app.py

import warnings
warnings.filterwarnings("ignore")

import torch
from fastapi import FastAPI
from pydantic import BaseModel
from transformers import AutoTokenizer, AutoModelForCausalLM

import gradio as gr
import threading

torch.set_num_threads(1)

app = FastAPI()

BASE_MODEL = "TinyLlama/TinyLlama-1.1B-Chat-v1.0"

print("Loading model...")

tokenizer = AutoTokenizer.from_pretrained(BASE_MODEL)
model = AutoModelForCausalLM.from_pretrained(BASE_MODEL)

model.eval()

print("Model ready")

# ─────────────────────────
# SQL FILTER
# ─────────────────────────
SQL_KEYWORDS = [
    "sql", "database", "table", "select", "insert",
    "update", "delete", "join", "group by",
    "postgres", "mysql", "sqlite", "query"
]

def is_sql_related(text):
    return any(k in text.lower() for k in SQL_KEYWORDS)

SYSTEM_PROMPT = """
You are an expert SQL generator.
Only output SQL query.
"""

def generate_sql(user_input: str):
    if not user_input.strip():
        return "Enter SQL question."

    if not is_sql_related(user_input):
        return "Only SQL/database questions allowed."

    prompt = f"{SYSTEM_PROMPT}\nUser: {user_input}\nSQL:"

    inputs = tokenizer(prompt, return_tensors="pt")

    with torch.no_grad():
        output = model.generate(
            **inputs,
            max_new_tokens=120,
            temperature=0.1,
            do_sample=False,
            pad_token_id=tokenizer.eos_token_id,
        )

    text = tokenizer.decode(output[0], skip_special_tokens=True)
    result = text.split("SQL:")[-1].strip().split("\n")[0]

    return result

# ─────────────────────────
# FastAPI Routes
# ─────────────────────────
class Query(BaseModel):
    text: str

@app.get("/")
def root():
    return {"status": "API running"}

@app.post("/generate")
def generate(query: Query):
    return {"result": generate_sql(query.text)}

# ─────────────────────────
# Gradio UI (for testing)
# ─────────────────────────
def launch_gradio():
    demo = gr.Interface(
        fn=generate_sql,
        inputs=gr.Textbox(lines=3, label="SQL Question"),
        outputs=gr.Textbox(lines=6, label="Generated SQL"),
        title="SQL Generator Test UI"
    )
    demo.launch(server_name="0.0.0.0", server_port=7861)

# Run Gradio in parallel thread
threading.Thread(target=launch_gradio).start()