"""
update.py - Checking for Program Updates.

Copyright (c) EDCD, All Rights Reserved
Licensed under the GNU General Public License.
See LICENSE file.
"""
from __future__ import annotations

import pathlib
import shutil
import sys
import threading
import os
from dataclasses import dataclass
from tkinter import messagebox
from traceback import print_exc
from typing import TYPE_CHECKING, cast, Any
from xml.etree import ElementTree
import requests
import semantic_version
from config import appname, appversion_nobuild, config, get_update_feed
from EDMCLogging import get_main_logger
from l10n import translations as tr

if TYPE_CHECKING:
    import tkinter as tk

logger = get_main_logger()


def read_normalized_file(path: pathlib.Path) -> str:
    """Read a UTF-8 (with BOM-safe) file and normalize line endings and whitespace."""
    try:
        return path.read_bytes().decode('utf-8-sig').replace('\r\n', '\n').strip()
    except FileNotFoundError:
        return ''


def copy_bundle_file(filename: str, dest_dir: pathlib.Path) -> str:
    """Attempt to copy a missing file from the bundled FDevIDs folder."""
    try:
        shutil.copy(f"FDevIDs/{filename}", dest_dir)
        return read_normalized_file(dest_dir / filename)
    except (FileNotFoundError, shutil.SameFileError):
        logger.info("Bundle copy failed or identical; continuing with empty content.")
        return ''


def fetch_remote_file(url: str) -> str | None:
    """Fetch a remote file and normalize its content."""
    try:
        response = requests.get(url, timeout=20)
        response.raise_for_status()
        return response.text.replace('\r\n', '\n').strip()
    except requests.RequestException:
        return None


def check_for_fdev_updates(silent: bool = False, local: bool = False) -> None:
    """Check for and download FDEV ID file updates."""
    base_path = config.respath_path if local else config.app_dir_path
    fdevid_dir = pathlib.Path(base_path, 'FDevIDs')
    fdevid_dir.mkdir(parents=True, exist_ok=True)

    files_urls = {
        'commodity.csv': 'https://raw.githubusercontent.com/EDCD/FDevIDs/master/commodity.csv',
        'rare_commodity.csv': 'https://raw.githubusercontent.com/EDCD/FDevIDs/master/rare_commodity.csv'
    }

    for filename, url in files_urls.items():
        file_path = fdevid_dir / filename
        local_content = read_normalized_file(file_path) or copy_bundle_file(filename, fdevid_dir)
        remote_content = fetch_remote_file(url)
        if not remote_content:
            if not silent:
                logger.error(f'Failed to download {filename}! Unable to continue.')
            continue

        if local_content == remote_content:
            if not silent:
                logger.info(f'FDEV ID file {filename} already up to date.')
            continue

        if not silent:
            logger.info(f'Updating FDEV ID file {filename}...')
        file_path.write_text(remote_content, encoding='utf-8', newline='\n')


@dataclass(slots=True)
class EDMCVersion:
    """
    Hold all the information about an EDMC version.

    Attributes
    ----------
    version : str
        Full version string
    title: str
        Title of the release
    sv: semantic_version.base.Version
        semantic_version object for this version
    """

    version: str
    title: str
    sv: semantic_version.Version


class Updater:
    """
    Handle checking for updates.

    This is used whether using internal code or an external library such as
    WinSparkle on win32.
    """

    def __init__(self, tkroot: tk.Tk | None = None, provider: str = 'internal'):
        """
        Initialise an Updater instance.

        :param tkroot: reference to the root window of the GUI
        :param provider: 'internal' or other string if not
        """
        self.root: tk.Tk | None = tkroot
        self.provider: str = provider
        self.thread: threading.Thread | None = None
        self.updater: Any | None = None  # ensure attribute exists

        if not self.use_internal() and sys.platform == 'win32':
            self._init_winsparkle()

    def shutdown_request(self) -> None:
        """Receive (Win)Sparkle shutdown request and send it to parent."""
        if not config.shutting_down and self.root:
            self.root.event_generate('<<Quit>>', when="tail")

    def use_internal(self) -> bool:
        """
        Signal if internal update checks should be used.

