from __future__ import annotations

import enum
import itertools
import logging
import pathlib
import re
from contextlib import ExitStack, contextmanager
from dataclasses import dataclass

# from itertools import product
from pathlib import Path
from test.utils import GraphHelper
from test.utils.exceptions import ExceptionChecker
from test.utils.httpfileserver import (
    HTTPFileInfo,
    HTTPFileServer,
    LocationType,
    ProtoFileResource,
    ProtoRedirectResource,
)
from typing import (  # Callable,
    IO,
    BinaryIO,
    Collection,
    ContextManager,
    Generator,
    Generic,
    Iterable,
    Optional,
    TextIO,
    Tuple,
    Type,
    TypeVar,
    Union,
)

import pytest
from _pytest.mark.structures import ParameterSet

from rdflib.graph import Graph
from rdflib.parser import (
    FileInputSource,
    InputSource,
    StringInputSource,
    URLInputSource,
    create_input_source,
)

from ..data import TEST_DATA_DIR


def test_empty_arguments():
    """create_input_source() function must receive exactly one argument."""
    with pytest.raises(ValueError):
        create_input_source()


def test_too_many_arguments():
    """create_input_source() function has a few conflicting arguments."""
    with pytest.raises(ValueError):
        create_input_source(source="a", location="b")


SourceParamType = Union[IO[bytes], TextIO, InputSource, str, bytes, pathlib.PurePath]
FileParamType = Union[BinaryIO, TextIO]
DataParamType = Union[str, bytes, dict]


class SourceParam(enum.Enum):
    """
    Indicates what kind of paramter should be passed as ``source`` to create_input_source().
    """

    BINARY_IO = enum.auto()
    TEXT_IO = enum.auto()
    INPUT_SOURCE = enum.auto()
    BYTES = enum.auto()
    PATH = enum.auto()
    PATH_STRING = enum.auto()
    FILE_URI = enum.auto()

    @contextmanager
    def from_path(self, path: Path) -> Generator[SourceParamType, None, None]:
        """
        Yields a value of the type indicated by the enum value which provides the data from the file at ``path``.


        :param path: Path to the file to read.
        :return: A context manager which yields a value of the type indicated by the enum value.
        """
        if self is SourceParam.BINARY_IO:
            yield path.open("rb")
        elif self is SourceParam.TEXT_IO:
            yield path.open("r", encoding="utf-8")
        elif self is SourceParam.INPUT_SOURCE:
            yield StringInputSource(path.read_bytes(), encoding="utf-8")
        elif self is SourceParam.BYTES:
            yield path.read_bytes()
        elif self is SourceParam.PATH:
            yield path
        elif self is SourceParam.PATH_STRING:
            yield f"{path}"
        elif self is SourceParam.FILE_URI:
            yield path.absolute().as_uri()
        else:
            raise ValueError(f"unsupported value self={self} self.value={self.value}")


class LocationParam(enum.Enum):
    """
    Indicates what kind of paramter should be passed as ``location`` to create_input_source().
    """

    FILE_URI = enum.auto()
    HTTP_URI = enum.auto()

    @contextmanager
    def from_path(
        self, path: Optional[Path], url: Optional[str]
    ) -> Generator[str, None, None]:
        """
        Yields a value of the type indicated by the enum value which provides the data from the file at ``path``.

        :param path: Path to the file to read.
        :return: A context manager which yields a value of the type indicated by the enum value.
        """
        if self is LocationParam.FILE_URI:
            assert path is not None
            yield path.absolute().as_uri()
        elif self is LocationParam.HTTP_URI:
            assert url is not None
            yield url
        else:
            raise ValueError(f"unsupported value self={self} self.value={self.value}")


class FileParam(enum.Enum):
    """
    Indicates what kind of paramter should be passed as ``file`` to create_input_source().
    """

    BINARY_IO = enum.auto()
    TEXT_IO = enum.auto()

    @contextmanager
    def from_path(self, path: Path) -> Generator[Union[BinaryIO, TextIO], None, None]:
        """
        Yields a value of the type indicated by the enum value which provides the data from the file at ``path``.

