from __future__ import annotations

import warnings

from dataclasses import dataclass
from pathlib import Path
from typing import Sequence

from .. import _log
from .. import _types as _t
from .._requirement_cls import extract_package_name
from .toml import TOML_RESULT
from .toml import InvalidTomlError
from .toml import read_toml_content

log = _log.log.getChild("pyproject_reading")

_ROOT = "root"


DEFAULT_PYPROJECT_PATH = Path("pyproject.toml")
DEFAULT_TOOL_NAME = "setuptools_scm"


@dataclass
class PyProjectData:
    path: Path
    tool_name: str
    project: TOML_RESULT
    section: TOML_RESULT
    is_required: bool
    section_present: bool
    project_present: bool
    build_requires: list[str]

    @classmethod
    def for_testing(
        cls,
        *,
        is_required: bool = False,
        section_present: bool = False,
        project_present: bool = False,
        project_name: str | None = None,
        has_dynamic_version: bool = True,
        build_requires: list[str] | None = None,
        local_scheme: str | None = None,
    ) -> PyProjectData:
        """Create a PyProjectData instance for testing purposes."""
        project: TOML_RESULT
        if project_name is not None:
            project = {"name": project_name}
            assert project_present
        else:
            project = {}

        # If project is present and has_dynamic_version is True, add dynamic=['version']
        if project_present and has_dynamic_version:
            project["dynamic"] = ["version"]

        if build_requires is None:
            build_requires = []
        if local_scheme is not None:
            assert section_present
            section = {"local_scheme": local_scheme}
        else:
            section = {}
        return cls(
            path=DEFAULT_PYPROJECT_PATH,
            tool_name=DEFAULT_TOOL_NAME,
            project=project,
            section=section,
            is_required=is_required,
            section_present=section_present,
            project_present=project_present,
            build_requires=build_requires,
        )

    @classmethod
    def empty(
        cls, path: Path = DEFAULT_PYPROJECT_PATH, tool_name: str = DEFAULT_TOOL_NAME
    ) -> PyProjectData:
        return cls(
            path=path,
            tool_name=tool_name,
            project={},
            section={},
            is_required=False,
            section_present=False,
            project_present=False,
            build_requires=[],
        )

    @property
    def project_name(self) -> str | None:
        return self.project.get("name")

    @property
    def project_version(self) -> str | None:
        """Return the static version from [project] if present.

        When the project declares dynamic = ["version"], the version
        is intentionally omitted from [project] and this returns None.
        """
        return self.project.get("version")

    def should_infer(self) -> bool:
        """
        Determine if setuptools_scm should infer version based on configuration.

        Infer when:
        1. An explicit [tool.setuptools_scm] section is present, OR
        2. setuptools-scm[simple] is in build-system.requires AND
           version is in project.dynamic

        Returns:
            True if [tool.setuptools_scm] is present, otherwise False
        """
        # Original behavior: explicit tool section
        if self.section_present:
            return True

        # New behavior: simple extra + dynamic version
        if self.project_present:
            dynamic_fields = self.project.get("dynamic", [])
            if "version" in dynamic_fields:
                if has_build_package_with_extra(
                    self.build_requires, "setuptools-scm", "simple"
                ):
                    return True

        return False


def has_build_package(
    requires: Sequence[str], canonical_build_package_name: str
) -> bool:
    for requirement in requires:
        package_name = extract_package_name(requirement)
        if package_name == canonical_build_package_name:
            return True
    return False


def has_build_package_with_extra(
    requires: Sequence[str], canonical_build_package_name: str, extra_name: str
) -> bool:
    """Check if a build dependency has a specific extra.

    Args:
        requires: List of requirement strings from build-system.requires
        canonical_build_package_name: The canonical package name to look for
        extra_name: The extra name to check for (e.g., "simple")

    Returns:
        True if the package is found with the specified extra
    """
    from .._requirement_cls import Requirement

    for requirement_string in requires:
        try:
            requirement = Requirement(requirement_string)
            package_name = extract_package_name(requirement_string)
            if package_name == canonical_build_package_name:
                if extra_name in requirement.extras:
                    return True
        except Exception:
            # If parsing fails, continue to next requirement
            continue
    return False


def read_pyproject(
    path: Path = DEFAULT_PYPROJECT_PATH,
    tool_name: str = DEFAULT_TOOL_NAME,
    canonical_build_package_name: str = "setuptools-scm",
    _given_result: _t.GivenPyProjectResult = None,
) -> PyProjectData:
    """Read and parse pyproject configuration.

    This function supports dependency injection for tests via `_given_result`.

    Parameters:
    - path: Path to the pyproject file
    - tool_name: The tool section name (default: `setuptools_scm`)
    - canonical_build_package_name: Normalized build requirement name
    - _given_result: Optional testing hook. Can be:
        - PyProjectData: returned directly
        - InvalidTomlError | FileNotFoundError: raised directly
        - None: read from filesystem
    """

    if _given_result is not None:
        if isinstance(_given_result, PyProjectData):
            return _given_result
        if isinstance(_given_result, (InvalidTomlError, FileNotFoundError)):
            raise _given_result

    defn = read_toml_content(path)

    requires: list[str] = defn.get("build-system", {}).get("requires", [])
    is_required = has_build_package(requires, canonical_build_package_name)

    tool_section = defn.get("tool", {})
    section = tool_section.get(tool_name, {})
    section_present = tool_name in tool_section

    if not section_present:
        log.warning(
            "toml section missing %r does not contain a tool.%s section",
            path,
            tool_name,
        )

    project = defn.get("project", {})
    project_present = "project" in defn
    pyproject_data = PyProjectData(
        path,
        tool_name,
        project,
        section,
        is_required,
        section_present,
        project_present,
        requires,
    )

    return pyproject_data


def get_args_for_pyproject(
    pyproject: PyProjectData,
    dist_name: str | None,
    kwargs: TOML_RESULT,
) -> TOML_RESULT:
    """drops problematic details and figures the distribution name"""
    section = pyproject.section.copy()
    kwargs = kwargs.copy()
    if "relative_to" in section:
        relative = section.pop("relative_to")
        warnings.warn(
            f"{pyproject.path}: at [tool.{pyproject.tool_name}]\n"
            f"ignoring value relative_to={relative!r}"
            " as its always relative to the config file"
        )
    if "dist_name" in section:
        if dist_name is None:
            dist_name = section.pop("dist_name")
        else:
            assert dist_name == section["dist_name"]
            section.pop("dist_name")
    if dist_name is None:
        # minimal pep 621 support for figuring the pretend keys
        dist_name = pyproject.project_name
    if _ROOT in kwargs:
        if kwargs[_ROOT] is None:
            kwargs.pop(_ROOT, None)
        elif _ROOT in section:
            if section[_ROOT] != kwargs[_ROOT]:
                warnings.warn(
                    f"root {section[_ROOT]} is overridden"
                    f" by the cli arg {kwargs[_ROOT]}"
                )
            section.pop(_ROOT, None)
    return {"dist_name": dist_name, **section, **kwargs}
