bash <<'EOF'
#!/usr/bin/env bash

set -e

if [ "$(id -u)" -ne 0 ]; then
    echo "错误：请使用 root 执行"
    exit 1
fi

if [ ! -f /etc/os-release ]; then
    echo "错误：无法识别系统"
    exit 1
fi

. /etc/os-release

if [ "$ID" != "debian" ]; then
    echo "错误：当前系统不是 Debian"
    exit 1
fi

CODENAME="${VERSION_CODENAME:-trixie}"

if [ "$CODENAME" != "trixie" ]; then
    echo "警告：当前系统代号为 $CODENAME，不是 trixie"
    read -r -p "是否仍然继续？[y/N] " answer
    case "$answer" in
        y|Y) ;;
        *)
            echo "已取消"
            exit 0
            ;;
    esac
fi

BACKUP_DIR="/root/apt-backup-$(date +%Y%m%d-%H%M%S)"

echo "备份现有 APT 配置到：$BACKUP_DIR"
mkdir -p "$BACKUP_DIR"

cp -a /etc/apt/sources.list "$BACKUP_DIR/" 2>/dev/null || true
cp -a /etc/apt/sources.list.d "$BACKUP_DIR/" 2>/dev/null || true

echo "禁用旧的软件源配置..."

mkdir -p /etc/apt/sources.list.d.disabled

for file in /etc/apt/sources.list.d/*.list /etc/apt/sources.list.d/*.sources; do
    [ -e "$file" ] || continue
    mv "$file" /etc/apt/sources.list.d.disabled/
done

cat > /etc/apt/sources.list <<'SOURCE'
deb https://mirrors.aliyun.com/debian trixie main contrib non-free non-free-firmware
deb https://mirrors.aliyun.com/debian trixie-updates main contrib non-free non-free-firmware
deb https://mirrors.aliyun.com/debian-security trixie-security main contrib non-free non-free-firmware
SOURCE

echo "新的软件源配置："
cat /etc/apt/sources.list

echo
echo "正在更新软件包索引..."

if apt-get update; then
    echo
    echo "======================================"
    echo "Debian 13 阿里云源切换成功"
    echo "备份目录：$BACKUP_DIR"
    echo "======================================"
else
    echo
    echo "APT 更新失败，正在提示恢复方式"
    echo "原配置备份目录：$BACKUP_DIR"
    echo
    echo "如需恢复，可以执行："
    echo "cp -a $BACKUP_DIR/sources.list /etc/apt/sources.list"
    echo "rm -rf /etc/apt/sources.list.d"
    echo "cp -a $BACKUP_DIR/sources.list.d /etc/apt/"
    exit 1
fi
EOF