#!/usr/bin/env bash
# Beschreibung: Aktualisiert livekit.yaml (rtc.ips.includes) bei IP-Wechsel (IPv4 ODER IPv6),
#               restarte den LiveKit-Dienst (Docker oder Docker Compose), wartet konfigurierbar und prüft Health.
#               Mit Backup + Rollback, optionalen ntfy-Notifications, YAML-Update via yq (Fallback eingebaut).
# Synapse:      https://git.techniverse.net/scriptos/livekit-ip-watch.git
# Autor:        Patrick Asmus
# Web:          https://www.cleveradmin.de
# Version:      1.0
# Datum:        27.10.2025
# Modifikation: Initial
#####################################################

set -euo pipefail

############################
# Konfiguration (Variablen)
############################

# Pfad zur LiveKit-Konfiguration
CONFIG_FILE="/home/docker-container/matrix-rtc/data/matrix-element-call-livekit/config.yaml"

# Betriebsmodus: "compose" oder "docker"
RUNTIME="compose"

# Compose: Kompletter Pfad zur Compose-Datei + Service-Name
COMPOSE_FILE_PATH="/home/docker-container/matrix-rtc/docker-compose.yaml"
COMPOSE_SERVICE="matrix-element-call-livekit"

# Plain-Docker: Container-Name (nur genutzt, wenn RUNTIME="docker")
CONTAINER_NAME="matrix-element-call-livekit"

# IP-Variante: IPv4 oder IPv6
ENABLE_IPV6=false

# Wartezeit nach Neustart (Sekunden), dann Healthcheck
WAIT_AFTER_RESTART=20

# Healthcheck-Konfiguration: nur TCP
TCP_HOST="127.0.0.1"
TCP_PORT="7881"
HEALTHCHECK_TIMEOUT=3

# ntfy (optional)
NTFY_URL=""
NTFY_TOKEN=""

############################
# Hauptscript
############################

# Skriptverzeichnis, Lock- und State-Dateien
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
LOCKFILE="$SCRIPT_DIR/livekit-ip-watch.lock"
STATE_FILE_V4="$SCRIPT_DIR/last_ip_v4"
STATE_FILE_V6="$SCRIPT_DIR/last_ip_v6"
BACKUP_DIR="$SCRIPT_DIR/backups"
mkdir -p "$BACKUP_DIR"

log()  { printf '[%(%Y-%m-%d %H:%M:%S)T] %s\n' -1 "$*" >&2; }
die()  { log "ERROR: $*"; notify "error" "$*"; exit 1; }
warn() { log "WARN:  $*"; notify "warn"  "$*"; }
info() { log "INFO:  $*"; }

# Ntfy
notify() {
  local level="${1:-info}"
  shift || true
  local msg="${*:-}"
  [[ -z "$NTFY_URL" ]] && return 0
  local hdr=(-H "Title: livekit-ip-watch" -H "Priority: default" -H "Tags: $level")
  [[ -n "$NTFY_TOKEN" ]] && hdr+=(-H "Authorization: Bearer $NTFY_TOKEN")
  curl -fsS -X POST "${hdr[@]}" -d "$msg" "$NTFY_URL" >/dev/null 2>&1 || true
}

# Lock
acquire_lock() {
  if command -v flock >/dev/null 2>&1; then
    exec 9>"$LOCKFILE"
    if ! flock -n 9; then
      info "Läuft bereits (Lock vorhanden): $LOCKFILE"
      exit 0
    fi
  else
    set -o noclobber
    if ! : > "$LOCKFILE"; then
      info "Läuft bereits (Lock vorhanden): $LOCKFILE"
      exit 0
    fi
    set +o noclobber
  fi
  trap 'release_lock' EXIT
}

release_lock() {
  rm -f "$LOCKFILE" 2>/dev/null || true
}

# IP-Ermittlung
get_ipv4() {
  local ip
  ip="$(dig +short myip.opendns.com @resolver1.opendns.com 2>/dev/null || true)"
  [[ -z "$ip" ]] && ip="$(curl -fsS https://api.ipify.org 2>/dev/null || true)"
  [[ "$ip" =~ ^([0-9]{1,3}\.){3}[0-9]{1,3}$ ]] || ip=""
  echo "$ip"
}

get_ipv6() {
  local ip
  ip="$(curl -fsS -6 https://api6.ipify.org 2>/dev/null || true)"
  if [[ "$ip" =~ : ]]; then
    echo "$ip"
  else
    echo ""
  fi
}

have_yq() { command -v yq >/dev/null 2>&1; }

backup_config() {
  [[ -r "$CONFIG_FILE" ]] || die "Config nicht lesbar: $CONFIG_FILE"
  local ts backup
  ts="$(date +%Y%m%d%H%M%S)"
  backup="$BACKUP_DIR/$(basename "$CONFIG_FILE").$ts.bak"
  cp -a "$CONFIG_FILE" "$backup"
  echo "$backup"
}

update_yaml_with_yq() {
  local cidr="$1"
  YQ_VAR_CIDR="$cidr" yq -i '
    .rtc |= (. // {}) |
    .rtc.ips |= (. // {}) |
    .rtc.ips.includes = [env(YQ_VAR_CIDR)]
  ' "$CONFIG_FILE"
}