        :param path: Path to the file to read.
        :return: A context manager which yields a value of the type indicated by the enum value.
        """
        if self is FileParam.BINARY_IO:
            yield path.open("rb")
        elif self is FileParam.TEXT_IO:
            yield path.open("r", encoding="utf-8")
        else:
            raise ValueError(f"unsupported value self={self} self.value={self.value}")


class DataParam(enum.Enum):
    """
    Indicates what kind of paramter should be passed as ``data`` to create_input_source().
    """

    STRING = enum.auto()
    BYTES = enum.auto()
    # DICT = enum.auto()

    @contextmanager
    def from_path(self, path: Path) -> Generator[Union[bytes, str, dict], None, None]:
        """
        Yields a value of the type indicated by the enum value which provides the data from the file at ``path``.

        :param path: Path to the file to read.
        :return: A context manager which yields a value of the type indicated by the enum value.
        """
        if self is DataParam.STRING:
            yield path.read_text(encoding="utf-8")
        elif self is DataParam.BYTES:
            yield path.read_bytes()
        else:
            raise ValueError(f"unsupported value self={self} self.value={self.value}")


@contextmanager
def call_create_input_source(
    input: Union[HTTPFileInfo, Path],
    source_param: Optional[SourceParam] = None,
    # source_slot: SourceSlot,
    public_id: Optional[str] = None,
    location_param: Optional[LocationParam] = None,
    file_param: Optional[FileParam] = None,
    data_param: Optional[DataParam] = None,
    format: Optional[str] = None,
) -> Generator[InputSource, None, None]:
    """
    Calls create_input_source() with parameters of the specified types.
    """

    logging.debug(
        "source_param = %s, location_param = %s, file_param = %s, data_param = %s",
        source_param,
        location_param,
        file_param,
        data_param,
    )

    source: Optional[SourceParamType] = None
    location: Optional[str] = None
    file: Optional[FileParamType] = None
    data: Optional[DataParamType] = None

    input_url = None
    if isinstance(input, HTTPFileInfo):
        input_path = input.path
        input_url = input.request_url
    else:
        input_path = input

    with ExitStack() as xstack:
        if source_param is not None:
            source = xstack.enter_context(source_param.from_path(input_path))
        if location_param is not None:
            location = xstack.enter_context(
                location_param.from_path(input_path, input_url)
            )
        if file_param is not None:
            file = xstack.enter_context(file_param.from_path(input_path))
        if data_param is not None:
            data = xstack.enter_context(data_param.from_path(input_path))

        logging.debug(
            "source = %s/%r, location = %s/%r, file = %s/..., data = %s/...",
            type(source),
            source,
            type(location),
            location,
            type(file),
            type(data),
        )
        input_source = create_input_source(
            source=source,
            publicID=public_id,
            location=location,
            file=file,
            data=data,
            format=format,
        )
        yield input_source


AnyT = TypeVar("AnyT")


@dataclass
class Holder(Generic[AnyT]):
    value: AnyT


class StreamCheck(enum.Enum):
    BYTE = enum.auto()
    CHAR = enum.auto()
    GRAPH = enum.auto()


@dataclass
class InputSourceChecker:
    """
    Checker for input source objects.

    :param type: Expected type of input source.
    :param stream_check: What kind of stream check to perform.
    :param encoding: Expected encoding of input source. If ``None``, then the encoding is not checked. If it has a value (i.e. an instance of :class:`Holder`), then the encoding is expected to match ``encoding.value``.
    """

    type: Type[InputSource]
    stream_check: StreamCheck
    encoding: Optional[Holder[Optional[str]]]
    public_id: Optional[str]
    system_id: Optional[str]
    # extra_checks: List[Callable[[InputSource], None]] = field(factory=list)

    def check(
        self,
        params: CreateInputSourceTestParams,
        input_path: Path,
        input_source: InputSource,
    ) -> None:
        """
        Check that ``input_source`` matches expectations.
        """
        logging.debug(
            "input_source = %s / %s, self.type = %s",
            type(input_source),
            input_source,
            self.type,
        )
        assert isinstance(input_source, InputSource)
        if self.type is not None:
            assert isinstance(input_source, self.type)

