# main.py
from fastapi import FastAPI, File, UploadFile
from fastapi.responses import JSONResponse
from pydantic import BaseModel
import json

import litellm  # Minimalistic LLM library (you can replace with huggingface, etc.)

app = FastAPI()

class InferenceRequest(BaseModel):
    prompt: str
    max_tokens: int = 512

@app.post("/v1/inference")
async def inference(request: InferenceRequest):
    """
    Inference endpoint using deepseek-r1-distill-7b (uncensored).
    """
    response = litellm.completion(
        model="deepseek/deepseek-r1-distill-7b",
        messages=[{"role": "user", "content": request.prompt}],
        max_tokens=request.max_tokens
    )
    return JSONResponse(content=response)

@app.post("/v1/finetune")
async def finetune(file: UploadFile = File(...)):
    """
    Fine-tune endpoint that accepts a JSONL file.
    """
    if not file.filename.endswith('.jsonl'):
        return JSONResponse(
            status_code=400,
            content={"error": "Only .jsonl files are accepted for fine-tuning"}
        )

    # Read lines from uploaded file
    data = [json.loads(line) for line in file.file]

    # Perform or schedule a fine-tuning job here (simplified placeholder)
    # You can integrate with your training pipeline below.
    
    return JSONResponse(content={"status": "Fine-tuning request received", "samples": len(data)})

# finetune_pipeline.py

import os
import torch
from transformers import (AutoModelForCausalLM, AutoTokenizer, 
                          Trainer, TrainingArguments)
from datasets import load_dataset

from trl import PPOTrainer, PPOConfig, AutoModelForCausalLMWithValueHead
from transformers import pipeline, AutoModel

# 1. Cold Start Phase
def cold_start_finetune(
    base_model="deepseek-ai/deepseek-r1-distill-7b",
    train_file="cold_start_data.jsonl",
    output_dir="cold_start_finetuned_model"
):
    # Load model and tokenizer
    model = AutoModelForCausalLM.from_pretrained(base_model)
    tokenizer = AutoTokenizer.from_pretrained(base_model)

    # Load dataset
    dataset = load_dataset("json", data_files=train_file, split="train")

    # Simple tokenization function
    def tokenize_function(example):
        return tokenizer(
            example["prompt"] + "\n" + example["completion"],
            truncation=True,
            max_length=512
        )

    dataset = dataset.map(tokenize_function, batched=True)
    dataset = dataset.shuffle()

    # Define training arguments
    training_args = TrainingArguments(
        output_dir=output_dir,
        num_train_epochs=1,
        per_device_train_batch_size=2,
        gradient_accumulation_steps=4,
        save_steps=50,
        logging_steps=50,
        learning_rate=5e-5
    )

    # Trainer
    trainer = Trainer(
        model=model,
        args=training_args,
        train_dataset=dataset
    )

    trainer.train()
    trainer.save_model(output_dir)
    tokenizer.save_pretrained(output_dir)
    return output_dir


# 2. Reasoning RL Training
def reasoning_rl_training(
    cold_start_model_dir="cold_start_finetuned_model",
    train_file="reasoning_data.jsonl",
    output_dir="reasoning_rl_model"
):
    # Config for PPO
    config = PPOConfig(
        batch_size=16,
        learning_rate=1e-5,
        log_with=None,  # or 'wandb'
        mini_batch_size=4
    )

    # Load model and tokenizer
    model = AutoModelForCausalLMWithValueHead.from_pretrained(cold_start_model_dir)
    tokenizer = AutoTokenizer.from_pretrained(cold_start_model_dir)

    # Create a PPO trainer
    ppo_trainer = PPOTrainer(
        config,
        model,
        tokenizer=tokenizer,
    )

    # Load dataset
    dataset = load_dataset("json", data_files=train_file, split="train")

    # Simple RL loop (pseudo-coded for brevity)
    for sample in dataset:
        prompt = sample["prompt"]
        desired_answer = sample["completion"]  # For reward calculation

