from sqlalchemy import (
    create_engine,
    MetaData,
    Table,
    Column,
    String,
    Integer,
    Float,
    insert,
    text,
)

# Use a persistent SQLite database file
engine = create_engine("sqlite:///database.db")
metadata_obj = MetaData()

def create_dynamic_table(df):
    """
    Creates a table dynamically based on DataFrame schema.

    Args:
        df: pandas DataFrame containing the data

    Returns:
        SQLAlchemy Table object
    """
    # Drop existing table if it exists
    if 'data_table' in metadata_obj.tables:
        metadata_obj.remove(metadata_obj.tables['data_table'])

    # Define columns with a new auto-incrementing primary key
    columns = [Column("uuid", Integer, primary_key=True, autoincrement=True)]  # New primary key

    # Add columns based on DataFrame dtypes
    for col_name, dtype in df.dtypes.items():
        if 'int' in str(dtype):
            col_type = Integer
        elif 'float' in str(dtype):
            col_type = Float
        else:
            col_type = String(255)  # Using a generous length for string columns

        columns.append(Column(col_name, col_type))

    # Create new table
    table = Table('data_table', metadata_obj, *columns)

    # Create table in database
    metadata_obj.create_all(engine, tables=[table])

    return table

def clear_database():
    """
    Removes all tables from the database.
    """
    metadata_obj.drop_all(engine)
    metadata_obj.clear()

def insert_rows_into_table(rows, table):
    """
    Inserts rows into the specified table.
    
    Args:
        rows: List of dictionaries containing the row data
        table: SQLAlchemy Table object
    """
    with engine.begin() as connection:
        connection.execute(insert(table), rows)

def get_table_schema():
    """
    Returns the current table schema as a string.
    """
    try:
        # Get list of tables
        with engine.connect() as con:
            tables = con.execute(text(
                "SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%'"
            )).fetchall()
            
        if not tables:
            return None
            
        # Use the first table found
        table_name = tables[0][0]
        
        # Get column information
        with engine.connect() as con:
            columns = con.execute(text(f"PRAGMA table_info({table_name})")).fetchall()
            
        schema = []
        for col in columns:
            col_name = col[1]
            col_type = col[2]
            is_primary = "primary key" if col[5] == 1 else ""
            schema.append(f"- {col_name} ({col_type}) {is_primary}".strip())
        
        return "\n".join(schema)
        
    except Exception as e:
        return None