#!/bin/bash

SCRIPT_DESC="WebDav 备份脚本"
SCRIPT_VERSION=1.0
SCRIPT_AUTHOR=KAAAsS

show_help() {
	__opt() { printf " %-30s%s\n" "$1" "$2"; }
    echo "用法："
    echo " $0 待备份文件路径"
    echo " $0 [选项] [--] 待备份文件路径"
    echo
    echo $SCRIPT_DESC
    echo
    echo "选项："
    __opt "-x, --prefix <name>"      "备份文件前缀"
    __opt "-s, --server <url>"       "WebDav 服务器地址，以 \"/\" 结束"
    __opt "-P, --server-path <path>" "WebDav 备份路径，以 \"/\" 结束"
    __opt "-u, --user <user>"        "WebDav 用户名"
    __opt "-p, --pass <password>"    "WebDav 密码"
    __opt "-k, --keeps n"            "保留最近几个备份文件。默认为0，不删除备份文件"
    __opt "-I, --ignore-cert"        "忽略 WebDav 证书"
    echo
    __opt "-c, --config"      "配置文件"
    __opt "-v, --verbose"     "打印调试信息"
    __opt "-h, --help"        "显示此帮助"
    __opt "-V, --version"     "显示版本"
    echo
}

#----------#
# 可配置变量 #
#----------#

verbose=false
tmpfs="/tmp"
prefix="backup"
server="http://your-site/dav"
server_path=
user="guest"
pass=""
backup_path=-
keeps=0
retry=3
ignore_cert=false
curl_extra_args=

#--------
# 脚本逻辑
#--------

filename=-
backup_dir=-

exit_handler() {
    local error_code="$?"
    # test $error_code == 0 && return;
    __dbg "清理临时文件..."
    if [[ -f $filename ]]; then
        __dbg " $filename"
        rm -rf $filename
    fi
    if [[ -d $backup_dir ]]; then
        __dbg " $backup_dir"
        rm -rf $backup_dir
    fi
    exit "$error_code"
}

make_backup() {
    if [ ! -d $backup_path ]; then
        __err "待备份路径不存在！"
        exit 2
    fi
    
    filename="$tmpfs/$prefix"_"$(date +%y%m%d_%H%M%S).tar.gz"
    backup_dir=$tmpfs/${prefix}_$(date +%H%M%S)
    
    if [ -d $backup_dir ]; then
        rm -rf $backup_dir
    fi
    
    __dbg "备份文件路径 $backup_path 至 $backup_dir"
    
    echo -n "打包备份路径... "
    mkdir $backup_dir
    __try cp -r $backup_path $backup_dir
    __try tar -czvf $filename -C $backup_dir .
    
    if __catch e; then
        __color $RED '错误\n'
        __err "打包失败: $e"
        exit 2
    fi
    
    __color $GREEN '成功\n'
    __dbg "成功打包至: $filename"
}

upload() {
    for retry_count in $( seq 0 $retry ); do
        
        if [[ $retry_count -eq 0 ]]; then
            echo -n "上传备份文件... "
        else
            echo -n "上传备份文件: 第 $retry_count 次重试... "
        fi
        
        __try curl -sS --user "$user:$pass" -T $1 "$server$server_path" -f $curl_extra_args
        
        if __catch e; then
            __color $RED '错误\n'
            __err "上传失败: $e"
            continue
        fi
        
        __color $GREEN '成功\n'
        return 0
    done
    
    __err "超过失败重试次数"
    exit 3
}

get_file_list() {
    flist_html=$(curl -sS --user "$user:$pass" -X PROPFIND "$server$server_path" -f --header 'Depth: 1' $curl_extra_args)
    echo $flist_html | grep -Po '<D:href>.+?\/\K(.+?)(?=<\/D:href>)' -o | grep $prefix | sort
}

delete_file() {
    local file=$1
    
    for retry_count in $( seq 0 $retry ); do
        
        if [[ $retry_count -eq 0 ]]; then
            echo -n "删除备份 $file... "
        else
            echo -n "删除备份 $file: 第 $retry_count 次重试... "
        fi
        
        __try curl -sS --user "$user:$pass" -X DELETE "$server$server_path$file" -f $curl_extra_args
        
        if __catch e; then
            __color $RED '错误\n'
            __err "删除失败: $e"
            continue
        fi
        
