#
# This file is distributed under the MIT License. See LICENSE.md for details.
#

import os
import re
from collections.abc import Sequence
from pathlib import Path
from typing import Any, Callable, Optional
from urllib.parse import urlparse

import click
from click.core import ParameterSource

from revng.pypeline.container import ContainerDeclaration, ContainerFormat
from revng.pypeline.model import ReadOnlyModel
from revng.pypeline.object import Kind, ObjectID, ObjectSet
from revng.pypeline.storage.storage_provider import StorageProviderFactory
from revng.pypeline.task.task import TaskArgument
from revng.pypeline.utils.registry import get_registry, get_singleton


class PypeCommand(click.Command):
    """
    An extension of click.Command that modifies the usage line to document that the arguments after
    "--" are passed to the pipebox initialize function.
    """

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if self.help is None:
            self.help = ""
        self.help += (
            "\n\nNote: All arguments after '--' are passed to the pipebox initialize function."
        )

    def collect_usage_pieces(self, ctx: click.Context) -> list[str]:
        if not isinstance(self, PypeGroup):
            return super().collect_usage_pieces(ctx) + ["--", "[PIPEBOX ARGS...]"]
        else:
            return super().collect_usage_pieces(ctx)


class PypeGroup(click.Group, PypeCommand):
    """
    An extension of click.Group that inherits the changes from `PypeCommand`,
    and verifies that all sub-commands inherit from `PypeCommand`.
    """

    def add_command(self, cmd: click.Command, name: str | None = None) -> None:
        if isinstance(cmd, click.Group) and not isinstance(cmd, PypeGroup):
            raise ValueError(f"All sub-groups must be of type PypeGroup, {name}: {type(cmd)}")
        return super().add_command(cmd, name)

    def collect_usage_pieces(self, ctx: click.Context) -> list[str]:
        rv = super().collect_usage_pieces(ctx)
        rv.extend(["--", "[PIPEBOX ARGS...]"])
        return rv


class RegistryChoice(click.Choice):
    """A click.Choice that uses the registry of a given type, and
    returns the actual object from the registry instead of just the string."""

    def __init__(
        self, ty: type, case_sensitive: bool = False, subclass_filter: Optional[type] = None
    ) -> None:
        self.ty = ty
        self.registry: dict[str, type] = {  # type: ignore[var-annotated]
            k: v
            for k, v in get_registry(ty).items()
            if subclass_filter is None or issubclass(v, subclass_filter)
        }
        super().__init__(
            choices=sorted(self.registry.keys()),
            case_sensitive=case_sensitive,
        )

    def convert(
        self, value: Any, param: Optional[click.Parameter], ctx: Optional[click.Context]
    ) -> Any:
        res = super().convert(value, param, ctx)
        # Compared to a normal click.Choice, we need to return the actual object
        # from the registry, not just the string
        if isinstance(res, str):
            if res not in self.registry:
                raise ValueError("This should already be checked by click. ")
            return self.registry[res]
        return super().convert(value, param, ctx)


class EagerParsedPath(click.Path):
    """
    A click.Path that does eager parsing, meaning that it will call your function during parsing.
    This is useful for arguments that need to be parsed in order to provide
    useful auto-completion or validation.
    The cli and other arguments can retrieve the parsed value from the context object
    using the name of the argument, like `ctx.obj['pipebox']`.
    Additionally, it stores the path used to parse the value as `ctx.obj[self.name + "_path"]`.
    """

    def __init__(
        self,
        name: str,
        parser: Callable[[str, click.Context], Any],
        *args,
        **kwargs,
    ):
        # Sensible defaults for our use case
        kwargs.setdefault("exists", True)
        kwargs.setdefault("dir_okay", False)
        kwargs.setdefault("resolve_path", True)
        super().__init__(*args, **kwargs)
        self.parser = parser
        self.name = name

    def convert(
        self, value: Any, param: Optional[click.Parameter], ctx: Optional[click.Context]
    ) -> Any:
        path = super().convert(value, param, ctx)
        if not isinstance(path, str):
            raise ValueError(f"Invalid path: {path!r}")
        # If the value is a string, we parse it using the provided parser
        if ctx is None:
            raise ValueError("Context is required for parsing")
        res = self.parser(path, ctx)
        if ctx is not None:
            if ctx.obj is None:
                ctx.obj = {}
            # Store the parsed value in the context object
            ctx.obj[self.name] = res
            # And also store the path to the parsed value
            ctx.obj[self.name + "_path"] = Path(path).resolve()
        return res


class StorageProviderUrl(click.ParamType):
    """A custom type for the URL of a storage provider that is validated."""

    name = "url"

    def convert(self, value, param, ctx):
        # Ensure we are dealing with a string
        if not isinstance(value, str):
            self.fail(
                f"Expected a string, but got value of type {type(value).__name__}.", param, ctx
            )

        try:
            parsed_url = urlparse(value)
        except ValueError:
            # urlparse can raise ValueError on rare malformed inputs
            self.fail(f'"{value}" could not be parsed as a URL.', param, ctx)

