import os
import requests
import torch
from typing import Optional

from fastapi import FastAPI, Header, HTTPException, BackgroundTasks
import asyncio
from fastapi.responses import FileResponse
from huggingface_hub.hf_api import HfApi
from huggingface_hub import login
import huggingface_hub as hf

from .models import config, WebhookPayload
# import models

import pandas as pd
import numpy as np
import random

from sklearn.preprocessing import LabelEncoder
from transformers import TrainingArguments, Trainer

import datasets
import evaluate
import accuracy  # unused here but required import for evaluate

import time

from transformers import AutoModelForSequenceClassification, AutoTokenizer

import subprocess

from datetime import datetime

WEBHOOK_SECRET = os.getenv("WEBHOOK_SECRET")
HF_ACCESS_TOKEN = os.getenv("HF_ACCESS_TOKEN")

# Local repository path (not on the Hub)
REPOSITORY_PATH = "staging/brand-classifier-stage"
INPUT_DIR = config.input_model
# OUTPUT_DIR = "magellan-ai/brand-classifier-stage" # Model to be updated
OUTPUT_DIR = config.input_model
ENDPOINT_ID = "magellan-ai/magellan-brand-recent"  # Endpoint to be updated
DATASET_PATH = config.input_dataset

print('logging in')
login(token=HF_ACCESS_TOKEN)
print('logged in')

print(f"Is CUDA available: {torch.cuda.is_available()}")
# True
print(
    f"CUDA device: {torch.cuda.get_device_name(torch.cuda.current_device())}")
# Tesla T4

print('setting device')
device = torch.device("cuda")
print(device)
print('set device')

print('setting up Repository')
# TODO: Change based on whether input dir is stage to output to prod or other way
repo = hf.Repository(local_dir=REPOSITORY_PATH,
                     clone_from=INPUT_DIR,
                     token=HF_ACCESS_TOKEN)
repo.git_pull()

model_nm = "gpt2"  # this is for the full re-training.

max_concurrent_requests = 1
request_queue = asyncio.Queue(maxsize=max_concurrent_requests)

app = FastAPI()


@app.get("/")
async def home():
    # nvidia-smi
    print('printing nvidia smi')
    print(subprocess.run(["nvidia-smi"], capture_output=True).stdout.decode())

    return FileResponse("home.html")


@app.post("/webhook")
async def post_webhook(
    payload: WebhookPayload,
    task_queue: BackgroundTasks,
    repo=repo,
    REPOSITORY_PATH: str = REPOSITORY_PATH,
    OUTPUT_DIR: str = OUTPUT_DIR,
    x_webhook_secret:  Optional[str] = Header(default=None),
):

    try:
        print('received webhook:')

        # Add a request to the queue with a timeout
        await asyncio.wait_for(request_queue.put(True), timeout=1)

        if x_webhook_secret is None:
            raise HTTPException(401)
        if x_webhook_secret != WEBHOOK_SECRET:
            raise HTTPException(403)
        if not (
                (payload.event.action == "update" or payload.event.action == "create")
                and (payload.event.scope.startswith("repo.content") or payload.event.scope.startswith("repo"))
                # and payload.repo.name == DATASET_PATH # commented out because no difference between prod and stage
                and payload.repo.type == "dataset"
        ):
            # no-op
            print('webhook oh no')
            print(payload.event.action)
            print(payload.event.scope)
            print(payload.repo.name)
            print(payload.repo.type)

            raise HTTPException(400)

            return {"processed": False}

        print('scheduling retrain')
        task_queue.add_task(
            schedule_retrain,
            payload,
            repo,
            REPOSITORY_PATH,
            OUTPUT_DIR,
            HF_ACCESS_TOKEN,
        )

        return {"message": "Webhook request accepted for processing"}

    except asyncio.TimeoutError:
        raise HTTPException(
            status_code=503, detail="Previous webhook is being processed. Try again later.")


