


def generate_autosummary_docs(
    sources: list[str],
    output_dir: str | os.PathLike[str] | None = None,
    suffix: str = '.rst',
    base_path: str | os.PathLike[str] | None = None,
    imported_members: bool = False,
    app: Sphinx | None = None,
    overwrite: bool = True,
    encoding: str = 'utf-8',
) -> list[Path]:
    """Generate autosummary documentation for the given sources.

    :returns: list of generated files (both new and existing ones)
    """
    assert app is not None, 'app is required'

    showed_sources = sorted(sources)
    if len(showed_sources) > 20:
        showed_sources = showed_sources[:10] + ['...'] + showed_sources[-10:]
    logger.info(
        __('[autosummary] generating autosummary for: %s'), ', '.join(showed_sources)
    )

    if output_dir:
        logger.info(__('[autosummary] writing to %s'), output_dir)

    if base_path is not None:
        sources = [os.path.join(base_path, filename) for filename in sources]

    template = AutosummaryRenderer(app)

    # read
    items = find_autosummary_in_files(sources)

    # keep track of new files
    new_files: list[Path] = []
    all_files: list[Path] = []

    filename_map = app.config.autosummary_filename_map

    # write
    for entry in sorted(set(items), key=str):
        if entry.path is None:
            # The corresponding autosummary:: directive did not have
            # a :toctree: option
            continue

        path = output_dir or os.path.abspath(entry.path)
        ensuredir(path)

        try:
            name, obj, parent, modname = import_by_name(entry.name)
            qualname = name.replace(modname + '.', '')
        except ImportExceptionGroup as exc:
            try:
                # try to import as an instance attribute
                name, obj, parent, modname = import_ivar_by_name(entry.name)
                qualname = name.replace(modname + '.', '')
            except ImportError as exc2:
                if exc2.__cause__:
                    exceptions: list[BaseException] = [*exc.exceptions, exc2.__cause__]
                else:
                    exceptions = [*exc.exceptions, exc2]

                errors = list({f'* {type(e).__name__}: {e}' for e in exceptions})
                logger.warning(
                    __('[autosummary] failed to import %s.\nPossible hints:\n%s'),
                    entry.name,
                    '\n'.join(errors),
                )
                continue

        context: dict[str, Any] = {**app.config.autosummary_context}

        content = generate_autosummary_content(
            name,
            obj,
            parent,
            template,
            entry.template,
            imported_members,
            app,
            entry.recursive,
            context,
            modname,
            qualname,
        )

        file_path = Path(path, filename_map.get(name, name) + suffix)
        all_files.append(file_path)
        if file_path.is_file():
            with file_path.open(encoding=encoding) as f:
                old_content = f.read()

            if content == old_content:
                continue
            if overwrite:  # content has changed
                with file_path.open('w', encoding=encoding) as f:
                    f.write(content)
                new_files.append(file_path)
        else:
            with open(file_path, 'w', encoding=encoding) as f:
                f.write(content)
            new_files.append(file_path)

    # descend recursively to new files
    if new_files:
        all_files.extend(
            generate_autosummary_docs(
                [str(f) for f in new_files],
                output_dir=output_dir,
                suffix=suffix,
                base_path=base_path,
                imported_members=imported_members,
                app=app,
                overwrite=overwrite,
            )
        )

    return all_files


# -- Finding documented entries in files ---------------------------------------


def find_autosummary_in_files(filenames: list[str]) -> list[AutosummaryEntry]:
    """Find out what items are documented in source/*.rst.

    See `find_autosummary_in_lines`.
    """
    documented: list[AutosummaryEntry] = []
    for filename in filenames:
        with open(filename, encoding='utf-8', errors='ignore') as f:
            lines = f.read().splitlines()
            documented.extend(find_autosummary_in_lines(lines, filename=filename))
    return documented


def find_autosummary_in_docstring(
    name: str,
    filename: str | None = None,
) -> list[AutosummaryEntry]:
    """Find out what items are documented in the given object's docstring.

    See `find_autosummary_in_lines`.
    """
    try:
        real_name, obj, parent, modname = import_by_name(name)
        lines = pydoc.getdoc(obj).splitlines()
        return find_autosummary_in_lines(lines, module=name, filename=filename)
    except AttributeError:
        pass
    except ImportExceptionGroup as exc:
        errors = '\n'.join({f'* {type(e).__name__}: {e}' for e in exc.exceptions})
        logger.warning(f'Failed to import {name}.\nPossible hints:\n{errors}')  # NoQA: G004
    except SystemExit:
        logger.warning(
            "Failed to import '%s'; the module executes module level "
            'statement and it might call sys.exit().',
            name,
        )
    return []


def find_autosummary_in_lines(
    lines: list[str],
    module: str | None = None,
    filename: str | None = None,
) -> list[AutosummaryEntry]:
    """Find out what items appear in autosummary:: directives in the
    given lines.

