"""
Module for PiSCSI Web Interface utility methods
"""

import logging
from grp import getgrall
from os import path
from pathlib import Path
from ua_parser import user_agent_parser
from re import findall

from flask import request, make_response, abort
from flask_babel import _
from werkzeug.utils import secure_filename

from piscsi.sys_cmds import SysCmds


def working_dirs_exist(working_dirs):
    """
    Method for validating that working dirs exist.
    Takes (tuple) of (str) working_dirs with paths to required dirs.
    """
    for dir_path in working_dirs:
        if not Path(dir_path).exists():
            abort(
                503,
                _(f"Please create directory: {dir_path}"),
            )


def get_valid_scsi_ids(devices, reserved_ids):
    """
    Takes a list of (dict)s devices, and list of (int)s reserved_ids.
    Returns:
    - (list) of (int)s valid_ids, which are the SCSI ids that are not reserved
    - (list) of (int)s occupied_ids, which are the SCSI ids were a device is attached
    - (int) recommended_id, which is the id that the Web UI should default to recommend
    """
    occupied_ids = []
    for device in devices:
        occupied_ids.append(device["id"])

    unoccupied_ids = [i for i in list(range(8)) if i not in reserved_ids + occupied_ids]
    unoccupied_ids.sort()
    valid_ids = [i for i in list(range(8)) if i not in reserved_ids]
    valid_ids.sort(reverse=True)

    if unoccupied_ids:
        recommended_id = unoccupied_ids[-1]
    else:
        if occupied_ids:
            recommended_id = occupied_ids[0]
        else:
            recommended_id = 0

    return {
        "valid_ids": valid_ids,
        "occupied_ids": occupied_ids,
        "recommended_id": recommended_id,
    }


def sort_and_format_devices(devices):
    """
    Takes a (list) of (dict)s devices and returns a (list) of (dict)s.
    Sorts by SCSI ID acending (0 to 7).
    For SCSI IDs where no device is attached, inject a (dict) with placeholder text.
    """
    occupied_ids = []
    formatted_devices = []
    for device in devices:
        occupied_ids.append(device["id"])
        device["device_name"] = get_device_name(device["device_type"])
        formatted_devices.append(device)

    # Add placeholder data for non-occupied IDs
    for scsi_id in range(8):
        if scsi_id not in occupied_ids:
            formatted_devices.append(
                {
                    "id": scsi_id,
                    "unit": "-",
                    "device_name": "-",
                    "status": "-",
                    "file": "-",
                    "product": "-",
                }
            )

    return formatted_devices


def map_device_types_and_names(device_types):
    """
    Takes a (dict) corresponding to the data structure returned by PiscsiCmds.get_device_types()
    Returns a (dict) of device_type:device_name mappings of localized device names
    """
    for device in device_types.keys():
        device_types[device]["name"] = get_device_name(device)

    return device_types


# pylint: disable=too-many-return-statements
def get_device_name(device_type):
    """
    Takes a four letter device acronym (str) device_type.
    Returns the human-readable name for the device type.
    """
    if device_type == "SCHD":
        return _("Hard Disk Drive")
    if device_type == "SCRM":
        return _("Removable Disk Drive")
    if device_type == "SCMO":
        return _("Magneto-Optical Drive")
    if device_type == "SCCD":
        return _("CD/DVD Drive")
    if device_type == "SCBR":
        return _("Host Bridge")
    if device_type == "SCDP":
        return _("Ethernet Adapter")
    if device_type == "SCLP":
        return _("Printer")
    if device_type == "SCHS":
        return _("Host Services")
    return device_type


def map_image_file_descriptions(file_suffixes):
    """
    Takes a (list) of (str) file suffixes for images file types.
    Returns a (dict) with file suffix and description pairs, both (str)
    """
    supported_image_types = {}
    for suffix in file_suffixes:
        supported_image_types[suffix] = get_image_description(suffix)