        # Generate response
        query_tensors = tokenizer.encode(prompt, return_tensors="pt")
        response_tensors = ppo_trainer.generate(query_tensors, max_new_tokens=50)
        response_text = tokenizer.decode(response_tensors[0], skip_special_tokens=True)

        # Calculate reward (simplistic: measure overlap or correctness)
        reward = 1.0 if desired_answer in response_text else -1.0

        # Run a PPO step
        ppo_trainer.step([query_tensors[0]], [response_tensors[0]], [reward])

    model.save_pretrained(output_dir)
    tokenizer.save_pretrained(output_dir)
    return output_dir


# 3. Data Collection
def collect_data(
    rl_model_dir="reasoning_rl_model",
    num_samples=1000,
    output_file="data_collection.jsonl"
):
    """
    Example data collection: generate completions from the RL model.
    This is a simple version that just uses random prompts or a given file of prompts.
    """
    tokenizer = AutoTokenizer.from_pretrained(rl_model_dir)
    model = AutoModelForCausalLM.from_pretrained(rl_model_dir)

    # Suppose we have some random prompts:
    prompts = [
        "Explain quantum entanglement",
        "Summarize the plot of 1984 by George Orwell",
        # ... add or load from a prompt file ...
    ]

    collected = []
    for i in range(num_samples):
        prompt = prompts[i % len(prompts)]
        inputs = tokenizer(prompt, return_tensors="pt")
        outputs = model.generate(**inputs, max_new_tokens=50)
        completion = tokenizer.decode(outputs[0], skip_special_tokens=True)
        collected.append({"prompt": prompt, "completion": completion})

    # Save to JSONL
    with open(output_file, "w") as f:
        for item in collected:
            f.write(f"{item}\n")

    return output_file


# 4. Final RL Phase
def final_rl_phase(
    rl_model_dir="reasoning_rl_model",
    final_data="final_data.jsonl",
    output_dir="final_rl_model"
):
    """
    Another RL phase using a new dataset or adding human feedback. 
    This is a simplified approach similar to the reasoning RL training step.
    """
    config = PPOConfig(
        batch_size=16,
        learning_rate=1e-5,
        log_with=None,
        mini_batch_size=4
    )

    model = AutoModelForCausalLMWithValueHead.from_pretrained(rl_model_dir)
    tokenizer = AutoTokenizer.from_pretrained(rl_model_dir)
    ppo_trainer = PPOTrainer(config, model, tokenizer=tokenizer)

    dataset = load_dataset("json", data_files=final_data, split="train")

    for sample in dataset:
        prompt = sample["prompt"]
        desired_answer = sample["completion"]
        query_tensors = tokenizer.encode(prompt, return_tensors="pt")
        response_tensors = ppo_trainer.generate(query_tensors, max_new_tokens=50)
        response_text = tokenizer.decode(response_tensors[0], skip_special_tokens=True)

        reward = 1.0 if desired_answer in response_text else 0.0
        ppo_trainer.step([query_tensors[0]], [response_tensors[0]], [reward])

    model.save_pretrained(output_dir)
    tokenizer.save_pretrained(output_dir)
    return output_dir


# END-TO-END PIPELINE EXAMPLE
if __name__ == "__main__":
    # 1) Cold Start
    cold_start_out = cold_start_finetune(
        base_model="deepseek-ai/deepseek-r1-distill-7b",
        train_file="cold_start_data.jsonl",
        output_dir="cold_start_finetuned_model"
    )

    # 2) Reasoning RL
    reasoning_rl_out = reasoning_rl_training(
        cold_start_model_dir=cold_start_out,
        train_file="reasoning_data.jsonl",
        output_dir="reasoning_rl_model"
    )

    # 3) Data Collection
    data_collection_out = collect_data(
        rl_model_dir=reasoning_rl_out,
        num_samples=100,
        output_file="data_collection.jsonl"
    )

    # 4) Final RL Phase
    final_rl_out = final_rl_phase(
        rl_model_dir=reasoning_rl_out,
        final_data="final_data.jsonl",
        output_dir="final_rl_model"
    )

    print("All done! Final model stored in:", final_rl_out)