import os

import fasttext
import gradio as gr
from transformers import AutoTokenizer, AutoModelForSeq2SeqLM, pipeline
import torch

title = "Community Tab Language Detection & Translation"
description = """
When comments are created in the community tab, detect the language of the content.
Then, if the detected language is different from the user's language, display an option to translate it.
"""

model = AutoModelForSeq2SeqLM.from_pretrained("facebook/nllb-200-distilled-600M")
tokenizer = AutoTokenizer.from_pretrained("facebook/nllb-200-distilled-600M")
device = 0 if torch.cuda.is_available() else -1
print(f"Is CUDA available: {torch.cuda.is_available()}")

language_code_map = {
    "English": "eng_Latn",
    "French": "fra_Latn",
    "German": "deu_Latn",
    "Spanish": "spa_Latn",
    "Korean": "kor_Hang",
    "Japanese": "jpn_Jpan",
    "Polish": "pol_Latn"
}


def identify_language(text):
    model_file = "lid218e.bin"
    model_full_path = os.path.join(os.path.dirname(__file__), model_file)
    model = fasttext.load_model(model_full_path)
    predictions = model.predict(text, k=1)  # e.g., (('__label__eng_Latn',), array([0.81148803]))

    CHAR_TO_STRIP = 9  # To strip away '__label__' from language code
    language_code = predictions[0][0][CHAR_TO_STRIP:]

    return language_code


def display(user_lang, text):
    user_lang_code = language_code_map[user_lang]
    language_code = identify_language(text)

    translate_button_visibility = language_code != user_lang_code

    detected_language_text = f"""
    Detected Language: {language_code}\n
    User Content Language: {user_lang_code}\n
    {"" if translate_button_visibility else "[NOT TRANSLATABLE] Detected Language and Content Language are the same"}
    """

    return text, gr.update(value="", placeholder="Leave a comment"), gr.update(value=detected_language_text), gr.update(visible=translate_button_visibility, variant="primary")


def translate(text, src_lang, tgt_lang):
    CHAR_TO_STRIP = 22  # To strip away 'Detected Language: ' from language code
    LANGUAGE_CODE_LENGTH = 8  # To strip away 'Detected Language: ' from language code
    src_lang_code = src_lang[CHAR_TO_STRIP:CHAR_TO_STRIP + LANGUAGE_CODE_LENGTH]
    tgt_lang_code = language_code_map[tgt_lang]

    translation_pipeline = pipeline(
        "translation", model=model, tokenizer=tokenizer, src_lang=src_lang_code, tgt_lang=tgt_lang_code, device=device)
    result = translation_pipeline(text)
    return result[0]['translation_text']

with gr.Blocks() as demo:
    gr.HTML(
        f"""
            <div style="text-align: center; margin: 0 auto;">
              <div style=" display: inline-flex; align-items: center; gap: 0.8rem; font-size: 1.75rem;">
                <h1 style="font-weight: 900; margin-bottom: 7px;margin-top:5px">
                  {title}
                </h1>
              </div>
              <p style="margin-bottom: 10px; font-size: 94%; line-height: 23px;">
                {description}
              </p>
            </div>
        """
    )

    user_langugage_radio = gr.Radio(["English", "Spanish", "Korean", "French", "German", "Japanese", "Polish"],
                                    value="English", label="User Content Language")

    comment_input_textbox = gr.Textbox(
        lines=3, label="Write a Comment", placeholder="Leave a comment")
    comment_out_textbox = gr.Textbox(lines=3, label="Comment")
    detected_lang_markdown = gr.Markdown("", elem_id="detect-lang-md")

    comment_btn = gr.Button("Comment")

    translate_btn = gr.Button("Translate", visible=False)
    detected_language_value = gr.Textbox("", visible=False)


    comment_btn.click(display,
                      inputs=[user_langugage_radio, comment_input_textbox],
                      outputs=[
                          comment_out_textbox,
                          comment_input_textbox,
                          detected_lang_markdown,
                          translate_btn
                      ])

    translate_btn.click(translate,
                        inputs=[
                            comment_out_textbox,
                            detected_lang_markdown,
                            user_langugage_radio
                        ],
                        outputs=comment_out_textbox)

demo.launch()