import os
from typing import Iterator

import gradio as gr

from dotenv import load_dotenv
from distutils.util import strtobool

from model import LLAMA2_WRAPPER

load_dotenv()

DEFAULT_SYSTEM_PROMPT = (
    os.getenv("DEFAULT_SYSTEM_PROMPT")
    if os.getenv("DEFAULT_SYSTEM_PROMPT") is not None
    else ""
)
MAX_MAX_NEW_TOKENS = (
    int(os.getenv("MAX_MAX_NEW_TOKENS"))
    if os.getenv("DEFAULT_MAX_NEW_TOKENS") is not None
    else 2048
)
DEFAULT_MAX_NEW_TOKENS = (
    int(os.getenv("DEFAULT_MAX_NEW_TOKENS"))
    if os.getenv("DEFAULT_MAX_NEW_TOKENS") is not None
    else 1024
)
MAX_INPUT_TOKEN_LENGTH = (
    int(os.getenv("MAX_INPUT_TOKEN_LENGTH"))
    if os.getenv("MAX_INPUT_TOKEN_LENGTH") is not None
    else 4000
)

MODEL_PATH = os.getenv("MODEL_PATH")
assert MODEL_PATH is not None, f"MODEL_PATH is required, got: {MODEL_PATH}"

LOAD_IN_8BIT = bool(strtobool(os.getenv("LOAD_IN_8BIT", "True")))

LOAD_IN_4BIT = bool(strtobool(os.getenv("LOAD_IN_4BIT", "True")))

LLAMA_CPP = bool(strtobool(os.getenv("LLAMA_CPP", "True")))

if LLAMA_CPP:
    print("Running on CPU with llama.cpp.")
else:
    import torch

    if torch.cuda.is_available():
        print("Running on GPU with torch transformers.")
    else:
        print("CUDA not found.")

config = {
    "model_name": MODEL_PATH,
    "load_in_8bit": LOAD_IN_8BIT,
    "load_in_4bit": LOAD_IN_4BIT,
    "llama_cpp": LLAMA_CPP,
    "MAX_INPUT_TOKEN_LENGTH": MAX_INPUT_TOKEN_LENGTH,
}
llama2_wrapper = LLAMA2_WRAPPER(config)
llama2_wrapper.init_tokenizer()
llama2_wrapper.init_model()

DESCRIPTION = """
# llama2-webui

This is a chatbot based on Llama-2. 
- Supporting models: [Llama-2-7b](https://huggingface.co/TheBloke/Llama-2-7B-Chat-GGML)/[13b](https://huggingface.co/llamaste/Llama-2-13b-chat-hf)/[70b](https://huggingface.co/llamaste/Llama-2-70b-chat-hf), all [Llama-2-GPTQ](https://huggingface.co/TheBloke/Llama-2-7b-Chat-GPTQ), all [Llama-2-GGML](https://huggingface.co/TheBloke/Llama-2-7B-Chat-GGML) ...
- Supporting model backends
  - Nvidia GPU(at least 6 GB VRAM): tranformers, [bitsandbytes(8-bit inference)](https://github.com/TimDettmers/bitsandbytes), [AutoGPTQ(4-bit inference)](https://github.com/PanQiWei/AutoGPTQ)
  - CPU(at least 6 GB RAM), Mac/AMD GPU: [llama.cpp](https://github.com/ggerganov/llama.cpp)
"""


def clear_and_save_textbox(message: str) -> tuple[str, str]:
    return "", message


def display_input(
    message: str, history: list[tuple[str, str]]
) -> list[tuple[str, str]]:
    history.append((message, ""))
    return history


def delete_prev_fn(history: list[tuple[str, str]]) -> tuple[list[tuple[str, str]], str]:
    try:
        message, _ = history.pop()
    except IndexError:
        message = ""
    return history, message or ""


def generate(
    message: str,
    history_with_input: list[tuple[str, str]],
    system_prompt: str,
    max_new_tokens: int,
    temperature: float,
    top_p: float,
    top_k: int,
) -> Iterator[list[tuple[str, str]]]:
    if max_new_tokens > MAX_MAX_NEW_TOKENS:
        raise ValueError

    history = history_with_input[:-1]
    generator = llama2_wrapper.run(
        message, history, system_prompt, max_new_tokens, temperature, top_p, top_k
    )
    try:
        first_response = next(generator)
        yield history + [(message, first_response)]
    except StopIteration:
        yield history + [(message, "")]
    for response in generator:
        yield history + [(message, response)]


def process_example(message: str) -> tuple[str, list[tuple[str, str]]]:
    generator = generate(message, [], DEFAULT_SYSTEM_PROMPT, 1024, 1, 0.95, 50)
    for x in generator:
        pass
    return "", x