        # Get all the registered providers
        allowed_schemes = {
            factory.scheme() for factory in get_registry(StorageProviderFactory).values()
        }
        # Check that the scheme is supported
        if parsed_url.scheme not in allowed_schemes:
            allowed_str = ", ".join(sorted(allowed_schemes))
            self.fail(
                f'URL scheme "{parsed_url.scheme}" is not supported. '
                f"Allowed schemes are: {allowed_str}.",
                param,
                ctx,
            )
        # If all checks pass, return the original, validated string
        return value


def normalize_whitespace(text: str) -> str:
    """
    Normalize whitespace in a string by removing leading and trailing
    whitespace and replacing multiple spaces with a single space.
    """
    text = re.sub(r"\s+", " ", text)
    return text.strip()


def normalize_flag(name: str) -> str:
    """
    Normalize a flag name by replacing spaces and underscores with
    hyphens and converting it to lowercase.
    """
    return normalize_whitespace(name).replace(" ", "-").replace("_", "-").lower()


def normalize_pos_arg_name(name: str) -> str:
    """
    Normalize a positional argument name by replacing spaces and underscores
    with hyphens and converting it to lowercase.
    This is used for positional arguments that are not flags.
    """
    return normalize_whitespace(name).replace(" ", "_").replace("-", "_").upper()


def normalize_kwarg_name(name: str) -> str:
    """
    Normalize the provided name to the convention used by click on naming
    command handler variable arguments.
    """
    return name.replace("-", "_").lower()


def build_arg_objects(
    container_decl: ContainerDeclaration,
) -> Callable:
    """
    A decorator that adds an argument to a click command for
    the objects that the user wants in a specific container.
    """
    arg_name = normalize_flag(container_decl.name)
    kind = container_decl.container_type.kind
    return click.option(
        f"--{arg_name}-objects",
        metavar=f"/{kind.serialize()}1,/{kind.serialize()}2,...",
        type=str,
        help=(
            f"The objects to require from container {arg_name.upper()}"
            " as a comma-separated list of IDs. If not passed, all "
            "objects will be requested."
        ),
    )


def build_help_text(
    args: Sequence[TaskArgument],
    prologue: str = "",
    epilogue: str = "",
    extra_args: list[str] | None = None,
    model_help: bool = True,
) -> str:
    """
    Build a standardized help text for a command.
    """
    help_text: str = prologue
    if args or model_help or extra_args is not None:
        help_text += "\n\n\b\nArguments:"
    if model_help:
        help_text += "\n - MODEL : Path - The path to the model file to use."

    if extra_args is not None:
        for extra_arg in extra_args:
            help_text += f"\n - {extra_arg}"

    for arg in args:
        help_text += _build_help_line(arg)

    help_text += epilogue
    return help_text


def _build_help_line(arg: TaskArgument) -> str:
    arg_name = normalize_pos_arg_name(arg.name)
    line = f"\n - {arg_name} : "
    line += f"{arg.container_type.__name__} - "
    line += normalize_whitespace(arg.help_text)
    return line.rstrip()


def list_objects_for_container(
    model: ReadOnlyModel,
    arg_name: str,
    kind: Kind,
):
    """
    Print all available objects for a given container kind in the model.
    """
    print(f'Available objects for "{arg_name}" kind: "{kind.serialize()}"')
    for obj in model.all_objects(kind):
        print(f" - {obj}")


def compute_objects(
    model: ReadOnlyModel,
    arg_name: str,
    kind: Kind,
    kwargs: dict[str, str],
) -> ObjectSet:
    """
    Check if the user provided a list of objects for the given
    argument name, and if so, return an ObjectSet with those objects
    deserialized.
    Otherwise, return all objects of the given kind from the model.
    """
    arg_name = normalize_flag(arg_name)
    obj_id_type = get_singleton(ObjectID)  # type: ignore[type-abstract]
    if f"{arg_name}_objects" in kwargs:
        objects = kwargs.get(f"{arg_name}_objects", "")
        if objects:
            return ObjectSet(
                kind=kind,
                objects={obj_id_type.deserialize(obj) for obj in objects.split(",") if obj.strip()},
            )
    return model.all_objects(kind)


# Options that are common to multiple commands
project_id_option = click.option(
    "--project-id",
    type=str,
    help=("Project id to use for the storage provider."),
    # TODO: discuss env var names
    default=os.environ.get("PROJECT_ID"),
    show_default=True,
)

list_objects_option = click.option(
    "--list",
    type=bool,
    is_flag=True,
    default=False,
    help="List the available objects for each argument.",
)

token_option = click.option(
    "--token",
    type=str,
    required=False,
    help="The token to pass to the storage provider.",
)


def handle_format_option(ctx, param, value):
    """
    Handles mutual exclusivity, converts strings to Enums,
    and manages precedence between flags and defaults.
    """
    # Handle shortcuts the value is boolean here
    if param.name in [f.value for f in ContainerFormat]:
        if not value:
            return None

        if ctx.params.get("format") is not None:
            raise click.BadOptionUsage(
                param.name, f"Mutually exclusive: --{param.name} cannot be used with other formats."
            )

        ctx.params["format"] = ContainerFormat(param.name)
        return None

    # Handle --format, value is a string passed from click.Choice or default

    # Check if a shortcut already populated the format
    existing_format = ctx.params.get("format")
    if existing_format is not None:
        # If the user EXPLICITLY typed --format AND used a flag -> Error
        if ctx.get_parameter_source(param.name) != ParameterSource.DEFAULT:
            raise click.BadOptionUsage(
                param.name,
                "Mutually exclusive: Cannot specify "
                f"--format when --{existing_format.value} is used.",
            )
        # If --format is just running its default 'yaml', let the Flag win
        return existing_format

    # If no flag was used, convert the string value to Enum and return
    return ContainerFormat(value)


def container_format_options(func):
    func = click.option(
        "--format",
        "container_format",
        type=click.Choice([x.value for x in ContainerFormat]),
        default=ContainerFormat.YAML.value,
        show_default=True,
        callback=handle_format_option,
        help=("Format to use for the output container, either on stdout or in the result path."),
    )(func)
    for member in ContainerFormat:
        func = click.option(
            f"--{member.value}",
            is_flag=True,
            expose_value=False,
            help=f"Shortcut for --format={member.value}.",
            callback=handle_format_option,
        )(func)
    return func