"""
Utility functions for data handling and export.
"""

import os
import json
import csv
import pandas as pd
from datetime import datetime


def save_json(data, file_path):
    """
    Save data to a JSON file.
    
    Args:
        data: data to save
        file_path: path to the output file
        
    Returns:
        bool: True if successful, False otherwise
    """
    try:
        with open(file_path, 'w', encoding='utf-8') as f:
            json.dump(data, f, indent=2, ensure_ascii=False)
        return True
    except Exception as e:
        print(f"Error saving JSON: {e}")
        return False


def load_json(file_path):
    """
    Load data from a JSON file.
    
    Args:
        file_path: path to the JSON file
        
    Returns:
        dict: loaded data, or None if an error occurred
    """
    try:
        with open(file_path, 'r', encoding='utf-8') as f:
            return json.load(f)
    except Exception as e:
        print(f"Error loading JSON: {e}")
        return None


def save_csv(data, file_path, headers=None):
    """
    Save data to a CSV file.
    
    Args:
        data: list of dictionaries or list of lists
        file_path: path to the output file
        headers: optional list of column headers
        
    Returns:
        bool: True if successful, False otherwise
    """
    try:
        if isinstance(data, list) and len(data) > 0:
            if isinstance(data[0], dict):
                # List of dictionaries
                if headers is None:
                    headers = list(data[0].keys())
                
                with open(file_path, 'w', newline='', encoding='utf-8') as f:
                    writer = csv.DictWriter(f, fieldnames=headers)
                    writer.writeheader()
                    writer.writerows(data)
            else:
                # List of lists
                with open(file_path, 'w', newline='', encoding='utf-8') as f:
                    writer = csv.writer(f)
                    if headers:
                        writer.writerow(headers)
                    writer.writerows(data)
        return True
    except Exception as e:
        print(f"Error saving CSV: {e}")
        return False


def dataframe_to_formats(df, base_path, formats=None):
    """
    Export a pandas DataFrame to multiple formats.
    
    Args:
        df: pandas DataFrame
        base_path: base path for output files (without extension)
        formats: list of formats to export to ('csv', 'excel', 'html', 'json')
        
    Returns:
        dict: dictionary with format names as keys and file paths as values
    """
    if formats is None:
        formats = ['csv', 'excel', 'html']
    
    result = {}
    
    try:
        for fmt in formats:
            if fmt == 'csv':
                file_path = f"{base_path}.csv"
                df.to_csv(file_path)
                result['csv'] = file_path
            elif fmt == 'excel':
                file_path = f"{base_path}.xlsx"
                df.to_excel(file_path)
                result['excel'] = file_path
            elif fmt == 'html':
                file_path = f"{base_path}.html"
                df.to_html(file_path)
                result['html'] = file_path
            elif fmt == 'json':
                file_path = f"{base_path}.json"
                df.to_json(file_path, orient='records', indent=2)
                result['json'] = file_path
    except Exception as e:
        print(f"Error exporting DataFrame: {e}")
    
    return result


def generate_timestamp():
    """
    Generate a timestamp string for file naming.
    
    Returns:
        str: timestamp string
    """
    return datetime.now().strftime("%Y%m%d_%H%M%S")


def create_results_filename(prefix="evaluation", extension=""):
    """
    Create a filename for results with timestamp.
    
    Args:
        prefix: prefix for the filename
        extension: file extension (with or without dot)
        
    Returns:
        str: filename with timestamp
    """
    timestamp = generate_timestamp()
    
    if extension:
        if not extension.startswith('.'):
            extension = f".{extension}"
        return f"{prefix}_{timestamp}{extension}"
    else:
        return f"{prefix}_{timestamp}"