# Copyright (c) 2023 - 2025, AG2ai, Inc., AG2ai open-source projects maintainers and core contributors
#
# SPDX-License-Identifier: Apache-2.0
#
# Portions derived from  https://github.com/microsoft/autogen are under the MIT License.
# SPDX-License-Identifier: MIT
import functools
import inspect
import json
from collections.abc import Callable
from logging import getLogger
from typing import Annotated, Any, ForwardRef, Literal, TypeVar, get_args, get_origin

from packaging.version import parse
from pydantic import BaseModel, Field, TypeAdapter
from pydantic import __version__ as pydantic_version
from pydantic.json_schema import JsonSchemaValue

from ..doc_utils import export_module
from .dependency_injection import Field as AG2Field

if parse(pydantic_version) < parse("2.10.2"):
    from pydantic._internal._typing_extra import eval_type_lenient as try_eval_type
else:
    from pydantic._internal._typing_extra import try_eval_type


__all__ = ["get_function_schema", "load_basemodels_if_needed", "serialize_to_str"]

logger = getLogger(__name__)

T = TypeVar("T")


def get_typed_annotation(annotation: Any, globalns: dict[str, Any]) -> Any:
    """Get the type annotation of a parameter.

    Args:
        annotation: The annotation of the parameter
        globalns: The global namespace of the function

    Returns:
        The type annotation of the parameter
    """
    if isinstance(annotation, AG2Field):
        annotation = annotation.description
    if isinstance(annotation, str):
        annotation = ForwardRef(annotation)
        annotation, _ = try_eval_type(annotation, globalns, globalns)
    return annotation


def get_typed_signature(call: Callable[..., Any]) -> inspect.Signature:
    """Get the signature of a function with type annotations.

    Args:
        call: The function to get the signature for

    Returns:
        The signature of the function with type annotations
    """
    signature = inspect.signature(call)
    globalns = getattr(call, "__globals__", {})
    typed_params = [
        inspect.Parameter(
            name=param.name,
            kind=param.kind,
            default=param.default,
            annotation=get_typed_annotation(param.annotation, globalns),
        )
        for param in signature.parameters.values()
    ]
    typed_signature = inspect.Signature(typed_params)
    return typed_signature


def get_typed_return_annotation(call: Callable[..., Any]) -> Any:
    """Get the return annotation of a function.

    Args:
        call: The function to get the return annotation for

    Returns:
        The return annotation of the function
    """
    signature = inspect.signature(call)
    annotation = signature.return_annotation

    if annotation is inspect.Signature.empty:
        return None

    globalns = getattr(call, "__globals__", {})
    return get_typed_annotation(annotation, globalns)


def get_param_annotations(typed_signature: inspect.Signature) -> dict[str, Annotated[type[Any], str] | type[Any]]:
    """Get the type annotations of the parameters of a function

    Args:
        typed_signature: The signature of the function with type annotations

    Returns:
        A dictionary of the type annotations of the parameters of the function
    """
    return {
        k: v.annotation for k, v in typed_signature.parameters.items() if v.annotation is not inspect.Signature.empty
    }


class Parameters(BaseModel):
    """Parameters of a function as defined by the OpenAI API"""

    type: Literal["object"] = "object"
    properties: dict[str, JsonSchemaValue]
    required: list[str]


class Function(BaseModel):
    """A function as defined by the OpenAI API"""

    description: Annotated[str, Field(description="Description of the function")]
    name: Annotated[str, Field(description="Name of the function")]
    parameters: Annotated[Parameters, Field(description="Parameters of the function")]


class ToolFunction(BaseModel):
    """A function under tool as defined by the OpenAI API."""

    type: Literal["function"] = "function"
    function: Annotated[Function, Field(description="Function under tool")]


def get_parameter_json_schema(k: str, v: Any, default_values: dict[str, Any]) -> JsonSchemaValue:
    """Get a JSON schema for a parameter as defined by the OpenAI API

    Args:
        k: The name of the parameter
        v: The type of the parameter
        default_values: The default values of the parameters of the function

