import contextlib
import importlib.metadata
import importlib.util
import logging
import os
import sys
import types
from collections import defaultdict
from pathlib import Path, PurePosixPath, PureWindowsPath

import toml
from pydantic import BaseModel, ConfigDict, field_validator

from arcade_core.errors import ToolkitLoadError
from arcade_core.parse import get_tools_from_file

logger = logging.getLogger(__name__)


class Toolkit(BaseModel):
    model_config = ConfigDict(populate_by_name=True)

    name: str
    """Name of the toolkit"""

    package_name: str
    """Name of the package holding the toolkit"""

    tools: dict[str, list[str]] = defaultdict(list)
    """Mapping of module names to tools"""

    # Other python package metadata
    version: str
    description: str
    author: list[str] = []
    repository: str | None = None
    homepage: str | None = None

    @field_validator("name", mode="before")
    def strip_arcade_prefix(cls, value: str) -> str:
        """
        Validator to strip the 'arcade_' prefix from the name if it exists.
        """
        return cls._strip_arcade_prefix(value)

    @classmethod
    def _strip_arcade_prefix(cls, value: str) -> str:
        """
        Strip the 'arcade_' prefix from the name if it exists.
        """
        if value.startswith("arcade_"):
            return value[len("arcade_") :]
        return value

    @classmethod
    def from_module(cls, module: types.ModuleType) -> "Toolkit":
        """
        Load a toolkit from an imported python module

        >>> import arcade_math
        >>> toolkit = Toolkit.from_module(arcade_math)
        """
        return cls.from_package(module.__name__)

    @classmethod
    def from_directory(cls, directory: Path) -> "Toolkit":
        """
        Load a Toolkit from a directory.
        """
        pyproject_path = directory / "pyproject.toml"
        if not pyproject_path.exists():
            raise ToolkitLoadError(f"pyproject.toml not found in {directory}")

        try:
            with open(pyproject_path, encoding="utf-8") as f:
                pyproject_data = toml.load(f)

            project_data = pyproject_data.get("project", {})
            name = project_data.get("name")
            if not name:

                def _missing_name_error() -> ToolkitLoadError:
                    return ToolkitLoadError("name not found in pyproject.toml")

                raise _missing_name_error()  # noqa: TRY301

            package_name = name
            version = project_data.get("version", "0.0.0")
            description = project_data.get("description", "")
            authors = project_data.get("authors", [])
            author_names = [author.get("name", "") for author in authors]

            # For homepage and repository, you might need to look under project.urls
            urls = project_data.get("urls", {})
            homepage = urls.get("Homepage")
            repo = urls.get("Repository")

        except Exception as e:
            raise ToolkitLoadError(f"Failed to load metadata from {pyproject_path}: {e}")

        # Determine the actual package directory (supports src/ layout and flat layout)
        package_dir = directory
        try:
            src_candidate = directory / "src" / package_name
            flat_candidate = directory / package_name
            if src_candidate.is_dir():
                package_dir = src_candidate
            elif flat_candidate.is_dir():
                package_dir = flat_candidate
            else:
                # Fallback to the provided directory; tools_from_directory will de-duplicate prefixes
                package_dir = directory
        except Exception:
            package_dir = directory

        toolkit = cls(
            name=name,
            package_name=package_name,
            version=version,
            description=description,
            author=author_names,
            homepage=homepage,
            repository=repo,
        )

        toolkit.tools = cls.tools_from_directory(package_dir, package_name)

        return toolkit

    @classmethod
    def from_package(cls, package: str) -> "Toolkit":
        """
        Load a Toolkit from a Python package
        """
        try:
            metadata = importlib.metadata.metadata(package)
            name = metadata["Name"]
            package_name = package
            version = metadata["Version"]
            description = metadata.get("Summary", "")  # type: ignore[attr-defined]
            author = metadata.get_all("Author-email")
            homepage = metadata.get("Home-page", None)  # type: ignore[attr-defined]
            repo = metadata.get("Repository", None)  # type: ignore[attr-defined]

        except importlib.metadata.PackageNotFoundError as e:
            raise ToolkitLoadError(f"Package '{package}' not found.") from e
        except KeyError as e:
            raise ToolkitLoadError(f"Metadata key error for package '{package}'.") from e
        except Exception as e:
            raise ToolkitLoadError(f"Failed to load metadata for package '{package}'.") from e

