"""Agent that interacts with OpenAPI APIs via a hierarchical planning approach."""
import json
import re
from functools import partial
from typing import Any, Callable, Dict, List, Optional

import yaml
from pydantic_v1 import Field

from langchain.agents.agent import AgentExecutor
from langchain.agents.agent_toolkits.openapi.planner_prompt import (
    API_CONTROLLER_PROMPT,
    API_CONTROLLER_TOOL_DESCRIPTION,
    API_CONTROLLER_TOOL_NAME,
    API_ORCHESTRATOR_PROMPT,
    API_PLANNER_PROMPT,
    API_PLANNER_TOOL_DESCRIPTION,
    API_PLANNER_TOOL_NAME,
    PARSING_DELETE_PROMPT,
    PARSING_GET_PROMPT,
    PARSING_PATCH_PROMPT,
    PARSING_POST_PROMPT,
    REQUESTS_DELETE_TOOL_DESCRIPTION,
    REQUESTS_GET_TOOL_DESCRIPTION,
    REQUESTS_PATCH_TOOL_DESCRIPTION,
    REQUESTS_POST_TOOL_DESCRIPTION,
)
from langchain.agents.agent_toolkits.openapi.spec import ReducedOpenAPISpec
from langchain.agents.mrkl.base import ZeroShotAgent
from langchain.agents.tools import Tool
from langchain.callbacks.base import BaseCallbackManager
from langchain.chains.llm import LLMChain
from langchain.llms.openai import OpenAI
from langchain.memory import ReadOnlySharedMemory
from langchain.prompts import PromptTemplate
from langchain.schema import BasePromptTemplate
from langchain.schema.language_model import BaseLanguageModel
from langchain.tools.base import BaseTool
from langchain.tools.requests.tool import BaseRequestsTool
from langchain.utilities.requests import RequestsWrapper

#
# Requests tools with LLM-instructed extraction of truncated responses.
#
# Of course, truncating so bluntly may lose a lot of valuable
# information in the response.
# However, the goal for now is to have only a single inference step.
MAX_RESPONSE_LENGTH = 5000
"""Maximum length of the response to be returned."""


def _get_default_llm_chain(prompt: BasePromptTemplate) -> LLMChain:
    return LLMChain(
        llm=OpenAI(),
        prompt=prompt,
    )


def _get_default_llm_chain_factory(
    prompt: BasePromptTemplate,
) -> Callable[[], LLMChain]:
    """Returns a default LLMChain factory."""
    return partial(_get_default_llm_chain, prompt)


class RequestsGetToolWithParsing(BaseRequestsTool, BaseTool):
    """Requests GET tool with LLM-instructed extraction of truncated responses."""

    name = "requests_get"
    """Tool name."""
    description = REQUESTS_GET_TOOL_DESCRIPTION
    """Tool description."""
    response_length: Optional[int] = MAX_RESPONSE_LENGTH
    """Maximum length of the response to be returned."""
    llm_chain: LLMChain = Field(
        default_factory=_get_default_llm_chain_factory(PARSING_GET_PROMPT)
    )
    """LLMChain used to extract the response."""

    def _run(self, text: str) -> str:
        try:
            data = json.loads(text)
        except json.JSONDecodeError as e:
            raise e
        data_params = data.get("params")
        response = self.requests_wrapper.get(data["url"], params=data_params)
        response = response[: self.response_length]
        return self.llm_chain.predict(
            response=response, instructions=data["output_instructions"]
        ).strip()

    async def _arun(self, text: str) -> str:
        raise NotImplementedError()


class RequestsPostToolWithParsing(BaseRequestsTool, BaseTool):
    """Requests POST tool with LLM-instructed extraction of truncated responses."""

    name = "requests_post"
    """Tool name."""
    description = REQUESTS_POST_TOOL_DESCRIPTION
    """Tool description."""
    response_length: Optional[int] = MAX_RESPONSE_LENGTH
    """Maximum length of the response to be returned."""
    llm_chain: LLMChain = Field(
        default_factory=_get_default_llm_chain_factory(PARSING_POST_PROMPT)
    )
    """LLMChain used to extract the response."""

