#!/bin/bash
# The desktop session: labwc nested as a client of the app's compositor, with LXQt's panel and
# file manager started from its autostart, and Xwayland for the X11 programs (the Steam client,
# most emulators). Run by bannerlator-session in place of gamescope for mode "lxqt".
# Staged by the app over the desktop package's copy on every launch, so a fix here reaches an
# installed desktop without re-downloading the package.
set -u
export XDG_SESSION_TYPE=wayland XDG_CURRENT_DESKTOP=LXQt XDG_SESSION_DESKTOP=lxqt
export QT_QPA_PLATFORM=wayland GDK_BACKEND=wayland,x11 SDL_VIDEODRIVER=wayland,x11
export QT_QPA_PLATFORMTHEME=lxqt
# Firefox's child processes sandbox themselves with seccomp and namespaces, neither of which
# behaves under proot: the content process ends up unable to read the font files its parent can,
# reports "no fonts" and dies - the tab crash, with the chrome around it still drawing text.
# The prefs for this are only advisory and a profile can override them; the environment is not.
export MOZ_DISABLE_CONTENT_SANDBOX=1 MOZ_DISABLE_GMP_SANDBOX=1 MOZ_DISABLE_RDD_SANDBOX=1
export MOZ_DISABLE_SOCKET_PROCESS_SANDBOX=1 MOZ_DISABLE_UTILITY_SANDBOX=1
# pixman composites in software and gives programs shm buffers only, so a Vulkan program on it
# fails at its swapchain. vulkan (or gles2) composite on the GPU and give programs DMA-BUFs, but
# stock wlroots allocates through gbm on a real DRM node and the KGSL stand-in is not one ("unable
# to create allocator"): they need the app's patched wlroots (tools/wlroots), whose Vulkan
# allocator exports the buffers instead. BL_WLR_RENDERER picks; see the fallback at the end.
export WLR_RENDERER=${BL_WLR_RENDERER:-vulkan}
WLROOTS_DIR=/usr/local/lib/droiddeck-wlroots
BASE_LD_LIBRARY_PATH=${LD_LIBRARY_PATH:-}
use_renderer() {
  export WLR_RENDERER=$1
  if [ "$1" != pixman ] && [ -f "$WLROOTS_DIR/libwlroots-0.20.so" ]; then
    export LD_LIBRARY_PATH=$WLROOTS_DIR${BASE_LD_LIBRARY_PATH:+:$BASE_LD_LIBRARY_PATH}
  elif [ -n "$BASE_LD_LIBRARY_PATH" ]; then
    export LD_LIBRARY_PATH=$BASE_LD_LIBRARY_PATH
  else
    unset LD_LIBRARY_PATH
  fi
}
use_renderer "$WLR_RENDERER"
# A GPU renderer that failed to start here is not tried again on every desktop start (each try costs
# up to 20 s): the failure is kept with what it failed on - the renderer, the patched wlroots and the
# Linux driver - so an app update or a different driver retries, and so does picking a renderer
# again in the app's settings (which deletes the file).
FAILED_FILE=$HOME/.droiddeck-renderer-failed
renderer_key() {
  echo "$WLR_RENDERER $(md5sum "$WLROOTS_DIR/libwlroots-0.20.so" 2>/dev/null | cut -d' ' -f1) ${BL_VK_DRIVER:-runtime}"
}
if [ "$WLR_RENDERER" != pixman ] && [ "$(cat "$FAILED_FILE" 2>/dev/null)" = "$(renderer_key)" ]; then
  echo "== droiddeck-desktop: $WLR_RENDERER failed to start here before; using pixman (choose a renderer in the settings to retry)"
  use_renderer pixman
fi
# The desktop's own log, beside the session's, so labwc and the programs on it can be read apart
# from the session that started them. The session log keeps the milestones either way.
if [ -n "${BL_DEBUG_DIR:-}" ]; then
  mkdir -p "$BL_DEBUG_DIR" 2>/dev/null || true
  exec >>"$BL_DEBUG_DIR/desktop.log" 2>&1
  echo "== droiddeck-desktop $(date -u '+%Y-%m-%d %H:%M:%S UTC') renderer=$WLR_RENDERER"
fi
export WLR_BACKENDS=wayland
mkdir -p "$HOME/.config/labwc" "$HOME/.config/lxqt"