        # Get the package directory
        try:
            package_dir = Path(get_package_directory(package))
        except (ImportError, AttributeError) as e:
            raise ToolkitLoadError(f"Failed to locate package directory for '{package}'.") from e

        toolkit = cls(
            name=name,
            package_name=package_name,
            version=version,
            description=description,
            author=author if author else [],
            homepage=homepage,
            repository=repo,
        )

        toolkit.tools = cls.tools_from_directory(package_dir, package_name)

        return toolkit

    @classmethod
    def from_entrypoint(cls, entry: importlib.metadata.EntryPoint) -> "Toolkit":
        """
        Load a Toolkit from an entrypoint.

        The entrypoint value is used as the toolkit name, while the package name
        is extracted from the distribution that owns the entrypoint.

        Args:
            entry: The EntryPoint object from importlib.metadata

        Returns:
            A Toolkit instance

        Raises:
            ToolkitLoadError: If the toolkit cannot be loaded
        """
        # Get the package name from the distribution that owns this entrypoint
        if not hasattr(entry, "dist") or entry.dist is None:
            raise ToolkitLoadError(
                f"Entry point '{entry.name}' does not have distribution metadata. "
                f"This may indicate an incomplete package installation."
            )

        package_name = entry.dist.name

        toolkit = cls.from_package(package_name)
        toolkit.name = cls._strip_arcade_prefix(entry.value)

        return toolkit

    @classmethod
    def find_arcade_toolkits_from_entrypoints(cls) -> list["Toolkit"]:
        """
        Find and load as Toolkits all installed packages in the
        current Python interpreter's environment that have a
        registered entrypoint under the 'arcade.toolkits' group.
        """
        toolkits = []
        toolkit_entries: list[importlib.metadata.EntryPoint] = []

        try:
            toolkit_entries = importlib.metadata.entry_points(
                group="arcade_toolkits", name="toolkit_name"
            )
            for entry in toolkit_entries:
                try:
                    toolkit = cls.from_entrypoint(entry)
                    toolkits.append(toolkit)
                    logger.debug(
                        f"Loaded toolkit from entry point: {entry.name} = '{toolkit.name}'"
                    )
                except ToolkitLoadError as e:
                    logger.warning(
                        f"Warning: {e} Skipping toolkit from entry point '{entry.value}'"
                    )
        except Exception as e:
            logger.debug(f"Entry point discovery failed or not available: {e}")

        return toolkits

    @classmethod
    def find_arcade_toolkits_from_prefix(cls) -> list["Toolkit"]:
        """
        Find and load as Toolkits all installed packages in the
        current Python interpreter's environment that are prefixed with 'arcade_'.
        """
        import sysconfig

        toolkits = []
        site_packages_dir = sysconfig.get_paths()["purelib"]

        arcade_packages = [
            dist.metadata["Name"]
            for dist in importlib.metadata.distributions(path=[site_packages_dir])
            if dist.metadata["Name"].startswith("arcade_")
        ]

        for package in arcade_packages:
            try:
                toolkit = cls.from_package(package)
                toolkits.append(toolkit)
                logger.debug(f"Loaded toolkit from prefix discovery: {package}")
            except ToolkitLoadError as e:
                logger.warning(f"Warning: {e} Skipping toolkit {package}")

        return toolkits

    @classmethod
    def find_all_arcade_toolkits(cls) -> list["Toolkit"]:
        """
        Find and load as Toolkits all installed packages in the
        current Python interpreter's environment that either
        1. Have a registered entrypoint under the 'arcade.toolkits' group, or
        2. Are prefixed with 'arcade_'

        Returns:
            List[Toolkit]: A list of Toolkit instances.
        """
        # Find toolkits
        entrypoint_toolkits = cls.find_arcade_toolkits_from_entrypoints()
        prefix_toolkits = cls.find_arcade_toolkits_from_prefix()

