# SPDX-License-Identifier: GPL-3.0-or-later
# Copyright (c) 2008-2026 Andrew Ziem.
#
# This work is licensed under the terms of the GNU GPL, version 3 or
# later.  See the COPYING file in the top-level directory.


"""
Centralized GTK import handling.

This module handles importing GTK and related libraries (e.g., Gdk)
in a way that:
- Avoids crashes when GTK is unavailable
- Suppresses warning messages in non-GUI scenarios
- Provides a single source of truth for GTK availability

Scenarios when GTK is not needed or not available:
- CLI mode requested
- GTK/PyGObject not installed
- chroot
- crontab
- ssh
- limited environment variables (e.g., missing DISPLAY/XAUTHORITY)

Usage:
    from bleachbit.GtkShim import Gtk, Gdk, GObject, GLib, Gio, HAVE_GTK

    if HAVE_GTK:
        # do GTK stuff
"""

import ctypes
import logging
import os
import sys
import tempfile
import warnings
import webbrowser
from pathlib import PureWindowsPath
from html import escape as esc
from traceback import format_exc

from bleachbit import bleachbit_exe_path

HELP_URL = 'https://link.bleachbit.org/get-help'
PYGOBJECT_URL = 'https://link.bleachbit.org/pygobject-lib-bin-error'

logger = logging.getLogger(__name__)

# Module-level GTK availability flag and placeholder objects
HAVE_GTK = False
gi = None
Gtk = None
Gdk = None
GObject = None
GLib = None
Gio = None

# Reason that GTK is unavailable
_gtk_unavailable_reason = None


def path_has_lib_or_bin(path):
    """Check if any directory component is exactly 'lib' or 'bin'.

    This detects a PyGObject bug where certain directory names cause
    Gtk to fail to import.

    https://github.com/bleachbit/bleachbit/issues/1822
    https://github.com/bleachbit/bleachbit/issues/1978

    Returns the matched component name, or None.
    """
    if not path:
        return None

    try:
        parts = PureWindowsPath(path).parts
    except TypeError:
        return None

    for part in parts:
        if part and part.lower() in ('lib', 'bin'):
            return part.lower()
    return None


def _build_error_html(error, traceback_text=None):
    """Build an HTML error report string.

    Include traceback, system information, and a copyable bug-report block.

    It does not write to a file.
    """

    try:
        # Import here to avoid a circular import.
        from bleachbit.SystemInformation import get_system_information
        sysinfo_text = get_system_information()
    except Exception:
        sysinfo_text = '(unavailable)'

    bug_info = (
        f"Error: {error}\n\n"
        f"{traceback_text or ''}\n\n"  # It already has "Traceback:" header
        f"System information:\n{sysinfo_text}"
    )

    return f"""<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>BleachBit Error</title>
<style>
body {{ font-family: sans-serif; margin: 2em; }}
pre {{ background: #f4f4f4; padding: 1em; overflow-x: auto; }}
textarea {{ width: 100%; font-family: monospace; }}
</style>
<script type="text/javascript">
function copyBugReport() {{
  var textarea = document.getElementById('bug-report');
  var confirm = document.getElementById('copy-confirm');
  if (!textarea) {{
    return;
  }}
  textarea.focus();
  textarea.select();
  try {{
    document.execCommand('copy');
    if (confirm) {{
      confirm.style.display = 'inline';
      setTimeout(function() {{ confirm.style.display = 'none'; }}, 2000);
    }}
  }} catch (error) {{
  }}
}}
</script>
</head>
<body>
<h2>BleachBit cannot start</h2>
<p id="pygobject-unknown-error">BleachBit failed to load its graphical interface.</p>
<p>Error: {esc(str(error))}</p>
<p><a id="get-help" href="{esc(HELP_URL)}">Get help</a></p>
<h3>Copy this for a bug report</h3>
<p><button type="button" onclick="copyBugReport()">Copy to clipboard</button>
<span id="copy-confirm" style="display:none; color:green; margin-left:1em;">Copied!</span></p>
<textarea id="bug-report" rows="10" cols="80" readonly onclick="this.select()">{esc(bug_info)}</textarea>
</body>
</html>
"""


def _show_windows_error_dialog(title, html_content):
    """Show a concise error dialog on Windows and optionally save an HTML log.

