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

SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
INSTALL_ROOT="${PT_INSTALL_ROOT:-$SCRIPT_DIR}"
SERVER_NAME="${PT_SERVER:-${1:-}}"
RUNTIME_BASE_DIR="${PT_RUNTIME_DIR:-$INSTALL_ROOT/.pt-panel-runtime}"
DOWNLOAD_DIR="$RUNTIME_BASE_DIR/downloads"
BOOTSTRAP_JAR="$DOWNLOAD_DIR/packwiz-installer-bootstrap.jar"
PACKWIZ_META_FILE="packwiz-installer.json"

JAVA_BIN="${JAVA_BIN:-java}"
JAVA_ARGS="${PT_JAVA_ARGS:--Xms1G -Xmx1G}"
SERVER_JAR_OVERRIDE="${PT_SERVER_JAR:-}"
FORCE_UPDATE="${PT_FORCE_UPDATE:-0}"
DRY_RUN="${PT_DRY_RUN:-0}"
AUTO_EULA="${PT_AUTO_EULA:-TRUE}"
PACKWIZ_BOOTSTRAP_NO_UPDATE="${PT_PACKWIZ_BOOTSTRAP_NO_UPDATE:-0}"
FABRIC_INSTALLER_VERSION="${PT_FABRIC_INSTALLER_VERSION:-}"
PACKWIZ_BOOTSTRAP_URL="${PT_PACKWIZ_BOOTSTRAP_URL:-https://github.com/packwiz/packwiz-installer-bootstrap/releases/latest/download/packwiz-installer-bootstrap.jar}"

PACK_DIR=""
PACK_URL=""
PACK_SLUG=""
STAMP_FILE=""

log() {
  printf '[pt-panel] %s\n' "$*"
}

fail() {
  printf '[pt-panel] ERROR: %s\n' "$*" >&2
  exit 1
}

need_cmd() {
  command -v "$1" >/dev/null 2>&1 || fail "缺少命令: $1"
}

fetch() {
  local url="$1"
  local dest="$2"

  if command -v curl >/dev/null 2>&1; then
    curl -fL --retry 3 --retry-delay 2 -o "$dest" "$url"
  elif command -v wget >/dev/null 2>&1; then
    wget -O "$dest" "$url"
  else
    fail "缺少 curl 或 wget，无法下载文件"
  fi
}

fetch_to_stdout() {
  local url="$1"

  if command -v curl >/dev/null 2>&1; then
    curl -fL --retry 3 --retry-delay 2 "$url"
  elif command -v wget >/dev/null 2>&1; then
    wget -O - "$url"
  else
    fail "缺少 curl 或 wget，无法下载文件"
  fi
}

trim_quotes() {
  local value="$1"
  value="${value#\"}"
  value="${value%\"}"
  printf '%s' "$value"
}

toml_value() {
  local key="$1"
  local file="$2"
  local line

  line="$(grep -E "^${key}[[:space:]]*=" "$file" | head -n 1 || true)"
  [ -n "$line" ] || return 1
  line="${line#*=}"
  line="${line#${line%%[![:space:]]*}}"
  trim_quotes "$line"
}

list_available_servers() {
  find "$SCRIPT_DIR" -mindepth 1 -maxdepth 1 -type d -name 'server-*' -exec basename {} \; | sort
}

select_server() {
  local available count first

  if [ -n "$SERVER_NAME" ]; then
    PACK_DIR="$SCRIPT_DIR/$SERVER_NAME"
    [ -f "$PACK_DIR/pack.toml" ] || fail "指定的服务端不存在: $SERVER_NAME"
    return 0
  fi

  available="$(list_available_servers || true)"
  count="$(printf '%s\n' "$available" | sed '/^$/d' | wc -l | awk '{print $1}')"

  if [ "$count" = "1" ]; then
    first="$(printf '%s\n' "$available" | sed -n '1p')"
    SERVER_NAME="$first"
    PACK_DIR="$SCRIPT_DIR/$SERVER_NAME"
    return 0
  fi