        if self.stream_check is StreamCheck.BYTE:
            binary_io: BinaryIO = input_source.getByteStream()
            if params.data_param is DataParam.STRING:
                assert (
                    binary_io.read() == input_path.read_text(encoding="utf-8").encode()
                )
            else:
                assert binary_io.read() == input_path.read_bytes()
        elif self.stream_check is StreamCheck.CHAR:
            text_io: TextIO = input_source.getCharacterStream()
            assert text_io.read() == input_path.read_text(encoding="utf-8")
        elif self.stream_check is StreamCheck.GRAPH:
            graph = Graph()
            graph.parse(input_source, format=params.format)
            assert len(graph) > 0
            GraphHelper.assert_triple_sets_equals(BASE_GRAPH, graph)
        else:
            raise ValueError(f"unsupported stream_check value {self.stream_check}")

        if self.encoding is not None:
            assert self.encoding.value == input_source.getEncoding()

        logging.debug("input_source.getPublicId() = %r", input_source.getPublicId())
        logging.debug("self.public_id = %r", self.public_id)
        if self.public_id is not None and input_source.getPublicId() is not None:
            assert f"{self.public_id}" == f"{input_source.getPublicId()}"
        else:
            assert self.public_id == input_source.getPublicId()

        logging.debug("input_source.getSystemId() = %r", input_source.getSystemId())
        logging.debug("self.system_id = %r", self.system_id)
        if self.system_id is not None and input_source.getSystemId() is not None:
            assert f"{self.system_id}" == f"{input_source.getSystemId()}"
        else:
            assert self.system_id == input_source.getSystemId()

    @classmethod
    def type_from_param(
        cls, param: Union[SourceParam, FileParam, DataParam, LocationParam, enum.Enum]
    ) -> Type[InputSource]:
        """
        Return the type of input source that should be created for the given parameter.

        :param param: The parameter that will be passed to :func:`create_input_source`.
        :return: Type of input source that should be created for the given parameter.
        """
        if param in (
            SourceParam.PATH,
            SourceParam.PATH_STRING,
            SourceParam.FILE_URI,
            LocationParam.FILE_URI,
        ):
            return FileInputSource
        if param in (SourceParam.BINARY_IO, SourceParam.TEXT_IO):
            return InputSource
        if param in (*FileParam,):
            return FileInputSource
        if param in (SourceParam.BYTES, SourceParam.INPUT_SOURCE, *DataParam):
            return StringInputSource
        if param in (LocationParam.HTTP_URI,):
            return URLInputSource
        raise ValueError(f"unknown param {param}")


FileParamTypeCM = ContextManager[FileParamType]


CreateInputSourceTestParamsTuple = Tuple[
    Path,
    Optional[SourceParam],
    Optional[str],
    Optional[LocationParam],
    Optional[FileParam],
    Optional[DataParam],
    Optional[str],
    Union[ExceptionChecker, InputSourceChecker],
]
"""
Type alias for the tuple representation of :class:`CreateInputSourceTestParams`.
"""


@dataclass
class CreateInputSourceTestParams:
    """
    Parameters for :func:`create_input_source`.
    """

    input_path: Path
    source_param: Optional[SourceParam]
    public_id: Optional[str]
    location_param: Optional[LocationParam]
    file_param: Optional[FileParam]
    data_param: Optional[DataParam]
    format: Optional[str]
    expected_result: Union[ExceptionChecker, InputSourceChecker]

    def as_tuple(self) -> CreateInputSourceTestParamsTuple:
        return (
            self.input_path,
            self.source_param,
            self.public_id,
            self.location_param,
            self.file_param,
            self.data_param,
            self.format,
            self.expected_result,
        )

    @property
    def input_param(self) -> Union[SourceParam, LocationParam, FileParam, DataParam]:
        values = [
            param
            for param in (
                self.source_param,
                self.location_param,
                self.file_param,
                self.data_param,
            )
            if param is not None
        ]
        if len(values) != 1:
            raise ValueError(f"multiple input params: {values}")
        return values[0]

