#!/usr/bin/env bash
# Synchronizes the destination to the source, preserving metadata (owner, 
# group, permissions, timestamps, etc...) and symbolic links. It also skips
# replacing files based on a calculated checksum, which can save a lot of time
# with backups! ssh is used for encryption, and the script displays the sync
# progress with what SHOULD be human-readable numbers.
# - x1phosura

# '-a' preserves attributes like permissions, owner/group, and more
# '-v' is verbose
# '-h' is "human readable"
# '-c' compares files to-be synced/ transfered, if already existing, by
#      checksum (rather than by filesize or modified time)
# '--stats' and '--progress' simply show a lot of info about the file transfers
# '-z' compresses data during the transfer
options="-avhcz --stats --progress"

# TODO: rework to take command-line arguments

echo "If the destination is remote, enter '(y)es'; otherwise, press enter: "
read remote

if [ "$remote" != "" ]; then
    echo "Enter the username for the remote machine: "
    read ruser
    echo "Enter the hostname (if DNS) or IPv4 address for the remote machine: "
    read rhost
    # '-e' specifies the remote shell to use (ssh here)
    options="$options -e ssh"
    dest="${ruser}@${rhost}:~/"
else
    echo "Enter the path to the destination directory: "
    read dest
fi

echo "Delete files at destination not present in source directories? (y/n):"
read del_remote

if [ "$del_remote" = "y" ]; then # TEST THIS OPTION OUT BEFORE USE!!
    # '--delete' deletes files at the destination that are NOT present from the
    # source. USE CAREFULLY!! '--force' modifies '--delete' to handle something
    # do to with non-empty directories being deleted or overridden, so I'm 
    # guessing I want it
    echo "Extraneous files found in destination will be deleted."
    options="$options --delete --force"
elif [ "$del_remote" = "n" ]; then
    echo "Extraneous files found in destination will be kept."
else
    echo "Error: expected 'y' or 'n' character as input. Aborting for safety..."
    exit 1
fi

# Note: as they currently stand, DO NOT add trailing slashes to these
# filenames!! Why? Here is the best explanation I've seen as to how trailing
# slashes work in rsync:
# Without a slash on the source directory means copy both the source 
# directory, and the contents (recursively if specified) to the destination
# directory while adding a trailing slash means only copy the contents of
# the source directory, recursively if specified, to the destination.
# TODO: auto-generate paths (or read from textfile) instead of hardcoding
filelist="$HOME/73h4x \
$HOME/Desktop \
$HOME/Documents \
$HOME/Downloads \
$HOME/Library \
$HOME/Subgenius \
$HOME/tmp"

# copy from here to destination (remote or local)
# Note: destination needs to be left unquoted for this to work
rsync $options $filelist "$dest"