update_yaml_fallback() {
  local cidr="$1"
  local tmp
  tmp="$(mktemp)"
  awk -v newcidr="$cidr" '
    BEGIN{ in_rtc=0; in_ips=0; ips_indent=""; printed_ips=0 }
    function print_ips_block() {
      if (!printed_ips) {
        print "  ips:"
        print "    includes:"
        print "      - " newcidr
        printed_ips=1
      }
    }
    {
      line=$0
      if ($0 ~ /^[[:space:]]*rtc:[[:space:]]*$/) { in_rtc=1; in_ips=0; ips_indent=""; print; next }
      if (in_rtc) {
        if (in_ips) {
          if (ips_indent=="" ) { next }
          if ($0 ~ "^" ips_indent "[^[:space:]]") { next }
          in_ips=0
          print_ips_block()
        }
        if ($0 ~ /^[[:space:]]{2}ips:[[:space:]]*$/) {
          in_ips=1
          match($0,/^([[:space:]]*)ips:/,m)
          ips_indent=m[1]"  "
          next
        }
        if ($0 ~ /^[[:space:]]{2}[[:alnum:]_]+:[[:space:]]*$/) {
          if (!printed_ips) { print_ips_block() }
        }
        if ($0 ~ /^[[:alnum:]_]+:[[:space:]]*$/) {
          if (!printed_ips && in_rtc) { print_ips_block() }
          in_rtc=0
        }
        print line
        next
      }
      print line
    }
    END{
      if (in_rtc && !printed_ips) {
        print "  ips:"
        print "    includes:"
        print "      - " newcidr
      }
    }
  ' "$CONFIG_FILE" > "$tmp"
  mv "$tmp" "$CONFIG_FILE"
}

detect_compose_cmd() {
  if command -v docker-compose >/dev/null 2>&1; then
    echo "docker-compose"
  else
    echo "docker compose"
  fi
}

restart_service() {
  if [[ "$RUNTIME" == "compose" ]]; then
    local dir file
    dir="$(dirname "$COMPOSE_FILE_PATH")"
    file="$(basename "$COMPOSE_FILE_PATH")"
    local COMPOSE_CMD
    COMPOSE_CMD="$(detect_compose_cmd)"
    ( cd "$dir" && "$COMPOSE_CMD" -f "$file" restart "$COMPOSE_SERVICE" )
  else
    docker restart "$CONTAINER_NAME"
  fi
}

healthcheck_tcp() {
  if (exec 3<>/dev/tcp/"$TCP_HOST"/"$TCP_PORT") 2>/dev/null; then
    exec 3<&-
    exec 3>&-
    return 0
  elif command -v nc >/dev/null 2>&1; then
    nc -z -w "$HEALTHCHECK_TIMEOUT" "$TCP_HOST" "$TCP_PORT"
  else
    return 1
  fi
}

main() {
  acquire_lock

  [[ -f "$CONFIG_FILE" ]] || die "Config-Datei nicht gefunden: $CONFIG_FILE"
  if [[ "$RUNTIME" == "compose" ]]; then
    [[ -f "$COMPOSE_FILE_PATH" ]] || die "Compose-Datei nicht gefunden: $COMPOSE_FILE_PATH"
    [[ -n "$COMPOSE_SERVICE" ]] || die "COMPOSE_SERVICE ist leer."
  else
    [[ -n "$CONTAINER_NAME" ]] || die "CONTAINER_NAME ist leer."
  fi

  local current_ip cidr state_file
  if [[ "$ENABLE_IPV6" == true ]]; then
    current_ip="$(get_ipv6)"
    [[ -z "$current_ip" ]] && die "Konnte keine öffentliche IPv6 ermitteln."
    cidr="${current_ip}/128"
    state_file="$STATE_FILE_V6"
  else
    current_ip="$(get_ipv4)"
    [[ -z "$current_ip" ]] && die "Konnte keine öffentliche IPv4 ermitteln."
    cidr="${current_ip}/32"
    state_file="$STATE_FILE_V4"
  fi

  local last_ip=""
  [[ -f "$state_file" ]] && last_ip="$(cat "$state_file" 2>/dev/null || true)"

  if [[ "$current_ip" == "$last_ip" && -n "$last_ip" ]]; then
    info "IP unverändert: $current_ip"
    notify "info" "Keine Änderung. Öffentliche IP bleibt $current_ip."
    exit 0
  fi

  info "Neue IP erkannt: $current_ip (alt: ${last_ip:-none})"
  local backup
  backup="$(backup_config)"
  info "Backup erstellt: $backup"

  if have_yq; then
    info "Aktualisiere YAML mit yq → .rtc.ips.includes = [ \"$cidr\" ]"
    update_yaml_with_yq "$cidr"
  else
    warn "yq nicht gefunden – Fallback-Editor wird verwendet."
    update_yaml_fallback "$cidr"
  fi

  info "Restart des Dienstes..."
  restart_service

  info "Warte $WAIT_AFTER_RESTART Sekunden..."
  sleep "$WAIT_AFTER_RESTART"

  if healthcheck_tcp; then
    info "Healthcheck OK."
    echo "$current_ip" > "$state_file"
    notify "info" "IP geändert auf $current_ip, Dienst gesund."
    exit 0
  fi

  warn "Healthcheck fehlgeschlagen – führe Rollback durch."
  cp -a "$backup" "$CONFIG_FILE"
  info "Rollback-Konfiguration wiederhergestellt: $backup"

  info "Restart nach Rollback..."
  restart_service

  info "Warte $WAIT_AFTER_RESTART Sekunden (Rollback)..."
  sleep "$WAIT_AFTER_RESTART"

  if healthcheck_tcp; then
    warn "Rollback erfolgreich. System läuft wieder mit alter Konfiguration."
    notify "warn" "Rollback erfolgreich. Bitte prüfen. Alte IP bleibt ${last_ip:-unbekannt}."
    exit 10
  else
    die "Rollback fehlgeschlagen. Manuelles Eingreifen erforderlich."
  fi
}

main "$@"