    Returns a list of (name, toctree, template) where *name* is a name
    of an object and *toctree* the :toctree: path of the corresponding
    autosummary directive (relative to the root of the file name), and
    *template* the value of the :template: option. *toctree* and
    *template* ``None`` if the directive does not have the
    corresponding options set.
    """
    autosummary_re = re.compile(r'^(\s*)\.\.\s+autosummary::\s*')
    automodule_re = re.compile(r'^\s*\.\.\s+automodule::\s*([A-Za-z0-9_.]+)\s*$')
    module_re = re.compile(r'^\s*\.\.\s+(current)?module::\s*([a-zA-Z0-9_.]+)\s*$')
    autosummary_item_re = re.compile(r'^\s+(~?[_a-zA-Z][a-zA-Z0-9_.]*)\s*.*?')
    recursive_arg_re = re.compile(r'^\s+:recursive:\s*$')
    toctree_arg_re = re.compile(r'^\s+:toctree:\s*(.*?)\s*$')
    template_arg_re = re.compile(r'^\s+:template:\s*(.*?)\s*$')

    documented: list[AutosummaryEntry] = []

    recursive = False
    toctree: str | None = None
    template = ''
    current_module = module
    in_autosummary = False
    base_indent = ''

    for line in lines:
        if in_autosummary:
            m = recursive_arg_re.match(line)
            if m:
                recursive = True
                continue

            m = toctree_arg_re.match(line)
            if m:
                toctree = m.group(1)
                if filename:
                    toctree = os.path.join(os.path.dirname(filename), toctree)
                continue

            m = template_arg_re.match(line)
            if m:
                template = m.group(1).strip()
                continue

            if line.strip().startswith(':'):
                continue  # skip options

            m = autosummary_item_re.match(line)
            if m:
                name = m.group(1).strip().removeprefix('~')
                if current_module and not name.startswith(current_module + '.'):
                    name = f'{current_module}.{name}'
                documented.append(AutosummaryEntry(name, toctree, template, recursive))
                continue

            if not line.strip() or line.startswith(base_indent + ' '):
                continue

            in_autosummary = False

        m = autosummary_re.match(line)
        if m:
            in_autosummary = True
            base_indent = m.group(1)
            recursive = False
            toctree = None
            template = ''
            continue

        m = automodule_re.search(line)
        if m:
            current_module = m.group(1).strip()
            # recurse into the automodule docstring
            documented.extend(
                find_autosummary_in_docstring(current_module, filename=filename)
            )
            continue

        m = module_re.match(line)
        if m:
            current_module = m.group(2)
            continue

    return documented


def get_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(
        usage='%(prog)s [OPTIONS] <SOURCE_FILE>...',
        epilog=__('For more information, visit <https://www.sphinx-doc.org/>.'),
        description=__("""
Generate ReStructuredText using autosummary directives.

sphinx-autogen is a frontend to sphinx.ext.autosummary.generate. It generates
the reStructuredText files from the autosummary directives contained in the
given input files.

The format of the autosummary directive is documented in the
``sphinx.ext.autosummary`` Python module and can be read using::

  pydoc sphinx.ext.autosummary
"""),
    )

    parser.add_argument(
        '--version',
        action='version',
        dest='show_version',
        version='%%(prog)s %s' % __display_version__,
    )

    parser.add_argument(
        'source_file', nargs='+', help=__('source files to generate rST files for')
    )

    parser.add_argument(
        '-o',
        '--output-dir',
        action='store',
        dest='output_dir',
        help=__('directory to place all output in'),
    )
    parser.add_argument(
        '-s',
        '--suffix',
        action='store',
        dest='suffix',
        default='rst',
        help=__('default suffix for files (default: %(default)s)'),
    )
    parser.add_argument(
        '-t',
        '--templates',
        action='store',
        dest='templates',
        default=None,
        help=__('custom template directory (default: %(default)s)'),
    )
    parser.add_argument(
        '-i',
        '--imported-members',
        action='store_true',
        dest='imported_members',
        default=False,
        help=__('document imported members (default: %(default)s)'),
    )
    parser.add_argument(
        '-a',
        '--respect-module-all',
        action='store_true',
        dest='respect_module_all',
        default=False,
        help=__(
            'document exactly the members in module __all__ attribute. '
            '(default: %(default)s)'
        ),
    )
    parser.add_argument(
        '--remove-old',
        action='store_true',
        dest='remove_old',
        default=False,
        help=__(
            'Remove existing files in the output directory that were not generated'
        ),
    )

    return parser


def main(argv: Sequence[str] = (), /) -> None:
    locale.setlocale(locale.LC_ALL, '')
    sphinx.locale.init_console()

    app = DummyApplication(sphinx.locale.get_translator())
    logging.setup(app, sys.stdout, sys.stderr)  # type: ignore[arg-type]
    setup_documenters(app)
    args = get_parser().parse_args(argv or sys.argv[1:])

    if args.templates:
        app.config.templates_path.append(path.abspath(args.templates))
    app.config.autosummary_ignore_module_all = not args.respect_module_all

    written_files = generate_autosummary_docs(
        args.source_file,
        args.output_dir,
        '.' + args.suffix,
        imported_members=args.imported_members,
        app=app,  # type: ignore[arg-type]
    )

    if args.remove_old:
        for existing in Path(args.output_dir).glob(f'**/*.{args.suffix}'):
            if existing not in written_files:
                try:
                    existing.unlink()
                except OSError as exc:
                    logger.warning(
                        __('Failed to remove %s: %s'),
                        existing,
                        exc.strerror,
                        type='autosummary',
                    )


if __name__ == '__main__':
    main(sys.argv[1:])