import logging
import os
import sys
import uvicorn
from fastapi import FastAPI
from schemas import RequirementInfo, ReqGroupingCategory, ReqGroupingResponse, ReqGroupingRequest, _ReqGroupingCategory, _ReqGroupingOutput
from jinja2 import Environment, FileSystemLoader
from litellm import acompletion
from dotenv import load_dotenv

logging.basicConfig(
    level=logging.INFO,
    format='[%(asctime)s][%(levelname)s][%(filename)s:%(lineno)d]: %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S'
)

# Load .env files
load_dotenv()

if "LLM_API_MODEL" not in os.environ or "LLM_API_KEY" not in os.environ:
    logging.error(
        "No LLM token (`LLM_API_TOKEN`) and/or LLM model (`LLM_API_KEY`) were provided in the env vars. Exiting")
    sys.exit(-1)

LLM_API_MODEL = os.environ.get("LLM_API_MODEL")
LLM_API_KEY = os.environ.get("LLM_API_KEY")

# Jinja2 environment to load prompt templates
prompt_env = Environment(loader=FileSystemLoader('prompts'), enable_async=True)

fastapi = FastAPI()


@fastapi.post("/categorize_requirements")
async def categorize_reqs(params: ReqGroupingRequest) -> ReqGroupingResponse:
    """Categorize the given service requirements into categories"""

    MAX_ATTEMPTS = 5

    categories: list[_ReqGroupingCategory] = []
    messages = []

    # categorize the requirements using their indices
    req_prompt = await prompt_env.get_template("classify.txt").render_async(**{
        "requirements": [rq.model_dump() for rq in params.requirements],
        "max_n_categories": params.max_n_categories,
        "response_schema": _ReqGroupingOutput.model_json_schema()})

    # add system prompt with requirements
    messages.append({"role": "user", "content": req_prompt})

    # ensure all requirements items are processed
    for attempt in range(MAX_ATTEMPTS):
        req_completion = await acompletion(model=LLM_API_MODEL, api_key=LLM_API_KEY, messages=messages, response_format=_ReqGroupingOutput)
        output = _ReqGroupingOutput.model_validate_json(
            req_completion.choices[0].message.content)

        # quick check to ensure no requirement was left out by the LLM by checking all IDs are contained in at least a single category
        assigned_ids = {
            req_id for cat in output.categories for req_id in cat.items}
        unassigned_ids = set(range(1, len(params.requirements))) - assigned_ids

        if len(unassigned_ids) == 0:
            categories.extend(output.categories)
            break
        else:
            messages.append(req_completion.choices[0].message)
            messages.append(
                {"role": "user", "content": f"You haven't categorized the following requirements in at least one category {unassigned_ids}. Please do so."})

            if attempt == MAX_ATTEMPTS - 1:
                raise Exception("Failed to classify all requirements")

    # build the final category objects
    # remove the invalid (likely hallucinated) requirement IDs
    final_categories = []
    for idx, cat in enumerate(output.categories):
        final_categories.append(ReqGroupingCategory(
            id=idx,
            title=cat.title,
            requirements=[params.requirements[i]
                          for i in cat.items if i < len(params.requirements)]
        ))

    return ReqGroupingResponse(categories=final_categories)


uvicorn.run(fastapi, host="0.0.0.0", port=8000)