#!/usr/bin/env bash
# Set up headless streaming mode: install prep-cmd hook scripts into a stable
# location and ensure they're executable. The actual sunshine.conf entries
# (capture=wlr, output_name=HEADLESS-1, global_prep_cmd=[...]) are written
# by lib/config.sh.
#
# Two compositor backends supported:
#   - hyprland (default on Omarchy/Arch): bin/sunshine-stream-{do,undo}.sh
#   - sway     (default on Debian/Ubuntu): bin/sunshine-stream-{do,undo}-sway.sh
# detect_compositor (lib/detect.sh) decides which to install. The script names
# at the install target are *always* sunshine-stream-do.sh / -undo.sh, so the
# rest of the installer (config.sh, verify.sh) doesn't have to branch.

HEADLESS_BIN_DIR="$HOME/.local/share/omarchy-moonlight/bin"

DO_SCRIPT="$HEADLESS_BIN_DIR/sunshine-stream-do.sh"
UNDO_SCRIPT="$HEADLESS_BIN_DIR/sunshine-stream-undo.sh"
PRESTART_SCRIPT="$HEADLESS_BIN_DIR/sunshine-prestart.sh"
export DO_SCRIPT UNDO_SCRIPT PRESTART_SCRIPT

# Resolve which hook source files to install based on the detected compositor.
_headless_hook_sources() {
  case "${COMPOSITOR:-hyprland}" in
    sway)
      echo "$SCRIPT_DIR/bin/sunshine-stream-do-sway.sh"
      echo "$SCRIPT_DIR/bin/sunshine-stream-undo-sway.sh"
      echo "$SCRIPT_DIR/bin/sunshine-prestart-sway.sh"
      ;;
    hyprland|*)
      echo "$SCRIPT_DIR/bin/sunshine-stream-do.sh"
      echo "$SCRIPT_DIR/bin/sunshine-stream-undo.sh"
      echo "$SCRIPT_DIR/bin/sunshine-prestart.sh"
      ;;
  esac
}

# The X11/NVENC headless backend (capture = x11, headless Xorg on :0) isn't
# selected by --headless/--mirror — those pick the *Wayland* capture method.
# It's identified by an existing `capture = x11` in sunshine.conf, the
# hand-built path documented in FOLLOWUPS.md P3. When that backend is in play,
# the headless Xorg needs a window manager rendering on :0 or Sunshine
# captures a black screen.
capture_backend_is_x11() {
  local conf="$HOME/.config/sunshine/sunshine.conf"
  [[ -f "$conf" ]] || return 1
  grep -qE '^[[:space:]]*capture[[:space:]]*=[[:space:]]*x11' "$conf"
}

HEADLESS_DESKTOP_UNIT="headless-desktop.service"

# Which desktop to render on the headless Xorg :0. Default is a full GNOME
# session (the familiar Ubuntu desktop). Set HEADLESS_DESKTOP=openbox for a
# lightweight bare WM instead — lower overhead, better for a truly minimal or
# low-power host, but no panel/launcher out of the box (right-click menu only).
: "${HEADLESS_DESKTOP:=gnome}"

# Install the packages the chosen desktop needs. Idempotent — pkg_install
# skips what's already present.
ensure_headless_desktop_packages() {
  case "$HEADLESS_DESKTOP" in
    gnome)
      case "$DISTRO" in
        debian) pkg_install gnome-session gnome-shell ubuntu-session ;;
        arch)   pkg_install gnome-shell gnome-session ;;
      esac
      ;;
    openbox)
      command -v openbox-session >/dev/null 2>&1 || pkg_install openbox
      # xsetroot paints a solid root so the bare desktop is visibly non-black.
      if ! command -v xsetroot >/dev/null 2>&1; then
        case "$DISTRO" in
          debian) pkg_install x11-xserver-utils ;;
          arch)   pkg_install xorg-xsetroot ;;
        esac
      fi
      ;;
    *)
      err "Unknown HEADLESS_DESKTOP='$HEADLESS_DESKTOP' (expected: gnome | openbox)"
      return 1
      ;;
  esac
}

