#!/bin/bash

set -euo pipefail

# Declarar varables
dir_disk=("/dev/nvme0n1p3" "/dev/bcache0")

dir_temp=("/tmp/root" "/tmp/srv")

name_snapshot=$(date +"%m%d%Y")

#Montar rutas

for i in "${!dir_disk[@]}"; do
    disk_origen="${dir_disk[$i]}"
    dir_backup="${dir_temp[$i]}"
    dir_snapshot="$dir_backup/snapshot/daily"

    # Crear directrio y montar disco
    mkdir -p "$dir_backup"
    mount "$disk_origen" "$dir_backup"

    # Verificar que existan rutas, caso contrario crearlas

    [ -d "$dir_snapshot" ] || mkdir -p  "$dir_snapshot"

    # Hacer snapshot
    if [ $i -eq 0 ]; then 
        btrfs subvolume snapshot / "$dir_snapshot/$name_snapshot"
    else 
        btrfs subvolume snapshot /srv "$dir_snapshot/$name_snapshot"
    fi
    # Desmontar rutas

    readarray -t snapshots < <(ls -1 "$dir_snapshot" | sort)

    total=${#snapshots[@]}

    if (( total > 3 )); then
        borrar=$(( total - 3 ))
        for (( contador=0; contador<borrar; contador++ )); do
            echo "Eliminando snapshot: ${snapshots[$contador]}"
            btrfs subvolume delete "$dir_snapshot/${snapshots[$contador]}"
        done
    fi

    #Desmontar la ruta
    umount "$dir_backup"
    mount | grep btrfs | grep "$dir_backup" || echo "Se desmonto $dir_backup"
    rmdir "$dir_backup"
done