#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
Convert JSONL files to Parquet format with support for Indic languages.
This script discovers all JSONL files in a specified language folder and 
converts them to Parquet format using the HuggingFace datasets library.
"""

import os
import sys
import json
import logging
import argparse
from pathlib import Path
from typing import Dict, List, Any, Optional

import datasets
from datasets import Dataset

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
    handlers=[
        logging.StreamHandler(),
        logging.FileHandler('convert_to_parquet.log')
    ]
)
logger = logging.getLogger(__name__)

# List of supported language folders
SUPPORTED_LANGUAGES = ['ar', 'bn', 'gu', 'hi', 'kn', 'ml', 'mr', 'pa', 'ta', 'te', 'ur']

# Required fields in each JSON record
REQUIRED_FIELDS = ['en', 'translation', 'target_lang', 'domain', 'complexity']


def validate_language_folder(folder_path: str) -> bool:
    """
    Validate if the provided language folder exists and is supported.
    
    Args:
        folder_path: Path to the language folder
        
    Returns:
        bool: True if valid, False otherwise
    """
    if not os.path.isdir(folder_path):
        logger.error(f"Directory does not exist: {folder_path}")
        return False
    
    # Extract the language code from the folder path
    lang_code = os.path.basename(folder_path)
    if lang_code not in SUPPORTED_LANGUAGES:
        logger.warning(f"Language '{lang_code}' is not in the list of supported languages: {SUPPORTED_LANGUAGES}")
        # We'll allow processing anyway but warn the user
    
    return True


def discover_jsonl_files(folder_path: str) -> List[str]:
    """
    Discover all JSONL files in the specified folder.
    
    Args:
        folder_path: Path to the language folder
        
    Returns:
        List[str]: List of paths to JSONL files
    """
    jsonl_files = []
    for root, _, files in os.walk(folder_path):
        for file in files:
            if file.endswith('.jsonl'):
                jsonl_files.append(os.path.join(root, file))
    
    logger.info(f"Found {len(jsonl_files)} JSONL files in {folder_path}")
    return jsonl_files


def is_valid_json_record(record: Dict[str, Any]) -> bool:
    """
    Validate that a JSON record contains all required fields.
    
    Args:
        record: JSON record to validate
        
    Returns:
        bool: True if valid, False otherwise
    """
    for field in REQUIRED_FIELDS:
        if field not in record:
            return False
    return True


def load_and_validate_jsonl(file_path: str) -> Optional[List[Dict[str, Any]]]:
    """
    Load a JSONL file and validate each record.
    
    Args:
        file_path: Path to the JSONL file
        
    Returns:
        Optional[List[Dict[str, Any]]]: List of valid JSON records or None if errors occurred
    """
    valid_records = []
    invalid_count = 0
    
    try:
        with open(file_path, 'r', encoding='utf-8') as f:
            for i, line in enumerate(f, 1):
                try:
                    line = line.strip()
                    if not line:
                        continue
                    
                    record = json.loads(line)
                    
                    if is_valid_json_record(record):
                        valid_records.append(record)
                    else:
                        logger.warning(f"Line {i} in {file_path} is missing required fields")
                        invalid_count += 1
                        
                except json.JSONDecodeError:
                    logger.warning(f"Failed to parse JSON at line {i} in {file_path}")
                    invalid_count += 1
                except Exception as e:
                    logger.warning(f"Error processing line {i} in {file_path}: {str(e)}")
                    invalid_count += 1
        
        if invalid_count > 0:
            logger.warning(f"Found {invalid_count} invalid records in {file_path}")
        
        logger.info(f"Successfully loaded {len(valid_records)} valid records from {file_path}")
        return valid_records
    
    except Exception as e:
        logger.error(f"Failed to process file {file_path}: {str(e)}")
        return None


def convert_jsonl_to_parquet(jsonl_file: str) -> bool:
    """
    Convert a JSONL file to Parquet format.
    
    Args:
        jsonl_file: Path to the JSONL file
        
    Returns:
        bool: True if conversion was successful, False otherwise
    """
    try:
        logger.info(f"Processing {jsonl_file}")
        
        # Load and validate the JSONL file
        records = load_and_validate_jsonl(jsonl_file)
        if not records:
            logger.error(f"No valid records found in {jsonl_file}")
            return False
        
        # Create output file path
        output_file = jsonl_file.replace('.jsonl', '.parquet')
        
        # Create the dataset
        dataset = Dataset.from_list(records)
        
        # Save as Parquet
        dataset.to_parquet(output_file)
        
        logger.info(f"Successfully converted {jsonl_file} to {output_file}")
        return True
    
    except Exception as e:
        logger.error(f"Failed to convert {jsonl_file} to Parquet: {str(e)}")
        return False


def process_language_folder(folder_path: str) -> Dict[str, int]:
    """
    Process all JSONL files in a language folder.
    
    Args:
        folder_path: Path to the language folder
        
    Returns:
        Dict[str, int]: Statistics about the conversion process
    """
    stats = {
        'total': 0,
        'success': 0,
        'failed': 0
    }
    
    if not validate_language_folder(folder_path):
        return stats
    
    jsonl_files = discover_jsonl_files(folder_path)
    stats['total'] = len(jsonl_files)
    
    if not jsonl_files:
        logger.warning(f"No JSONL files found in {folder_path}")
        return stats
    
    for jsonl_file in jsonl_files:
        success = convert_jsonl_to_parquet(jsonl_file)
        if success:
            stats['success'] += 1
        else:
            stats['failed'] += 1
    
    return stats


def main():
    """
    Main entry point for the script.
    """
    parser = argparse.ArgumentParser(
        description='Convert JSONL files to Parquet format with support for Indic languages.'
    )
    parser.add_argument(
        'language_folder', 
        type=str,
        help='Path to the language folder (e.g., ar, bn, gu, hi, kn, ml, mr, pa, ta, te, ur)'
    )
    
    args = parser.parse_args()
    
    logger.info("Starting conversion process")
    stats = process_language_folder(args.language_folder)
    
    logger.info(f"Conversion completed. Stats: {stats}")
    
    if stats['failed'] > 0:
        logger.warning(f"Failed to convert {stats['failed']} out of {stats['total']} files.")
        return 1
    
    return 0


if __name__ == '__main__':
    sys.exit(main())