def schedule_retrain(payload: WebhookPayload,
                     repo: repo,
                     REPOSITORY_PATH: REPOSITORY_PATH,
                     OUTPUT_DIR: OUTPUT_DIR,
                     HF_ACCESS_TOKEN: HF_ACCESS_TOKEN
                     ):
    # Create re-training project
    print("loading dataset")
    dataset = datasets.load_dataset(DATASET_PATH)
    dataset, le = load_data(dataset)
    # Now, you can create id2label and label2id for Hugging Face as follows:
    label2id = {str(label): int(id)
                for label, id in zip(le.classes_, le.transform(le.classes_))}
    id2label = {int(id): str(label) for label, id in label2id.items()}
    print("loaded dataset")

    print("tokenizing dataset")
    tokenizer, tok_ds = tokenizer_func(dataset)
    print("tokenized dataset")

    print("splitting dataset")
    tok_train_ds = tok_ds.train_test_split(test_size=0.2, seed=42)
    tok_val_ds = tok_train_ds['test']
    tok_train_ds = tok_train_ds['train']
    print("split dataset")

    bs = 16
    RESUME_LAST = False
    if RESUME_LAST:
        epochs = 2
    else:
        epochs = 8
    lr = 8e-5

    torch.backends.cuda.matmul.allow_tf32 = True

    print("setting arguments")
    args = TrainingArguments(REPOSITORY_PATH,
                             learning_rate=lr,
                             warmup_ratio=0.1,
                             lr_scheduler_type='cosine',
                             tf32=True,
                             evaluation_strategy="epoch",
                             per_device_train_batch_size=bs,
                             per_device_eval_batch_size=bs*2,
                             num_train_epochs=epochs,
                             weight_decay=0.01,
                             report_to='none',
                             gradient_accumulation_steps=2,
                             save_strategy="epoch",
                             gradient_checkpointing=True,
                             optim="adafactor",
                             log_level="debug",)

    # args.set_push_to_hub(OUTPUT_DIR, token=HF_ACCESS_TOKEN, private_repo=True)

    print("setting model")
    model = AutoModelForSequenceClassification.from_pretrained(model_nm, num_labels=len(np.unique(tok_ds['labels'])), ignore_mismatched_sizes=True,
                                                               id2label=id2label, label2id=label2id)
    model.resize_token_embeddings(len(tokenizer))
    model.config.pad_token_id = model.config.eos_token_id
    trainer = Trainer(model, args, train_dataset=tok_train_ds.shuffle(seed=42), eval_dataset=tok_val_ds.shuffle(seed=42),
                      tokenizer=tokenizer, compute_metrics=compute_metrics)

    print("training model")
    trainer.train()

    print("evaluating model")
    eval = trainer.evaluate()
    print(eval)
    eval_accuracy = round(eval['eval_accuracy'], 2)
    print("evaluated model")

    # Save the model and tokenizer
    tokenizer.save_pretrained(REPOSITORY_PATH)
    model.save_pretrained(REPOSITORY_PATH)
    trainer.save_model(REPOSITORY_PATH)

    # Save evaluation metrics and accuracy
    with open(os.path.join(REPOSITORY_PATH, 'eval_metrics.txt'), 'w') as f:
        f.write(str(eval))
    with open(os.path.join(REPOSITORY_PATH, 'eval_accuracy.txt'), 'w') as f:
        f.write(str(eval_accuracy))

    # Pushing Repository to the hub
    print("pushing repository")

    now = datetime.now()
    dt_string = now.strftime("%m/%d/%Y %H:%M:%S")
    repo.git_add('.', auto_lfs_track=True)
    repo.git_commit(f're-trained {dt_string}, acc: {eval_accuracy}')
    repo.git_push()
    print("pushed repository")

    # Update the endpoint
    print("updating endpoint")
    hf_api = HfApi(token=HF_ACCESS_TOKEN)
    update_endpoint(hf_api)
    print("updated endpoint")

    # Notify in the community tab
    print("notifying success")
    notify_success()
    print("notified success")

    # Remove from queue
    # request_queue.task_done()  # Mark the request as done in the queue # Keep in queue because we only want one at a time

    # Restart space to clear cache
    hf_api.restart_space('magellan-ai/brand-classifier')

    return {"processed": True}


def load_data(dataset):
    df = pd.DataFrame(dataset['train'])