    def _run(self, text: str) -> str:
        try:
            data = json.loads(text)
        except json.JSONDecodeError as e:
            raise e
        response = self.requests_wrapper.post(data["url"], data["data"])
        response = response[: self.response_length]
        return self.llm_chain.predict(
            response=response, instructions=data["output_instructions"]
        ).strip()

    async def _arun(self, text: str) -> str:
        raise NotImplementedError()


class RequestsPatchToolWithParsing(BaseRequestsTool, BaseTool):
    """Requests PATCH tool with LLM-instructed extraction of truncated responses."""

    name = "requests_patch"
    """Tool name."""
    description = REQUESTS_PATCH_TOOL_DESCRIPTION
    """Tool description."""
    response_length: Optional[int] = MAX_RESPONSE_LENGTH
    """Maximum length of the response to be returned."""
    llm_chain: LLMChain = Field(
        default_factory=_get_default_llm_chain_factory(PARSING_PATCH_PROMPT)
    )
    """LLMChain used to extract the response."""

    def _run(self, text: str) -> str:
        try:
            data = json.loads(text)
        except json.JSONDecodeError as e:
            raise e
        response = self.requests_wrapper.patch(data["url"], data["data"])
        response = response[: self.response_length]
        return self.llm_chain.predict(
            response=response, instructions=data["output_instructions"]
        ).strip()

    async def _arun(self, text: str) -> str:
        raise NotImplementedError()


class RequestsDeleteToolWithParsing(BaseRequestsTool, BaseTool):
    """A tool that sends a DELETE request and parses the response."""

    name = "requests_delete"
    """The name of the tool."""
    description = REQUESTS_DELETE_TOOL_DESCRIPTION
    """The description of the tool."""

    response_length: Optional[int] = MAX_RESPONSE_LENGTH
    """The maximum length of the response."""
    llm_chain: LLMChain = Field(
        default_factory=_get_default_llm_chain_factory(PARSING_DELETE_PROMPT)
    )
    """The LLM chain used to parse the response."""

    def _run(self, text: str) -> str:
        try:
            data = json.loads(text)
        except json.JSONDecodeError as e:
            raise e
        response = self.requests_wrapper.delete(data["url"])
        response = response[: self.response_length]
        return self.llm_chain.predict(
            response=response, instructions=data["output_instructions"]
        ).strip()

    async def _arun(self, text: str) -> str:
        raise NotImplementedError()


#
# Orchestrator, planner, controller.
#
def _create_api_planner_tool(
    api_spec: ReducedOpenAPISpec, llm: BaseLanguageModel
) -> Tool:
    endpoint_descriptions = [
        f"{name} {description}" for name, description, _ in api_spec.endpoints
    ]
    prompt = PromptTemplate(
        template=API_PLANNER_PROMPT,
        input_variables=["query"],
        partial_variables={"endpoints": "- " + "- ".join(endpoint_descriptions)},
    )
    chain = LLMChain(llm=llm, prompt=prompt)
    tool = Tool(
        name=API_PLANNER_TOOL_NAME,
        description=API_PLANNER_TOOL_DESCRIPTION,
        func=chain.run,
    )
    return tool