    Returns:
        A Pydanitc model for the parameter
    """

    def type2description(k: str, v: Annotated[type[Any], str] | type[Any]) -> str:
        if not hasattr(v, "__metadata__"):
            return k

        # handles Annotated
        retval = v.__metadata__[0]
        if isinstance(retval, AG2Field):
            return retval.description  # type: ignore[return-value]
        else:
            raise ValueError(f"Invalid {retval} for parameter {k}, should be a DescriptionField, got {type(retval)}")

    schema = TypeAdapter(v).json_schema()
    if k in default_values:
        dv = default_values[k]
        schema["default"] = dv

    schema["description"] = type2description(k, v)

    return schema


def get_required_params(typed_signature: inspect.Signature) -> list[str]:
    """Get the required parameters of a function

    Args:
        typed_signature: The signature of the function as returned by inspect.signature

    Returns:
        A list of the required parameters of the function
    """
    return [k for k, v in typed_signature.parameters.items() if v.default == inspect.Signature.empty]


def get_default_values(typed_signature: inspect.Signature) -> dict[str, Any]:
    """Get default values of parameters of a function

    Args:
        typed_signature: The signature of the function as returned by inspect.signature

    Returns:
        A dictionary of the default values of the parameters of the function
    """
    return {k: v.default for k, v in typed_signature.parameters.items() if v.default != inspect.Signature.empty}


def get_parameters(
    required: list[str],
    param_annotations: dict[str, Annotated[type[Any], str] | type[Any]],
    default_values: dict[str, Any],
) -> Parameters:
    """Get the parameters of a function as defined by the OpenAI API

    Args:
        required: The required parameters of the function
        param_annotations: The type annotations of the parameters of the function
        default_values: The default values of the parameters of the function

    Returns:
        A Pydantic model for the parameters of the function
    """
    return Parameters(
        properties={
            k: get_parameter_json_schema(k, v, default_values)
            for k, v in param_annotations.items()
            if v is not inspect.Signature.empty
        },
        required=required,
    )


def get_missing_annotations(typed_signature: inspect.Signature, required: list[str]) -> tuple[set[str], set[str]]:
    """Get the missing annotations of a function

    Ignores the parameters with default values as they are not required to be annotated, but logs a warning.

    Args:
        typed_signature: The signature of the function with type annotations
        required: The required parameters of the function

    Returns:
        A set of the missing annotations of the function
    """
    all_missing = {k for k, v in typed_signature.parameters.items() if v.annotation is inspect.Signature.empty}
    missing = all_missing.intersection(set(required))
    unannotated_with_default = all_missing.difference(missing)
    return missing, unannotated_with_default


@export_module("autogen.tools")
def get_function_schema(f: Callable[..., Any], *, name: str | None = None, description: str) -> dict[str, Any]:
    """Get a JSON schema for a function as defined by the OpenAI API

    Args:
        f: The function to get the JSON schema for
        name: The name of the function
        description: The description of the function

    Returns:
        A JSON schema for the function

    Raises:
        TypeError: If the function is not annotated

    Examples:
    ```python
    def f(a: Annotated[str, "Parameter a"], b: int = 2, c: Annotated[float, "Parameter c"] = 0.1) -> None:
        pass


    get_function_schema(f, description="function f")

    #   {'type': 'function',
    #    'function': {'description': 'function f',
    #        'name': 'f',
    #        'parameters': {'type': 'object',
    #           'properties': {'a': {'type': 'str', 'description': 'Parameter a'},
    #               'b': {'type': 'int', 'description': 'b'},
    #               'c': {'type': 'float', 'description': 'Parameter c'}},
    #           'required': ['a']}}}
    ```

