#!/bin/bash
# Ver: 1.3 by Endial Fang (endial@126.com)
#
# 文件管理函数库

# 加载依赖项
source "/usr/local/lib/liblog.sh"

# 函数列表

# 确保指定的 文件/路径 所属权为指定的 用户/组
# 参数:
#   $1 - 文件路径
#   $2 - 用户
#   $3 - 用户组
ensure_owned_by() {
    local path="${1:?path is missing}"
    local owner="${2:?owner is missing}"
    local group="${3:-}"

    if [[ -n $group ]]; then
        chown "$owner":"$group" "$path"
    else
        chown "$owner":"$owner" "$path"
    fi
}

# 检测目录是否存在，如果不存在则创建，同时修改为指定的用户
# 参数:
#   $1 - 目录路径
#   $2 - 用户
#   $3 - 用户组
ensure_dir_exists() {
    local dir="${1:?directory is missing}"
    local owner_user="${2:-}"
    local owner_group="${3:-}"

    [ -d "${dir}" ] || mkdir -p "${dir}"
    if [[ -n $owner_user ]]; then
        ensure_owned_by "$dir" "$owner_user" "$owner_group"
    fi
}

# 检测目录是否存在或为空
# 参数:
#   $1 - 目录路径
is_dir_empty() {
    local dir="${1:?missing directory}"

    # 计算真实路径，避免符号链接问题
    local -r dir="$(realpath "$path")"
    if [[ ! -e "$dir" ]] || [[ -z "$(ls -A "$dir")" ]]; then
        true
    else
        false
    fi
}

# 检测挂载的路径是否存在或为空
# 参数:
#   $1 - 文件或路径
is_mounted_dir_empty() {
    local dir="${1:?missing directory}"

    if is_dir_empty "$dir" || find "$dir" -mindepth 1 -maxdepth 1 -not -name ".snapshot" -not -name "lost+found" -exec false {} +; then
        true
    else
        false
    fi
}

# 检测指定的路径当前用户是否可写入
# 参数:
#   $1 - 文件或路径
is_writable() {
    local file="${1:?missing file}"
    local dir
    dir="$(dirname "$file")"

    if [[ (-f "$file" && -w "$file") || (! -f "$file" && -d "$dir" && -w "$dir") ]]; then
        true
    else
        false
    fi
}

# 生成相对路径
# 参数:
#   $1 - 路径
#   $2 - 基准路径
relativize() {
    local -r path="${1:?missing path}"
    local -r base="${2:?missing base}"

    pushd "$base" >/dev/null || exit
    realpath -q --no-symlinks --relative-base="$base" "$path" | sed -e 's|^/$|.|' -e 's|^/||'
    popd >/dev/null || exit
}

# 循环设置目录中子目录及文件权限
# 参数:
#   $1 - paths (as a string).
# Flags:
#   -f|--file-mode - 文件权限模式
#   -d|--dir-mode - 目录权限模式
#   -u|--user - 用户
#   -g|--group - 用户组
configure_permissions_ownership() {
    local -r paths="${1:?paths is missing}"
    local dir_mode=""
    local file_mode=""
    local user=""
    local group=""

    # 参数有效性校验
    shift 1
    while [ "$#" -gt 0 ]; do
        case "$1" in
            -f|--file-mode)
                shift
                file_mode="${1:?missing mode for files}"
                ;;
            -d|--dir-mode)
                shift
                dir_mode="${1:?missing mode for directories}"
                ;;
            -u|--user)
                shift
                user="${1:?missing user}"
                ;;
            -g|--group)
                shift
                group="${1:?missing group}"
                ;;
            *)
                error "Invalid command line flag $1" >&2
                return 1
                ;;
        esac
        shift
    done

    read -r -a filepaths <<< "$paths"
    for p in "${filepaths[@]}"; do
        if [[ -e "$p" ]]; then
            debug "Check $p"
            find -L "$p" -printf ""
            if [[ -n ${dir_mode} ]]; then
                debug "Change permissions to ${dir_mode} of directories in $p"
                find -L "$p" -type d ! -perm "$dir_mode" -print0 | xargs -r -0 chmod "$dir_mode"
            fi
            if [[ -n ${file_mode} ]]; then
                debug "Change permissions to ${file_mode} of files in $p"
                find -L "$p" -type f ! -perm "$file_mode" -print0 | xargs -r -0 chmod "$file_mode"
            fi
            if [[ -n $user ]] && [[ -n ${group} ]]; then
                debug "Change ownership to ${user}:${group} of files and directories in $p"
                find -L "$p" -print0 | xargs -r -0 chown "${user}:${group}"
            elif [[ -n $user ]] && [[ -z $group ]]; then
                debug "Change user to ${user} of files and directories in $p"
                find -L "$p" -print0 | xargs -r -0 chown "${user}"
            elif [[ -z $user ]] && [[ -n $group ]]; then
                debug "Change group to ${group} of files and directories in $p"
                find -L "$p" -print0 | xargs -r -0 chgrp "${group}"
            fi
        else
            error "$p does not exist"
        fi
    done
}