# Our defaults for labwc and the panel, refreshed every session. What a user changes in the
# panel's own settings lands in panel.conf and is kept; only rc.xml and autostart are ours.
# The nested output takes the app's surface size; left alone, wlroots' Wayland backend opens
# a 1280x720 window and the whole desktop is upscaled from that.
sed "s/@MODE@/${BL_WIDTH:-1280}x${BL_HEIGHT:-720}/" /etc/xdg/labwc/rc.xml > "$HOME/.config/labwc/rc.xml"
cp -f /etc/xdg/labwc/autostart "$HOME/.config/labwc/autostart"
# panel.conf is the user's once the panel has written it, except the one our first package
# shipped: it never named its panel ([General] panels=), so lxqt-panel built an empty default
# one. That file is replaced; one that names its panels is kept.
if ! grep -q '^panels=' "$HOME/.config/lxqt/panel.conf" 2>/dev/null; then
  cp -f /etc/xdg/lxqt/panel.conf "$HOME/.config/lxqt/panel.conf"
fi
[ -f "$HOME/.config/lxqt/lxqt.conf" ] || cp /etc/xdg/lxqt/lxqt.conf "$HOME/.config/lxqt/lxqt.conf"
# pcmanfm-qt paints the desktop; left unconfigured it paints it black, over swaybg's wallpaper.
if [ ! -f "$HOME/.config/pcmanfm-qt/lxqt/settings.conf" ]; then
  mkdir -p "$HOME/.config/pcmanfm-qt/lxqt"
  printf '[Desktop]\nWallpaper=/usr/share/backgrounds/steamdeck.png\nWallpaperMode=zoom\nBgColor=#1b1030\nShowHidden=false\n' \
    > "$HOME/.config/pcmanfm-qt/lxqt/settings.conf"
fi
# The runtime directory outlives a session. lxqt-panel and pcmanfm-qt are single-instance
# programs that leave a lock and a socket there; finding last session's, they decide they are
# already running and exit without a word - a desktop with a wallpaper and nothing on it.
# Only the app's own compositor socket (wayland-0) is kept.
find "$XDG_RUNTIME_DIR" -mindepth 1 -maxdepth 1 ! -name 'wayland-0*' ! -name 'keymap.xkb' -exec rm -rf {} + 2>/dev/null
# fontconfig's rules (sans-serif -> DejaVu Sans and the rest) live as links in /etc/fonts/conf.d,
# and the rootfs has none: applications then find fonts but no default font. Firefox logs
# "no fonts" and draws pages without text.
if [ -d /usr/share/fontconfig/conf.default ] && ! ls /etc/fonts/conf.d/*.conf >/dev/null 2>&1; then
  for f in /usr/share/fontconfig/conf.default/*.conf; do ln -sf "$f" /etc/fonts/conf.d/; done
  echo "== fontconfig: linked $(ls /etc/fonts/conf.d/*.conf | wc -l) default rules"
fi
# Those rules map sans-serif and friends onto whatever a full distribution installs, and this
# rootfs has one family. Naming it outright is what gives every toolkit a default font: without
# one Gecko reports "no fonts" with families found, and draws pages with no text at all.
if [ ! -f /etc/fonts/local.conf ]; then
  { echo '<?xml version="1.0"?><!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd"><fontconfig>'
    for generic in sans-serif sans serif monospace mono cursive fantasy system-ui ui-sans-serif; do
      case $generic in
        serif) face="DejaVu Serif" ;;
        mono*|ui-mono) face="DejaVu Sans Mono" ;;
        *) face="DejaVu Sans" ;;
      esac
      printf '<alias binding="weak"><family>%s</family><prefer><family>%s</family></prefer></alias>\n' "$generic" "$face"
    done
    echo '</fontconfig>'
  } > /etc/fonts/local.conf
  echo "== fontconfig: wrote local.conf (DejaVu as the default family)"
fi
# The cache in the image was built before those rules existed; rebuild it once, and only once.
if [ ! -f /var/cache/fontconfig/.droiddeck-built ] && command -v fc-cache >/dev/null 2>&1; then
  fc-cache -f >/dev/null 2>&1 && touch /var/cache/fontconfig/.droiddeck-built
  echo "== fontconfig: cache rebuilt, default sans is $(fc-match sans-serif 2>/dev/null)"
fi
# The menu's "Steam" / "Steam Big Picture" entries and one entry per installed game: all of them
# hand off to the app (bannerlator-steam-launch), since the client cannot draw on this desktop.
export BL_DESKTOP=1
ln -sf /usr/local/bin/bannerlator-steam-launch /usr/local/bin/steamdeck-steam 2>/dev/null
ln -sf /usr/local/bin/bannerlator-steam-shim /usr/local/bin/steam 2>/dev/null
python3 /usr/local/bin/bannerlator-desktop-games 2>&1 | sed 's/^/[games] /'
# Player 1 on the controller in every emulator that has no profile of its own yet - now, and again
# every half minute: an emulator started for the first time writes its own config, which is then
# given the controller for its next start without waiting for the next desktop.
python3 /usr/local/bin/bannerlator-pad-defaults 2>&1 | sed 's/^/[pads] /'
( while sleep 30; do python3 /usr/local/bin/bannerlator-pad-defaults 2>&1 | sed 's/^/[pads] /'; done ) &