    @property
    def requires_http(self) -> bool:
        if self.location_param in (LocationParam.HTTP_URI,):
            return True
        return False

    def as_pytest_param(
        self,
        marks: Union[
            pytest.MarkDecorator, Collection[Union[pytest.MarkDecorator, pytest.Mark]]
        ] = (),
        id: Optional[str] = None,
    ) -> ParameterSet:
        if id is None:
            id = f"{self.input_path.as_posix()}:source_param={self.source_param}:public_id={self.public_id}:location_param={self.location_param}:file_param={self.file_param}:data_param={self.data_param}:format={self.format}:{self.expected_result}"
        return pytest.param(self, marks=marks, id=id)


VARIANTS_DIR = TEST_DATA_DIR.relative_to(Path.cwd()) / "variants"
BASE_GRAPH = Graph()
BASE_GRAPH.parse(VARIANTS_DIR / "simple_triple.nt", format="nt")


def generate_create_input_source_cases() -> Iterable[ParameterSet]:
    """
    Generate cases for :func:`test_create_input_source`.
    """
    default_format = "turtle"
    input_paths = {
        "turtle": VARIANTS_DIR / "simple_triple.ttl",
        "json-ld": VARIANTS_DIR / "simple_triple.jsonld",
        "xml": VARIANTS_DIR / "simple_triple.xml",
        "nt": VARIANTS_DIR / "simple_triple.nt",
        "hext": VARIANTS_DIR / "simple_triple.hext",
        None: VARIANTS_DIR / "simple_triple.ttl",
    }
    formats = set(input_paths.keys())

    for use_source, use_location, use_file, use_data in itertools.product(
        (True, False), (True, False), (True, False), (True, False)
    ):
        flags = (use_source, use_location, use_file, use_data)
        true_flags = sum([1 if flag is True else 0 for flag in flags])
        if true_flags <= 1:
            # Only process combinations with at least two flags set
            continue

        yield CreateInputSourceTestParams(
            input_paths[default_format],
            source_param=SourceParam.PATH if use_source else None,
            public_id=None,
            location_param=LocationParam.FILE_URI if use_location else None,
            file_param=FileParam.TEXT_IO if use_file else None,
            data_param=DataParam.STRING if use_data else None,
            format=default_format,
            expected_result=ExceptionChecker(
                ValueError,
                re.compile(
                    "exactly one of source, location, file or data must be given"
                ),
            ),
        ).as_pytest_param(
            id=f"bad_arg_combination-use_source={use_source}-use_location={use_location}-use_file={use_file}-use_data={use_data}"
        )

    def make_params(
        param: enum.Enum,
        stream_check: StreamCheck,
        expected_encoding: Optional[Holder[Optional[str]]],
        format: Optional[str] = default_format,
        id: Optional[str] = None,
        public_id: Optional[str] = None,
        marks: Union[
            pytest.MarkDecorator, Collection[Union[pytest.MarkDecorator, pytest.Mark]]
        ] = (),
    ) -> Iterable[ParameterSet]:
        yield CreateInputSourceTestParams(
            input_paths[format],
            source_param=param if isinstance(param, SourceParam) else None,
            public_id=public_id,
            location_param=param if isinstance(param, LocationParam) else None,
            file_param=param if isinstance(param, FileParam) else None,
            data_param=param if isinstance(param, DataParam) else None,
            format=format,
            expected_result=InputSourceChecker(
                InputSourceChecker.type_from_param(param),
                stream_check=stream_check,
                encoding=expected_encoding,
                public_id=public_id,
                system_id=None,
            ),
        ).as_pytest_param(marks, id)

    for param, stream_check, format in itertools.product(
        itertools.chain(SourceParam, LocationParam, FileParam, DataParam),
        StreamCheck,
        formats,
    ):
        # Generate cases for all supported source parameters. And create
        # variants of cases to perfom different stream checks on created input
        # sources.
        if stream_check is StreamCheck.CHAR and param in (
            SourceParam.BINARY_IO,
            SourceParam.PATH,
            SourceParam.PATH_STRING,
            SourceParam.FILE_URI,
            LocationParam.FILE_URI,
            LocationParam.HTTP_URI,
            FileParam.BINARY_IO,
        ):
            # These do not have working characther streams. Maybe they
            # should, but they don't.
            continue
        expected_encoding: Optional[Holder[Optional[str]]]
        if param in (
            SourceParam.PATH,
            SourceParam.PATH_STRING,
            SourceParam.FILE_URI,
            LocationParam.FILE_URI,
            LocationParam.HTTP_URI,
            SourceParam.BINARY_IO,
            FileParam.BINARY_IO,
        ):
            # This should maybe be ``None`` instead of ``Holder(None)``, but as
            # there is no ecoding supplied it is probably safe to assert that no
            # encoding is associated with it.
            expected_encoding = Holder(None)
        else:
            expected_encoding = Holder("utf-8")