        __color $GREEN '成功\n'
        return 0
    done
    
    __err "超过失败重试次数"
    exit 3
}

remove_old_backup() {
    echo -n "检查已有备份... "
    __try get_file_list
    
    if __catch e; then
        __err "无法取得服务器文件信息: $e"
        __err "删除旧备份失败！"
        __color $RED '错误\n'
        exit 4
    fi
    
    __get_output file_list
    
    local bk_count=$(echo $file_list | wc -w)

    if [[ $bk_count -gt $keeps ]];then
        local del_count=`expr $bk_count - $keeps`
        
        __color $BLUE "$del_count 个过时备份\n"
        __dbg "现存文件列表：$file_list"

        # 删除文件
        local del_lst=$(echo $file_list | cut -d " " -f 1-$del_count)
        for file in $del_lst; do
            delete_file $file
        done
    else
        __color $GREEN '无需删除\n'
        __dbg "现存文件列表：$file_list"
    fi
}

main() {
    trap exit_handler EXIT
    make_backup
    upload $filename
    if [[ $keeps -gt 0 ]]; then
        remove_old_backup
    fi
}

#-------
# Utils
#-------

__init_util() {
    # DO NOT CALL ME OTHER THEN STARTUP
    _try_return=0
    _try_err=-
    _try_out=-
}

GREEN='0;32' RED='0;31' BLUE='0;34'

__color() {
    c=$1
    shift 1
    printf "\033[${c}m$@\033[0m"
}

__dbg() {
    if [ $verbose = true ]; then
        __color $BLUE "$@"
        echo
    fi
}

__err() {
    __color $RED "$0: $@" >&2
    echo
}

__try() {
    if [[ $_try_return -eq 0 ]]; then
        eval $({ ! _1=$({ _0=$($@); } 2>&1; echo -n "_try_out='$_0' _try_return=$? " >&2); echo -n "_try_err='$_1'"; } 2>&1)
    fi
}

__catch() {
    _old_try=$_try_return
    _try_return=0
    export $1="$_try_err"
    [[ $_old_try -ne 0 ]]
}

__get_output() {
    export $1="$_try_out"
}

#--------#
# 参数解析 #
#--------#

set -o errexit -o pipefail -o noclobber -o nounset

! getopt --test > /dev/null 
if [[ ${PIPESTATUS[0]} -ne 4 ]]; then
    __err '环境缺少 getopt 以解析参数'
    exit 1
fi

OPTIONS=c:vhVx:s:P:u:p:k:I
LONGOPTS=config,verbose,help,version,prefix:,server:,server-path:,user:,pass:,keeps:,ignore-cert

! PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "$0" -- "$@")
if [[ ${PIPESTATUS[0]} -ne 0 ]]; then
    exit 1
fi
eval set -- "$PARSED"

while true; do
    case "$1" in
        -c|--config)
            # 解析配置文件
            if [ ! -f "$2" ]; then
                __err "配置文件不存在！"
                exit 1
            fi
            source $2
            shift 2
            ;;
        -v|--verbose)
            verbose=true
            shift
            ;;
        -h|--help)
            show_help
            exit 0
            ;; 
        -V|--version)
            echo $SCRIPT_VERSION
            exit 0
            ;;
        -x|--prefix)
            prefix="$2"
            shift 2
            ;;
        -s|--server)
            server="$2"
            shift 2
            ;;
        -P|--server-path)
            server_path="$2"
            shift 2
            ;;
        -u|--user)
            user="$2"
            shift 2
            ;;
        -p|--pass)
            pass="$2"
            shift 2
            ;;
        -k|--keeps)
            keeps="$2"
            shift 2
            ;;
        -I|--ignore-cert)
            ignore_cert=true
            shift
            ;;
        --)
            # 结束参数解析
            shift
            break
            ;;
        *)
            __err "参数解析失败"
            exit 1
            ;;
    esac
done

if [[ $ignore_cert = "true" ]]; then
    curl_extra_args="$curl_extra_args -k"
fi

if [[ $# -gt 1 ]]; then
    __err "仅支持备份一个路径"
    exit 1
elif [[ $# -eq 1 ]]; then
    backup_path=$1
fi

if [[ $backup_path = - ]]; then
    __err "必须指定备份路径"
    exit 1
fi

__init_util
main