"""Read project metadata from pyproject.toml for packaging scripts."""

from __future__ import annotations

import ast
import importlib.util
import subprocess
import sys
from pathlib import Path

_BUILD_ROOT = Path(__file__).resolve().parents[1]


def _load_wheel_layout_module():
    layout_path = _BUILD_ROOT / "wheel" / "layout.py"
    spec = importlib.util.spec_from_file_location("_orisys_build_wheel_layout", layout_path)
    if spec is None or spec.loader is None:
        raise ImportError(f"Cannot load wheel layout helper from {layout_path}")
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


def _load_toml(text: str) -> dict:
    if sys.version_info >= (3, 11):
        import tomllib

        return tomllib.loads(text)
    try:
        import tomli
    except ImportError:
        subprocess.check_call([sys.executable, "-m", "pip", "install", "tomli", "-q"])
        import tomli
    return tomli.loads(text)


def load_pyproject(repo_root: Path) -> dict:
    path = repo_root / "pyproject.toml"
    return _load_toml(path.read_text(encoding="utf-8"))


def project_metadata(repo_root: Path) -> dict:
    return load_pyproject(repo_root)["project"]


def install_requires(repo_root: Path) -> list[str]:
    return list(project_metadata(repo_root)["dependencies"])


def extras_require(repo_root: Path) -> dict[str, list[str]]:
    optional = project_metadata(repo_root).get("optional-dependencies", {})
    return {name: list(requirements) for name, requirements in optional.items()}


def _resolve_version_attr(repo_root: Path, attr: str) -> str:
    """Resolve a setuptools dynamic version attr (e.g. orisys.__version__)."""
    module_name, _, attr_name = attr.partition(".")
    if not attr_name:
        raise RuntimeError(f"Invalid dynamic version attr: {attr!r}")

    # Avoid importing package modules here: __init__ may import heavy runtime deps
    # (e.g., cv2/numpy) that are not required just to read __version__.
    rel_module = Path(*module_name.split("."))
    module_file = repo_root / "src" / rel_module.with_suffix(".py")
    if not module_file.is_file():
        module_file = repo_root / "src" / rel_module / "__init__.py"
    if not module_file.is_file():
        raise RuntimeError(f"Cannot resolve module file for dynamic version attr: {attr!r}")

    tree = ast.parse(module_file.read_text(encoding="utf-8"), filename=str(module_file))
    target_name = attr_name.split(".")[0]
    for node in tree.body:
        if isinstance(node, ast.Assign):
            for target in node.targets:
                if isinstance(target, ast.Name) and target.id == target_name:
                    value = ast.literal_eval(node.value)
                    return str(value)

    raise RuntimeError(f"Attribute {target_name!r} not found in {module_file}")


def get_version(repo_root: Path) -> str:
    """Return project version from pyproject.toml (static or dynamic)."""
    project = project_metadata(repo_root)
    if "version" in project:
        return str(project["version"])

    dynamic = load_pyproject(repo_root).get("tool", {}).get("setuptools", {}).get("dynamic", {})
    version_cfg = dynamic.get("version")
    if isinstance(version_cfg, dict) and "attr" in version_cfg:
        return _resolve_version_attr(repo_root, version_cfg["attr"])

    raise RuntimeError("Project version is not defined in pyproject.toml")


def bundle_items(repo_root: Path) -> list[dict]:
    """Return bundle rules from [[tool.orisys.bundle.items]] in pyproject.toml."""
    items = load_pyproject(repo_root).get("tool", {}).get("orisys", {}).get("bundle", {}).get("items")
    if not items:
        raise RuntimeError("Missing [[tool.orisys.bundle.items]] in pyproject.toml")
    return list(items)


def bundle_data_files(repo_root: Path) -> list[tuple[str, list[str]]]:
    """Map bundle items marked dev_install=true to setuptools data_files entries."""
    resolve_bundle_source_files = _load_wheel_layout_module().resolve_bundle_source_files

    grouped: dict[str, list[str]] = {}
    for item in bundle_items(repo_root):
        if not item.get("dev_install", False):
            continue

        src_dir = repo_root / item["source"]
        base_dest = f"orisys/{item['target']}".replace("\\", "/")

        for src_file in resolve_bundle_source_files(repo_root, item):
            rel_src = src_file.relative_to(repo_root).as_posix()
            if item.get("preserve_tree", False):
                rel_parent = src_file.relative_to(src_dir).parent.as_posix()
                dest = base_dest if rel_parent == "." else f"{base_dest}/{rel_parent}"
            else:
                dest = base_dest
            grouped.setdefault(dest, []).append(rel_src)

    return [(dest, sorted(files)) for dest, files in sorted(grouped.items())]