#
# Copyright (C) 2022 Soleta Networks <info@soleta.eu>
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the
# Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.

import subprocess
import shutil
import logging
import hivex
import shlex
from src.log import OgError
from src.utils.grub import install_main_grub, install_linux_grub
from src.utils.bcd import update_bcd
from src.utils.probe import *
from src.utils.disk import *
from src.utils.winreg import *
from src.utils.fs import *
from src.utils.uefi import *
from src.utils.fstab import *
from socket import gethostname

CONFIGUREOS_LEGACY_ENABLED = False


def set_windows_hostname(disk, partition, name):
    logging.info(f'Setting Windows hostname to {name}')

    if len(name) > 15:
        logging.warning(f'Windows does not permit hostnames that exceed 15 characters. Truncating {name}')
        name = name[0:15]

    byte_name = name.encode(WINDOWS_HIVE_ENCODING)

    device = get_partition_device(disk, partition)
    mountpoint = device.replace('dev', 'mnt')

    if not mount_mkdir(device, mountpoint):
        raise OgError(f'Unable to mount {device} into {mountpoint}')

    try:
        hive_path = mountpoint + WINDOWS_HIVE_SYSTEM
        hive = hive_handler_open(hive_path, write=True)
        root = hive.root()

        select_node = get_node_child_from_path(hive, root, 'Select')
        current_control_set_number = get_value_from_node(hive, select_node, 'Current')

        control_set = f'ControlSet{current_control_set_number:03}'

        computer_name_node = get_node_child_from_path(hive, root, f'{control_set}/Control/ComputerName/ComputerName')
        name_value = {'key': 'ComputerName', 't': RegistryType.SZ.value, 'value': byte_name}
        hive.node_set_value(computer_name_node, name_value)

        parameters_node = get_node_child_from_path(hive, root, f'{control_set}/Services/Tcpip/Parameters')

        hostname_value = {'key': 'HostName', 't': RegistryType.SZ.value, 'value': byte_name}
        hive.node_set_value(parameters_node, hostname_value)

        nvhostname_value = {'key': 'NV Hostname', 't': RegistryType.SZ.value, 'value': byte_name}
        hive.node_set_value(parameters_node, nvhostname_value)

        hive.commit(hive_path)
    except Exception as e:
        raise OgError(f'Unable to set Windows hostname: {e}') from e
    finally:
        umount(mountpoint)


def set_linux_hostname(disk, partition, name):
    logging.info(f'Setting Linux hostname to {name}')

    if len(name) > 64:
        logging.warning(f'Linux does not permit hostnames that exceed 64 characters. Truncating {name}')
        name = name[0:64]

    device = get_partition_device(disk, partition)
    mountpoint = device.replace('dev', 'mnt')

    if not mount_mkdir(device, mountpoint):
        raise OgError(f'Unable to mount {device} into {mountpoint}')

    try:
        hostname_path = f'{mountpoint}/etc/hostname'
        with open(hostname_path, 'w') as f:
            f.write(name)
    except OSError as e:
        raise OgError(f'Unable to set Linux hostname: {e}') from e
    finally:
        umount(mountpoint)


def configure_os_custom(disk, partition):
    command_path = shutil.which('configureOsCustom')
    if not command_path:
        raise OgError('configureOsCustom not found')

    logging.info(f'Found configureOsCustom script, invoking it...')

    cmd_configure = f"{command_path} {disk} {partition}"

    proc = subprocess.run(shlex.split(cmd_configure),
                          stdout=subprocess.DEVNULL,
                          stderr=subprocess.DEVNULL,
                          encoding='utf-8',
                          check=True)
    if proc.returncode != 0:
        logging.warning(f'{cmd_configure} returned non-zero exit status {proc.returncode}')


def windows_register_c_drive(disk, partition):
    device = get_partition_device(disk, partition)
    mountpoint = device.replace('dev', 'mnt')

    if not mount_mkdir(device, mountpoint):
        raise OgError(f'Unable to mount {device} into {mountpoint}')

    hive_path = f'{mountpoint}{WINDOWS_HIVE_SYSTEM}'

    try:
        hive = hive_handler_open(hive_path, write=True)
        root = hive.root()
        device_node = get_node_child_from_path(hive, root, 'MountedDevices')

        if is_uefi_supported():
            part_id = get_part_id_bytes(disk, partition)
            value = b'DMIO:ID:' + part_id
        else:
            disk_id = get_disk_id_bytes(disk)
            part_offset = get_part_id_bytes(disk, partition)

            value = bytes(disk_id + part_offset)

        device_value = {'key': '\DosDevices\C:', 't': RegistryType.BINARY.value, 'value': value}
        hive.node_set_value(device_node, device_value)
        hive.commit(hive_path)
    finally:
        umount(mountpoint)


def configure_mbr_boot_sector(disk, partition):
    cmd_configure = f"ogFixBootSector {disk} {partition}"

    proc = subprocess.run(cmd_configure,
                          stdout=subprocess.DEVNULL,
                          stderr=subprocess.DEVNULL,
                          encoding='utf-8',
                          shell=True,
                          check=True)
    if proc.returncode != 0:
        logging.warning(f'{cmd_configure} returned non-zero exit status {proc.returncode}')


def configure_fstab(disk, partition):
    logging.info(f'Configuring /etc/fstab')
    device = get_partition_device(disk, partition)
    mountpoint = device.replace('dev', 'mnt')

    if not mount_mkdir(device, mountpoint):
        raise OgError(f'Unable to mount {device} into {mountpoint}')

    try:
        update_fstab(disk, partition, mountpoint)
    finally:
        umount(mountpoint)

def configure_os_linux(disk, partition):
    hostname = gethostname()
    set_linux_hostname(disk, partition, hostname)

    configure_fstab(disk, partition)

    install_linux_grub(disk, partition)

    if is_uefi_supported():
        _, _, esp_part_number = get_efi_partition(disk, enforce_gpt=True)
        install_main_grub()


def configure_os_windows(disk, partition):
    hostname = gethostname()
    set_windows_hostname(disk, partition, hostname)

    if is_uefi_supported():
        restore_windows_efi_bootloader(disk, partition)

        _, _, esp_part_number = get_efi_partition(disk, enforce_gpt=True)
        install_main_grub()
    else:
        configure_mbr_boot_sector(disk, partition)

    update_bcd(disk, partition)
    windows_register_c_drive(disk, partition)


def configure_os_legacy(disk, partition):
    cmd_configure = f"configureOs {disk} {partition}"

    try:
        proc = subprocess.run(cmd_configure,
                              stdout=subprocess.PIPE,
                              encoding='utf-8',
                              shell=True,
                              check=True)
        out = proc.stdout
    except OSError as e:
        raise OgError(f'Error processing configureOs: {e}') from e


def configure_os(disk, partition):
    if CONFIGUREOS_LEGACY_ENABLED:
        configure_os_legacy(disk, partition)

        if shutil.which('configureOsCustom'):
            configure_os_custom(disk, partition)

        return

    device = get_partition_device(disk, partition)
    mountpoint = device.replace('dev', 'mnt')

    logging.info(f'Configuring OS at {device}...')

    if not mount_mkdir(device, mountpoint):
        raise OgError(f'Cannot probe OS family. Unable to mount {device} into {mountpoint}')

    os_family = get_os_family(mountpoint)
    umount(mountpoint)

    if os_family == OSFamily.WINDOWS:
        configure_os_windows(disk, partition)
    elif os_family == OSFamily.LINUX:
        configure_os_linux(disk, partition)

    if shutil.which('configureOsCustom'):
        configure_os_custom(disk, partition)