  if [ "$count" = "0" ]; then
    fail "仓库中没有找到任何 server-* 服务端目录"
  fi

  printf '[pt-panel] 可选服务端：\n%s\n' "$(printf '%s\n' "$available" | sed 's/^/  - /')" >&2
  fail "检测到多个服务端，请通过 PT_SERVER=<目录名> 或第一个参数指定，例如：PT_SERVER=server-01-random-block bash start.sh"
}

ensure_dirs() {
  mkdir -p "$INSTALL_ROOT" "$RUNTIME_BASE_DIR" "$DOWNLOAD_DIR"
}

prepare_server_paths() {
  PACK_SLUG="$(printf '%s' "$SERVER_NAME" | tr '/' '_')"
  STAMP_FILE="$RUNTIME_BASE_DIR/fabric-install-${PACK_SLUG}.stamp"
}

load_pack_versions() {
  [ -f "$PACK_DIR/pack.toml" ] || fail "找不到 $PACK_DIR/pack.toml，请确认服务端 pack 存在"

  MINECRAFT_VERSION="$(toml_value 'minecraft' "$PACK_DIR/pack.toml")"
  FABRIC_LOADER_VERSION="$(toml_value 'fabric' "$PACK_DIR/pack.toml")"

  [ -n "$MINECRAFT_VERSION" ] || fail "无法从 $PACK_DIR/pack.toml 读取 minecraft 版本"
  [ -n "$FABRIC_LOADER_VERSION" ] || fail "无法从 $PACK_DIR/pack.toml 读取 fabric 版本"
}

compute_pack_url() {
  if [ -n "${PT_PACK_URL:-}" ]; then
    PACK_URL="$PT_PACK_URL"
    return 0
  fi

  if [ -n "${PT_REPO_URL:-}" ] && [ -n "${PT_REPO_REF:-}" ]; then
    PACK_URL="${PT_REPO_URL%/}/raw/branch/${PT_REPO_REF}/${SERVER_NAME}/pack.toml"
    return 0
  fi

  PACK_URL="$PACK_DIR/pack.toml"
}

load_latest_fabric_installer_version() {
  if [ -n "$FABRIC_INSTALLER_VERSION" ]; then
    printf '%s' "$FABRIC_INSTALLER_VERSION"
    return 0
  fi

  local meta version
  meta="$(fetch_to_stdout 'https://meta.fabricmc.net/v2/versions/installer')"
  version="$(printf '%s\n' "$meta" | grep '"version"' | head -n 1 | sed 's/.*"version": *"\([^"]*\)".*/\1/')"
  [ -n "$version" ] || fail "无法获取最新 Fabric installer 版本"
  printf '%s' "$version"
}

ensure_packwiz_bootstrap() {
  if [ -f "$BOOTSTRAP_JAR" ] && [ "$FORCE_UPDATE" != "1" ]; then
    return 0
  fi

  log "下载 packwiz-installer-bootstrap"
  fetch "$PACKWIZ_BOOTSTRAP_URL" "$BOOTSTRAP_JAR"
}

install_fabric_server() {
  local installer_version installer_jar wanted_stamp current_stamp

  installer_version="$(load_latest_fabric_installer_version)"
  installer_jar="$DOWNLOAD_DIR/fabric-installer-${installer_version}.jar"
  wanted_stamp="server=$SERVER_NAME mc=$MINECRAFT_VERSION loader=$FABRIC_LOADER_VERSION installer=$installer_version"
  current_stamp="$(cat "$STAMP_FILE" 2>/dev/null || true)"

  if [ "$FORCE_UPDATE" != "1" ] && [ -f "$INSTALL_ROOT/fabric-server-launch.jar" ] && [ "$wanted_stamp" = "$current_stamp" ]; then
    log "Fabric 服务端已就绪，跳过重复安装"
    return 0
  fi

  log "准备安装 Fabric 服务端：$SERVER_NAME (Minecraft $MINECRAFT_VERSION / Loader $FABRIC_LOADER_VERSION)"
  fetch "https://maven.fabricmc.net/net/fabricmc/fabric-installer/${installer_version}/fabric-installer-${installer_version}.jar" "$installer_jar"

  if [ "$DRY_RUN" = "1" ]; then
    log "DRY RUN: 跳过执行 Fabric installer"
    return 0
  fi

