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

show_zram_status() {
  echo "========== zram 运行战报 =========="

  if ! command -v zramctl >/dev/null 2>&1; then
    echo "未安装 zramctl。"
    return 1
  fi

  local table
  table=$(zramctl --noheadings --output NAME,ALGORITHM,DISKSIZE,DATA,COMPR,TOTAL,COMP-RATIO,MOUNTPOINT 2>/dev/null || true)

  if [ -z "$table" ]; then
    echo "未发现活跃的 zram 设备。"
    return 0
  fi

  printf '%s\n' "$table"

  local stats
  stats=$(zramctl --bytes --raw --noheadings --output DATA,COMPR,TOTAL 2>/dev/null || true)

  if [ -z "$stats" ]; then
    echo "未发现活跃的 zram 设备。"
    return 0
  fi

  local data_size compr_size total_mem saved_bytes ratio
  read -r data_size compr_size total_mem <<EOF
$(printf '%s\n' "$stats" | awk '{data += $1; compr += $2; total += $3} END {print data+0, compr+0, total+0}')
EOF

  if [ "$total_mem" -le 0 ]; then
    echo "当前 zram 尚无可统计的数据。"
    return 0
  fi

  saved_bytes=$((data_size - total_mem))
  if [ "$saved_bytes" -lt 0 ]; then
    saved_bytes=0
  fi

  ratio=$(awk -v data="$data_size" -v total="$total_mem" 'BEGIN { printf "%.2f", data / total }')

  format_bytes() {
    awk -v bytes="$1" 'BEGIN {
      split("B KiB MiB GiB TiB PiB", units, " ")
      idx = 1
      while (bytes >= 1024 && idx < 6) {
        bytes /= 1024
        idx++
      }
      printf "%.2f %s", bytes, units[idx]
    }'
  }

  echo "----------- 汇总 -----------"
  echo "1. 原始数据量: $(format_bytes "$data_size")"
  echo "2. 压缩后大小: $(format_bytes "$compr_size")"
  echo "3. 实际占用内存: $(format_bytes "$total_mem")"
  echo "4. 压缩倍率: ${ratio}x"
  echo "5. 为系统节省了: $(format_bytes "$saved_bytes") 物理内存"
  echo "==================================="
}

show_zram_status