        yield from make_params(param, stream_check, expected_encoding, format)

    for param in LocationParam:
        yield from make_params(
            param,
            StreamCheck.BYTE,
            Holder(None),
            public_id="https://example.com/explicit_public_id",
        )


@pytest.mark.parametrize(
    ["test_params"],
    generate_create_input_source_cases(),
)
def test_create_input_source(
    test_params: CreateInputSourceTestParams,
    http_file_server: HTTPFileServer,
) -> None:
    """
    A given set of parameters results in an input source matching specified
    invariants.

    :param test_params: The parameters to use for the test. This specifies what
        parameters should be passed to func:`create_input_source` and what
        invariants the resulting input source should match.
    :param http_file_server: The HTTP file server to use for the test.
    """
    logging.debug("test_params = %s", test_params)
    input_path = test_params.input_path
    input: Union[HTTPFileInfo, Path]
    if test_params.requires_http:
        http_file_info = http_file_server.add_file_with_caching(
            ProtoFileResource((), test_params.input_path),
            (ProtoRedirectResource((), 300, LocationType.URL),),
        )
        logging.debug("http_file_info = %s", http_file_info)
        input = http_file_info
    else:
        input = test_params.input_path

    if isinstance(test_params.expected_result, InputSourceChecker):
        expected_result = test_params.expected_result
        param = test_params.input_param
        if expected_result.public_id is None:
            if param in (
                SourceParam.PATH,
                SourceParam.PATH_STRING,
                SourceParam.FILE_URI,
                LocationParam.FILE_URI,
            ):
                expected_result.public_id = input_path.absolute().as_uri()
            elif param in (LocationParam.HTTP_URI,):
                expected_result.public_id = http_file_info.effective_url
            else:
                expected_result.public_id = ""

        if expected_result.system_id is None:
            if param in (
                SourceParam.BINARY_IO,
                SourceParam.TEXT_IO,
            ):
                expected_result.system_id = f"{input_path}"
            elif param in (
                SourceParam.INPUT_SOURCE,
                SourceParam.BYTES,
                DataParam.STRING,
                DataParam.BYTES,
            ):
                expected_result.system_id = None
            elif param in (
                SourceParam.PATH,
                SourceParam.PATH_STRING,
                SourceParam.FILE_URI,
                LocationParam.FILE_URI,
                FileParam.BINARY_IO,
                FileParam.TEXT_IO,
            ):
                expected_result.system_id = input_path.absolute().as_uri()
            elif param in (LocationParam.HTTP_URI,):
                expected_result.system_id = http_file_info.effective_url
            else:
                raise ValueError(
                    f"cannot determine expected_result.system_id for param={param!r}"
                )

    logging.info("expected_result = %s", test_params.expected_result)

    catcher: Optional[pytest.ExceptionInfo[Exception]] = None
    input_source: Optional[InputSource] = None
    with ExitStack() as xstack:
        if isinstance(test_params.expected_result, ExceptionChecker):
            catcher = xstack.enter_context(
                pytest.raises(test_params.expected_result.type)
            )

        input_source = xstack.enter_context(
            call_create_input_source(
                input,
                test_params.source_param,
                test_params.public_id,
                test_params.location_param,
                test_params.file_param,
                test_params.data_param,
                test_params.format,
            )
        )
        if not isinstance(test_params.expected_result, ExceptionChecker):
            assert input_source is not None
            test_params.expected_result.check(
                test_params, test_params.input_path, input_source
            )

    logging.debug("input_source = %s, catcher = %s", input_source, catcher)

    if isinstance(test_params.expected_result, ExceptionChecker):
        assert catcher is not None
        assert input_source is None
        test_params.expected_result.check(catcher.value)