from __future__ import annotations

from collections.abc import Mapping
from types import MappingProxyType

import boto3
import botocore
import botocore.exceptions
import gradio as gr
from langchain_aws import ChatBedrock
from langchain_core.messages import AIMessage, HumanMessage, SystemMessage
from langgraph.graph.graph import CompiledGraph
from langgraph.prebuilt import create_react_agent


#### Constants ####

SYSTEM_MESSAGE = SystemMessage(
    "You are a helpful assistant.",
)

GRADIO_ROLE_TO_LG_MESSAGE_TYPE = MappingProxyType(
    {
        "user": HumanMessage,
        "assistant": AIMessage,
    },
)


#### Shared variables ####

llm_agent: CompiledGraph | None = None

#### Utility functions ####


def create_bedrock_llm(
    bedrock_model_id: str,
    aws_access_key: str,
    aws_secret_key: str,
    aws_session_token: str,
    aws_region: str,
) -> tuple[ChatBedrock | None, str]:
    """Create a LangGraph Bedrock agent."""
    boto3_config = {
        "aws_access_key_id": aws_access_key,
        "aws_secret_access_key": aws_secret_key,
        "aws_session_token": aws_session_token if aws_session_token else None,
        "region_name": aws_region,
    }

    # Verify credentials
    try:
        sts = boto3.client("sts", **boto3_config)
        sts.get_caller_identity()
    except botocore.exceptions.ClientError as err:
        return None, str(err)

    try:
        bedrock_client = boto3.client("bedrock-runtime", **boto3_config)
        llm = ChatBedrock(
            model=bedrock_model_id,
            client=bedrock_client,
            model_kwargs={"temperature": 0.7},
        )
    except Exception as e:  # noqa: BLE001
        return None, str(e)

    return llm, ""


#### UI functionality ####


async def gr_connect_to_bedrock(
    model_id: str,
    access_key: str,
    secret_key: str,
    session_token: str,
    region: str,
) -> str:
    """Initialize Bedrock agent."""
    global llm_agent  # noqa: PLW0603

    if not access_key or not secret_key:
        return "❌ Please provide both Access Key ID and Secret Access Key"

    llm, error = create_bedrock_llm(
        model_id,
        access_key.strip(),
        secret_key.strip(),
        session_token.strip(),
        region,
    )

    if llm is None:
        return f"❌ Connection failed: {error}"

    llm_agent = create_react_agent(
        model=llm,
        tools=[],
        prompt=SYSTEM_MESSAGE,
    )

    return "✅ Successfully connected to AWS Bedrock!"


async def gr_chat_function(  # noqa: D103
    message: str,
    history: list[Mapping[str, str]],
) -> str:
    if llm_agent is None:
        return "Please configure your credentials first."

    messages = []
    for hist_msg in history:
        role = hist_msg["role"]
        message_type = GRADIO_ROLE_TO_LG_MESSAGE_TYPE[role]
        messages.append(message_type(content=hist_msg["content"]))

    messages.append(HumanMessage(content=message))

    llm_response = await llm_agent.ainvoke(
        {
            "messages": messages,
        },
    )

    return llm_response["messages"][-1].content


## UI components ##

with gr.Blocks() as gr_app:
    gr.Markdown("# 🔐 Secure Bedrock Chatbot")

    # Credentials section (collapsible)
    with gr.Accordion("🔑 Bedrock Configuration", open=True):
        gr.Markdown(
            "**Note**: Credentials are only stored in memory during your session.",
        )
        with gr.Row():
            bedrock_model_id_textbox = gr.Textbox(
                label="Bedrock Model Id",
                value="eu.anthropic.claude-3-5-sonnet-20240620-v1:0",
            )
        with gr.Row():
            aws_access_key_textbox = gr.Textbox(
                label="AWS Access Key ID",
                type="password",
                placeholder="Enter your AWS Access Key ID",
            )
            aws_secret_key_textbox = gr.Textbox(
                label="AWS Secret Access Key",
                type="password",
                placeholder="Enter your AWS Secret Access Key",
            )
        with gr.Row():
            aws_session_token_textbox = gr.Textbox(
                label="AWS Session Token",
                type="password",
                placeholder="Enter your AWS session token",
            )
        with gr.Row():
            aws_region_dropdown = gr.Dropdown(
                label="AWS Region",
                choices=[
                    "us-east-1",
                    "us-west-2",
                    "eu-west-1",
                    "eu-central-1",
                    "ap-southeast-1",
                ],
                value="eu-west-1",
            )
            connect_btn = gr.Button("🔌 Connect to Bedrock", variant="primary")

        status_textbox = gr.Textbox(label="Connection Status", interactive=False)

        connect_btn.click(
            gr_connect_to_bedrock,
            inputs=[
                bedrock_model_id_textbox,
                aws_access_key_textbox,
                aws_secret_key_textbox,
                aws_session_token_textbox,
                aws_region_dropdown,
            ],
            outputs=[status_textbox],
        )

    chat_interface = gr.ChatInterface(
        fn=gr_chat_function,
        type="messages",
        examples=[],
        title="Agent with MCP Tools",
        description="This is a simple agent that uses MCP tools.",
    )


if __name__ == "__main__":
    gr_app.launch()