#!/usr/bin/env python3
"""
Excel Formula Recalculation Script
Recalculates all formulas in an Excel file using LibreOffice.

If LibreOffice (`soffice`) is unavailable on this machine, the script returns
a clear error pointing to the pure-Python fallback `recalc_fallback.py`.
DO NOT work around the missing dependency by hardcoding computed values into
the cells — that breaks the spreadsheet's interactivity and violates the
xlsx skill's "Use Formulas, Not Hardcoded Values" rule.
"""

import json
import shutil
import sys
import subprocess
import os
import platform
from pathlib import Path
from openpyxl import load_workbook


def _libreoffice_missing_message(filename: str) -> dict:
    return {
        "status": "error",
        "error": "LibreOffice (`soffice`) is not installed or not on PATH.",
        "fallback": (
            "Run the pure-Python fallback instead — it preserves all formulas "
            "and tells Excel/WPS/Numbers to recompute on open:\n"
            f"    python scripts/recalc_fallback.py {filename}\n\n"
            "DO NOT hardcode computed values into formula cells to work around "
            "this. That breaks interactivity and violates the xlsx skill rules.\n\n"
            "To install LibreOffice (recommended for full QA):\n"
            "  macOS: brew install --cask libreoffice\n"
            "  Linux: sudo apt-get install libreoffice"
        ),
    }


def setup_libreoffice_macro():
    """Setup LibreOffice macro for recalculation if not already configured"""
    if platform.system() == 'Darwin':
        macro_dir = os.path.expanduser('~/Library/Application Support/LibreOffice/4/user/basic/Standard')
    else:
        macro_dir = os.path.expanduser('~/.config/libreoffice/4/user/basic/Standard')
    
    macro_file = os.path.join(macro_dir, 'Module1.xba')
    
    if os.path.exists(macro_file):
        with open(macro_file, 'r') as f:
            if 'RecalculateAndSave' in f.read():
                return True
    
    if not os.path.exists(macro_dir):
        subprocess.run(['soffice', '--headless', '--terminate_after_init'], 
                      capture_output=True, timeout=10)
        os.makedirs(macro_dir, exist_ok=True)
    
    macro_content = '''<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE script:module PUBLIC "-//OpenOffice.org//DTD OfficeDocument 1.0//EN" "module.dtd">
<script:module xmlns:script="http://openoffice.org/2000/script" script:name="Module1" script:language="StarBasic">
    Sub RecalculateAndSave()
      ThisComponent.calculateAll()
      ThisComponent.store()
      ThisComponent.close(True)
    End Sub
</script:module>'''
    
    try:
        with open(macro_file, 'w') as f:
            f.write(macro_content)
        return True
    except Exception:
        return False


def recalc(filename, timeout=30):
    """
    Recalculate formulas in Excel file and report any errors
    
    Args:
        filename: Path to Excel file
        timeout: Maximum time to wait for recalculation (seconds)
    
    Returns:
        dict with error locations and counts
    """
    if not Path(filename).exists():
        return {'error': f'File {filename} does not exist'}

    abs_path = str(Path(filename).absolute())

    # Detect missing LibreOffice up front so the agent gets clear guidance
    # instead of an opaque FileNotFoundError or "macro not configured".
    if shutil.which('soffice') is None:
        return _libreoffice_missing_message(filename)

    if not setup_libreoffice_macro():
        return {'error': 'Failed to setup LibreOffice macro'}
    
    cmd = [
        'soffice', '--headless', '--norestore',
        'vnd.sun.star.script:Standard.Module1.RecalculateAndSave?language=Basic&location=application',
        abs_path
    ]
    
    # Handle timeout command differences between Linux and macOS
    if platform.system() != 'Windows':
        timeout_cmd = 'timeout' if platform.system() == 'Linux' else None
        if platform.system() == 'Darwin':
            # Check if gtimeout is available on macOS
            try:
                subprocess.run(['gtimeout', '--version'], capture_output=True, timeout=1, check=False)
                timeout_cmd = 'gtimeout'
            except (FileNotFoundError, subprocess.TimeoutExpired):
                pass
        
        if timeout_cmd:
            cmd = [timeout_cmd, str(timeout)] + cmd
    
    try:
        result = subprocess.run(cmd, capture_output=True, text=True)
    except FileNotFoundError:
        return _libreoffice_missing_message(filename)
    
    if result.returncode != 0 and result.returncode != 124:  # 124 is timeout exit code
        error_msg = result.stderr or 'Unknown error during recalculation'
        if 'Module1' in error_msg or 'RecalculateAndSave' not in error_msg:
            return {'error': 'LibreOffice macro not configured properly'}
        else:
            return {'error': error_msg}
    
    # Check for Excel errors in the recalculated file - scan ALL cells
    try:
        wb = load_workbook(filename, data_only=True)
        
        excel_errors = ['#VALUE!', '#DIV/0!', '#REF!', '#NAME?', '#NULL!', '#NUM!', '#N/A']
        error_details = {err: [] for err in excel_errors}
        total_errors = 0
        
        for sheet_name in wb.sheetnames:
            ws = wb[sheet_name]
            # Check ALL rows and columns - no limits
            for row in ws.iter_rows():
                for cell in row:
                    if cell.value is not None and isinstance(cell.value, str):
                        for err in excel_errors:
                            if err in cell.value:
                                location = f"{sheet_name}!{cell.coordinate}"
                                error_details[err].append(location)
                                total_errors += 1
                                break
        
        wb.close()
        
        # Build result summary
        result = {
            'status': 'success' if total_errors == 0 else 'errors_found',
            'total_errors': total_errors,
            'error_summary': {}
        }
        
        # Add non-empty error categories
        for err_type, locations in error_details.items():
            if locations:
                result['error_summary'][err_type] = {
                    'count': len(locations),
                    'locations': locations[:20]  # Show up to 20 locations
                }
        
        # Add formula count for context - also check ALL cells
        wb_formulas = load_workbook(filename, data_only=False)
        formula_count = 0
        for sheet_name in wb_formulas.sheetnames:
            ws = wb_formulas[sheet_name]
            for row in ws.iter_rows():
                for cell in row:
                    if cell.value and isinstance(cell.value, str) and cell.value.startswith('='):
                        formula_count += 1
        wb_formulas.close()
        
        result['total_formulas'] = formula_count
        
        return result
        
    except Exception as e:
        return {'error': str(e)}


def main():
    if len(sys.argv) < 2:
        print("Usage: python recalc.py <excel_file> [timeout_seconds]")
        print("\nRecalculates all formulas in an Excel file using LibreOffice")
        print("\nReturns JSON with error details:")
        print("  - status: 'success' or 'errors_found'")
        print("  - total_errors: Total number of Excel errors found")
        print("  - total_formulas: Number of formulas in the file")
        print("  - error_summary: Breakdown by error type with locations")
        print("    - #VALUE!, #DIV/0!, #REF!, #NAME?, #NULL!, #NUM!, #N/A")
        sys.exit(1)
    
    filename = sys.argv[1]
    timeout = int(sys.argv[2]) if len(sys.argv) > 2 else 30
    
    result = recalc(filename, timeout)
    print(json.dumps(result, indent=2))


if __name__ == '__main__':
    main()