        # Deduplicate. Entrypoints are preferred over prefix-based toolkits.
        seen_package_names = set()
        all_toolkits = []
        for toolkit in entrypoint_toolkits + prefix_toolkits:
            if toolkit.package_name not in seen_package_names:
                all_toolkits.append(toolkit)
                seen_package_names.add(toolkit.package_name)

        return all_toolkits

    @classmethod
    def tools_from_directory(cls, package_dir: Path, package_name: str) -> dict[str, list[str]]:
        """
        Load a Toolkit from a directory.
        """
        # Get all python files in the package directory
        try:
            modules = [f for f in package_dir.glob("**/*.py") if f.is_file() and Validate.path(f)]
        except OSError as e:
            raise ToolkitLoadError(
                f"Failed to locate Python files in package directory for '{package_name}'."
            ) from e

        # Get the currently executing file (the entrypoint file) so that we can skip it when loading tools.
        # Skipping this file is necessary because tools are discovered via AST parsing, but those tools
        # aren't in the module's namespace yet since the file is still executing.
        current_file = None
        current_module_name = None
        main_module = sys.modules.get("__main__")
        if main_module:
            if hasattr(main_module, "__file__") and main_module.__file__:
                with contextlib.suppress(Exception):
                    current_file = Path(main_module.__file__).resolve()
            # Get module name from __spec__ if available (used when paths don't match,
            # e.g., script runs from bundle but package is in site-packages)
            main_spec = getattr(main_module, "__spec__", None)
            if main_spec and main_spec.name:
                current_module_name = main_spec.name

        tools: dict[str, list[str]] = {}

        for module_path in modules:
            # Build import path first (needed for module name comparison in skip logic)
            relative_path = module_path.relative_to(package_dir)
            relative_parts = relative_path.with_suffix("").parts
            import_path = ".".join(relative_parts)
            if relative_parts and relative_parts[0] == package_name:
                full_import_path = import_path
            else:
                full_import_path = f"{package_name}.{import_path}" if import_path else package_name

            # Skip logic: check by file path OR by module name
            # This handles cases where the script is run from a different location than
            # where the package is installed (e.g., deployment scenarios)
            should_skip = False
            if current_file:
                try:
                    module_path_resolved = module_path.resolve()
                    if module_path_resolved == current_file:
                        should_skip = True
                except Exception:  # noqa: S110
                    pass

            # Secondary check: compare module names when paths don't match
            if not should_skip and current_module_name and full_import_path == current_module_name:
                should_skip = True

            if should_skip:
                continue

            cls.validate_file(module_path)
            tools[full_import_path] = get_tools_from_file(str(module_path))

        if not tools:
            raise ToolkitLoadError(f"No tools found in package {package_name}")

        return tools

    @classmethod
    def validate_file(cls, file_path: str | Path) -> None:
        """
        Validate that the Python code in the given file is syntactically correct.

        Args:
            file_path: Path to the Python file to validate
        """
        # Convert string path to Path object if needed
        path = Path(file_path) if isinstance(file_path, str) else file_path

        # Check if file exists
        if not path.exists():
            raise ValueError(f"❌ File not found: {path}")

        # Check if it's a Python file
        if not path.suffix == ".py":
            raise ValueError(f"❌ Not a Python file: {path}")

        try:
            # Try to compile the code to check for syntax errors
            with open(path, encoding="utf-8") as f:
                source = f.read()

            compile(source, str(path), "exec")
        except Exception as e:
            raise SyntaxError(f"{path}: {e}")


def get_package_directory(package_name: str) -> str:
    """
    Get the directory of a Python package
    """

    spec = importlib.util.find_spec(package_name)
    if spec is None:
        raise ImportError(f"Cannot find package named {package_name}")

    if spec.origin:
        # If the package has an origin, return the directory of the origin
        return os.path.dirname(spec.origin)
    elif spec.submodule_search_locations:
        # If the package is a namespace package, return the first search location
        return spec.submodule_search_locations[0]
    else:
        raise ImportError(f"Package {package_name} does not have a file path associated with it")


class Validate:
    @classmethod
    def path(cls, path: str | Path) -> bool:
        """
        Validate if a path is valid to be served or deployed.
        """
        # Check both POSIX and Windows interpretations
        posix_path = PurePosixPath(path)
        windows_path = PureWindowsPath(path)

        # Get all possible parts from both interpretations
        all_parts = set(posix_path.parts) | set(windows_path.parts)

        for part in all_parts:
            if part in {"dist", "build", "__pycache__", "coverage.xml"}:
                return False
            if part.endswith(".lock"):
                return False

        return True
