from __future__ import annotations

import abc
import copy
from dataclasses import dataclass
from typing import TYPE_CHECKING, Any, Generic, Literal, TypeVar, Union

from openai.types.responses import (
    Response,
    ResponseComputerToolCall,
    ResponseFileSearchToolCall,
    ResponseFunctionToolCall,
    ResponseFunctionWebSearch,
    ResponseInputItemParam,
    ResponseOutputItem,
    ResponseOutputMessage,
    ResponseOutputRefusal,
    ResponseOutputText,
    ResponseStreamEvent,
)
from openai.types.responses.response_input_item_param import ComputerCallOutput, FunctionCallOutput
from openai.types.responses.response_reasoning_item import ResponseReasoningItem
from pydantic import BaseModel
from typing_extensions import TypeAlias

from .exceptions import AgentsException, ModelBehaviorError
from .usage import Usage

if TYPE_CHECKING:
    from .agent import Agent

TResponse = Response
"""A type alias for the Response type from the OpenAI SDK."""

TResponseInputItem = ResponseInputItemParam
"""A type alias for the ResponseInputItemParam type from the OpenAI SDK."""

TResponseOutputItem = ResponseOutputItem
"""A type alias for the ResponseOutputItem type from the OpenAI SDK."""

TResponseStreamEvent = ResponseStreamEvent
"""A type alias for the ResponseStreamEvent type from the OpenAI SDK."""

T = TypeVar("T", bound=Union[TResponseOutputItem, TResponseInputItem])


@dataclass
class RunItemBase(Generic[T], abc.ABC):
    agent: Agent[Any]
    """The agent whose run caused this item to be generated."""

    raw_item: T
    """The raw Responses item from the run. This will always be a either an output item (i.e.
    `openai.types.responses.ResponseOutputItem` or an input item
    (i.e. `openai.types.responses.ResponseInputItemParam`).
    """

    def to_input_item(self) -> TResponseInputItem:
        """Converts this item into an input item suitable for passing to the model."""
        if isinstance(self.raw_item, dict):
            # We know that input items are dicts, so we can ignore the type error
            return self.raw_item  # type: ignore
        elif isinstance(self.raw_item, BaseModel):
            # All output items are Pydantic models that can be converted to input items.
            return self.raw_item.model_dump(exclude_unset=True)  # type: ignore
        else:
            raise AgentsException(f"Unexpected raw item type: {type(self.raw_item)}")


@dataclass
class MessageOutputItem(RunItemBase[ResponseOutputMessage]):
    """Represents a message from the LLM."""

    raw_item: ResponseOutputMessage
    """The raw response output message."""

    type: Literal["message_output_item"] = "message_output_item"


@dataclass
class HandoffCallItem(RunItemBase[ResponseFunctionToolCall]):
    """Represents a tool call for a handoff from one agent to another."""

    raw_item: ResponseFunctionToolCall
    """The raw response function tool call that represents the handoff."""

    type: Literal["handoff_call_item"] = "handoff_call_item"


@dataclass
class HandoffOutputItem(RunItemBase[TResponseInputItem]):
    """Represents the output of a handoff."""

    raw_item: TResponseInputItem
    """The raw input item that represents the handoff taking place."""

    source_agent: Agent[Any]
    """The agent that made the handoff."""

    target_agent: Agent[Any]
    """The agent that is being handed off to."""

    type: Literal["handoff_output_item"] = "handoff_output_item"


ToolCallItemTypes: TypeAlias = Union[
    ResponseFunctionToolCall,
    ResponseComputerToolCall,
    ResponseFileSearchToolCall,
    ResponseFunctionWebSearch,
]
"""A type that represents a tool call item."""