    Prompts the user with Yes/No: if Yes, writes an HTML file to %TEMP% and
    opens it in the default browser.  If No, closes silently.
    """
    assert os.name == 'nt'
    prompt = (
        "BleachBit failed to load the graphical interface.\n\n"
        "This may be a bug or a broken installation."
        "\n\nSave error details to file and open in browser?"
    )
    try:
        MB_YESNO = 0x00000004
        MB_ICONERROR = 0x00000010
        IDYES = 6
        result = ctypes.windll.user32.MessageBoxW(
            0, prompt, title, MB_YESNO | MB_ICONERROR)
        if result == IDYES:
            tmp_dir = os.environ.get('TEMP', tempfile.gettempdir())
            html_path = os.path.join(tmp_dir, 'bleachbit_error.html')
            with open(html_path, 'w', encoding='utf-8') as f:
                f.write(html_content)
            webbrowser.open(f'file:///{html_path}')
    except Exception as e:
        logger.error('Failed to show Windows error dialog: %s', e)


def _handle_gtk_import_error(error):
    """On Windows, show a helpful error dialog when GTK import fails."""
    if os.name != 'nt':
        return

    logger.error('GTK not available: %s\n%s', error, format_exc())
    html_content = _build_error_html(
        error, traceback_text=format_exc())
    _show_windows_error_dialog('BleachBit', html_content)


def _check_display_available():
    """Check if a display server is available.

    Returns:
        tuple: (is_available: bool, reason: str or None)
    """
    if os.name == 'nt':
        # Windows always has a display
        return True, None

    # Check for X11 or Wayland display
    has_display = bool(
        os.environ.get('DISPLAY') or
        os.environ.get('WAYLAND_DISPLAY')
    )
    if not has_display:
        return False, 'No DISPLAY or WAYLAND_DISPLAY environment variable set'

    return True, None


def _try_import_gtk():
    """Attempt to import GTK and related libraries.

    Returns:
        tuple: (success: bool, reason: str or None)
    """
    global gi, Gtk, Gdk, GObject, GLib, Gio

    # Suppress GTK warning messages during import
    with warnings.catch_warnings():
        warnings.simplefilter("ignore")

        # Always try to import gi first (for gi.version reporting)
        try:
            import gi
        except ImportError:
            return False, 'PyGObject (gi) module not installed'

        # Check display availability before GTK imports (on POSIX)
        display_available, display_reason = _check_display_available()
        if not display_available:
            return False, display_reason

        if path_has_lib_or_bin(bleachbit_exe_path) and hasattr(sys, 'frozen'):
            # Setting search path prevents crash when importing GTK
            # when application is run from directory with foldername lib or bin.
            typelib_dir = os.path.join(
                bleachbit_exe_path, 'lib', 'girepository-1.0')
            if typelib_dir:
                logger.debug('Setting typelib search path to: %s', typelib_dir)
                gi._gi.Repository.get_default().prepend_search_path(typelib_dir)
            else:
                logger.warning('Typelib directory not found: %s', typelib_dir)

        try:
            gi.require_version('Gtk', '3.0')
        except Exception as e:
            _handle_gtk_import_error(e)
            return False, f'GTK 3.0 not available: {e}'

        try:
            from gi.repository import Gtk as _Gtk
            from gi.repository import Gdk as _Gdk
            from gi.repository import GObject as _GObject
            from gi.repository import GLib as _GLib
            from gi.repository import Gio as _Gio

            Gtk = _Gtk
            Gdk = _Gdk
            GObject = _GObject
            GLib = _GLib
            Gio = _Gio

        except (ImportError, RuntimeError, ValueError) as e:
            _handle_gtk_import_error(e)
            return False, f'Failed to import GTK libraries: {e}'

        # On POSIX, verify we can actually get a display
        if os.name == 'posix':
            try:
                if Gdk.get_default_root_window() is None:
                    return False, 'No default root window (display not accessible)'
            except Exception as e:
                return False, f'Display check failed: {e}'

    return True, None


def _init_gtk():
    """Initialize GTK imports. Called once at module load."""
    global HAVE_GTK, _gtk_unavailable_reason

    success, reason = _try_import_gtk()
    HAVE_GTK = success
    _gtk_unavailable_reason = reason

    if not success and reason:
        logger.debug('GTK not available: %s', reason)


def get_gtk_unavailable_reason():
    """Return the reason GTK is unavailable, or None if available."""
    return _gtk_unavailable_reason


def require_gtk():
    """Raise an exception if GTK is not available.

    Use this in modules that absolutely require GTK (e.g., GUI modules).
    """
    if not HAVE_GTK:
        reason = _gtk_unavailable_reason or 'unknown reason'
        raise RuntimeError(f'GTK is required but not available: {reason}')


# Perform initialization at module load
_init_gtk()