# Install + enable a desktop session that renders onto the headless Xorg
# display (:0), so the X11/NVENC capture path shows a real desktop instead of a
# black root window. Picks the GNOME or Openbox unit template per
# $HEADLESS_DESKTOP. Idempotent: safe to re-run. Bound to xorg-headless.service
# and to default.target (the lingering-user manager reaches it without a login).
install_headless_desktop() {
  local src="$SCRIPT_DIR/files/headless-desktop-${HEADLESS_DESKTOP}.service"
  if [[ ! -f "$src" ]]; then
    err "Desktop unit source missing: $src (HEADLESS_DESKTOP=$HEADLESS_DESKTOP)"
    return 1
  fi

  ensure_headless_desktop_packages || return 1

  local unit_dir="$HOME/.config/systemd/user"
  mkdir -p "$unit_dir"
  install -m 0644 "$src" "$unit_dir/$HEADLESS_DESKTOP_UNIT"
  systemctl --user daemon-reload

  # enable --now starts it immediately when a user manager is live; on a fresh
  # headless box with no session yet, fall back to enable-only so it comes up
  # on next boot via default.target.
  if systemctl --user enable --now "$HEADLESS_DESKTOP_UNIT" >/dev/null 2>&1; then
    ok "Enabled $HEADLESS_DESKTOP_UNIT ($HEADLESS_DESKTOP session on :0)"
  else
    systemctl --user enable "$HEADLESS_DESKTOP_UNIT" >/dev/null 2>&1 || true
    warn "Installed $HEADLESS_DESKTOP_UNIT but couldn't start it now — it will start on next login/boot."
  fi
}

install_headless_hooks() {
  mkdir -p "$HEADLESS_BIN_DIR"
  mapfile -t srcs < <(_headless_hook_sources)
  local do_src="${srcs[0]}" undo_src="${srcs[1]}" pre_src="${srcs[2]}"

  install -m 0755 "$do_src"   "$DO_SCRIPT"
  install -m 0755 "$undo_src" "$UNDO_SCRIPT"
  install -m 0755 "$pre_src"  "$PRESTART_SCRIPT"
  ok "Installed prep-cmd + prestart hooks ($COMPOSITOR) to $HEADLESS_BIN_DIR"
}

# Install a systemd-user drop-in that pre-creates HEADLESS-1 before Sunshine
# starts. Without this, Sunshine reports a fatal "Unable to find display or
# encoder during startup" on every restart, even though streaming works once
# a client connects.
install_headless_prestart_dropin() {
  local dropin_src="$SCRIPT_DIR/files/headless-prestart.conf"
  if [[ ! -f "$dropin_src" ]]; then
    err "Drop-in source missing: $dropin_src"
    return 1
  fi

  # Resolve the actual unit name. Prefer sunshine.service when present (alias,
  # sunshine-bin, or the .deb on Ubuntu); fall back to the AUR source pkg's
  # reverse-DNS name.
  local unit=""
  for u in sunshine.service app-dev.lizardbyte.app.Sunshine.service; do
    if systemctl --user list-unit-files "$u" >/dev/null 2>&1 \
       && systemctl --user cat "$u" >/dev/null 2>&1; then
      unit="$u"
      break
    fi
  done
  if [[ -z "$unit" ]]; then
    warn "Could not resolve a sunshine unit to attach the drop-in to; skipping."
    return 0
  fi

  local dropin_dir="$HOME/.config/systemd/user/${unit}.d"
  mkdir -p "$dropin_dir"
  install -m 0644 "$dropin_src" "$dropin_dir/headless-prestart.conf"
  systemctl --user daemon-reload
  ok "Installed headless prestart drop-in at $dropin_dir/headless-prestart.conf"
}