import os
import gradio as gr
import pandas as pd

def get_or_create_env_var(var_name, default_value):
    # Get the environment variable if it exists
    value = os.environ.get(var_name)
    
    # If it doesn't exist, set it to the default value
    if value is None:
        os.environ[var_name] = default_value
        value = default_value
    
    return value

# Retrieving or setting output folder
env_var_name = 'GRADIO_OUTPUT_FOLDER'
default_value = 'output/'

output_folder = get_or_create_env_var(env_var_name, default_value)
print(f'The value of {env_var_name} is {output_folder}')

def get_file_path_end(file_path):
    # First, get the basename of the file (e.g., "example.txt" from "/path/to/example.txt")
    basename = os.path.basename(file_path)
    
    # Then, split the basename and its extension and return only the basename without the extension
    filename_without_extension, _ = os.path.splitext(basename)

    #print(filename_without_extension)
    
    return filename_without_extension

def detect_file_type(filename):
    """Detect the file type based on its extension."""
    if (filename.endswith('.csv')) | (filename.endswith('.csv.gz')) | (filename.endswith('.zip')):
        return 'csv'
    elif filename.endswith('.xlsx'):
        return 'xlsx'
    elif filename.endswith('.parquet'):
        return 'parquet'
    elif filename.endswith('.pdf'):
        return 'pdf'
    elif filename.endswith('.jpg'):
        return 'jpg'
    elif filename.endswith('.jpeg'):
        return 'jpeg'
    elif filename.endswith('.png'):
        return 'png'
    else:
        raise ValueError("Unsupported file type.")

def read_file(filename):
    """Read the file based on its detected type."""
    file_type = detect_file_type(filename)
    
    if file_type == 'csv':
        return pd.read_csv(filename, low_memory=False)
    elif file_type == 'xlsx':
        return pd.read_excel(filename)
    elif file_type == 'parquet':
        return pd.read_parquet(filename)

def ensure_output_folder_exists():
    """Checks if the 'output/' folder exists, creates it if not."""

    folder_name = "output/"

    if not os.path.exists(folder_name):
        # Create the folder if it doesn't exist
        os.makedirs(folder_name)
        print(f"Created the 'output/' folder.")
    else:
        print(f"The 'output/' folder already exists.")

def put_columns_in_df(in_file):
    new_choices = []
    concat_choices = []
    
    for file in in_file:
        df = read_file(file.name)
        new_choices = list(df.columns)

        concat_choices.extend(new_choices)

    # Drop duplicate columns
    concat_choices = list(set(concat_choices))
        
    return gr.Dropdown(choices=concat_choices, value=concat_choices)

# Following function is only relevant for locally-created executable files based on this app (when using pyinstaller it creates a _internal folder that contains tesseract and poppler. These need to be added to the system path to enable the app to run)
def add_folder_to_path(folder_path: str):
    '''
    Check if a folder exists on your system. If so, get the absolute path and then add it to the system Path variable if it doesn't already exist.
    '''

    if os.path.exists(folder_path) and os.path.isdir(folder_path):
        print(folder_path, "folder exists.")

        # Resolve relative path to absolute path
        absolute_path = os.path.abspath(folder_path)

        current_path = os.environ['PATH']
        if absolute_path not in current_path.split(os.pathsep):
            full_path_extension = absolute_path + os.pathsep + current_path
            os.environ['PATH'] = full_path_extension
            print(f"Updated PATH with: ", full_path_extension)
        else:
            print(f"Directory {folder_path} already exists in PATH.")
    else:
        print(f"Folder not found at {folder_path} - not added to PATH")