#!/usr/bin/env bash
#
# ...
#
# 使用方法:
# URL="https://git.1-h.cc/Scripts/Linux/raw/branch/2026/zram/install.sh"; curl -fsSL "$URL" | bash
# URL="https://git.1-h.cc/Scripts/Linux/raw/branch/2026/zram/install.sh"; wget -q -O - "$URL" | bash

if ! declare -F print_red >/dev/null 2>&1; then
  print_red() { echo -e "\033[31m\033[01m$1$2\033[0m"; }
fi

if ! declare -F print_green >/dev/null 2>&1; then
  print_green() { echo -e "\033[32m\033[01m$1$2\033[0m"; }
fi

if ! declare -F print_yellow >/dev/null 2>&1; then
  print_yellow() { echo -e "\033[33m\033[01m$1$2\033[0m"; }
fi

if [ -z "${SYSTEM_TYPE:-}" ]; then
  if [ -f /etc/debian_version ]; then
    SYSTEM_TYPE="debian"
  elif [ -f /etc/alpine-release ]; then
    SYSTEM_TYPE="alpine"
  else
    SYSTEM_TYPE="unknown"
  fi
fi

install_zram() {
  print_green "###################"
  print_green "###### zram #######"
  print_green "###################"

  if [ "$SYSTEM_TYPE" != "debian" ]; then
    print_yellow "当前仅在 Debian 系统上配置 zram-tools，已跳过"
    return 0
  fi

  if [ -f /.dockerenv ] || grep -qaE '(docker|containerd|kubepods|lxc)' /proc/1/cgroup 2>/dev/null; then
    print_yellow "检测到容器环境，跳过 zram 配置"
    return 0
  fi

  echo "正在准备 zram-tools..."
  if dpkg -s zram-tools >/dev/null 2>&1; then
    echo "zram-tools 已安装，跳过安装步骤"
  else
    apt update && apt install zram-tools -y
  fi

  if command -v modprobe >/dev/null 2>&1; then
    if modprobe zram 2>/dev/null; then
      echo "zram 内核模块已加载"
    else
      print_yellow "内核不支持 zram 模块，跳过 zram 配置"
      return 0
    fi
  else
    print_yellow "未找到 modprobe，继续尝试配置 zram-tools"
  fi

  if command -v udevadm >/dev/null 2>&1; then
    udevadm settle || true
  fi

  if [ ! -d /sys/block/zram0 ] || [ ! -b /dev/zram0 ]; then
    print_yellow "未检测到可用的 zram0 设备，跳过 zram 配置"
    return 0
  fi

  local total_mem algo percent available_algorithms
  total_mem=$(awk '/MemTotal/{print int($2 / 1024)}' /proc/meminfo)

  if ! [[ "$total_mem" =~ ^[0-9]+$ ]] || [ "$total_mem" -le 0 ]; then
    print_yellow "无法准确检测总内存，跳过 zram 配置"
    return 0
  fi

  available_algorithms=$(tr ' ' '\n' </sys/block/zram0/comp_algorithm 2>/dev/null | tr -d '[]' || true)
  echo "检测到支持的 zram 算法: ${available_algorithms:-unknown}"
  echo "检测到总内存: ${total_mem}MB"

  choose_zram_algorithm() {
    local candidate
    for candidate in "$@"; do
      if printf '%s\n' "$available_algorithms" | grep -qx "$candidate"; then
        printf '%s\n' "$candidate"
        return 0
      fi
    done
    return 1
  }

  if [ "$total_mem" -le 2500 ]; then
    percent="100"

    if algo=$(choose_zram_algorithm zstd lz4 lzo-rle lzo); then
      if [ "$algo" = "zstd" ]; then
        echo "策略：内存 <= 2G，使用 zstd 算法 (100% 占比)"
      else
        echo "策略：内存 <= 2G，但内核未报告 zstd 支持，回退到 $algo (100% 占比)"
      fi
    else
      print_yellow "未检测到受支持的 zram 压缩算法，跳过 zram 配置"
      return 0
    fi
  else
    percent="60"

    if algo=$(choose_zram_algorithm lz4 zstd lzo-rle lzo); then
      if [ "$algo" = "lz4" ]; then
        echo "策略：内存 > 2G，使用 lz4 算法 (60% 占比)"
      else
        echo "策略：内存 > 2G，但内核未报告 lz4 支持，回退到 $algo (60% 占比)"
      fi
    else
      print_yellow "未检测到受支持的 zram 压缩算法，跳过 zram 配置"
      return 0
    fi
  fi

  cat <<EOF >/etc/default/zramswap
ALGO=$algo
PERCENT=$percent
PRIORITY=100
EOF

  if ! systemctl restart zramswap; then
    print_red "zramswap 服务重启失败"
    systemctl status zramswap.service --no-pager || true
    journalctl -u zramswap.service -n 20 --no-pager || true
    return 1
  fi

  echo "---------------------------------------"
  echo "zram 部署完成！当前状态："
  zramctl || true
  echo "---------------------------------------"
}

if [ "${BASH_SOURCE[0]:-}" = "$0" ] || [ -z "${BASH_SOURCE[0]:-}" ]; then
  if [ "$EUID" -ne 0 ]; then
    print_red "请使用 sudo 运行此脚本"
    exit 1
  fi

  install_zram
fi