        :return: bool
        """
        return self.provider == 'internal'

    def _init_winsparkle(self) -> None:
        """Initialize WinSparkle updater for Windows."""
        import ctypes
        try:
            self.updater = cast(ctypes.CDLL, ctypes.cdll.WinSparkle)
            self.updater.win_sparkle_set_appcast_url(get_update_feed().encode())  # Set the appcast URL

            # Set the appversion *without* build metadata, as WinSparkle
            # doesn't do proper Semantic Version checks.
            # NB: It 'accidentally' supports pre-release due to how it
            # splits and compares strings:
            # <https://github.com/vslavik/winsparkle/issues/214>
            self.updater.win_sparkle_set_app_build_version(str(appversion_nobuild()))

            # set up shutdown callback
            self.callback_t = ctypes.CFUNCTYPE(None)  # keep reference
            self.callback_fn = self.callback_t(self.shutdown_request)
            self.updater.win_sparkle_set_shutdown_request_callback(self.callback_fn)

            # Get WinSparkle running
            self.updater.win_sparkle_init()

        except Exception:
            print_exc()
            self.updater = None
            msg = "Updater Failed to Initialize. Please file a bug report!"
            if not os.getenv("EDMC_NO_UI"):
                messagebox.showerror(title=appname, message=msg)
            else:
                logger.error(msg)

    def set_automatic_updates_check(self, onoroff: bool) -> None:
        """
        Set (Win)Sparkle to perform automatic update checks, or not.

        :param onoroff: bool for if we should have the library check or not.
        """
        if self.use_internal():
            return

        if sys.platform == 'win32' and self.updater:
            self.updater.win_sparkle_set_automatic_check_for_updates(onoroff)

    def check_for_updates(self) -> None:
        """Trigger the requisite method to check for an update."""
        if self.use_internal():
            self.thread = threading.Thread(target=self.worker, name='update worker', daemon=True)
            self.thread.start()
        elif sys.platform == 'win32' and self.updater:
            self.updater.win_sparkle_check_update_with_ui()

        check_for_fdev_updates()
        # TEMP: Only include until 6.0
        try:
            check_for_fdev_updates(local=True)
        except Exception as e:
            logger.info("Tried to update bundle FDEV files but failed. Don't worry, "
                        "this likely isn't important and can be ignored unless"
                        f" you run into other issues. If you're curious: {e}")

    def check_appcast(self) -> EDMCVersion | None:
        """
        Manually (no Sparkle or WinSparkle) check the get_update_feed() appcast file.

        Checks if any listed version is semantically greater than the current
        running version.
        :return: EDMCVersion or None if no newer version found
        """
        newversion = None
        items = {}
        try:
            request = requests.get(get_update_feed(), timeout=10)

        except requests.RequestException as ex:
            logger.exception(f'Error retrieving update_feed file: {ex}')
            return None

        try:
            feed = ElementTree.fromstring(request.text)

        except SyntaxError as ex:
            logger.exception(f'Syntax error in update_feed file: {ex}')
            return None

        # For *these* purposes all systems are the same as 'windows', as
        # non-win32 would be running from source.
        sparkle_platform = 'windows'

        for item in feed.findall('channel/item'):
            # xml is a pain with types, hence these ignores
            ver = item.find('enclosure').attrib.get(  # type: ignore
                '{http://www.andymatuschak.org/xml-namespaces/sparkle}version'
            )
            ver_platform = item.find('enclosure').attrib.get(  # type: ignore
                '{http://www.andymatuschak.org/xml-namespaces/sparkle}os'
            )
            if ver_platform != sparkle_platform:
                continue

            # This will change A.B.C.D to A.B.C+D
            semver = semantic_version.Version.coerce(ver)

            items[semver] = EDMCVersion(
                version=str(ver),  # sv might have mangled version
                title=item.find('title').text,  # type: ignore
                sv=semver
            )

        # Look for any remaining version greater than appversion
        simple_spec = semantic_version.SimpleSpec(f'>{appversion_nobuild()}')
        newversion = simple_spec.select(items.keys())
        if newversion:
            return items[newversion]

        return None

    def worker(self) -> None:
        """Perform internal update checking & update GUI status if needs be."""
        newversion = self.check_appcast()

        if newversion and self.root:
            status = self.root.nametowidget(f'.{appname.lower()}.status')
            # LANG: Update Available Text
            status['text'] = tr.tl("{NEWVER} is available").format(NEWVER=newversion.title)
            self.root.update_idletasks()
        else:
            logger.info("No new version available at this time")

    def close(self) -> None:
        """
        Handle the EDMarketConnector.AppWindow.onexit() request.

        NB: We just 'pass' here because:
         1) We might have a worker() going, but no way to make that
            co-operative to respond to a "please stop now" message.
         2) If we're running frozen then we're using (Win)Sparkle to check
            and *it* might have asked this whole application to quit, in
            which case we don't want to ask *it* to quit
        """
        pass