import os
import time
import random
import logging
from openai import OpenAI
from dotenv import load_dotenv
from utils import read_config

# --- Load environment & config ---
load_dotenv()
_config = read_config()["llm"]

# --- Logging setup ---
LOG_LEVEL = os.getenv("LOG_LEVEL", "INFO").upper()
logger = logging.getLogger("polLLM")
logger.setLevel(LOG_LEVEL)
handler = logging.StreamHandler()
handler.setFormatter(logging.Formatter("%(asctime)s [%(levelname)s] %(message)s"))
logger.addHandler(handler)

# --- LLM settings from config.yaml ---
_DEFAULT_MODEL     = _config.get("model","chutesai/Llama-4-Maverick-17B-128E-Instruct-FP8")  # _config.get("model", "openai-large")
_SYSTEM_TEMPLATE   = _config.get("system_prompt", "")
_CHAR              = _config.get("char", "Eve")
_CHUTES_API_KEY    = os.getenv("CHUTES_API_KEY")

# --- Custom exception ---
class LLMBadRequestError(Exception):
    """Raised when the LLM returns HTTP 400 (Bad Request)."""
    pass

# --- OpenAI client init ---
client = OpenAI(
    base_url="https://llm.chutes.ai/v1/",
    api_key=_CHUTES_API_KEY
)

def _build_system_prompt() -> str:
    """
    Substitute {char} into the system prompt template.
    """
    return _SYSTEM_TEMPLATE.replace("{char}", _CHAR)

def generate_llm(
    prompt: str,
) -> str:
    """
    Send a chat-completion request to the LLM, with retries and backoff.
    Reads defaults from config.yaml, but can be overridden per-call.
    """
    model = _DEFAULT_MODEL
    system_prompt = _build_system_prompt()
    messages = [
        {"role": "system", "content": system_prompt},
        {"role": "user", "content": prompt},
    ]

    backoff = 1
    for attempt in range(1, 6):
        try:
            seed = random.randint(0, 2**31 - 1)
            logger.debug(f"LLM call attempt={attempt}, model={model}, seed={seed}")
            resp = client.chat.completions.create(
                model=model,
                messages=messages,
                seed=seed,
            )
            text = resp.choices[0].message.content.strip()
            logger.debug("LLM response received")
            return text
        except Exception as e:
            if getattr(e, "status_code", None) == 400:
                logger.error("LLM error 400 (Bad Request): Not retrying.")
                raise LLMBadRequestError("LLM returned HTTP 400")
            logger.error(f"LLM error on attempt {attempt}: {e}")
            if attempt < 5:
                time.sleep(backoff)
                backoff *= 2
            else:
                logger.critical("LLM failed after 5 attempts, raising")
                raise

# Example local test
if __name__ == "__main__":
    logger.info("Testing generate_llm() with a sample prompt")
    try:
        print(generate_llm("generate 4 images of 1:1 profile picture"))
    except LLMBadRequestError as e:
        logger.warning(f"Test failed with bad request: {e}")