"""ChatModel wrapper which returns user input as the response.."""
import asyncio
from functools import partial
from io import StringIO
from typing import Any, Callable, Dict, List, Mapping, Optional

import yaml
from langchain_core.messages import (
    BaseMessage,
    HumanMessage,
    _message_from_dict,
    messages_to_dict,
)
from langchain_core.outputs import ChatGeneration, ChatResult
from langchain_core.pydantic_v1 import Field

from langchain.callbacks.manager import (
    AsyncCallbackManagerForLLMRun,
    CallbackManagerForLLMRun,
)
from langchain.chat_models.base import BaseChatModel
from langchain.llms.utils import enforce_stop_tokens


def _display_messages(messages: List[BaseMessage]) -> None:
    dict_messages = messages_to_dict(messages)
    for message in dict_messages:
        yaml_string = yaml.dump(
            message,
            default_flow_style=False,
            sort_keys=False,
            allow_unicode=True,
            width=10000,
            line_break=None,
        )
        print("\n", "======= start of message =======", "\n\n")
        print(yaml_string)
        print("======= end of message =======", "\n\n")


def _collect_yaml_input(
    messages: List[BaseMessage], stop: Optional[List[str]] = None
) -> BaseMessage:
    """Collects and returns user input as a single string."""
    lines = []
    while True:
        line = input()
        if not line.strip():
            break
        if stop and any(seq in line for seq in stop):
            break
        lines.append(line)
    yaml_string = "\n".join(lines)

    # Try to parse the input string as YAML
    try:
        message = _message_from_dict(yaml.safe_load(StringIO(yaml_string)))
        if message is None:
            return HumanMessage(content="")
        if stop:
            if isinstance(message.content, str):
                message.content = enforce_stop_tokens(message.content, stop)
            else:
                raise ValueError("Cannot use when output is not a string.")
        return message
    except yaml.YAMLError:
        raise ValueError("Invalid YAML string entered.")
    except ValueError:
        raise ValueError("Invalid message entered.")


class HumanInputChatModel(BaseChatModel):
    """ChatModel which returns user input as the response."""

    input_func: Callable = Field(default_factory=lambda: _collect_yaml_input)
    message_func: Callable = Field(default_factory=lambda: _display_messages)
    separator: str = "\n"
    input_kwargs: Mapping[str, Any] = {}
    message_kwargs: Mapping[str, Any] = {}

    @property
    def _identifying_params(self) -> Dict[str, Any]:
        return {
            "input_func": self.input_func.__name__,
            "message_func": self.message_func.__name__,
        }

    @property
    def _llm_type(self) -> str:
        """Returns the type of LLM."""
        return "human-input-chat-model"

    def _generate(
        self,
        messages: List[BaseMessage],
        stop: Optional[List[str]] = None,
        run_manager: Optional[CallbackManagerForLLMRun] = None,
        **kwargs: Any,
    ) -> ChatResult:
        """
        Displays the messages to the user and returns their input as a response.

        Args:
            messages (List[BaseMessage]): The messages to be displayed to the user.
            stop (Optional[List[str]]): A list of stop strings.
            run_manager (Optional[CallbackManagerForLLMRun]): Currently not used.

        Returns:
            ChatResult: The user's input as a response.
        """
        self.message_func(messages, **self.message_kwargs)
        user_input = self.input_func(messages, stop=stop, **self.input_kwargs)
        return ChatResult(generations=[ChatGeneration(message=user_input)])

    async def _agenerate(
        self,
        messages: List[BaseMessage],
        stop: Optional[List[str]] = None,
        run_manager: Optional[AsyncCallbackManagerForLLMRun] = None,
        **kwargs: Any,
    ) -> ChatResult:
        func = partial(
            self._generate, messages, stop=stop, run_manager=run_manager, **kwargs
        )
        return await asyncio.get_event_loop().run_in_executor(None, func)
