"""Custom patches to make the world work."""
from __future__ import annotations

from functools import lru_cache
from typing import TYPE_CHECKING, Any

from docutils.parsers.rst.directives.admonitions import BaseAdmonition
from docutils.parsers.rst.states import Text
from sphinx.ext.napoleon.docstring import GoogleDocstring

from .attributes_patch import patch_attribute_handling

if TYPE_CHECKING:
    from sphinx.application import Sphinx
    from sphinx.ext.autodoc import Options


@lru_cache  # A cute way to make sure the function only runs once.
def fix_autodoc_typehints_for_overloaded_methods() -> None:
    """
    sphinx-autodoc-typehints responds to the "autodoc-process-signature" event to remove types from the signature line.

    Normally, `FunctionDocumenter.format_signature` and `MethodDocumenter.format_signature` call
    `super().format_signature` which ends up going to `Documenter.format_signature`, and this last method emits the
    `autodoc-process-signature` event. However, if there are overloads, `FunctionDocumenter.format_signature` does
    something else and the event never occurs. Here we remove this alternative code path by brute force.

    See https://github.com/tox-dev/sphinx-autodoc-typehints/issues/296
    """
    from sphinx.ext.autodoc import FunctionDocumenter, MethodDocumenter

    del FunctionDocumenter.format_signature
    del MethodDocumenter.format_signature


def napoleon_numpy_docstring_return_type_processor(  # noqa: PLR0913
    app: Sphinx,
    what: str,
    name: str,  # noqa: ARG001
    obj: Any,  # noqa: ARG001
    options: Options | None,  # noqa: ARG001
    lines: list[str],
) -> None:
    """Insert a : under Returns: to tell napoleon not to look for a return type."""
    if what not in ["function", "method"]:
        return
    if not getattr(app.config, "napoleon_numpy_docstring", False):
        return

    # Search for the returns header:
    # Returns:
    # --------
    for pos, line in enumerate(lines[:-2]):
        if line.lower().strip(":") not in ["return", "returns"]:
            continue
        # Underline detection.
        chars = set(lines[pos + 1].strip())
        # Napoleon allows the underline to consist of a bunch of weirder things...
        if len(chars) != 1 or next(iter(chars)) not in "=-~_*+#":
            continue
        pos = pos + 2  # noqa: PLW2901
        break
    else:
        return

    lines.insert(pos, ":")


def fix_napoleon_numpy_docstring_return_type(app: Sphinx) -> None:
    """If no return type is explicitly set, numpy docstrings will use the return type text as return types."""
    # standard priority is 500. Setting priority to 499 ensures this runs before
    # napoleon's docstring processor.
    app.connect("autodoc-process-docstring", napoleon_numpy_docstring_return_type_processor, priority=499)


def _patched_lookup_annotation(*_args: Any) -> str:
    """
    GoogleDocstring._lookup_annotation sometimes adds incorrect type annotations to constructor parameters.

    Disable it so we can handle this on our own.
    """
    return ""


def _patch_google_docstring_lookup_annotation() -> None:
    """Fix issue https://github.com/tox-dev/sphinx-autodoc-typehints/issues/308."""
    GoogleDocstring._lookup_annotation = _patched_lookup_annotation  # type: ignore[assignment] # noqa: SLF001


orig_base_admonition_run = BaseAdmonition.run


def _patched_base_admonition_run(self: BaseAdmonition) -> Any:
    result = orig_base_admonition_run(self)
    result[0].line = self.lineno
    return result


orig_text_indent = Text.indent


def _patched_text_indent(self: Text, *args: Any) -> Any:
    _, line = self.state_machine.get_source_and_line()
    result = orig_text_indent(self, *args)
    node = self.parent[-1]
    if node.tagname == "system_message":
        node = self.parent[-2]
    node.line = line
    return result


def _patch_line_numbers() -> None:
    """
    Make the rst parser put line numbers on more nodes.

    When the line numbers are missing, we have a hard time placing the :rtype:.
    """
    Text.indent = _patched_text_indent
    BaseAdmonition.run = _patched_base_admonition_run


def install_patches(app: Sphinx) -> None:
    """
    Install the patches.

    :param app: the Sphinx app
    """
    fix_autodoc_typehints_for_overloaded_methods()
    patch_attribute_handling(app)
    _patch_google_docstring_lookup_annotation()
    fix_napoleon_numpy_docstring_return_type(app)
    _patch_line_numbers()


___all__ = [
    "install_patches",
]