# Games and emulators from the menu run through droiddeck-gpu (their own gamescope on the app's
# compositor) while the desktop is on pixman, where they could not draw with the GPU.
# BL_DESKTOP_GPU=on/off overrides; each entry keeps "Run in a desktop window" either way.
gpu_entries() { python3 /usr/local/bin/droiddeck-desktop-gpu 2>&1 | sed 's/^/[gpu] /'; }
gpu_entries

# ~/.droiddeck-desktop-debug: labwc's own debug log (views and layer surfaces mapping) too. The GPU
# renderers are experimental and always log in full, so a desktop that does not come up says why.
DEBUG=; { [ -f "$HOME/.droiddeck-desktop-debug" ] || [ "$WLR_RENDERER" != pixman ]; } && DEBUG=-d
run_labwc() {
  echo "== droiddeck-desktop: labwc ($WLR_RENDERER${LD_LIBRARY_PATH:+, wlroots from $WLROOTS_DIR}) on $WAYLAND_DISPLAY"
  # A session bus: the panel's menus, the file manager and the portal all expect one.
  if command -v dbus-run-session >/dev/null 2>&1; then
    dbus-run-session -- labwc $DEBUG -C "$HOME/.config/labwc"
  else
    labwc $DEBUG -C "$HOME/.config/labwc"
  fi
}
pids_named() {
  local p
  for p in /proc/[0-9]*; do
    [ "$(cat "$p/comm" 2>/dev/null)" = "$1" ] && echo "${p#/proc/}"
  done
}
# labwc answers on its own socket (the one beside the app's wayland-0) once its event loop runs; a
# labwc stuck on the GPU never does.
labwc_answers() {
  local sock
  for sock in "$XDG_RUNTIME_DIR"/wayland-*; do
    case $sock in *.lock|*/wayland-0) continue ;; esac
    [ -S "$sock" ] || continue
    WAYLAND_DISPLAY=${sock##*/} timeout 3 wayland-info >/dev/null 2>&1 && return 0
  done
  return 1
}
if [ "$WLR_RENDERER" = pixman ]; then
  run_labwc
  exit $?
fi
# A GPU renderer this device cannot start either ends the desktop at once or leaves it hanging on
# the loading screen. Either way the desktop comes up on pixman instead, and the log says why.
started=$(date +%s)
run_labwc &
labwc_job=$!
answered=
while kill -0 "$labwc_job" 2>/dev/null; do
  if labwc_answers; then answered=1; break; fi
  [ $(( $(date +%s) - started )) -ge 20 ] && break
  sleep 1
done
if [ -n "$answered" ]; then
  echo "== droiddeck-desktop: labwc on $WLR_RENDERER is up after $(( $(date +%s) - started )) s"
  wait "$labwc_job"
  exit $?
fi
if kill -0 "$labwc_job" 2>/dev/null; then
  echo "== droiddeck-desktop: labwc on $WLR_RENDERER did not answer in 20 s; stopping it"
  kill -TERM $(pids_named labwc) 2>/dev/null
  sleep 2
  kill -KILL $(pids_named labwc) 2>/dev/null
  for prog in lxqt-panel pcmanfm-qt swaybg Xwayland; do kill -KILL $(pids_named "$prog") 2>/dev/null; done
  wait "$labwc_job" 2>/dev/null
  rc=124
else
  wait "$labwc_job"
  rc=$?
fi
if [ "$rc" -ne 0 ] && [ $(( $(date +%s) - started )) -lt 40 ]; then
  echo "== droiddeck-desktop: labwc on $WLR_RENDERER failed at start (exit $rc); starting on pixman instead"
  renderer_key > "$FAILED_FILE"
  use_renderer pixman
  DEBUG=; [ -f "$HOME/.droiddeck-desktop-debug" ] && DEBUG=-d
  find "$XDG_RUNTIME_DIR" -mindepth 1 -maxdepth 1 ! -name 'wayland-0*' ! -name 'keymap.xkb' -exec rm -rf {} + 2>/dev/null
  gpu_entries
  run_labwc
  rc=$?
fi
exit $rc