@dataclass
class ToolCallItem(RunItemBase[ToolCallItemTypes]):
    """Represents a tool call e.g. a function call or computer action call."""

    raw_item: ToolCallItemTypes
    """The raw tool call item."""

    type: Literal["tool_call_item"] = "tool_call_item"


@dataclass
class ToolCallOutputItem(RunItemBase[Union[FunctionCallOutput, ComputerCallOutput]]):
    """Represents the output of a tool call."""

    raw_item: FunctionCallOutput | ComputerCallOutput
    """The raw item from the model."""

    output: Any
    """The output of the tool call. This is whatever the tool call returned; the `raw_item`
    contains a string representation of the output.
    """

    type: Literal["tool_call_output_item"] = "tool_call_output_item"


@dataclass
class ReasoningItem(RunItemBase[ResponseReasoningItem]):
    """Represents a reasoning item."""

    raw_item: ResponseReasoningItem
    """The raw reasoning item."""

    type: Literal["reasoning_item"] = "reasoning_item"


RunItem: TypeAlias = Union[
    MessageOutputItem,
    HandoffCallItem,
    HandoffOutputItem,
    ToolCallItem,
    ToolCallOutputItem,
    ReasoningItem,
]
"""An item generated by an agent."""


@dataclass
class ModelResponse:
    output: list[TResponseOutputItem]
    """A list of outputs (messages, tool calls, etc) generated by the model"""

    usage: Usage
    """The usage information for the response."""

    response_id: str | None
    """An ID for the response which can be used to refer to the response in subsequent calls to the
    model. Not supported by all model providers.
    If using OpenAI models via the Responses API, this is the `response_id` parameter, and it can
    be passed to `Runner.run`.
    """

    def to_input_items(self) -> list[TResponseInputItem]:
        """Convert the output into a list of input items suitable for passing to the model."""
        # We happen to know that the shape of the Pydantic output items are the same as the
        # equivalent TypedDict input items, so we can just convert each one.
        # This is also tested via unit tests.
        return [it.model_dump(exclude_unset=True) for it in self.output]  # type: ignore


class ItemHelpers:
    @classmethod
    def extract_last_content(cls, message: TResponseOutputItem) -> str:
        """Extracts the last text content or refusal from a message."""
        if not isinstance(message, ResponseOutputMessage):
            return ""

        last_content = message.content[-1]
        if isinstance(last_content, ResponseOutputText):
            return last_content.text
        elif isinstance(last_content, ResponseOutputRefusal):
            return last_content.refusal
        else:
            raise ModelBehaviorError(f"Unexpected content type: {type(last_content)}")

    @classmethod
    def extract_last_text(cls, message: TResponseOutputItem) -> str | None:
        """Extracts the last text content from a message, if any. Ignores refusals."""
        if isinstance(message, ResponseOutputMessage):
            last_content = message.content[-1]
            if isinstance(last_content, ResponseOutputText):
                return last_content.text

        return None

    @classmethod
    def input_to_new_input_list(
        cls, input: str | list[TResponseInputItem]
    ) -> list[TResponseInputItem]:
        """Converts a string or list of input items into a list of input items."""
        if isinstance(input, str):
            return [
                {
                    "content": input,
                    "role": "user",
                }
            ]
        return copy.deepcopy(input)

    @classmethod
    def text_message_outputs(cls, items: list[RunItem]) -> str:
        """Concatenates all the text content from a list of message output items."""
        text = ""
        for item in items:
            if isinstance(item, MessageOutputItem):
                text += cls.text_message_output(item)
        return text

    @classmethod
    def text_message_output(cls, message: MessageOutputItem) -> str:
        """Extracts all the text content from a single message output item."""
        text = ""
        for item in message.raw_item.content:
            if isinstance(item, ResponseOutputText):
                text += item.text
        return text

    @classmethod
    def tool_call_output_item(
        cls, tool_call: ResponseFunctionToolCall, output: str
    ) -> FunctionCallOutput:
        """Creates a tool call output item from a tool call and its output."""
        return {
            "call_id": tool_call.call_id,
            "output": output,
            "type": "function_call_output",
        }