    return supported_image_types


# pylint: disable=too-many-return-statements
def get_image_description(file_suffix):
    """
    Takes a three char file suffix (str) file_suffix.
    Returns the help text description for said file suffix.
    """
    if file_suffix == "hds":
        return _("Hard Disk Image (Generic)")
    if file_suffix == "hda":
        return _("Hard Disk Image (Apple)")
    if file_suffix == "hdn":
        return _("Hard Disk Image (NEC)")
    if file_suffix == "hd1":
        return _("Hard Disk Image (SCSI-1)")
    if file_suffix == "hdr":
        return _("Removable Disk Image")
    if file_suffix == "mos":
        return _("Magneto-Optical Disk Image")
    return file_suffix


def format_image_list(image_files, device_types=None):
    """
    Takes a (list) of (dict) image_files and optional (list) device_types
    Returns a formatted (dict) with groups of image_files per subdir key
    """

    root_image_files = []
    subdir_image_files = {}
    for image in image_files:
        if (image["detected_type"] != "UNDEFINED") and device_types:
            image["detected_type_name"] = device_types[image["detected_type"]]["name"]
        subdir_path = findall("^.*/", image["name"])
        if subdir_path:
            subdir = subdir_path[0]
            if f"images/{subdir}" in subdir_image_files.keys():
                subdir_image_files[f"images/{subdir}"].append(image)
            else:
                subdir_image_files[f"images/{subdir}"] = [image]
        else:
            root_image_files.append(image)

    formatted_image_files = dict(sorted(subdir_image_files.items()))
    if root_image_files:
        formatted_image_files["images/"] = root_image_files
    return formatted_image_files


def format_drive_properties(drive_properties):
    """
    Takes a (dict) with structured drive properties data
    Returns a (dict) with the formatted properties, one (list) per device type
    """
    hd_conf = []
    cd_conf = []
    rm_conf = []
    mo_conf = []

    for device in drive_properties:
        # Fallback for when the properties data is corrupted, to avoid crashing the web app.
        # The integration tests will catch this scenario, but relies on the web app not crashing.
        if not device.get("name"):
            device["name"] = ""

        device["secure_name"] = secure_filename(device["name"])

        if device.get("size"):
            device["size_mb"] = f'{device["size"] / 1024 / 1024:,.2f}'

        if device["device_type"] == "SCHD":
            hd_conf.append(device)
        elif device["device_type"] == "SCCD":
            cd_conf.append(device)
        elif device["device_type"] == "SCRM":
            rm_conf.append(device)
        elif device["device_type"] == "SCMO":
            mo_conf.append(device)

    return {
        "hd_conf": hd_conf,
        "cd_conf": cd_conf,
        "rm_conf": rm_conf,
        "mo_conf": mo_conf,
    }


def get_properties_by_drive_name(drives, drive_name):
    """
    Takes (list) of (dict) drives, and (str) drive_name
    Returns (dict) with the collection of drive properties that matches drive_name
    """
    drives.sort(key=lambda item: item.get("name"))

    for drive in drives:
        if drive["name"] == drive_name:
            return {
                "file_type": drive["file_type"],
                "vendor": drive["vendor"],
                "product": drive["product"],
                "revision": drive["revision"],
                "block_size": drive["block_size"],
                "size": drive["size"],
            }

    logging.error("Properties for drive '%s' does not exist in database", drive_name)
    return False


def auth_active(group):
    """
    Inspects if the group defined in (str) group exists on the system.
    If it exists, tell the webapp to enable authentication.
    Returns a (dict) with (bool) status and (str) msg
    """
    groups = [g.gr_name for g in getgrall()]
    if group in groups:
        return {
            "status": True,
            "msg": _("You must log in to use this function"),
        }
    return {"status": False, "msg": ""}