  (
    cd "$INSTALL_ROOT"
    "$JAVA_BIN" -jar "$installer_jar" server -mcversion "$MINECRAFT_VERSION" -loader "$FABRIC_LOADER_VERSION" -downloadMinecraft
  )
  printf '%s\n' "$wanted_stamp" > "$STAMP_FILE"
}

run_packwiz_installer() {
  local args=( -jar "$BOOTSTRAP_JAR" -g --side server --pack-folder "$INSTALL_ROOT" --meta-file "$PACKWIZ_META_FILE" "$PACK_URL" )

  if [ "$PACKWIZ_BOOTSTRAP_NO_UPDATE" = "1" ]; then
    args=( -jar "$BOOTSTRAP_JAR" --bootstrap-no-update -g --side server --pack-folder "$INSTALL_ROOT" --meta-file "$PACKWIZ_META_FILE" "$PACK_URL" )
  fi

  if [ "$DRY_RUN" = "1" ]; then
    log "DRY RUN: 跳过执行 packwiz-installer"
    log "pack.toml URL: $PACK_URL"
    return 0
  fi

  log "使用 packwiz-installer 同步服务端模组"
  (
    cd "$INSTALL_ROOT"
    "$JAVA_BIN" "${args[@]}"
  )
}

write_eula() {
  if [ "$AUTO_EULA" = "TRUE" ] || [ "$AUTO_EULA" = "true" ] || [ "$AUTO_EULA" = "1" ]; then
    printf 'eula=true\n' > "$INSTALL_ROOT/eula.txt"
    log "已写入 eula.txt"
  else
    log "已跳过自动写入 EULA（PT_AUTO_EULA=$AUTO_EULA）"
  fi
}

find_server_jar() {
  if [ -n "$SERVER_JAR_OVERRIDE" ]; then
    printf '%s' "$SERVER_JAR_OVERRIDE"
    return 0
  fi

  if [ -f "$INSTALL_ROOT/fabric-server-launch.jar" ]; then
    printf '%s' "$INSTALL_ROOT/fabric-server-launch.jar"
    return 0
  fi

  local candidate
  candidate="$(find "$INSTALL_ROOT" -maxdepth 1 -type f \( -name 'fabric-server-launch.jar' -o -name 'fabric-server-*.jar' -o -name 'server.jar' \) | sort | head -n 1 || true)"
  [ -n "$candidate" ] || return 1
  printf '%s' "$candidate"
}

start_server() {
  local server_jar
  server_jar="$(find_server_jar || true)"

  if [ "$DRY_RUN" = "1" ]; then
    if [ -n "$server_jar" ]; then
      log "使用服务端文件: $server_jar"
    else
      log "DRY RUN: 当前尚未生成服务端 jar；正式运行时会先执行 Fabric installer"
    fi
    log "安装目录: $INSTALL_ROOT"
    log "启动参数: $JAVA_ARGS"
    log "DRY RUN: 跳过实际启动"
    return 0
  fi

  [ -n "$server_jar" ] || fail "找不到可启动的服务端 jar，请检查 Fabric 安装是否成功"

  log "使用服务端: $SERVER_NAME"
  log "使用服务端文件: $server_jar"
  log "安装目录: $INSTALL_ROOT"
  log "启动参数: $JAVA_ARGS"

  cd "$INSTALL_ROOT"
  exec "$JAVA_BIN" $JAVA_ARGS -jar "$server_jar" nogui
}

main() {
  need_cmd "$JAVA_BIN"
  need_cmd grep
  need_cmd sed
  need_cmd awk
  need_cmd find

  select_server
  ensure_dirs
  prepare_server_paths
  load_pack_versions
  compute_pack_url
  ensure_packwiz_bootstrap

  log "脚本目录: $SCRIPT_DIR"
  log "安装目录: $INSTALL_ROOT"
  log "选择服务端: $SERVER_NAME"
  log "Pack 目录: $PACK_DIR"
  log "Pack URL: $PACK_URL"
  log "Minecraft 版本: $MINECRAFT_VERSION"
  log "Fabric Loader 版本: $FABRIC_LOADER_VERSION"

  install_fabric_server
  run_packwiz_installer
  write_eula
  start_server
}

main "$@"