eos-shifttime

#!/bin/bash
#
# This script enables an after-the-fact timeshift equivalent for Arch systems
# Give it a date (as in 2020-09-20) and it will use the Arch archive repos 
# to revert to the package state that applied on that date.
#
# Note: no AUR package will be reverted.
#
# 21 September 2020 - freebird54
# 21 July 2021 - changes by manuel
#

# Get some useful definitions:
source /usr/share/endeavouros/scripts/eos-script-lib-yad || exit 1
export -f eos_yad
export -f eos_GetProgName
export -f eos_GetArch
# EOS_ROOTER

DIE() {
    local msg="$1"
    local title="$2"    # optional, default is "Error"
    [ -n "$title" ] || title="Error"
    echo "$1" | eos_yad --text-info --title="$title" --text="Message from '$progname':" --image=error --button=yad-quit
    exit 1
}
STOP() { DIE "$1" Warning; }

DateValidityCheck() {
    [ -n "$REVERTDATE" ] || exit 1                           # No date selected.
    [ "$REVERTDATE" = "$stopdate" ] && STOP "Current date selected, nothing to do."
    curl -Lsm 10 -o/dev/null --fail "$urlbase" || DIE "Archive at $REVERTDATE not found!"
}

Main()
{
    local progname="$(eos_GetProgName)"
    case "$(eos_GetArch)" in
        x86_64) ;;
        *) DIE "This program is supported only on x86_64 machines." ;;   # because of mirrors...
    esac
    eos_assert_deps $progname yad || return 1
    local date=$(/usr/bin/date +%Y%m%d-%H%M)        # for temporary backup file
    local stopdate="$(/usr/bin/date +%Y/%m/%d)"     # for checking if user selected this date
    local mlist=/etc/pacman.d/mirrorlist
    local bak="$mlist.$progname.$date"
    local txt="This app can revert (downgrade) packages of this system to the state they were in\non the selected date.\n"
          txt+="Note: AUR packages will <i>not</i> be reverted.\n\n"
          txt+="Please select the date to revert your packages to.\n"
    local REVERTDATE=$(eos_yad --calendar --title "Select Date" --text="$txt" --image=dialog-question --date-format=%C%y/%m/%d \
                               --button='yad-cancel!!Do nothing':1 --button='Revert!dialog-yes!Downgrade':0)
    local urlbase="https://archive.archlinux.org/repos/$REVERTDATE"
    local cmd=""
    local cmd2=""
    local tmpmlist

    DateValidityCheck

    # Create a temporary mirrorlist for the specified date.
    tmpmlist=$(mktemp)
    printf "## Reversion mirrorlist\n\n" > $tmpmlist
    printf "%s\n\n" "Server = $urlbase/\$repo/os/\$arch" >> $tmpmlist

    cmd="mv $mlist '$bak'"         # Backups original mirrorlist and
    cmd+=";mv $tmpmlist $mlist"    # uses the reverted list.
    cmd+=";pacman -Syyuu"          # Runs the 'downdate' command.
    cmd+=";mv '$bak' $mlist"       # Restores the original mirrorlist from backup.
    cmd+=";chmod 0644 $mlist"      # Make sure mirrorlist has proper permissions.

    cmd2="$(echo "$cmd" | tr ';' '\n' | sed 's|^|  |')"
    RunInTerminal "printf 'Reverting all packages to $REVERTDATE\n\n'; echo 'Need elevated privileges to run commands:'; echo '$cmd2'; $EOS_ROOTER '$cmd'"
}

Main "$@"