    """
    typed_signature = get_typed_signature(f)
    required = get_required_params(typed_signature)
    default_values = get_default_values(typed_signature)
    param_annotations = get_param_annotations(typed_signature)
    return_annotation = get_typed_return_annotation(f)
    missing, unannotated_with_default = get_missing_annotations(typed_signature, required)

    if return_annotation is None:
        logger.warning(
            f"The return type of the function '{f.__name__}' is not annotated. Although annotating it is "
            + "optional, the function should return either a string, a subclass of 'pydantic.BaseModel'."
        )

    if unannotated_with_default != set():
        unannotated_with_default_s = [f"'{k}'" for k in sorted(unannotated_with_default)]
        logger.warning(
            f"The following parameters of the function '{f.__name__}' with default values are not annotated: "
            + f"{', '.join(unannotated_with_default_s)}."
        )

    if missing != set():
        missing_s = [f"'{k}'" for k in sorted(missing)]
        raise TypeError(
            f"All parameters of the function '{f.__name__}' without default values must be annotated. "
            + f"The annotations are missing for the following parameters: {', '.join(missing_s)}"
        )

    fname = name if name else f.__name__

    parameters = get_parameters(required, param_annotations, default_values=default_values)

    function = ToolFunction(
        function=Function(
            description=description,
            name=fname,
            parameters=parameters,
        )
    )

    return function.model_dump()


def get_load_param_if_needed_function(t: Any) -> Callable[[dict[str, Any], type[BaseModel]], BaseModel] | None:
    """Get a function to load a parameter if it is a Pydantic model

    Args:
        t: The type annotation of the parameter

    Returns:
        A function to load the parameter if it is a Pydantic model, otherwise None

    """
    origin = get_origin(t)

    if origin is Annotated:
        args = get_args(t)
        if args:
            return get_load_param_if_needed_function(args[0])
        else:
            # Invalid Annotated usage
            return None

    # Handle generic types (list[str], dict[str,Any], Union[...], etc.) or where t is not a type at all
    # This means it's not a BaseModel subclass
    if origin is not None or not isinstance(t, type):
        return None

    def load_base_model(v: dict[str, Any], model_type: type[BaseModel]) -> BaseModel:
        return model_type(**v)

    # Check if it's a class and a subclass of BaseModel
    if issubclass(t, BaseModel):
        return load_base_model
    else:
        return None


@export_module("autogen.tools")
def load_basemodels_if_needed(func: Callable[..., Any]) -> Callable[..., Any]:
    """A decorator to load the parameters of a function if they are Pydantic models

    Args:
        func: The function with annotated parameters

    Returns:
        A function that loads the parameters before calling the original function

    """
    # get the type annotations of the parameters
    typed_signature = get_typed_signature(func)
    param_annotations = get_param_annotations(typed_signature)

    # get functions for loading BaseModels when needed based on the type annotations
    kwargs_mapping_with_nones = {k: get_load_param_if_needed_function(t) for k, t in param_annotations.items()}

    # remove the None values
    kwargs_mapping = {k: f for k, f in kwargs_mapping_with_nones.items() if f is not None}

    # a function that loads the parameters before calling the original function
    @functools.wraps(func)
    def _load_parameters_if_needed(*args: Any, **kwargs: Any) -> Any:
        # load the BaseModels if needed
        for k, f in kwargs_mapping.items():
            kwargs[k] = f(kwargs[k], param_annotations[k])

        # call the original function
        return func(*args, **kwargs)

    @functools.wraps(func)
    async def _a_load_parameters_if_needed(*args: Any, **kwargs: Any) -> Any:
        # load the BaseModels if needed
        for k, f in kwargs_mapping.items():
            kwargs[k] = f(kwargs[k], param_annotations[k])

        # call the original function
        return await func(*args, **kwargs)

    if inspect.iscoroutinefunction(func):
        return _a_load_parameters_if_needed
    else:
        return _load_parameters_if_needed


class _SerializableResult(BaseModel):
    result: Any


@export_module("autogen.tools")
def serialize_to_str(x: Any) -> str:
    if isinstance(x, str):
        return x
    if isinstance(x, BaseModel):
        return x.model_dump_json()

    retval_model = _SerializableResult(result=x)
    try:
        return str(retval_model.model_dump()["result"])
    except Exception:
        pass

    # try json.dumps() and then just return str(x) if that fails too
    try:
        return json.dumps(x, ensure_ascii=False)
    except Exception:
        return str(x)