def check_input_token_length(
    message: str, chat_history: list[tuple[str, str]], system_prompt: str
) -> None:
    input_token_length = llama2_wrapper.get_input_token_length(
        message, chat_history, system_prompt
    )
    if input_token_length > MAX_INPUT_TOKEN_LENGTH:
        raise gr.Error(
            f"The accumulated input is too long ({input_token_length} > {MAX_INPUT_TOKEN_LENGTH}). Clear your chat history and try again."
        )


with gr.Blocks(css="style.css") as demo:
    gr.Markdown(DESCRIPTION)

    with gr.Group():
        chatbot = gr.Chatbot(label="Chatbot")
        with gr.Row():
            textbox = gr.Textbox(
                container=False,
                show_label=False,
                placeholder="Type a message...",
                scale=10,
            )
            submit_button = gr.Button("Submit", variant="primary", scale=1, min_width=0)
    with gr.Row():
        retry_button = gr.Button("🔄  Retry", variant="secondary")
        undo_button = gr.Button("↩️ Undo", variant="secondary")
        clear_button = gr.Button("🗑️  Clear", variant="secondary")

    saved_input = gr.State()

    with gr.Accordion(label="Advanced options", open=False):
        system_prompt = gr.Textbox(
            label="System prompt", value=DEFAULT_SYSTEM_PROMPT, lines=6
        )
        max_new_tokens = gr.Slider(
            label="Max new tokens",
            minimum=1,
            maximum=MAX_MAX_NEW_TOKENS,
            step=1,
            value=DEFAULT_MAX_NEW_TOKENS,
        )
        temperature = gr.Slider(
            label="Temperature",
            minimum=0.1,
            maximum=4.0,
            step=0.1,
            value=1.0,
        )
        top_p = gr.Slider(
            label="Top-p (nucleus sampling)",
            minimum=0.05,
            maximum=1.0,
            step=0.05,
            value=0.95,
        )
        top_k = gr.Slider(
            label="Top-k",
            minimum=1,
            maximum=1000,
            step=1,
            value=50,
        )

    gr.Examples(
        examples=[
            "Hello there! How are you doing?",
            "Can you explain briefly to me what is the Python programming language?",
            "Explain the plot of Cinderella in a sentence.",
            "How many hours does it take a man to eat a Helicopter?",
            "Write a 100-word article on 'Benefits of Open-Source in AI research'",
        ],
        inputs=textbox,
        outputs=[textbox, chatbot],
        fn=process_example,
        cache_examples=True,
    )

    textbox.submit(
        fn=clear_and_save_textbox,
        inputs=textbox,
        outputs=[textbox, saved_input],
        api_name=False,
        queue=False,
    ).then(
        fn=display_input,
        inputs=[saved_input, chatbot],
        outputs=chatbot,
        api_name=False,
        queue=False,
    ).then(
        fn=check_input_token_length,
        inputs=[saved_input, chatbot, system_prompt],
        api_name=False,
        queue=False,
    ).success(
        fn=generate,
        inputs=[
            saved_input,
            chatbot,
            system_prompt,
            max_new_tokens,
            temperature,
            top_p,
            top_k,
        ],
        outputs=chatbot,
        api_name=False,
    )

    button_event_preprocess = (
        submit_button.click(
            fn=clear_and_save_textbox,
            inputs=textbox,
            outputs=[textbox, saved_input],
            api_name=False,
            queue=False,
        )
        .then(
            fn=display_input,
            inputs=[saved_input, chatbot],
            outputs=chatbot,
            api_name=False,
            queue=False,
        )
        .then(
            fn=check_input_token_length,
            inputs=[saved_input, chatbot, system_prompt],
            api_name=False,
            queue=False,
        )
        .success(
            fn=generate,
            inputs=[
                saved_input,
                chatbot,
                system_prompt,
                max_new_tokens,
                temperature,
                top_p,
                top_k,
            ],
            outputs=chatbot,
            api_name=False,
        )
    )

    retry_button.click(
        fn=delete_prev_fn,
        inputs=chatbot,
        outputs=[chatbot, saved_input],
        api_name=False,
        queue=False,
    ).then(
        fn=display_input,
        inputs=[saved_input, chatbot],
        outputs=chatbot,
        api_name=False,
        queue=False,
    ).then(
        fn=generate,
        inputs=[
            saved_input,
            chatbot,
            system_prompt,
            max_new_tokens,
            temperature,
            top_p,
            top_k,
        ],
        outputs=chatbot,
        api_name=False,
    )

    undo_button.click(
        fn=delete_prev_fn,
        inputs=chatbot,
        outputs=[chatbot, saved_input],
        api_name=False,
        queue=False,
    ).then(
        fn=lambda x: x,
        inputs=[saved_input],
        outputs=textbox,
        api_name=False,
        queue=False,
    )

    clear_button.click(
        fn=lambda: ([], ""),
        outputs=[chatbot, saved_input],
        queue=False,
        api_name=False,
    )

demo.queue(max_size=20).launch(share=True)