import os
import torch
import gradio as gr
import time
from transformers import AutoTokenizer, AutoModelForSeq2SeqLM, pipeline
from flores200_codes import flores_codes

def load_models():
    model_name_dict = {
        "nllb-distilled-1.3B": "facebook/nllb-200-distilled-1.3B",
    }

    model_dict = {}

    for call_name, real_name in model_name_dict.items():
        print("\tLoading model:", call_name)
        model = AutoModelForSeq2SeqLM.from_pretrained(real_name)
        tokenizer = AutoTokenizer.from_pretrained(real_name)
        model_dict[call_name] = {
            "model": model,
            "tokenizer": tokenizer,
        }

    return model_dict

# Load models and tokenizers once during initialization
model_dict = load_models()

# Translate text using preloaded models and tokenizers
def translate_text(source, target, text):
    model_name = "nllb-distilled-1.3B"

    if model_name in model_dict and model_dict[model_name]["model"] is not None:
        model = model_dict[model_name]["model"]
        tokenizer = model_dict[model_name]["tokenizer"]

        start_time = time.time()
        source = flores_codes[source]
        target = flores_codes[target]

        translator = pipeline(
            "translation",
            model=model,
            tokenizer=tokenizer,
            src_lang=source,
            tgt_lang=target,
        )
        output = translator(text, max_length=400)

        end_time = time.time()

        output = output[0]["translation_text"]
        result = {
            "inference_time": end_time - start_time,
            "source": source,
            "target": target,
            "result": output,
        }
        return result
    else:
        raise KeyError(f"Model '{model_name}' not found in model_dict")

if __name__ == "__main__":
    print("\tInitializing models")

    lang_codes = list(flores_codes.keys())
    inputs = [
        gr.inputs.Dropdown(lang_codes, default="English", label="Source"),
        gr.inputs.Dropdown(lang_codes, default="Nepali", label="Target"),
        gr.inputs.Textbox(lines=5, label="Input text"),
    ]

    outputs = gr.outputs.JSON()

    title = "The Master Betters Translator"

    desc = "This is a beta version of The Master Betters Translator that utilizes pre-trained language models for translation. To use this app you need to have chosen the source and target language with your input text to get the output."
    description = (
        f"{desc}"
    )
    examples = [["English", "Nepali", "The Master Betters Translator Welcomes You."]]

    gr.Interface(
        translate_text,
        inputs,
        outputs,
        title=title,
        description=description,
        examples=examples,
        examples_per_page=50,
    ).launch()