def is_bridge_configured(interface):
    """
    Takes (str) interface of a network device being attached.
    Returns a (dict) with (bool) status and (str) msg
    """
    PATH_SYSCTL = "/etc/sysctl.conf"
    PATH_IPTV4 = "/etc/iptables/rules.v4"
    PATH_DHCPCD = "/etc/dhcpcd.conf"
    PATH_BRIDGE = "/etc/network/interfaces.d/piscsi_bridge"
    return_msg = _("Configure the network bridge for %(interface)s first: ", interface=interface)
    to_configure = []
    sys_cmd = SysCmds()
    if interface.startswith("wlan"):
        if not sys_cmd.introspect_file(PATH_SYSCTL, r"^net\.ipv4\.ip_forward=1$"):
            to_configure.append("IPv4 forwarding")
        if not Path(PATH_IPTV4).is_file():
            to_configure.append("NAT")
    else:
        if not sys_cmd.introspect_file(PATH_DHCPCD, r"^denyinterfaces " + interface + r"$"):
            to_configure.append(PATH_DHCPCD)
        if not Path(PATH_BRIDGE).is_file():
            to_configure.append(PATH_BRIDGE)

    if to_configure:
        return {"status": False, "msg": return_msg + ", ".join(to_configure)}

    return {"status": True, "msg": ""}


def is_safe_path(file_name):
    """
    Takes (Path) file_name with the path to a file on the file system
    Returns True if the path is safe
    Returns False if the path is either absolute, or tries to traverse the file system
    """
    if file_name.is_absolute() or ".." in str(file_name) or str(file_name)[0] == "~":
        return {
            "status": False,
            "msg": _("No permission to use path '%(file_name)s'", file_name=file_name),
        }

    return {"status": True, "msg": ""}


def upload_with_dropzonejs(image_dir):
    """
    Takes (str) image_dir which is the path to the image dir to store files.
    Opens a stream to transfer a file via the embedded dropzonejs library.
    """
    log = logging.getLogger("pydrop")
    file_object = request.files["file"]
    file_name = secure_filename(file_object.filename)

    save_path = path.join(image_dir, file_name)
    current_chunk = int(request.form["dzchunkindex"])

    # Makes sure not to overwrite an existing file,
    # but continues writing to a file transfer in progress
    if path.exists(save_path) and current_chunk == 0:
        return make_response(_("The file already exists!"), 400)

    try:
        with open(save_path, "ab") as save:
            save.seek(int(request.form["dzchunkbyteoffset"]))
            save.write(file_object.stream.read())
    except OSError:
        log.exception("Could not write to file")
        return make_response(_("Unable to write the file to disk!"), 500)

    total_chunks = int(request.form["dztotalchunkcount"])

    if current_chunk + 1 == total_chunks:
        # Validate the resulting file size after writing the last chunk
        if path.getsize(save_path) != int(request.form["dztotalfilesize"]):
            log.error("File size mismatch between the original file and transferred file.")
            return make_response(_("Transferred file corrupted!"), 500)

    return make_response(_("File upload successful!"), 200)


def browser_supports_modern_themes():
    """
    Determines if the browser supports the HTML/CSS/JS features used in non-legacy themes.
    """
    user_agent_string = request.headers.get("User-Agent")
    if not user_agent_string:
        return False

    user_agent = user_agent_parser.Parse(user_agent_string)
    if not user_agent["user_agent"]["family"]:
        return False

    # (family, minimum version)
    supported_browsers = [
        ("Safari", 14),
        ("Chrome", 100),
        ("Firefox", 100),
        ("Edge", 100),
        ("Mobile Safari", 14),
        ("Chrome Mobile", 100),
    ]

    current_ua_family = user_agent["user_agent"]["family"]
    current_ua_version = user_agent["user_agent"]["major"]
    logging.info(f"Identified browser as family={current_ua_family}, version={current_ua_version}")

    # Supported browsers cannot be identified without a version
    if not current_ua_version:
        return False

    for supported_browser, supported_version in supported_browsers:
        if (
            current_ua_family == supported_browser
            and float(current_ua_version) >= supported_version
        ):
            return True
    return False