import builtins
import os
import types
import typing
from pathlib import Path
from types import UnionType
from typing import Any, Literal, get_args, get_origin

from functional2.testlib.fixtures.file_helper import (
    CopyFile,
    CopyTree,
    FileDeclaration,
    merge_file_declaration,
    Fileish,
    CopyTemplate,
)

# Things have to be resolved from top to bottom, because otherwise the tests behave flakey
# due to the internal file structure

functional2_base_folder = Path(__file__).parent.parent.absolute()
"""
Resolves to `tests/functional2` folder
"""


test_base_folder = functional2_base_folder.parent
"""
Resolves the base path to the `tests` folder of the project
This ensures that the relative path all start with functional2.
"""

lix_base_folder = test_base_folder.parent
"""
Resolves to the base path of the lix git repository
"""


def get_functional2_files(additional_files: FileDeclaration | None = None) -> FileDeclaration:
    """
    Returns the very basic Configuration of functional2 (i.e. its init and pyproject toml file)
    Note that this does not include the conftest.py nor anything from testlib
    as those might want to be configured manually
    :param additional_files: any additional files, one wants to have
    :return: file declaration to be used for the files fixtures to set up functional2 within a temp folder
    """
    if additional_files is None:
        additional_files = {}
    return merge_file_declaration(
        {
            "functional2": {
                "__init__.py": CopyFile(functional2_base_folder / "__init__.py"),
                "pyproject.toml": CopyFile(functional2_base_folder / "pyproject.toml"),
            }
        },
        additional_files,
    )


def get_functional2_files_with_testlib(
    additional_files: FileDeclaration | None = None, no_tests: bool = True
) -> FileDeclaration:
    if additional_files is None:
        additional_files = {}
    if no_tests:

        def ignore(_: Any, names: list[str]) -> list[str]:
            return [name for name in names if name.startswith("test_")]
    else:
        ignore = None
    return get_functional2_files(
        merge_file_declaration(
            {
                "functional2": {
                    "conftest.py": CopyFile(functional2_base_folder / "conftest.py"),
                    "testlib": CopyTree(functional2_base_folder / "testlib", ignore=ignore),
                }
            },
            additional_files,
        )
    )


def get_functional2_lang_files(additional_files: FileDeclaration | None = None) -> FileDeclaration:
    if additional_files is None:
        additional_files = {}
    return get_functional2_files_with_testlib(
        merge_file_declaration(
            {
                "functional2": {
                    "lang": {
                        "__init__.py": CopyFile(functional2_base_folder / "lang/__init__.py"),
                        "lang_util.py": CopyFile(functional2_base_folder / "lang/lang_util.py"),
                        "test_lang.py": CopyFile(functional2_base_folder / "lang/test_lang.py"),
                        "lib.nix": CopyFile(functional2_base_folder / "lang/lib.nix"),
                    }
                }
            },
            additional_files,
        )
    )


def is_value_of_type(value: Any, expected_type: type[Any] | UnionType) -> bool:
    """
    checks if the given value conforms to the type.
    This function is useful, to check if all values conform to the inner iterable type
    :param value: value to check
    :param expected_type: what type each item should be; must be a non-generic type or one of {dict, list, set, UnionType, Literal}
    :return: True if it conforms, otherwise False
    """
    supported_origin_types = {dict, list, set, type, UnionType, Literal}
    origin = get_origin(expected_type)
    if expected_type is Any:
        return True
    match origin:
        case None | types.UnionType:
            return isinstance(value, expected_type)
        case typing.Literal:
            return value in get_args(expected_type)
        case builtins.type:
            return value is get_args(expected_type)[0]
        case builtins.list | builtins.set | builtins.dict:
            matches_origin = isinstance(value, origin)
            if not matches_origin:
                return False
            matches = all(is_value_of_type(v, get_args(expected_type)[0]) for v in value)
            if origin is dict:
                # also check the value side of dicts
                matches = matches and all(
                    is_value_of_type(v, get_args(expected_type)[1]) for v in value.values()
                )
            return matches
        case _:
            msg = f"Unsupported expected_type. Must be a non-generic or one of {supported_origin_types!r}"
            raise ValueError(msg)


def get_global_asset(name: str) -> Fileish:
    if name == "config.nix":
        return CopyTemplate(
            functional2_base_folder / "testlib" / "global_assets" / "config.nix.template",
            {
                "system": os.environ.get("system"),  # noqa: SIM112 # system is actually lowercase here
                # Either just the build shell or entire global path if we are darwin
                "path": os.environ.get("BUILD_TEST_SHELL") or os.environ.get("PATH"),
            },
        )
    return CopyFile(functional2_base_folder / "testlib" / "global_assets" / name)


def get_global_asset_pack(name: Literal["dependencies"]) -> FileDeclaration:
    match name:
        case "dependencies":
            return {
                "config.nix": get_global_asset("config.nix"),
                "dependencies.nix": get_global_asset("dependencies.nix"),
                "dependencies.builder0.sh": get_global_asset("dependencies.builder0.sh"),
            }
        case _:
            msg = f"invalid pack name {name!r}"
            raise ValueError(msg)