#!/usr/bin/env bash
#!/bin/bash
# Beschreibung: Minecraft → ntfy Notifier (Join/Leave + optional Up/Down)
# Autor:        Patrick Asmus
# Web:          https://www.cleveradmin.de
# Repository:   https://git.techniverse.net/scriptos/minecraft-ntfy-notify
# Version:      1.0
# Datum:        18.09.2025
# Modifikation: Initial
#####################################################
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
if [[ -f "${SCRIPT_DIR}/.env" ]]; then
  set -a
  . "${SCRIPT_DIR}/.env"
  set +a
fi

# ===== Konfiguration via ENV =====
MC_HOST="${MC_HOST:-127.0.0.1}"
RCON_PORT="${RCON_PORT:-25575}"
RCON_PASSWORD="${RCON_PASSWORD:-changeme}"

POLL_SECONDS="${POLL_SECONDS:-10}"
ANNOUNCE_SERVER_UPDOWN="${ANNOUNCE_SERVER_UPDOWN:-true}"

# ntfy
NTFY_SERVER="${NTFY_SERVER:-}"
NTFY_TOPIC="${NTFY_TOPIC:-}"
NTFY_TOKEN="${NTFY_TOKEN:-}"
NTFY_TITLE_PREFIX="${NTFY_TITLE_PREFIX:-Minecraft}"
NTFY_TAGS_BASE="${NTFY_TAGS_BASE:-minecraft}"
NTFY_PRIORITY_JOIN="${NTFY_PRIORITY_JOIN:-3}"
NTFY_PRIORITY_LEAVE="${NTFY_PRIORITY_LEAVE:-3}"
NTFY_PRIORITY_UP="${NTFY_PRIORITY_UP:-4}"
NTFY_PRIORITY_DOWN="${NTFY_PRIORITY_DOWN:-5}"
NTFY_MARKDOWN="${NTFY_MARKDOWN:-false}"

# State (standardmäßig im Script-Ordner, root-frei)
STATE_DIR="${STATE_DIR:-${SCRIPT_DIR}/state}"
STATE_PLAYERS="${STATE_DIR}/players.prev"
STATE_UP="${STATE_DIR}/server_up.prev"

# ===== Helpers =====
die() { echo "ERROR: $*" >&2; exit 1; }
need_bin() { command -v "$1" >/dev/null 2>&1 || die "Benötigtes Tool fehlt: $1"; }

ntfy_notify() {
  local title="$1" body="$2" tags="$3" priority="$4"
  [[ -z "$NTFY_SERVER" || -z "$NTFY_TOPIC" ]] && { echo "ntfy Server/Topic fehlt – skip"; return 1; }
  local url="${NTFY_SERVER%/}/${NTFY_TOPIC}"
  local args=(-sS -X POST "$url" -H "Title: ${title}" -H "Priority: ${priority}" -H "Tags: ${tags}")
  [[ "$NTFY_MARKDOWN" == "true" ]] && args+=(-H "Markdown: yes")
  [[ -n "$NTFY_TOKEN" ]] && args+=(-H "Authorization: Bearer ${NTFY_TOKEN}")
  curl "${args[@]}" --data-raw "$body" >/dev/null 2>&1 || return 1
  return 0
}

ensure_state() {
  mkdir -p "$STATE_DIR"
  touch "$STATE_PLAYERS"
  [[ -f "$STATE_UP" ]] || echo "unknown" >"$STATE_UP"
}

get_players() {
  local out
  if ! out=$(mcrcon -H "$MC_HOST" -P "$RCON_PORT" -p "$RCON_PASSWORD" "list" 2>/dev/null); then
    return 1
  fi
  if grep -q "players online:" <<<"$out"; then
    local names="${out#*:}"
    names="$(echo "$names" | sed 's/^ *//;s/ *$//')"
    if [[ -n "$names" ]]; then
      tr ',' '\n' <<<"$names" | sed 's/^ *//;s/ *$//' | sed '/^$/d' | sort -u
      return 0
    fi
  fi
  return 0
}

# ===== Checks =====
need_bin curl
need_bin mcrcon
[[ -n "${NTFY_SERVER}" && -n "${NTFY_TOPIC}" ]] || die "NTFY_SERVER/NTFY_TOPIC nicht gesetzt"
ensure_state

echo "Starte Polling ${MC_HOST}:${RCON_PORT} → ntfy ${NTFY_SERVER}/${NTFY_TOPIC}"
prev_up="$(cat "$STATE_UP")"

while :; do
  tmp_players="$(mktemp)"
  if players=$(get_players); then
    server_up="true"
    printf "%s\n" $players 2>/dev/null | sed '/^$/d' | sort -u >"$tmp_players"
  else
    server_up="false"
    : >"$tmp_players"
  fi

  if [[ "$ANNOUNCE_SERVER_UPDOWN" == "true" && "$prev_up" != "unknown" && "$server_up" != "$prev_up" ]]; then
    if [[ "$server_up" == "true" ]]; then
      ntfy_notify "${NTFY_TITLE_PREFIX}: Server up" \
                  "Server ist wieder erreichbar (${MC_HOST}:${RCON_PORT})." \
                  "${NTFY_TAGS_BASE},up" "$NTFY_PRIORITY_UP" || true
    else
      ntfy_notify "${NTFY_TITLE_PREFIX}: Server down" \
                  "Server ist nicht erreichbar (${MC_HOST}:${RCON_PORT})." \
                  "${NTFY_TAGS_BASE},down" "$NTFY_PRIORITY_DOWN" || true
    fi
  fi

  if [[ "$server_up" == "true" ]]; then
    sort -u "$STATE_PLAYERS" -o "$STATE_PLAYERS"
    joined="$(comm -13 "$STATE_PLAYERS" "$tmp_players" || true)"
    left="$(comm -23 "$STATE_PLAYERS" "$tmp_players" || true)"

    if [[ -n "$joined" ]]; then
      while IFS= read -r name; do
        [[ -z "$name" ]] && continue
        ntfy_notify "${NTFY_TITLE_PREFIX}: Join" \
                    "Player ${name} ist beigetreten." \
                    "${NTFY_TAGS_BASE},join" "$NTFY_PRIORITY_JOIN" || true
      done <<<"$joined"
    fi
    if [[ -n "$left" ]]; then
      while IFS= read -r name; do
        [[ -z "$name" ]] && continue
        ntfy_notify "${NTFY_TITLE_PREFIX}: Leave" \
                    "Player ${name} hat den Server verlassen." \
                    "${NTFY_TAGS_BASE},leave" "$NTFY_PRIORITY_LEAVE" || true
      done <<<"$left"
    fi

    mv "$tmp_players" "$STATE_PLAYERS"
  else
    rm -f "$tmp_players"
  fi

  echo -n "$server_up" >"$STATE_UP"
  prev_up="$server_up"
  sleep "$POLL_SECONDS"
done