#!/bin/bash
#===============================================================================
# 从SD卡操作eMMC备份脚本
#===============================================================================

set -e
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

error_msg() { echo -e "${RED}[ERROR] $1${NC}" >&2; exit 1; }
info_msg() { echo -e "${GREEN}[INFO] $1${NC}"; }
warn_msg() { echo -e "${YELLOW}[WARN] $1${NC}"; }

[[ $EUID -eq 0 ]] || error_msg "需要root权限"

EMMC_DEV="/dev/mmcblk0"
USB_DIR="/mnt/XIN_USB/rock5c"
OUTPUT_FILE="${USB_DIR}/rock5c_emmc_$(date +%Y%m%d_%H%M%S).img"

info_msg "从SD卡备份eMMC..."
info_msg "eMMC设备: ${EMMC_DEV}"
info_msg "输出到: ${OUTPUT_FILE}"

# 检查设备
[[ -b "${EMMC_DEV}" ]] || error_msg "eMMC设备不存在: ${EMMC_DEV}"
[[ -d "${USB_DIR}" ]] || error_msg "USB目录不存在: ${USB_DIR}"

# 检查eMMC没有被挂载
if mount | grep -q mmcblk0; then
    error_msg "eMMC还在使用中！请确保从SD卡启动"
fi

info_msg "✅ eMMC设备可安全操作"

# 步骤1: 检查eMMC分区信息
info_msg "步骤1: 分析eMMC分区..."
parted -s ${EMMC_DEV} unit MB print

# 检查eMMC上的数据大小
info_msg "检查eMMC数据使用量..."
TEMP_MOUNT="/tmp/check_emmc"
mkdir -p "${TEMP_MOUNT}"

# 临时挂载检查使用量
mount ${EMMC_DEV}p2 "${TEMP_MOUNT}" -o ro
EMMC_USED=$(df --block-size=1M "${TEMP_MOUNT}" | tail -1 | awk '{print $3}')
umount "${TEMP_MOUNT}"

mount ${EMMC_DEV}p1 "${TEMP_MOUNT}" -o ro  
EMMC_BOOT_USED=$(df --block-size=1M "${TEMP_MOUNT}" | tail -1 | awk '{print $3}')
umount "${TEMP_MOUNT}"

rm -rf "${TEMP_MOUNT}"

info_msg "eMMC使用情况: Root ${EMMC_USED}MB + Boot ${EMMC_BOOT_USED}MB"

# 步骤2: 智能收缩eMMC分区
info_msg "步骤2: 智能收缩eMMC分区..."

# 文件系统检查
e2fsck -f -y ${EMMC_DEV}p2

# 先尝试收缩到最小值
info_msg "计算文件系统最小大小..."
resize2fs -M ${EMMC_DEV}p2

# 获取收缩后的实际大小
FS_SIZE_BLOCKS=$(dumpe2fs -h ${EMMC_DEV}p2 2>/dev/null | grep "^Block count:" | awk '{print $3}')
FS_SIZE_MB=$(( (FS_SIZE_BLOCKS * 4) / 1024 + 200 ))  # 块大小4KB + 200MB缓冲

info_msg "文件系统最小大小: ${FS_SIZE_MB}MB"

# 扩展一点给缓冲空间
SHRINK_TARGET=$((FS_SIZE_MB + 300))
resize2fs ${EMMC_DEV}p2 ${SHRINK_TARGET}M

# 收缩分区
P2_START=$(parted -s ${EMMC_DEV} unit B print | grep "^ 2" | awk '{print $2}' | sed 's/B$//')
NEW_P2_END=$((P2_START + SHRINK_TARGET * 1048576))

# 记录原始分区信息
parted -s ${EMMC_DEV} unit B print > "${USB_DIR}/emmc_original_layout.txt"
ORIGINAL_P2_END=$(parted -s ${EMMC_DEV} unit B print | grep "^ 2" | awk '{print $3}' | sed 's/B$//')

# 重新创建收缩的分区
parted -s ${EMMC_DEV} rm 2
parted -s ${EMMC_DEV} mkpart primary ext4 ${P2_START}B ${NEW_P2_END}B

info_msg "✅ eMMC分区已收缩"

# 步骤3: 备份收缩后的eMMC
info_msg "步骤3: 备份收缩后的eMMC..."
BACKUP_SIZE_MB=$(( (NEW_P2_END / 1048576) + 100 ))
dd if=${EMMC_DEV} of="${OUTPUT_FILE}" bs=1M count=${BACKUP_SIZE_MB} status=progress

info_msg "✅ eMMC备份完成"

# 步骤4: 恢复eMMC原始大小
info_msg "步骤4: 恢复eMMC原始分区大小..."
parted -s ${EMMC_DEV} rm 2
parted -s ${EMMC_DEV} mkpart primary ext4 ${P2_START}B ${ORIGINAL_P2_END}B
resize2fs ${EMMC_DEV}p2

info_msg "✅ eMMC已恢复原始大小"

# 验证备份镜像
info_msg "步骤5: 验证备份镜像..."
LOOP_DEV=$(losetup -P -f --show "${OUTPUT_FILE}")
sleep 3

if [[ -b "${LOOP_DEV}p1" ]] && [[ -b "${LOOP_DEV}p2" ]]; then
    info_msg "✅ 备份镜像分区表完整"
    parted -s "${LOOP_DEV}" print
    
    # 检查文件系统
    e2fsck -n "${LOOP_DEV}p1" && echo "✅ Boot分区文件系统正常"
    e2fsck -n "${LOOP_DEV}p2" && echo "✅ Root分区文件系统正常"
else
    warn_msg "❌ 备份镜像分区表有问题"
fi

losetup -d "${LOOP_DEV}"

FINAL_SIZE=$(du -h "${OUTPUT_FILE}" | cut -f1)
FINAL_SIZE_ACTUAL=$(du --apparent-size -h "${OUTPUT_FILE}" | cut -f1)

info_msg "========================================="
info_msg "🎉 eMMC备份成功完成!"
info_msg "========================================="
info_msg "📁 备份文件: ${OUTPUT_FILE}"
info_msg "📏 实际大小: ${FINAL_SIZE}"
info_msg "📐 逻辑大小: ${FINAL_SIZE_ACTUAL}"
info_msg "💾 eMMC已恢复原状"
info_msg ""
info_msg "🚀 部署到新设备:"
info_msg "   dd if=$(basename ${OUTPUT_FILE}) of=/dev/mmcblk0 bs=4M status=progress"
info_msg ""
info_msg "✅ 包含完整分区表和bootloader"
info_msg "✅ 保持所有原始配置不变"
info_msg "✅ 可在任意Rock5c上启动"
info_msg "========================================="