import time
import requests
import json

def generate(message, max_new_tokens=256, temperature=0.9, top_p=0.95, repetition_penalty=1.0):
    """
    Generates an enhanced prompt using the streaming inference mechanism from a Hugging Face API endpoint.
    This function formats the prompt with a system instruction, sends a streaming request to the API,
    and yields the accumulated text as tokens are received.

    Parameters:
        message (str): The user's input prompt.
        max_new_tokens (int): The maximum number of tokens to generate.
        temperature (float): Sampling temperature.
        top_p (float): Nucleus sampling parameter.
        repetition_penalty (float): Penalty factor for repetition (not used in the payload but kept for API consistency).

    Yields:
        str: The accumulated generated text as it streams in.
    """
    # Define the system prompt.
    SYSTEM_PROMPT = (
        "You are a prompt enhancer and your work is to enhance the given prompt under 100 words "
        "without changing the essence, only write the enhanced prompt and nothing else."
    )
    # Format the prompt with a timestamp for uniqueness.
    timestamp = time.time()
    formatted_prompt = (
        f"<s>[INST] SYSTEM: {SYSTEM_PROMPT} [/INST]"
        f"[INST] {message} {timestamp} [/INST]"
    )
    
    # Define the API endpoint and headers.
    api_url = "https://ruslanmv-hf-llm-api.hf.space/api/v1/chat/completions"
    headers = {"Content-Type": "application/json"}
    
    # Build the payload for the inference request.
    payload = {
        "model": "mixtral-8x7b",
        "messages": [{"role": "user", "content": formatted_prompt}],
        "temperature": temperature,
        "top_p": top_p,
        "max_tokens": max_new_tokens,
        "use_cache": False,
        "stream": True
    }
    
    try:
        response = requests.post(api_url, headers=headers, json=payload, stream=True)
        response.raise_for_status()
        full_output = ""
        
        # Process the streaming response line by line.
        for line in response.iter_lines():
            if not line:
                continue
            
            decoded_line = line.decode("utf-8").strip()
            # Remove the "data:" prefix if present.
            if decoded_line.startswith("data:"):
                decoded_line = decoded_line[len("data:"):].strip()
            
            # Check if the stream is finished.
            if decoded_line == "[DONE]":
                break
            
            try:
                json_data = json.loads(decoded_line)
                for choice in json_data.get("choices", []):
                    delta = choice.get("delta", {})
                    content = delta.get("content", "")
                    full_output += content
                    yield full_output  # Yield the accumulated text so far.
                    
                    # If the finish reason is provided, stop further streaming.
                    if choice.get("finish_reason") == "stop":
                        return
            except json.JSONDecodeError:
                # If a line is not valid JSON, skip it.
                continue
    except requests.exceptions.RequestException as e:
        yield f"Error during generation: {str(e)}"