def _create_api_controller_agent(
    api_url: str,
    api_docs: str,
    requests_wrapper: RequestsWrapper,
    llm: BaseLanguageModel,
) -> AgentExecutor:
    get_llm_chain = LLMChain(llm=llm, prompt=PARSING_GET_PROMPT)
    post_llm_chain = LLMChain(llm=llm, prompt=PARSING_POST_PROMPT)
    tools: List[BaseTool] = [
        RequestsGetToolWithParsing(
            requests_wrapper=requests_wrapper, llm_chain=get_llm_chain
        ),
        RequestsPostToolWithParsing(
            requests_wrapper=requests_wrapper, llm_chain=post_llm_chain
        ),
    ]
    prompt = PromptTemplate(
        template=API_CONTROLLER_PROMPT,
        input_variables=["input", "agent_scratchpad"],
        partial_variables={
            "api_url": api_url,
            "api_docs": api_docs,
            "tool_names": ", ".join([tool.name for tool in tools]),
            "tool_descriptions": "\n".join(
                [f"{tool.name}: {tool.description}" for tool in tools]
            ),
        },
    )
    agent = ZeroShotAgent(
        llm_chain=LLMChain(llm=llm, prompt=prompt),
        allowed_tools=[tool.name for tool in tools],
    )
    return AgentExecutor.from_agent_and_tools(agent=agent, tools=tools, verbose=True)


def _create_api_controller_tool(
    api_spec: ReducedOpenAPISpec,
    requests_wrapper: RequestsWrapper,
    llm: BaseLanguageModel,
) -> Tool:
    """Expose controller as a tool.

    The tool is invoked with a plan from the planner, and dynamically
    creates a controller agent with relevant documentation only to
    constrain the context.
    """

    base_url = api_spec.servers[0]["url"]  # TODO: do better.

    def _create_and_run_api_controller_agent(plan_str: str) -> str:
        pattern = r"\b(GET|POST|PATCH|DELETE)\s+(/\S+)*"
        matches = re.findall(pattern, plan_str)
        endpoint_names = [
            "{method} {route}".format(method=method, route=route.split("?")[0])
            for method, route in matches
        ]
        endpoint_docs_by_name = {name: docs for name, _, docs in api_spec.endpoints}
        docs_str = ""
        for endpoint_name in endpoint_names:
            docs = endpoint_docs_by_name.get(endpoint_name)
            if not docs:
                raise ValueError(f"{endpoint_name} endpoint does not exist.")
            docs_str += f"== Docs for {endpoint_name} == \n{yaml.dump(docs)}\n"

        agent = _create_api_controller_agent(base_url, docs_str, requests_wrapper, llm)
        return agent.run(plan_str)

    return Tool(
        name=API_CONTROLLER_TOOL_NAME,
        func=_create_and_run_api_controller_agent,
        description=API_CONTROLLER_TOOL_DESCRIPTION,
    )


def create_openapi_agent(
    api_spec: ReducedOpenAPISpec,
    requests_wrapper: RequestsWrapper,
    llm: BaseLanguageModel,
    shared_memory: Optional[ReadOnlySharedMemory] = None,
    callback_manager: Optional[BaseCallbackManager] = None,
    verbose: bool = True,
    agent_executor_kwargs: Optional[Dict[str, Any]] = None,
    **kwargs: Dict[str, Any],
) -> AgentExecutor:
    """Instantiate OpenAI API planner and controller for a given spec.

    Inject credentials via requests_wrapper.

    We use a top-level "orchestrator" agent to invoke the planner and controller,
    rather than a top-level planner
    that invokes a controller with its plan. This is to keep the planner simple.
    """
    tools = [
        _create_api_planner_tool(api_spec, llm),
        _create_api_controller_tool(api_spec, requests_wrapper, llm),
    ]
    prompt = PromptTemplate(
        template=API_ORCHESTRATOR_PROMPT,
        input_variables=["input", "agent_scratchpad"],
        partial_variables={
            "tool_names": ", ".join([tool.name for tool in tools]),
            "tool_descriptions": "\n".join(
                [f"{tool.name}: {tool.description}" for tool in tools]
            ),
        },
    )
    agent = ZeroShotAgent(
        llm_chain=LLMChain(llm=llm, prompt=prompt, memory=shared_memory),
        allowed_tools=[tool.name for tool in tools],
        **kwargs,
    )
    return AgentExecutor.from_agent_and_tools(
        agent=agent,
        tools=tools,
        callback_manager=callback_manager,
        verbose=verbose,
        **(agent_executor_kwargs or {}),
    )
