core/data_prep.py

import os
import sqlite3
import pandas as pd
from sklearn.model_selection import train_test_split
import os

PROJECT_ROOT = os.path.dirname(os.path.dirname(__file__))   # goes from src/ → project root
DB_PATH = os.path.join(PROJECT_ROOT, "data", "database", "merged_CN_YSI_SMILES_Cleaned.csv")

TARGET_CN = "cn"      # Cetane number
N_FOLDS = 5
TOP_K = 5
#print("Connecting to SQLite database...")
#conn = sqlite3.connect(DB_PATH)

#query = """
#SELECT 
 #   F.Fuel_Name,
  #  F.SMILES,
   # T.Standardised_DCN AS cn
#FROM FUEL F
#LEFT JOIN TARGET T ON F.fuel_id = T.fuel_id
#ORDER BY F.fuel_id ASC;
#"""
#df = pd.read_sql_query(query, conn)
#conn.close()

df = pd.read_csv(DB_PATH)
df = df.rename(columns={
    "CN_Measured": "cn",
    "SMILES_Standardized": "SMILES"
})

print(df.columns.tolist())

df.dropna(subset=[TARGET_CN, "SMILES"], inplace=True)

train_df, test_df = train_test_split(df, test_size=0.2, random_state=42)
print(df.head())
print(df.columns)

def load_data():
    return df