#!/usr/bin/env bash
set -euo pipefail

log(){ printf '[%s] %s\n' "$(date +'%F %T')" "$*"; }

need_root() {
  if [[ "${EUID:-$(id -u)}" -ne 0 ]]; then
    echo "Esegui come root (usa sudo)." >&2
    exit 1
  fi
}

detect_os() {
  local id="unknown" like=""
  if [[ -r /etc/os-release ]]; then
    # shellcheck disable=SC1091
    . /etc/os-release
    id="${ID:-unknown}"
    like="${ID_LIKE:-}"
  fi
  echo "$id" "$like"
}

is_arch_like() {
  local id="$1" like="$2"
  [[ "$id" == "arch" || "$id" == "manjaro" || "$id" == "endeavouros" ]] && return 0
  [[ "$like" == *"arch"* ]] && return 0
  return 1
}

is_fedora_like() {
  local id="$1" like="$2"
  [[ "$id" == "fedora" ]] && return 0
  [[ "$like" == *"fedora"* || "$like" == *"rhel"* ]] && return 0
  return 1
}

is_suse_like() {
  local id="$1" like="$2"
  [[ "$id" == opensuse* || "$id" == "suse" || "$id" == "sles" ]] && return 0
  [[ "$like" == *"suse"* ]] && return 0
  return 1
}

have_systemd() {
  command -v systemctl >/dev/null 2>&1
}

# Robust: works for installed units, generated units, aliases
unit_exists() {
  local u="$1"
  systemctl cat "$u" >/dev/null 2>&1
}

unit_active() {
  local u="$1"
  systemctl is-active --quiet "$u" 2>/dev/null
}

disable_stop_if_present() {
  local u="$1"
  if unit_exists "$u" || systemctl list-units --type=service --all 2>/dev/null | awk '{print $1}' | grep -qx "$u"; then
    log "Stop+disable (se presente): $u"
    systemctl disable --now "$u" >/dev/null 2>&1 || true
  fi
}

daemon_reload() {
  systemctl daemon-reload >/dev/null 2>&1 || true
}

# ---- BRIDGE IMPLEMENTATIONS ----

# Fedora-like: wrapper unit che comanda clamd@scan
write_bridge_wrapper_fedora() {
  local bridge="/etc/systemd/system/clamav-daemon.service"
  local target="clamd@scan.service"

  unit_exists "$target" || { echo "Fedora-like: manca $target" >&2; exit 1; }

  log "Creo bridge wrapper: clamav-daemon.service -> $target (wrapper oneshot)"
  cat > "$bridge" <<'EOF'
[Unit]
Description=ClamAV daemon bridge (wrapper to clamd@scan)
Wants=clamd@scan.service
After=network.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/bin/systemctl start clamd@scan.service
ExecStop=/usr/bin/systemctl stop clamd@scan.service
ExecReload=/usr/bin/systemctl reload clamd@scan.service

[Install]
WantedBy=multi-user.target
EOF
}

# openSUSE-like: wrapper (robusto) verso clamd.service
write_bridge_wrapper_suse() {
  local bridge="/etc/systemd/system/clamav-daemon.service"
  local target="clamd.service"

  unit_exists "$target" || { echo "openSUSE-like: manca $target" >&2; exit 1; }

  log "Creo bridge wrapper: clamav-daemon.service -> $target (wrapper oneshot)"
  cat > "$bridge" <<'EOF'
[Unit]
Description=ClamAV daemon bridge (wrapper to clamd)
Wants=clamd.service
After=network.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/bin/systemctl start clamd.service
ExecStop=/usr/bin/systemctl stop clamd.service
ExecReload=/usr/bin/systemctl reload clamd.service

[Install]
WantedBy=multi-user.target
EOF
}

enable_start_common() {
  local to_enable=("$@")
  for u in "${to_enable[@]}"; do
    if unit_exists "$u"; then
      log "Enable+start: $u"
      systemctl enable --now "$u" >/dev/null 2>&1 || true
      systemctl restart "$u" >/dev/null 2>&1 || true
    fi
  done
}

show_status() {
  local u="$1"
  log "Stato servizio: $u"
  systemctl --no-pager --full status "$u" || true
}

main() {
  need_root

  local id like
  read -r id like < <(detect_os)
  log "OS rilevato: ID=${id} ID_LIKE=${like}"

  if is_arch_like "$id" "$like"; then
    log "Arch-like: richiesto NO-OP. Esco senza modifiche."
    exit 0
  fi

  if ! is_fedora_like "$id" "$like" && ! is_suse_like "$id" "$like"; then
    log "Distro non target (né Fedora-like né SUSE-like): nessuna modifica."
    exit 0
  fi

  have_systemd || { echo "systemd/systemctl non trovato: impossibile creare bridge" >&2; exit 1; }

  # Ferma/disable eventuali definizioni precedenti del bridge e socket
  disable_stop_if_present "clamav-daemon.socket"
  disable_stop_if_present "clamav-daemon.service"

  if is_fedora_like "$id" "$like"; then
    write_bridge_wrapper_fedora
    daemon_reload

    # abilita target + bridge (bridge utile per comandi uniformi)
    enable_start_common "clamd@scan.service" "clamav-daemon.service"

    show_status "clamd@scan.service"
    show_status "clamav-daemon.service"
    exit 0
  fi

  if is_suse_like "$id" "$like"; then
    write_bridge_wrapper_suse
    daemon_reload

    # abilita target + bridge (bridge utile per comandi uniformi)
    enable_start_common "clamd.service" "clamav-daemon.service"

    show_status "clamd.service"
    show_status "clamav-daemon.service"
    exit 0
  fi
}

main "$@"