rc_files=(
    "/etc/bashrc"
    "/etc/bash.bashrc"
    "/etc/zshrc"
    "/etc/zsh/zshrc"
)

start_line="# sk-chos user-motd"
end_line="# sk-chos user-motd end"

read -rd '' motd_command <<EOF
$start_line
if test -d "\$HOME"; then
  if test ! -e "\$HOME"/.config/no-show-user-motd; then
    if test -x "/usr/libexec/chos-motd"; then
      /usr/libexec/chos-motd
    elif test -s "/etc/user-motd"; then
      cat /etc/user-motd
    fi
  fi
fi
$end_line
EOF

update_motd() {
    echo "Updating motd..."
    for rc_file in "${rc_files[@]}"; do
        if [ -f "$rc_file" ]; then
            if ! grep -q "$start_line" "$rc_file"; then
                echo "$motd_command" >>"$rc_file"
            else
                sed -i "/$start_line/,/$end_line/d" "$rc_file"
                echo "$motd_command" >>"$rc_file"
            fi
        else
            echo "$motd_command" >"$rc_file"
        fi
    done
}

remove_motd() {
    echo "Removing motd..."
    for rc_file in "${rc_files[@]}"; do
        if [ -f "$rc_file" ]; then
            sed -i "/$start_line/,/$end_line/d" "$rc_file"
        fi
    done
}

# 安装或升级后的操作
post_upgrade_or_install() {
    update_motd
}

# 安装前的操作
pre_install() {
    echo ""
}

# 升级前的操作
pre_upgrade() {
    echo ""
}

# 安装后的操作
post_install() {
    post_upgrade_or_install
}

# 升级后的操作
post_upgrade() {
    post_upgrade_or_install
}

pre_remove() {
    echo ""
}

post_remove() {
    remove_motd
}