#!/usr/bin/env bash

set -u
PATH=/usr/sbin:/usr/bin:/sbin:/bin
export PATH

die() {
    echo "ZBX_NOTSUPPORTED"
    exit 1
}

BASE="${2:-}"

[ -n "$BASE" ] || die
[ -d "$BASE" ] || die

BASE="${BASE%/}"

#
# Convert:
#
#   260924-0949
#   260924-0949_Image_C
#
# to Unix timestamp.
#
name_to_epoch() {
    local n="$1"
    local yy mm dd hh mi year

    # Remove Image suffix
    n="${n%%_Image_*}"

    if [[ "$n" =~ ^([0-9]{2})([0-9]{2})([0-9]{2})-([0-9]{2})([0-9]{2})$ ]]; then

        yy="${BASH_REMATCH[1]}"
        mm="${BASH_REMATCH[2]}"
        dd="${BASH_REMATCH[3]}"
        hh="${BASH_REMATCH[4]}"
        mi="${BASH_REMATCH[5]}"

        if (( 10#$yy >= 70 )); then
            year="19$yy"
        else
            year="20$yy"
        fi

        date -d "${year}-${mm}-${dd} ${hh}:${mi}:00" +%s 2>/dev/null
        return
    fi

    echo 0
}

valid_client() {
    [[ -n "$1" ]] || return 1
    [[ "$1" != "." ]] || return 1
    [[ "$1" != ".." ]] || return 1
    [[ "$1" != *"/"* ]] || return 1
}

client_dir() {
    local client="$1"

    valid_client "$client" || die

    printf '%s/%s\n' "$BASE" "$client"
}

#
# File backup:
#
#   260924-0936
#
is_file_backup() {
    local d="$1"
    local n="${1##*/}"

    [[ "$n" =~ ^[0-9]{6}-[0-9]{4}$ ]] || return 1
    [ -d "$d" ] || return 1

    return 0
}

#
# Image backup:
#
#   260924-0949_Image_C
#
# Must also contain a non-empty image file (.vhdz, .vhd or .raw).
#
is_image_backup() {
    local d="$1"
    local n="${1##*/}"
    local vhdz

    [[ "$n" =~ ^[0-9]{6}-[0-9]{4}_Image_.*$ ]] || return 1
    [ -d "$d" ] || return 1

    # Ищет любые типы виртуальных дисков, которые создает UrBackup
    vhdz="$(find "$d" \
        -maxdepth 1 \
        -type f \
        \( -name '*.vhdz' -o -name '*.vhd' -o -name '*.raw' \) \
        -size +0c \
        -print -quit 2>/dev/null)"

    [ -n "$vhdz" ]
}

#
# Find latest backup timestamp.
#
latest_epoch() {

    local dir="$1"
    local kind="$2"

    local best=0
    local d
    local n
    local e

    [ -d "$dir" ] || {
        echo 0
        return
    }

    while IFS= read -r -d '' d; do

        n="${d##*/}"

        case "$kind" in

            file)
                is_file_backup "$d" || continue
                ;;

            image)
                is_image_backup "$d" || continue
                ;;

            *)
                echo 0
                return
                ;;

        esac

        e="$(name_to_epoch "$n")"

        if (( e > best )); then
            best="$e"
        fi

    done < <(
        find "$dir" \
            -mindepth 1 \
            -maxdepth 1 \
            -type d \
            -print0 2>/dev/null
    )

    echo "$best"
}

#
# Determine whether directory is a real UrBackup client.
#
is_client_dir() {

    local dir="$1"
    local d

    while IFS= read -r -d '' d; do

        if is_file_backup "$d"; then
            return 0
        fi

        if is_image_backup "$d"; then
            return 0
        fi

    done < <(
        find "$dir" \
            -mindepth 1 \
            -maxdepth 1 \
            -type d \
            -print0 2>/dev/null
    )

    return 1
}

#
# MAIN
#

case "${1:-}" in

    discovery)

        printf '{"data":['

        first=1

        while IFS= read -r -d '' d; do

            client="${d##*/}"

            valid_client "$client" || continue

            is_client_dir "$d" || continue

            [ "$first" -eq 1 ] || printf ','

            esc="$(printf '%s' "$client" | \
                sed 's/\\/\\\\/g; s/"/\\"/g')"

            printf '{"{#CLIENT}":"%s"}' "$esc"

            first=0

        done < <(
            find "$BASE" \
                -mindepth 1 \
                -maxdepth 1 \
                -type d \
                -print0 2>/dev/null |
            sort -z
        )

        printf ']}\n'

        ;;

    last_ts)

        [ "$#" -eq 4 ] || die

        client="$3"
        kind="$4"

        latest_epoch \
            "$(client_dir "$client")" \
            "$kind"

        ;;

    last_age)

        [ "$#" -eq 4 ] || die

        client="$3"
        kind="$4"

        ts="$(
            latest_epoch \
                "$(client_dir "$client")" \
                "$kind"
        )"

        if [ "$ts" -le 0 ]; then

            # No backup found.
            echo 999999999

        else

            now="$(date +%s)"

            age=$((now - ts))

            (( age < 0 )) && age=0

            echo "$age"

        fi

        ;;

    count)

        [ "$#" -eq 4 ] || die

        client="$3"
        kind="$4"

        dir="$(client_dir "$client")"

        count=0

        while IFS= read -r -d '' d; do

            case "$kind" in

                file)
                    is_file_backup "$d" || continue
                    ;;

                image)
                    is_image_backup "$d" || continue
                    ;;

                all)

                    if is_file_backup "$d"; then
                        :
                    elif is_image_backup "$d"; then
                        :
                    else
                        continue
                    fi

                    ;;

                *)
                    die
                    ;;

            esac

            count=$((count + 1))

        done < <(
            find "$dir" \
                -mindepth 1 \
                -maxdepth 1 \
                -type d \
                -print0 2>/dev/null
        )

        echo "$count"

        ;;

    image_size)

        [ "$#" -eq 3 ] || die

        client="$3"

        dir="$(client_dir "$client")"

        ts="$(latest_epoch "$dir" image)"

        [ "$ts" -gt 0 ] || {
            echo 0
            exit
        }

        best=""

        while IFS= read -r -d '' d; do

            is_image_backup "$d" || continue

            n="${d##*/}"

            e="$(name_to_epoch "$n")"

            [ "$e" -eq "$ts" ] || continue

            best="$d"

            break

        done < <(
            find "$dir" \
                -mindepth 1 \
                -maxdepth 1 \
                -type d \
                -print0 2>/dev/null
        )

        [ -n "$best" ] || {
            echo 0
            exit
        }

        # Ищет размер для любых форматов образов (.vhdz, .vhd, .raw)
        vhdz="$(
            find "$best" \
                -maxdepth 1 \
                -type f \
                \( -name '*.vhdz' -o -name '*.vhd' -o -name '*.raw' \) \
                -size +0c \
                -print -quit 2>/dev/null
        )"

        [ -n "$vhdz" ] || {
            echo 0
            exit
        }

        stat -c '%s' "$vhdz" 2>/dev/null || echo 0

        ;;

    disk_free_pct)

        df -P "$BASE" 2>/dev/null |
            awk 'NR==2 {
                gsub(/%/,"",$5);
                print 100-$5
            }'

        ;;

    *)

        die

        ;;

esac