import os
from transformers import AutoTokenizer
from vllm import LLM, SamplingParams
from db_utils import get_schema, execute_sql

# Initialize model at startup
model = None
tokenizer = None
try:
    tokenizer = AutoTokenizer.from_pretrained(
        "Snowflake/Arctic-Text2SQL-R1-7B",
        cache_dir="/tmp/cache/huggingface",
        trust_remote_code=True
    )
    model = LLM(
        model="Snowflake/Arctic-Text2SQL-R1-7B",
        dtype="float16",
        gpu_memory_utilization=0.75,
        max_model_len=1024,
        max_num_seqs=1,
        enforce_eager=True,
        trust_remote_code=True
    )
except Exception as e:
    print(f"Error loading model at startup: {e}")
    raise

def text_to_sql(nl_query):
    try:
        schema = get_schema()
        prompt = f"""### Task
Generate a SQL query to answer the following natural language question: {nl_query}

### Database Schema
{schema}

### Response Format
Output only the SQL query.
"""
        sampling_params = SamplingParams(
            temperature=0,
            max_tokens=128,
            stop=["\n\n"]
        )
        outputs = model.generate([prompt], sampling_params)
        sql = outputs[0].outputs[0].text.strip()
        results = execute_sql(sql)
        return sql, results
    except Exception as e:
        print(f"Error in text_to_sql: {e}")
        raise