#!/usr/bin/env python3
"""
Excel to Tabulated Text Converter

Converts Excel files in the reports directory to tabulated text format
for processing by LLM.
"""

import os
import pandas as pd
from pathlib import Path
from typing import List, Optional
from tabulate import tabulate


def excel_to_tabulated_text(excel_path: str, output_file: Optional[str] = None) -> str:
    """
    Convert Excel file to tabulated text format.
    
    Args:
        excel_path: Path to Excel file
        output_file: Optional path to save output. If None, returns string.
    
    Returns:
        Tabulated text representation of Excel data
    """
    try:
        xl_file = pd.ExcelFile(excel_path)
        filename = Path(excel_path).name
        output_lines = []
        
        for sheet_name in xl_file.sheet_names:
            # Try reading with header first
            try:
                df = pd.read_excel(xl_file, sheet_name=sheet_name)
                if df.empty:
                    # Try without header
                    df = pd.read_excel(xl_file, sheet_name=sheet_name, header=None)
            except Exception:
                # Fallback: read without header
                df = pd.read_excel(xl_file, sheet_name=sheet_name, header=None)
            
            if df.empty:
                continue
            
            # Add file and sheet headers
            output_lines.append(f"FILENAME: {filename}")
            output_lines.append(f"SHEET: {sheet_name}")
            output_lines.append("")
            
            # Replace NaN with empty string
            df = df.fillna("")
            
            # Use tabulate to format the table nicely
            # Using 'simple' format for clean, readable tables
            # First row as headers if column names exist, otherwise use indices
            if df.columns.tolist() and not all(str(col).startswith('Unnamed') for col in df.columns):
                # Use column names as headers
                table_str = tabulate(df, headers='keys', tablefmt='simple', showindex=False)
            else:
                # No meaningful headers, use first row or no headers
                table_str = tabulate(df, headers='firstrow' if len(df) > 0 else 'keys', tablefmt='simple', showindex=False)
            
            output_lines.append(table_str)
            output_lines.append("")
            output_lines.append("=" * 80)
            output_lines.append("")
        
        result = "\n".join(output_lines)
        
        if output_file:
            with open(output_file, 'w', encoding='utf-8') as f:
                f.write(result)
        
        return result
    
    except Exception as e:
        error_msg = f"Error processing {excel_path}: {str(e)}"
        return error_msg


def process_reports_directory(reports_dir: str = "reports") -> str:
    """
    Process all Excel files in the reports directory.
    
    Args:
        reports_dir: Directory containing Excel files
    
    Returns:
        Combined tabulated text from all Excel files
    """
    reports_path = Path(reports_dir)
    if not reports_path.exists():
        return f"Reports directory '{reports_dir}' not found."
    
    all_outputs = []
    excel_files = list(reports_path.glob("*.xlsx")) + list(reports_path.glob("*.xls"))
    
    if not excel_files:
        return f"No Excel files found in '{reports_dir}' directory."
    
    for excel_file in excel_files:
        text_output = excel_to_tabulated_text(str(excel_file))
        all_outputs.append(text_output)
    
    return "\n\n".join(all_outputs)


if __name__ == "__main__":
    import sys
    
    # Process all files in reports directory
    if len(sys.argv) > 1:
        # Single file mode
        output = excel_to_tabulated_text(sys.argv[1])
        print(output)
    else:
        # Directory mode
        output = process_reports_directory()
        print(output)
        
        # Optionally save to file
        output_path = Path("output")
        output_path.mkdir(exist_ok=True)
        with open(output_path / "excel_data.txt", 'w', encoding='utf-8') as f:
            f.write(output)
        print(f"\nOutput saved to: {output_path / 'excel_data.txt'}")