#!/usr/bin/env python3
"""
Utility for building and installing nginx mod_rewrite module.
This script handles downloading, extracting, building, and installing the module.
Returns None on success, or error message string on failure.
"""

import os
import sys
import shutil
import subprocess
import zipfile
import datetime


def build_mod_rewrite():
    """
    Build and install the nginx mod_rewrite module.
    
    Returns:
        str: Error message on failure, None on success
    """
    tmp_dir = '/tmp/nginx-mod-rewrite'
    log_path = '/usr/local/mgr5/var/nginx-mod-rewrite-plugin.log'

    try:
        # Ensure log directory exists
        log_dir = os.path.dirname(log_path)
        if log_dir and not os.path.exists(log_dir):
            os.makedirs(log_dir, exist_ok=True)

        # Setup temporary directory: create or clean
        if os.path.isdir(tmp_dir):
            shutil.rmtree(tmp_dir)
        os.makedirs(tmp_dir, exist_ok=True)

        with open(log_path, 'a') as log_file:
            log_file.write(f'=== Starting module download and install: {datetime.datetime.now()} ===\n')

            # Copy the ZIP file into the temporary directory
            src_zip = '/usr/local/ispmanager-mod_rewrite/mod_rewrite.zip'
            dst_zip = os.path.join(tmp_dir, 'mod_rewrite.zip')
            try:
                shutil.copy(src_zip, dst_zip)
                log_file.write(f'Copied zip to {dst_zip}\n')
            except Exception as e:
                return f'Failed to copy zip: {e}'

            # Extract the ZIP file
            try:
                with zipfile.ZipFile(dst_zip, 'r') as zip_ref:
                    zip_ref.extractall(tmp_dir)
                log_file.write('Extracted zip contents.\n')
            except Exception as e:
                return f'Failed to extract zip: {e}'

            # Locate the extracted root directory
            extracted_root = None
            for entry in os.listdir(tmp_dir):
                full_path = os.path.join(tmp_dir, entry)
                if os.path.isdir(full_path):
                    extracted_root = full_path
                    break
            if not extracted_root:
                return 'Extracted folder not found.'
            log_file.write(f'Using extracted root: {extracted_root}\n')

            # Define the sequence of commands to run
            commands = [
                ['bash', 'package_preparer.sh', 'installdeps'],
                ['bash', 'package_preparer.sh', 'download', '.', 'system'],
                ['bash', 'package_preparer.sh', 'build'],
                ['bash', 'package_preparer.sh', 'installmod']
            ]

            for cmd in commands:
                log_file.write(f'Running command: {" ".join(cmd)}\n')
                result = subprocess.run(cmd, cwd=extracted_root, stdout=log_file, stderr=log_file)
                if result.returncode != 0:
                    return f'Command {" ".join(cmd)} failed with exit code {result.returncode}'

            log_file.write('All commands executed successfully.\n')
    except Exception as exc:
        return f'Unexpected error: {exc}'
    finally:
        # Clean up temporary directory
        try:
            if os.path.isdir(tmp_dir):
                shutil.rmtree(tmp_dir)
        except Exception:
            pass

    return None


if __name__ == '__main__':
    # Run the build process and output result to stdout
    result = build_mod_rewrite()
    if result is not None:
        # On error, write error message to stderr
        print(result, file=sys.stderr)
        sys.exit(1)
    else:
        # On success, exit with 0 (no output)
        sys.exit(0)