    # Drop duplicates based on episode copy ID column
    df.drop_duplicates(['simhash'], inplace=True)

    # Sort the DataFrame by brand_id and then by downloaded_at
    df.sort_values(['brand_id', 'downloaded_at'], ascending=[True, False],
                   inplace=True)

    # Create a new column called 'rank' which indicates how recent the brand name is seen
    df['rank'] = df.groupby('brand_name').cumcount() + 1

    # Keep only the last 100 occurences for each brand
    sampled_df = df[df['rank'] <= 100]

    # Drop the 'rank' column from the final sampled DataFrame
    sampled_df.drop('rank', axis=1, inplace=True)

    # reducing sample
    df = sampled_df
    brands = df['brand_name'].unique()
    random.shuffle(brands)
    df = df[df['brand_name'].isin(brands[:])]

    # Create a label encoder
    label_encoder = LabelEncoder()

    # Fit the encoder and transform your labels
    df['labels'] = label_encoder.fit_transform(df['brand_id'])
    # df['labels'] = df['brand_id']

    ds = datasets.Dataset.from_pandas(df)
    return ds, label_encoder


def tokenizer_func(ds):
    tokenizer = AutoTokenizer.from_pretrained(model_nm)
    tokenizer.add_special_tokens({'pad_token': '[PAD]'})
    tok_ds = ds.map(tok_func, batched=True, fn_kwargs={'tokenizer': tokenizer})

    return tokenizer, tok_ds


def tok_func(x, tokenizer):
    encoding = tokenizer(x['plain_text'], max_length=1024,
                         return_overflowing_tokens=False)
    return encoding


def compute_metrics(eval_pred):
    scoring = evaluate.load("accuracy")
    predictions, labels = eval_pred
    predictions = np.argmax(predictions, axis=1)
    return scoring.compute(predictions=predictions, references=labels)


def update_endpoint(hf_api):
    # Get most recent revision
    revisions = hf_api.list_repo_commits(OUTPUT_DIR)
    revision = revisions[0].commit_id

    # Pause
    headers = {
        'Authorization': 'Bearer ' + HF_ACCESS_TOKEN,  # 'Bearer ' + HF_ACCESS_TOKEN,
        'accept': 'application/json',
        'content-type': 'application/x-www-form-urlencoded',
    }
    response = requests.post(
        f'https://api.endpoints.huggingface.cloud/v2/endpoint/{ENDPOINT_ID}/pause',
        headers=headers,
    )

    print('pause response:', response)
    time.sleep(10)

    # Update
    headers = {
        'Authorization': 'Bearer ' + HF_ACCESS_TOKEN,  # 'Bearer ' + HF_ACCESS_TOKEN,
        'accept': 'application/json',
        'Content-Type': 'application/json',
    }
    json_data = {}
    response = requests.put(
        f'https://api.endpoints.huggingface.cloud/v2/endpoint/{ENDPOINT_ID}',
        headers=headers,
        json=json_data,
    )
    print('update response:', response)
    time.sleep(10)

    # Resume
    headers = {
        'Authorization': 'Bearer ' + HF_ACCESS_TOKEN,  # 'Bearer ' + HF_ACCESS_TOKEN,
        'accept': 'application/json',
        'content-type': 'application/x-www-form-urlencoded',
    }
    response = requests.post(
        f'https://api.endpoints.huggingface.cloud/v2/endpoint/{ENDPOINT_ID}/resume',
        headers=headers,
    )
    print('resume response:', response)


def notify_success():
    message = NOTIFICATION_TEMPLATE.format(
        input_model=config.input_model,
        input_dataset=DATASET_PATH,
    )
    return HfApi(token=HF_ACCESS_TOKEN).create_discussion(
        repo_id=DATASET_PATH,
        repo_type="dataset",
        title="✨ Retraining started!",
        description=message,
        token=HF_ACCESS_TOKEN,
    )


NOTIFICATION_TEMPLATE = """\
🌸 Hello there!

Following an update of [{input_dataset}](https://huggingface.co/datasets/{input_dataset}), an automatic re-training of [{input_model}](https://huggingface.co/{input_model}) has been scheduled and completed!

(This is an automated message)
"""