# -*- coding: utf-8 -*-
"""
SPDX-FileCopyrightText: 2023-2025 PeppermintOS Team
(peppermintosteam@proton.me)

SPDX-License-Identifier: GPL-3.0-or-later

This module is responsible for creating a SquashFS image from the root filesystem directory.
It utilizes the `mksquashfs` utility found within the PEPHOSTDIR to generate a compressed
read-only filesystem image that will be used in the PeppermintOS ISO.

The module handles the process of determining the required size, creating a temporary ext3 filesystem,
copying the root filesystem to it, unmounting, and then using `mksquashfs` to create the final image.
Temporary directories are cleaned up after the process is complete.

Credits:
  - PeppermintOS Team (peppermintosteam@proton.me) - Development and maintenance of the project.

License:
  This code is distributed under the GNU General Public License version 3 or later (GPL-3.0-or-later).
  For more details, please refer to the LICENSE file included in the project or visit:
  https://www.gnu.org/licenses/gpl-3.0.html
"""

import subprocess
import logging
import os
import sys
import tempfile
import shutil

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.insert(0, BASE_DIR)

try:
    from builder.core.bootstrap.paths import paths
    from builder.core.command_runner import run_command
    from builder.configs import logger_config
    logger = logger_config.setup_logger('squashfs')  # Pass the 'squashfs' argument
except ImportError as e:
    print(f"Error importing necessary modules: {e}. Ensure your environment is set up correctly.")
    sys.exit(1)


def create_squashfs_image(rootfs_dir, squashfs_output_file, pep_host_dir, logger):
    """
    Initiates the creation of the SquashFS image using mksquashfs from PEPHOSTDIR.

    Args:
        rootfs_dir (str): The path to the root filesystem directory.
        squashfs_output_file (str): The desired path for the output SquashFS image file.
        pep_host_dir (str): The path to the PEPHOSTDIR, which should contain the mksquashfs utility.
        logger (logging.Logger): The logger instance to use for logging messages.

    Returns:
        str or None: The path to the created SquashFS image file if successful, otherwise None.
    """
    logger.info("=> Initiating SquashFS image creation using mksquashfs from PEPHOSTDIR...")
    logger.info(f"=> Source ROOTFS directory: {rootfs_dir}")
    logger.info(f"=> Output SquashFS file: {squashfs_output_file}")
    logger.info(f"=> PEPHOSTDIR: {pep_host_dir}")

    build_dir = paths['BUILDDIR']
    image_dir = paths['IMAGEDIR']
    liveos_tmp_dir = os.path.join(build_dir, "tmp", "LiveOS")
    temp_rootfs_mount_dir = os.path.join(build_dir, "tmp-rootfs")

    os.makedirs(liveos_tmp_dir, exist_ok=True)
    os.makedirs(temp_rootfs_mount_dir, exist_ok=True)

    try:
        # Find out required size for the rootfs
        rootfs_size_command = ["du", "--apparent-size", "-sm", rootfs_dir]
        result = run_command(rootfs_size_command)
        if result.returncode != 0:
            logger.error(f"Error getting ROOTFS size: {result.stderr.strip()}")
            return None
        rootfs_size_mb = int(result.stdout.split()[0])
        ext3_image_size_mb = 2 * rootfs_size_mb # Double the size

        ext3_image_file = os.path.join(liveos_tmp_dir, "ext3fs.img")
        truncate_command = ["truncate", "-s", f"{ext3_image_size_mb}M", ext3_image_file]
        run_command(truncate_command)

        mkfs_command = ["mkfs.ext3", "-F", "-m1", ext3_image_file]
        run_command(mkfs_command)

        mount_command = ["mount", "-o", "loop", ext3_image_file, temp_rootfs_mount_dir]
        run_command(mount_command)

        copy_command = ["cp", "-a", f"{rootfs_dir}/.", temp_rootfs_mount_dir]
        run_command(copy_command)

        umount_command = ["umount", "-f", temp_rootfs_mount_dir]
        run_command(umount_command)

        output_dir = os.path.dirname(squashfs_output_file)
        os.makedirs(output_dir, exist_ok=True)
        mksquashfs_path = os.path.join(pep_host_dir, "usr", "bin", "mksquashfs")
        mksquashfs_command = [
            mksquashfs_path,
            os.path.join(build_dir, "tmp"),
            squashfs_output_file,
            "-comp", "zstd",
            "-e19",
        ]

        logger.info(f"=> Executing mksquashfs command: {' '.join(mksquashfs_command)}")
        result = run_command(mksquashfs_command)
        if result.returncode != 0:
            logger.error(f"Error creating SquashFS image: {result.stderr.strip()}")
            return None

        chmod_command = ["chmod", "444", squashfs_output_file]
        run_command(chmod_command)

        return squashfs_output_file

    except Exception as e:
        logger.error(f"Unexpected error while creating SquashFS image: {e}")
        return None

    finally:
        # Cleanup temporary directories
        if os.path.exists(temp_rootfs_mount_dir):
            shutil.rmtree(temp_rootfs_mount_dir, ignore_errors=True)
        if os.path.exists(os.path.join(build_dir, "tmp")):
            shutil.rmtree(os.path.join(build_dir, "tmp"), ignore_errors=True)
        if os.path.exists(os.path.join(image_dir, "rootfs")):
            shutil.rmtree(os.path.join(image_dir, "rootfs"), ignore_errors=True)